EAGON & ASSOCIATES - Records Collections

SDMS US EPA REGION V -1

SOME IMAGES WITHIN THISDOCUMENT MAY BE ILLEGIBLE

DUE TO BAD SOURCEDOCUMENTS.

Tremont City Landfill SiteDoc. # 139 .

FINAL REVISED

HYDROGEOLOGIC REPORT

CLARKCO LANDFILL

O H ; o .'- ~

JAN 2 71994

SOUTHWLoi u.^

GERMAN TOWNSfflP, CLARK COUNTY, OfflO

DANIS CLARKCO LANDFILL

David J. SugarHydrogeologist

Eagon &WorthingtoW

January

/.

Frank L. Majchsz;Hydrogeologist

Approved by:

Herbert B. Eagon, Jr.Hydrogeologist

TABLE OF CONTENTS

VOLUME I

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ES-1

1 . 0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 11.1 Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l-\1.2 Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-11.3 Report Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-21.4 Site History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-41.5 Development Plan Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

Figure 1-1 Site Location MapFigure 1-2 Relationship of Proposed Clarkco Landfill to Existing Facilities

Table 1-1 Hydrogeologic Reports and Data Produced Clarkco Property andAdjoining Sites

2 . 0 REGIONAL HYDROGEOLOGY . . . . . . . . . . . . . . . . .2-12.1 Aquifers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12.2 Water Supply Wells Within One Mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-32.3 Average Yield of Water Supply Wells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42.4 Public Water Supplies Within 10 Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-52.5 Stratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.6 Structural Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.7 Regional Geomorphology and Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.8 Direction of Ground-Water Flow in the Regional Aquifers . . . . . . . . . . . . . . 2-102.9 Identification of Recharge and Discharge Areas of the Regional Aquifers . . . . 2-10

Figure 2-1 Ground-Water Resources MapFigure 2-2 Sole Source Aquifer MapFigure 2-3 Public Water Supply Wells Within 10 MilesFigure 2-4 Soils MapFigure 2-5 Description of Soil Mapping Units

Table 2-1 Water Wells Within 2000 FeetTable 2-2 Community Public Water Supplies Within 10 MilesTable 2-3 Transient, Non-Community Public Water Supplies Within 10

MilesTable 2-4 Non-Transient, Non-Community Public Water Supplies Within 10

Miles

Eagon & Associates, Inc. i January 1994

TABLE OF CONTENTS (cont'd)

3.0 LOCAL HYDROGEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .313.1 Available Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13.2 Stratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23.3 Occurrence and Movement of Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . 3-63.4 Recharge and Discharge Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

4.0 SITE GEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-14.1 Stratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

4.1.1 Upper Till . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-24.1.1.1 Sedimentary Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24.1.1.2 Thickness and Area! Extent . . . . . . . . . . . . . . . . . . . . . . . . . 4-34.1.1.3 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

4.1.2 Inter-till Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-64.1.2.1 Sedimentary Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-74.1.2.2 Thickness and Area! Extent . . . . . . . . . . . . . . . . . . . . . . . . . 4-74.1.2.3 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-8

4.1.3 Lower Till . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-104.1.3.1 Sedimentary Composition . . . . . . . . . . . . . . . . . . . . . . . . . . 4-104.1.3.2 Thickness and Areal Extent . . . . . . . . . . . . . . . . . . . . . . . . 4-104.1.3.3 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-11

4.1.4 Stratified Drift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-134.1.4.1 Sedimentary Composition . . . . . . . . . . . . . . . . . . . . . . . . . . 4-134.1.4.2 Thickness and Areal Extent . . . . . . . . . . . . . . . . . . . . . . . . 4-144.1.4.3 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15

4.1.5 Bedrock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-174.1.5.1 Sedimentary Composition . . . . . . . . . . . . . . . . . . . . . . . . . . 4-174.1.5.2 Thickness and Areal Extent . . . . . . . . . . . . . . . . . . . . . . . . 4-184.1.5.3 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18

4.2 Geomorphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-184.3 Structural Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-19

Figure 4-1 Generalized Stratigraphic Column for the Clarkco SiteFigure 4-2 Thickness and Areal Extent of 1092 SandFigure 4-3 Thickness and Areal Extent of 1086 SandFigure 4-4 Thickness and Areal Extent of 1077 SandFigure 4-5 Thickness and Areal Extent of 1070 SandFigure 4-6 Thickness and Areal Extent of 1060 SandFigure 4-7 Thickness and Areal Extent of 1050 SandFigure 4-8 Thickness and Areal Extent of 1035 Sand

Eagon & Associates, Inc. ii January 1994


Table 4-1 Summary of Test BoringsTable 4-2 Summary of 2-Inch Wells Arranged by ClusterTable 4-3 Geotechnical Test Results for Undisturbed Samples

- Table 4-4 Geotechnical Test Results for Samples of Granular Materials

5.0 SITE HYDROGEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-15.1 Conceptual Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-15.2 Significant Saturated Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-2

5.2.1 Hydraulic Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-45.2.2 Ground-Water Level Fluctuations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-55.2.3 Recharge and Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-75.2.4 Ground-Water Row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8

5.3 Uppermost Aquifer System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-145.3.1 Hydraulic Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-155.3.2 Ground-Water Level Fluctuations . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-195.3.3 Recharge and Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-205.3.4 Ground-Water Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-21

5.4 Interconnections Between Uppermost Aquifer System and Significant Zones ofSaturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-225.4.1 72-Hour Pumping Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22

5.4.1.1 Test Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-235.4.1.2 Trends and Data Correction . . . . . . . . . . . . . . . . . . . . . . . . 5-265.4.1.3 Evaluation of Vertical Interconnection . . . . . . . . . . . . . . . . . 5-305.4.1.4 Evaluation of Lateral Interconnection . . . . . . . . . . . . . . . . . . 5-305.4.1.5 Calculation of Aquifer Characteristics . . . . . . . . . . . . . . . . . 5-32

5.4.2 Lower Till In-situ Permeability Tests . . . . . . . . . . . . . . . . . . . . . . . . 5-335.4.3 Tritium Age-Dating of Ground-Water Samples . . . . . . . . . . . . . . . . . 5-35

Figure 5-1 Hydrogeologic Column for the Clarkco SiteFigure 5-2 Conceptual Model of Ground-water Movement for the Clarkco

SiteFigure 5-3 Hydrographs for Wells Screened in the 1092 SandFigure 5-4 Hydrographs for Wells Screened in the 1077 and 1070 SandsFigure 5-5 Hydrographs for Wells Screened in the 1060 SandFigure 5-6 Hydrographs for Wells Screened in the 1050 SandFigure 5-7 Hydrographs for Wells Screened in the 1035 SandFigure 5-8 Comparison of Water-Level Fluctuation to Distance to Nearest

Outcrop for Intra-Till Sand WellsFigure 5-9 Comparison of Water-Level Fluctuation to Top of Sand Pack for

Intra-Till Sand Wells

Eagon & Associates, Inc. iii January 1994


Figure 5-11 Ground-Water Flow in the 1086 SandFigure 5-12 Ground-Water Flow in the 1077 SandFigure 5-13 Ground-Water Flow in the 1070 SandFigure 5-14 Ground-Water Flow in the 1060 SandFigure 5-15 Ground-Water Flow in the 1050 SandFigure 5-16 Ground-Water Flow in the 1035 SandFigure 5-17 Area where Uppermost Aquifer is ConfinedFigure 5-18 Potentiometric Surface of Uppermost Aquifer, 8/20/91Figure 5-19 Potentiometric Surface of Uppermost Aquifer, October, 1992Figure 5-20 Potentiometric Surface of Uppermost Aquifer, February, 1993Figure 5-21 Graphic Summary of Observation Wells Used for 72-hour Pumping

TestFigure 5-22 Pumping Test Hydrographs for Well PW-3Figure 5-23 Pumping Test Hydrographs for the Closest Observation Wells in the

Uppermost AquiferFigure 5-24 Pumping Test Hydrographs for the Closest Observation Wells in the

Intra-Till Sand ZonesFigure 5-25 Illustration of Method Used to Determine Barometric EfficiencyFigure 5-26 Drawdown in Uppermost Aquifer at the End of 72-hour Pumping

Test

Table 5-1 Field Hydraulic Conductivity Tests for Intra-Till Sand WellsTable 5-2 Ground-Water LevelsTable 5-3 Summary of Data Relative to Water Level Fluctuations, Intra-Till

Sand WellsTable 5-4 Summary of Hydraulic Conductivity Tests for the Uppermost

AquiferTable 5-5 Observation Wells used During 72-hour Pumping TestTable 5-6 Results of Slug Tests on Till WellsTable 5-7 Results of Tritium Analyses

6.0 SITE GROUND-WATER QUALITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

Figure 6-1 Trilinear DiagramTable 6-1 Ground-Water Quality Data

7.0 LANDFILL DEVELOPMENT EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . 7-17.1 Siting Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-17.2 Site Suitability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -7-77.3 Design and Construction Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-97.4 Ground-Water Monitoring Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11

Eagon & Associates, Inc. IV January 1994


Figure 7-1 Conceptual Design for Landfill Construction at the Clarkco SiteFigure 7-2 Proposed Ground-Water Monitoring Wells

8.0 METHODS AND PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-18.1 Drilling and Geologic Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1

8.1.1 The 1989 Reconnaissance Study . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-18.1.2 Test Well Installations PW-1, PW-2, and PW-3 . . . . . . . . . . . . . . . . . . 8-18.1.3 Phase I and Phase n Clarkco Hydrogeologic Investigations . . . . . . . . . . 8-28.1.4 Phase ID Clarkco Hydrogeologic Investigation . . . . . . . . . . . . . . . . . . . 8-7

8.2 Well Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-88.2.1 Test Wells PW-1, PW-2, and PW-3 . . . . . . . . . . . . . . . . . . . . . . . . . . 8-88.2.2 Clarkco Phase I and Phase D Installations (1990 and 1991 Wells) . . . . . 8-98.2.3 Clarkco Phase IH Installations (1992 Wells) . . . . . . . . . . . . . . . . . . . 8-10

8.3 Well Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-118.3.1 Test Wells PW-1, PW-2, and PW-3 . . . . . . . . . . . . . . . . . . . . . . . . . 8-118.3.2 Clarkco Phase I and Phase D Wells . . . . . . . . . . . . . . . . . . . . . . . . . 8-118.3.3 Clarkco Phase IH (1992 Wells) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11

8.4 Water-Level Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-118.5 Hydraulic Conductivity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12

8.5.1 Slug Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-128.5.2 Pumping Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-14

8.5.2.1 Pumping Tests on the 2-Inch Wells . . . . . . . . . . . . . . . . . . . 8-148.5.2.2 Pumping Tests Conducted on wells PW-1, PW-2, and PW-3 hi

1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-148.5.2.3 72-Hour Pumping Test on PW-3 . . . . . . . . . . . . . . . . . . . . . 8-15

8.6 Geotechnical Testing of Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-168.7 Ground-Water Quality Determinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16

8.7.1 Detection of Immiscible Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-178.7.2 Collection of Ground-Water Samples . . . . . . . . . . . . . . . . . . . . . . . . 8-178.7.3 Performance of Field Measurements . . . . . . . . . . . . . . . . . . . . . . . . . 8-188.7.4 Decontamination of Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-198.7.5 Analysis of Ground-Water Samples . . . . . . . . . . . . . . . . . . . . . . . . . 8-208.7.6 Chain of Custody Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-208.7.7 QA/QC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-21

Table 8-1 Well Development Summary

9.0 REFERENCES CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1

10.0 PLATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1

Eagon & Associates, Inc. v January 1994


LIST OF PLATES

Plate 1. Water Supply Wells Within One MilePlate 2. Regional Cross-Section TracesPlate 3. Regional Hydrogeologic Cross Section W-EPlate 4. Regional Hydrogeologic Cross Section S-NPlate 5. Regional Hydrogeologic Cross Section NW-SEPlate 6. Regional Bedrock TopographyPlate 7. Potentiometric Surface of the Regional Carbonate AquiferPlate 8. Local Cross-Section TracesPlate 9. Local Cross Sections U & VPlate 10. Local Cross Sections W & XPlate 11. Local Cross Sections Y & ZPlate 12. Potentiometric Surface of the Stratified DriftPlate 13. Boring Locations and Cross Section TracesPlate 14. Cross Section A-A'Plate 15. Cross Section B-B'Plate 16. Cross Section C-C'Plate 17. Cross Section CC-C'C'Plate 18. Cross Section D-D'Plate 19. Cross Section E-E'Plate 20. Cross Section F-F'Plate 21. Cross Section G-G'Plate 22. Cross Section H-H'Plate 23. Cross Section I-I'Plate 24. Cross Section J-J'Plate 25. Cross Section K-K'Plate 26. Base of Lower TillPlate 27. Hydrographs for all Wells at Clarkco FacilityPlate 28. Potentiometric Surface of Uppermost Aquifer, 2/8/93

Eagon & Associates, Inc. vi January 1994


LIST OF APPENDICES

VOLUME II

Appendix A. Water Wells Within One MileAppendix B. Public Water Supply Wells Within 10 MilesAppendix C. Boring Logs

VOLUME III

Appendix D. Well Construction DiagramsAppendix E. Boring Logs From Investigations at Adjacent FacilitiesAppendix F. Geotechnical Testing ResultsAppendix G. Slug Tests and Pumping Tests on Significant Saturated ZonesAppendix H. 1990 Pumping Tests Results - Uppermost AquiferAppendix I. 72-Hour Pumping Test on Uppermost AquiferAppendix J. Water Quality Testing Results

Eagon & Associates, Inc. vu January 1994

3.0 LOCAL HYDROGEOLOGY

3.1 Available Information

Previous investigations at the facilities on the adjoining properties to the west have

generated hydrogeologic information that is extremely beneficial to the analysis and interpretation

of the local hydrogeology surrounding the proposed Clarkco facility. Particularly useful are test

borings which were drilled to bedrock or to sufficient depths to penetrate the entire thickness of

the glacial till confining bed and at least part of the underlying stratified drift. Many of these

borings have been sampled continuously and wells have been installed in some of the deep

boreholes. Boring logs from these investigations that were utilized in the analysis of local

conditions are presented in Appendix E. The borings for well installations TBF-19D and TBF-

20D at the Barrel Fill were drilled to depths of 160.5 and 139 feet, respectively. Boring 16 at

the Barrel Fill was drilled to a depth of 100 feet.

Pertinent hydrogeologic information was generated by the ground-water assessment at the

south end of the Tremont landfill. One test boring, 89-3 (adjacent to wells A89-3S and A89-3D)

was drilled to bedrock. A new monitor well, (91- drilled during the assessment and

located west of the landfill, was drilled to bedrock. Two water wells in the assessment area, 1-

943 and 201, also were drilled to bedrock. Three borings drilled during the west seep

investigation, WS92-22B, WS92-24B, and WS92-25B, were of sufficient depth to be useful in

making correlations with the deeper borings at the proposed facility.

During the 1992 phase of the hydrologic investigation for the Clarkco site, ten deep borings

were drilled to bedrock in order to characterize the stratified drift. Two of these, 92-HDD and

92-27DD, were within or at the edge of the footprint of the proposed landfill, while five others,

C92-5DD, 92-20D, 92-2ID, 92-22DD, and 92-23D, were drilled at more distant locations on the

property hi order to characterize the local geology south and southeast of the proposed landfill.

In addition, three deep borings were drilled offsite. Two of these were drilled southeast of the

proposed landfill. Boring 92-30 was drilled and sampled to bedrock using an auger rig and was

.———._____— -—_—_- ——_ ——„———————.—————————- — . - _ . - . . . ____________________________________'————————~——~

Eagon & Associates, Inc. 3-1 January 1994

converted to a water well by deepening the hole into bedrock with a rotary rig. Boring 92-34

was drilled at the base of a sand outcrop in a borrow area behind a residence on Owner's Road.

The boring for well 92-35DD was drilled on Tremont landfill property about 390 feet west of

the existing landfill. Due to equipment limitations this boring was terminated at a depth of 152

feet before reaching bedrock.

In addition to the test borings, water-well logs in the immediate area were utilized. Some

water wells were field located more precisely with the aid of a detailed topographic map for the

area to the southeast in the vicinity of Owners Road. The base map on which these wells and

boring locations are plotted (Plate 8) is an enlargement of Plate 1 having a scale of 1 inch to 400feet. Information that was not available at the time of the January 1992 report was added toPlate 8, and some well locations were shifted as a result of additional or more accurateinformation that was included hi the April 1993 version of the Hydrogeologic Report.

Off-site borings which provide information relevant to the characterization of the

surrounding area, and that can be correlated with data that has been generated on the proposed

landfill site are included in Appendix E. Information recorded on the water well logs copied

from ODNR files (Appendix A), although much less detailed and reliable, was used to furthercharacterize the local hydrogeology. The area of interest for this characterization includes thearea bordered by Willow Dale Road on the west, Upper Valley Pike on the east, Storms Creek

on the north, and Chapman Creek on the south.

3.2 Stratigraphy

Numerous cross sections have been prepared with the data from the local area in order to

graphically portray the local geologic setting within the vicinity of the site to the extent possiblewith the available information. The purpose of these local cross sections, the traces of which areshown on Plate 8, is to show the relationship of the major hydrostratigraphic units at the site to

the surrounding area. In some cases, correlating detailed site boring logs with generalized water

well log information is somewhat difficult. In certain off-site areas where there are several


water-well logs within a small area, information recorded on the logs sometimes seems

contradictory. This may be due to significant variations in lithology over short distances, or it

may be the result of varying interpretations of the drillers or differences in the level of

descriptive detail, or a combination of these. In those areas where multiple interpretations are

possible, the log or logs judged to be the most reliable or reasonable based on correlations and

other lines of evidence, are shown on the cross section.

The stratigraphy illustrated by the cross sections presented on Plates 9, 10, and 11, while

not labeled as such, is consistent with the units defined and described in detail in Sections 4.0

and 5.0 of this report. Generally, the upland areas are comprised of a thick till sequence that is

underlain by stratified drift consisting of sand and gravel layers interbedded with till and other

cohesive materials. Beneath the Clarkco site, part of the stratified drift has been defined as the

uppermost aquifer system. As shown by both the detailed and the local cross sections, the

stratified drift is quite variable with sand zones and till layers pinching out or thickening, and hi

some areas changing abruptly over short distances. In several instances, correlations of sand

zones are made on the basis of the relative water-level elevations in wells and borings, i.e. similar

water levels indicate interconnection, whereas significantly different water levels strongly suggest

no interconnection, or at the very least, a poor connection.

East-west cross sections show sand and gravel in direct contact with the carbonate bedrockwhere the latter occurs at higher elevations west of the Clarkco site. This is true on cross

sections U-U', W-W', and X-X'. In boring 89-2 on cross section W-W', the thick sands extend

to as high as elevation 1040. About 450 feet east, however, beneath the Closed Barrel Fill, these

sands are virtually nonexistent except below elevation 955, feet as shown by the log of well TBF-

19D on the same cross section. The thinning and pinching out of sand beds that are replaced by

till also is apparent on cross section X-X' in the vicinity of the Tremont Landfill and proposed

Clarkco landfill.

Cross section U-U' illustrates the poor or non-existent connection between the deep sand

zones screened in wells 90-7D and PW-2. Based on the different water level and hydrograph


pattern of PW-2, as well as the log of boring 90-15 and the driller's and gamma-ray logs of PW-

2, it seems clear that PW-2 is screened in a different aquifer than are the wells which are

completed in the unconfined uppermost aquifer to the west and southwest. The top of the

bedrock surface shown on cross section U-U' is based on the bedrock contour map (Plate 6).

Inferred stratified layers at depths greater than penetrated by boring 89-1 and well 90-6D are

based on conditions observed on cross sections further south. Data are insufficient to prove or

disprove the physical continuity of any of the sand zones hi PW-2 with the gravel zone logged

at water well 65 to the east. However, well 65 was developed in the bedrock, suggesting that

the gravel is not particularly productive. There are two sand and gravel wells (22 and 23) located

near well 65 with water-level elevations of about 951 and 945, respectively as compared to about

973 at PW-2. This water level difference of more than 20 feet indicates that there is not a direct

Interconnection between PW-2 and wells 22 and 23.

Cross section V-V' illustrates the restriction or poor connection between the aquifer

screened in PW-1 and the uppermost aquifer beneath the Clarkco site. Southeast of the Clarkco

proposed landfill, the water level hi well 92-20D reflects the deep and seemingly isolated sand

zone hi which this well is screened. Additionally, the water-level elevation of about 960 feet In

92-20D is substantially higher than the water levels in wells to the east beyond the upland till

area indicating a lack of direct interconnection to these wells also.

Cross section W-W' illustrates several examples of abrupt lateral changes in lithology. For

example, thick.silty sand and gravel is encountered as high as elevation 1040 hi boring 89-2,

whereas hi boring TBF-19D no significant water-bearing sand zone was encountered in the

stratified drift above about elevation 935. Deep sands are probably in direct contact with thebedrock aquifer to the west as illustrated. Although not illustrated on a cross section, there is

an abrupt change in lithology between wells TBF-19D and TBF-20D. The 72-hour pumping test

of PW-3 that is described in Section 5.0 of the report demonstrates a lack of interconnection

between the sand zones screened in these wells. The fact that these nearby wells were each part

of a separate flow system had been Inferred on the basis of the water-level data.


An abrupt change also is illustrated on section W-W between well 511 and boring 92-34.

This may be due in part to sophistication of the logging (92-34 was continuously sampled and

logged by a geologist while well 511 was logged by a residential well driller). The granular

material encountered in boring 92-34 was not considered to be particularly productive for water-

supply development in the deeper saturated zones. It is important to note that all of the domestic

water wells that have been installed on Owners Road are developed in the carbonate bedrock

aquifer. Sand and gravel zones which may connect laterally with zones at the Clarkco site are

dry or poorly permeable. If a significant sand and gravel-aquifer were present in this area it

would be reasonable to expect that a well would have been developed in it.

The conditions encountered at boring 92-30 shown on cross section X-X' probably are

typical of the experiences in developing water wells southeast of the Clarkco site. The upper

sand was dry in boring 92-30. The only zone which was seriously considered to have the

potential for a dependable domestic supply was the basal sand which was about 2 feet thick at

the top of bedrock. However, when the borehole was converted to a water well, it was

questionable whether this zone would provide a reliable supply, so the well was completed in the

underlying bedrock where an adequate supply was assured. Cross section X-X' (Plate 10)

illustrates that to the east of boring 92-30, there is a bedrock high and clay deposits that

precludes a lateral connection of the saturated sand zones in stratified drift with the buried-valley

aquifer that is further to the east.

Cross section Z-Z' (Plate 11) illustrates the uppermost aquifer pinching out to the southwest

and northeast. The interconnection between the sand zone screened in PW-3 (72-hour pumpingtest well) and the sand beds screened at the C91-5 and 92-22 well clusters is based on die

pumping-test results. Farther to the southwest, wells along Chapman Creek (south of the

Tremont Landfill) showed no response to pumping during the 72-hour pumping test. Both the

saturated and unsaturated portions of the uppermost aquifer wedge out to the northeast toward

PW-2. The sand zone that is screened in PW-2 is considered to be part of a flow system that

is separate from the uppermost aquifer underlying the Clarkco site. Because the hydrograph of

PW-2 shows that PW-2 is responsive to infiltration, the sand zone screened in this well is


probably interconnected with sands associated with the floor of the Storms Creek valley farther

downstream to the northeast. Cross section Y-Y' (Plate 11) illustrates that the uppermost aquifer

at the Clarkco site is contiguous with sand and gravel deposits that crop out in Storms Creek to

the north. Field reconnaissance of Storms Creek in the vicinity of well location 407 and to a

point approximately 1600 feet east, has identified surficial materials as probable sand and gravel

deposits. Storms Creek appears to flow on top of till both to the east and west of this reach.

3.3 Occurrence and Movement of Ground Water

The local cross sections illustrate rapidly changing hydrogeologic conditions in the vicinity

of the Clarkco site. Pertinent water-level data shown on the cross sections has been used to

interpret lateral and vertical components of ground-water movement, and to identify theunsaturated zones. Plate 12 is a potentiometric map that includes various saturated zones within

the stratified drift sequence based on February 8, 1993 water-level measurements for wells at the

Clarkco and Tremont sites, and on static water levels reported on the drillers logs for the off-site

water wells at the time they were installed. Obviously, these data are not directly comparable

because the water-well information represents a wide range of time and conditions. Moreover,

it should be noted that this map represents conditions within the stratified drift as though it

comprised a single flow system. The potentiometric map of the stratified drift, however, does

not portray the potentiometric surface of a discrete saturated zone or flow system within the

stratified drift. In other words, vertical gradients and the lack of lateral connections between

zones screened in specific wells may be such that water levels are not representative of the same

system. This fact generally has been ignored in preparing this map. Therefore, conclusionsderived from the interpretation must be kept in perspective. Plate 12 illustrates the potential for

ground-water flow within the stratified drift in the immediate area around the proposed Clarkco

Landfill. The actual flow in the direction suggested by potentiometric contours, however, may

be relatively small as a result of poor lateral interconnection between individual saturated zones

or flow systems.


The potentiometric contours shown on Plate 12 indicate that general direction of ground-

water migration within the stratified drift sequence is from west to east with components to the

northeast toward Storms Creek and southeast toward Chapman Creek. This configuration

generally conforms to regional ground-water flow directions in the regional bedrock aquifer as

shown on Plate 7. However, the quantity of ground-water flow in any given direction is a

function of the hydraulic conductivity of the materials through which the ground water must

move. Potentiometric contours that are closely spaced indicate flow restrictions or boundaries

between ground-water flow systems. Conversely, where contours are widely spaced, good lateral

continuity and uniformity in hydraulic conductivity are indicated. The potentiometric map of the

stratified drift sequence can be used in this manner to interpret lateral continuity, or a lack

thereof.

The closely-spaced contours immediately west of the Clarkco site suggest a restriction to

flow from west to east as described in the previous discussion of local cross sections. Although

less pronounced, a second "step down" of the potentiometric contours is evident between the

Clarkco site and the valley floor to the east. The consistency of water-level elevations in the area

of the proposed landfill footprint is quite evident and strongly indicates continuity within what

has been defined as the uppermost aquifer. The apparent limits of the "uppermost aquifer"

beneath the proposed landfill that have been delineated on Plate 12 are based on the interpretation

of water-level data, boring logs, and the 72-hour pumping test. Note that the potentiometric

surface for the uppermost aquifer flow system has a contour interval of only 0.20 foot, as

compared to a contour interval of 10 feet for the stratified drift as a whole.

The dominant flow direction in the uppermost aquifer beneath the Clarkco site is to the

east-northeast. The lack of detailed water-level information off site makes it difficult to infer

flow directions within the uppermost aquifer beyond the site boundaries. Because the aquifer

pinches out to the east, the actual flow in that direction probably is small. The potential for flow

from the area of wells 92-22D and 92-22DD to the southeast toward Chapman Creek is small

because there is no evidence of an interconnection with the thin sand beds within the stratified

drift in that direction. Similarly, between wells 90-7D and PW-2 the amount of flow is small


or nonexistent due to the reduced permeability or a complete lack of interconnection. The

greatest quantity of flow from the site is thought to be to the north-northeast toward Storms

Creek, where the more permeable zones of the uppermost aquifer are thought to extend off site

(See cross section Y-Y' on Plate 11). The area in which sand and gravel has been observed to

crop out in the channel of Storms Creek is shown on Plate 12.

3.4 Recharge and Discharge Areas

The primary source of recharge to the uppermost aquifer beneath the Clarkco site appears

to be from the lower reaches of the ravine near boring 92-22D and the flats beyond, where the

uppermost aquifer system is exposed, or nearly exposed, at the surface. A component of

recharge also may come from the stratified drift west of the site where sand zones are in directcontact with the regional bedrock aquifer and where sand zones may be close to the land surface.

Comparison of the bedrock potentiometric map (Plate 7) with Plate 12, reveals that there are

areas west of the Clarkco site where there is an upward gradient between the bedrock aquifer and

the stratified drift. Available water-level elevations for bedrock wells are shown on Plate 12, but

there are few locations where both bedrock and stratified drift water-level elevations are

available. East of the Clarkco site, it appears that bedrock water levels are lower, indicating a

downward gradient and the potential for saturated zones in the stratified drift to recharge the

bedrock aquifer. Vertical gradients within the uppermost aquifer at the Clarkco site appear to

be slightly downward, except at well pair 90-14D and 92-14DD, where there is a slight upward

gradient.

The discharge areas for the stratified drift as a whole are Chapman Creek, Storms Creek,

and the valley to the east. Discharge from the uppermost aquifer beneath the Clarkco site is

thought to be to Storms Creek to the north and northeast, and potentially to deeper or laterally

contiguous zones in the stratified drift to the east. The potential for a southerly component of

flow from the area south of the proposed landfill with discharge to Chapman Creek is minimal.

The reach of Chapman Creek which receives ground-water discharge that was identified in Eagon

& Associates, 1992a is located west of well A89-1. South of the Clarkco site, the conditions are


similar to those described at the southeast corner of the Tremont Landfill, where the stream is

flowing mostly on till.

To the east of the limit of the uppermost aquifer (as delineated on Plate 12) discharge from

the uppermost aquifer may occur to some of the deeper sand or laterally contiguous zones in the

stratified drift. On the local cross sections most of the sands identified east of the Clarkco site

that seem to be lateral equivalents of the uppermost aquifer are dry. Most of the ground-water

discharge from the uppermost aquifer probably occurs to the northeast to Storms Creek. The

reach of Storms Creek in which sand and gravel has been observed and which may be the

primary discharge area for the uppermost aquifer beneath the Clarkco site is shown on Plate 12

by the extension of the lines delineating the uppermost aquifer north to the stream channel.


4.0 SITE GEOLOGY

Site-specific geologic data for the proposed Clarkco Landfill has been gathered from

December 1988 to the present. Table 4-1 is a chronological listing of all soil-boring and well-

installation activities from the preliminary feasibility study through detailed investigations

directed toward a PTI application. Table 4-1 documents 100 soil borings that were drilled at 55

locations for the purpose of evaluating the Clarkco site. Including PW-1, PW-2, and PW-3, the

four recently-installed till piezometers, and 92-35DD, a total of 64 wells have been installed to

date. Well construction details for each of the 2-inch PVC installations also are summarized in

Table 4-1. The same information is included in Table 4-2 in which the wells are grouped by

well cluster. The well-cluster locations are listed in chronological order in Table 4-2, and wells

within each cluster are in order of well screen depth. Plate 13 is a base map for the Clarkco site

showing the locations of all borings and wells and the traces of geologic cross sections

constructed from them.

Numerous laboratory tests have been performed on representative soil-boring samples in

order to classify and characterize the unconsolidated materials. Geotechnical test results on

undisturbed samples are presented hi Table 4-3. Geotechnical test results on jar samples from

split spoons or the continuous sampler are presented in Table 4-4. Most of the jar samples tested

are granular materials in which a well has been installed.

4.1 Stratigraphy

Hydrogeologic cross sections A-A' through K-K' (Plates 14 through 25) have been

developed to facilitate interpretation of the soil-boring data, and to aid in formulating and

illustrating the stratigraphic relationships among the unconsolidated materials which underlie the

Clarkco site. Figure 4-1 is a generalized stratigraphic column which illustrates the manner in

which stratigraphic units at the Clarkco site have been defined and subdivided based on their

lithology, physical properties and hydrogeologic significance.


At the Clarkco site, a thick sequence of glacial drift overlies carbonate bedrock. Glacial

drift is a general term applied to all material (clay, silt, sand, gravel, boulders) transported by a

glacier, and deposited directly by or from the ice, or by water emanating from a glacier. It

includes both stratified and unstratified material. The upper part of the glacial drift at the

Clarkco site consists primarily of glacial till which has been mapped previously by others as thick

ground moraine (Goldthwait, 1951). On the basis of detailed study of closely-spaced on-site

borings, this till has been sub-divided in to an upper till and a lower till member. These are

separated by an inter-till zone that also is mostly till but is differentiated on the basis of a greater

incidence of sand and silt partings, seams, thin beds, and/or subtle differences in the texture or

fabric of the till that suggest reworking. In many borings, the contact between the upper or lower

till and the inter-till zone is not distinct but rather represents a gradational contact. The lower part

of the drift is stratified and the thick and highly permeable beds that are part of this unit

constitute a sand, or sand and gravel, water-table aquifer. The portion of the stratified drift that

constitutes a local aquifer beneath the Clarkco site is identified as the uppermost aquifer which

will be defined and characterized in Section 5.0. As shown in Figure 4-1, five stratigraphic units

have been recognized and defined at the Clarkco site. From youngest to oldest, the five units

are: the Upper Till, the Inter-Till zone, the Lower Till, the Stratified Drift, and Bedrock. Each

of the five stratigraphic units will be described and discussed separately.

4.1.1 Upper Till

4.1.1.1 Sedimentary Composition

Glacial till is an unsorted, unstratified mixture of rock debris, soils, and other near- surface

materials that have been picked up, mixed, modified by glacial transport, and re-deposited by

processes of glaciation. Sizes of these materials range from float blocks and large boulders to

cobbles, gravel, sand, silt, and clay. Till sheets and glacial episodes often are differentiated on

the basis of the relative amounts of particle-size groups and material types. The predominant

grain sizes usually are silt and clay with lesser amounts of sand, with traces of gravel sizes and

larger rocks.


4.1.1.2 Thickness and Areal Extent

Thickness variation in the upper till is primarily a function of topography. The upper till

is thinnest in the small areas where erosion (caused by drainage flowing into ravines which

border the site) has cut into and removed most or all of the unit. The upper till extends from

grade down to the elevation of the base of this unit which ranges from about 1050 to 1057 feet.

Surface elevations within the footprint of the proposed landfill range approximately from 1112

to 1010 feet. Due to the variations in surface topography, the upper till is missing in the deep

ravines, but ranges up to about 60 feet in thickness. As seen on the cross sections, however, the

average thickness of this unit typically ranges from 40 to 60 feet hi the western part of the site

and from 20 to 40 feet in the eastern part.

Clastic units are present as minor interbeds within the upper till. These vary from sand or

silt partings less than Va-rnch thick to sand and gravel beds that, in places, are a few feet thick.

Cross sections A-A' through K-K' illustrate the absence of thick and extensive permeable beds

within the upper till.

The sand zones in the upper till are not thick blanket sands that can be consistently

encountered in all borings at specific elevations.. Attempts to correlate upper till sand zones

between the soil borings drilled in 1990 and 1991 led to an informal nomenclature based on the

approximate average elevation at which a group of beds were clustered. The addition of the 1992

borehole data prompted a review of all of the soil-boring data and a refinement of the

classification scheme. This was accomplished by posting the elevation and thickness of all sand

partings, seams, and beds on a site base map in order to identify natural groupings of beds that

may constitute ground-water pathways. The natural groupings within the upper till that wereidentified by detailed analysis of the borehole data and that are used in this report are the 1092,

1086, 1077, 1070 and 1060 sands. Although some sand zones can be correlated between borings

based on similarity of elevations, they are not necessarily continuous between borings. A fairly

common occurrence when installing multiple wells at cluster locations, was that a borehole drilled

ten feet away from an existing boring in which a certain sand was present, would encounter only


till. Sometimes when the targeted sand was encountered, its thickness would be quite different.

Some of these sands have lateral continuity and constitute pathways for lateral ground-water

migration. However, many are very local in nature and occur as pods or discontinuous lenses.

A map has been prepared that shows the thickness and areal extent of each of the five

upper-till sand groupings (Figures 4-2 through 4-6). Shown on each map is an appropriate

topographic contour which, by definition, limits the possible extent of that particular sand. (If

present, the sand would outcrop at this approximate elevation.) None of these zones produce

enough water to be considered aquifers, as will be discussed in detail in Section 5.0. A short

discussion of the thickness and areal extent of each of the upper till sand zones follows.

The 1092 sand is restricted by topography to the more upland parts of the proposed Clarkco

landfill (Figure 4-2). It has been encountered only in the extreme northwest comer of the site.

It is shown to be thickest (4.0') in boring 89-3. However, this may be an exaggerated thickness

because boring 89-3 was not continuously sampled. Note that other borings nearby, 92-24Y and

92-24Z, encountered only 2.0 feet and 0.8 foot of sand, respectively. The 1092 sand is 2.6 feet

thick where it is screened in boring 90-6W. It is 0.8 foot thick where it is screened in boring

92-24Z, and 2.1 feet thick in adjacent boring 92-24Y. It was not identified in any borings south

or east of the zero sand line shown on Figure 4-2.

The 1086 sand has been identified only within a narrow band that trends northeast-

southwest through the west-center portion of the site (Figure 4-3). The maximum thickness of

the 1086 sand shown on Figure 4-3 (3.0 feet in boring 90-5) may be an exaggerated thickness

as a result of sand heave incurred while drilling. The only other significant thicknesses of 1086

sand were encountered in borings 90-1, 92-19X, and 90-12 where bed thicknesses are 1.5, 1.1,

and 1.4-foot, respectively. As shown on Figure 4-3, the 1.4-foot thickness shown for boring 90-

12 is the aggregate thickness of three separate beds.

Figure 4-4 shows the thickness and areal extent of the 1077 sand. Sand beds at this

elevation are thin or absent in the northern and southern extremes of the site and thickest near

———.—————————————————————.———————————,__________- — - ______-______________________________________.—————•—————


the eastern and western boundaries of the Clarkco site. Split-spoon sampling in boring C92-9Y

strongly suggests that the sand thickness shown for boring C91-9 was greatly exaggerated as a

result of sand heave induced by the continuous sampler that was used to sample boring C91-9.

The 5.0 foot sand thickness shown for boring 90-13D may be an exaggeration, also. Only 1.2

feet of sand was recovered in the sampler, but the entire 5-foot sample run was logged as being

sand.

Figure 4-5 shows the thickness and areal extent of the 1070 sand grouping. Only six

boring locations encountered 1070 sand thicknesses of one foot or more, and all but one of these

is along the western boundary of the Clarkco site. Except for isolated occurrences in borings 92-

19X, 90-3, and 92-28X, the 1070 sand is absent over most of the rest of the Clarkco site.

As shown on Figure 4-6, the 1060 sand is the thickest and most widely distributed of the

upper till sand zones. In the north-central and northeastern parts of the site, it is present at seven

boring locations but more than one foot thick only in five borings. The 1060 sand is thickest in

the southeastern and southern parts of the site. Where the 1060 sand is thick, it may have cut

into the underlying inter-till zone.

4.1.1.3 Physical Properties

USCS Textural Classification. As seen in Table 4-3, the upper till typically is a CL material and

is quite uniform. In places, its engineering characteristics vary slightly and it is classified as CL-

ML material.

Atterberg Limits. Liquid limits in the upper till range from 18 to 23. Plastic limits range

narrowly from 11 to 13. The plasticity index varies within the narrow range of 6 to 10 which

straddles the division between CL-ML and CL materials of low plasticity.

Grain Size Distribution. The principal textural component in the upper till is silt with the major

secondary component being sand. (The opposite is true in the case of the undisturbed samples


from borings C91-9 and 90-10Y.) Silt content ranges from 34.4 to 44.1%. Clay is a significant

minor component ranging from 16.4 to 20.4%. Gravel typically is a trace component ranging

from 3.4 to 15.7%.

Hydraulic Conductivity. Hydraulic conductivities determined in the laboratory on undisturbed

samples from the upper till consistently are extremely low ranging narrowly from approximately

1.2 x 10'8 to 6.3 x 108 cm/sec.

Moisture Content and Dry Unit Weight. As seen in Table 4-3, moisture contents of upper till

undisturbed samples range from 8.0 to 12.3 percent. Dry unit weight ranges from 127.65 to

136.99 pounds per cubic foot.

None of the upper till interbeds have a lithology that is distinctive. Any of the units may

range in grain size from silt to sand and gravel. All are non-plastic. The most frequently

encountered lithology is fine sand and silty sand. Grain sizes, USCS classifications, and other

characteristics, are described on the individual boring logs and laboratory determinations are

listed in Table 4-4.

4.1.2 Inter-till Zone

Whether or not the inter-till zone should be considered as a separate mapping unit is

somewhat debatable. However, for descriptive purposes, this zone is identified on the site cross

sections (Plates 14 through 25). Generally it is bracketed by elevations 1055 and 1040 feet. The

concept of a "transition zone" between two till sheets was formulated on the basis of the results

of drilling at the adjacent disposal facilities. The name inter-till zone originally was applied to

similar materials when evaluating the 1990 and 1991 boring data for the Clarkco site to reflect

the supposition that the non-till components within the inter-till zone represented an episode of

glacial retreat. This may or may not be the case. Because the term was introduced and

extensively used in the 1992 Clarkco hydrogeological report, the additional boring data recently

obtained has been used to refine the definition of this stratigraphic unit. However, an equally


valid mapping approach would be to treat the inter-till zone in the same manner as the other

ground moraine units because it is predominantly till at most locations. If this approach weretaken and the concept of an inter-till zone de-emphasized, there would not be a compelling reason

to subdivide the till sequence into an upper and lower member. Sand beds within the inter-till

zone at the Clarkco site are referred to as the 1050 sand in this report, an approach which is

consistent with the description of the geology at adjacent sites.


The dominant material in the inter-till zone is till that is physically similar to the upper tillor lower till. In some parts of the Clarkco site, one or two sand or silt partings are the onlyobservable features that separates the inter-till zone from the upper or lower till. In other areas,several interbeds of sand and/or silt at various elevations or a thicker sequence of interlayered

sand and silt, with or without cohesive interbeds, may be present. Another constituent of theinter-till zone is a cohesive material that has essentially the same particle size distribution as thetill considered to be ground moraine, but displays subtle textures or fabrics that suggest re-working. Such material has been variously referred to as re-worked till, ablational till, glacial

backwater sediments, till-like, or "till on the boring logs. As a practical hydrogeological matter,

all such materials can be grouped because they have essentially the same physical properties.


As illustrated on cross sections A-A' through K-K' (Plates 14-25), the inter-till zone rangesin thickness from 0 to about 20 feet and probably averages 12 to 14 feet. As seen on crosssections E-E' and H-H' (Plates 19 and 22), the inter-till zone has been removed by erosion inthe deeper parts of the ravine draining the area to the south of the proposed landfill footprint.It is also absent beyond its outcrop in the other ravines and lowlands north and east of the site.

Figure 4-7 illustrates the thickness and area! extent of the 1050 sand, which is the nameapplied to sand interbeds within the inter-till zone. Figure 4-7 is different than the other sand


maps because individual bed thicknesses are not posted. Shown instead is a net sand thickness

which is the sum of all interbeds that are 0.1 foot or thicker. The thickness of four, five or more

beds have been combined at some boring locations. In a few instances, the net sand thicknessshown on Figure 4-7 is an estimate of the sand portion of a finely interbedded sequence of sand

and/or silt and cohesive materials.

Figure 4-7 shows that there are only a few, relatively small areas in the central,northeastern and southern parts of the Qarkco site where the net thickness of the 1050 sandexceeds two feet. Much of the site is underlain by a combined thickness of 1050 sand that isa foot or more, but individual seams may be only 0.1 to 0.4 feet thick. If sand seams less thanone-half foot in thickness were not counted, the net thickness of the 1050 sand would bediminished almost everywhere, and in some places more than halved. Individual control points,and larger areas of no 1050 sand also would be depicted.


USCS Textural Classification. The sedimentary composition of the inter-till zone is more

variable than that of the other stratigraphic units because materials other than typical till

constitute a greater percentage of its relatively small thickness. Despite this variability, it remains

a fact that the predominant material in the inter-till zone is till that is virtually indistinguishablefrom upper till or lower till samples (CL with minor CL-ML materials). The CL materials from

borings 90-11 (67.0-68.0 feet) and C91-3 (48.3-49.5 feet) are examples (see Table 4-3). Thesame USCS soil classifications (CL and CL-ML) generally apply to similar materials that havebeen described on the boring logs as till-like, glacial backwater sediments, ablational till, and re-worked till. Interbeds assigned to the 1050 sand include saturated and unsaturated silts (ML),silty sands (SM), well-graded silty sands (SW-SM), poorly-graded silty sands (SP-SM), and sandysilts (ML). Representative samples of the 1050 sand selected for laboratory characterization arelisted in Table 4-4. These include the SW-SM sand sampled from boring 90-6D (55.8-56.3) and

screened in well 90-6Z, the silty sand (SM material) screened in well 90-10X, the SP-SM sandscreened in well C91-4X, and the silty sand (SM material) sampled from boring C91-8D (42.7-


44.1 feet) and screened in well C91-8X. As seen on the boring logs (Appendix C) and in Table

4-4, coarser-grained and well-sorted "clean" sands generally are absent.

Atterberg Limits. As seen in Table 4-3, undisturbed samples of cohesive materials from the

inter-till zone have engineering properties that are essentially identical to those of the surrounding

tills and that appear to resemble the upper till a little more closely. Samples from borings C91-3

and 90-11 have liquid limits of 20 and 21 and plastic limits of 12 and 13, respectively. The

plasticity index for each is 8. All of the inter-till zone samples that are not classified as CL-ML

or CL are non-plastic (Table 4-4).

Grain Size Distribution. The dominant material in the inter-till zone is glacial till. In someborings, part of the till appears to be re-worked. Like the upper and lower till stratigraphic units,the inter-till zone may contain clastic interbeds (either saturated or unsaturated). All suchinterbeds have been assigned to the 1050 sand group. Grain-size distributions of till samples

from the inter-till zone are within the ranges specified for both the upper and lower till sampleslisted in Table 4-3.

The grain-size distributions and resulting USCS classifications of three 1050 sand samplesfrom the inter-till zone (from borings 90-6D, C91-8D, and 90-10X) are listed in Table 4A.

Generally, medium and fine sand sizes predominate. A significant amount of gravel was foundonly in the sample from boring 90-6D. None of these samples are "clean" enough (have lessthan 5% by weight passing the #200 sieve) to avoid inclusion of the SM designation as part oftheir USCS classification symbol.

Hydraulic Conductivity. Permeability of the inter-till zone materials ranges approximately from7.2 x 10^ cm/sec for till (Table 4-3, boring 90-11) through about 1.1 x 10'7 cm/sec for thepredominantly silt interbeds, (estimate based on an actual determination on similar materialssampled from the lower till (Table 4-3, boring 91-9Y, WS-3) to as much as 2.3 x 1Q-2 cm/sec forthe better-sorted and "cleaner" sand units (based on the pump tests results on well 90-6Z, Table

5-1). Although thin, the sand unit screened in this well is judged to be the cleanest of the 1050


sands that were encountered in any of the on-site borings that penetrated this horizon. The

second highest permeability measured in a well screened across the 1050 sand zone is 1.5 x 10"2

cm/sec based on the slug test of well C91-4Z, (Table 5-1). Permeability calculated from the

pump test of this well is about one third of the slug-test permeability (5.4 x 10"3 cm/sec). Thepump test value is considered the more accurate estimate because the pump test evaluates naturalformation beyond the developed zone surrounding the well screen.

4.1.3 Lower Till

The lower till as defined on the cross sections in Plates 14 through 22 generally occursfrom elevation 1040 down to about elevation 1015 to 1010.


Like the upper till unit and most of the inter-till zone, the lower till is predominantly

massive till that was deposited as ground moraine. The lower till contains a single clasticinterbed which is referred to in this report as the 1035 sand.


Figure 4-8 shows the thickness and area! extent of the 1035 sand. Generally speaking, the1035 sand is present in a north-south band that traverses the central and eastern portion of theClarkco site. Over much of the northern half of this band, the 1035 sand is less than two feetthick. To the south, it is more than one foot thick only at two locations, 92-3IX and C91-4.Combined bed thicknesses exceeding 2.0 feet are present only at five boring locations (92-19X,92-14X, 92-4X, 92-2X, and 92-15X).

Within the footprint of the proposed Clarkco landfill, the average thickness of the lowertill is about 30 feet, but its thickness may range from zero to more than 40 feet. The lower tillhas been truncated by erosion and is absent in the ravine south of boring C91-5D which is


located about 1180 feet south of the proposed landfill footprint. Although surface topography

in the ravine to the south is the primary cause of rapid thickness variations, less-significant

thickness changes also result from the fact that both the upper and lower contacts of the lowertill are affected by localized stratigraphic variations in the adjacent units. This is more the case

for the contact with the underlying stratified drift in the southern and western parts of the sitethan for the contact with the overlying inter-till zone where the contact typically is subtle orgradational.


USCS Textural Classification. The lower till typically is a CL material. In places, however, ithas slightly less plasticity and is classified as a CL-ML material.

Atterberg Limits. Liquid limits in the lower till range from 18 to 25 (Table 4-3). Plastic limits

range from 12 to 16. The plasticity index ranges from 6 to 11. Atterberg results for the lowertill are quite similar to those for the upper till.

Grain Size Distribution. Table 4-3 shows that the principal textural component in the lower till

is silt which ranges from 34.7 to 43.3%. The major secondary component is sand which ranges

from 27.8 to 38.7%. In the case of the undisturbed samples from boring C91-1, however, there

is slightly more sand than silt. Clay is a significant minor textural component of the lower till,ranging from 13.6 to 25.5%. Gravel contents varies from 1.5 to 16.6%.

Hydraulic Conductivity. Hydraulic conductivities determined in the laboratory on eightundisturbed samples of the lower till taken within the landfill footprint are extremely low, ranging

from approximately 1.3 x 10^ to 3.1 x 10"8 cm/sec. These values fall within a narrow range withthe average being about 1.9 x IQ* cm/sec. Four samples of the lower till from outside thefootprint also were analyzed. One sample (from boring C91-4) had a laboratory-derived value

for hydraulic conductivity of 4.5 x 10"7 cm/sec, which is uncharacteristic for the lower till (see

Table 4-3). Moreover, that analytical result is inconsistent with the physical properties of the


the value derived is a statistical outlier. Such material cannot have a hydraulic conductivity of

4.45 x 10"7 cm/sec, based on experience with similar till samples at this site. In order to provide

further evidence to support this assertion, a split spoon sample (45.0 - 46.9 ft) from boring C91-4

was tested. The sample was trimmed, placed in a triaxial chamber, back saturated and tested inthe same manner as a Shelby tube or waxed sample. The value of hydraulic conductivity derived

was 3.91 x 10^ cm/sec as shown on the laboratory report which is included in Appendix F.

Results of in-situ permeability tests on four wells installed in the lower till range from 1.5x 10"7 cm/sec to 3.1 x 10"7 cm/sec. The laboratory tests are designed to measure the verticalhydraulic conductivity of the till whereas the field tests measure hydraulic conductivity in thehorizontal direction.

Moisture Content and Dry Unit Weight. The moisture content of lower till samples in Table 4-3

ranges from 9.3 to 14.1 percent. Dry weight varies from 123.71 to 134.10 pounds per cubic foot.

As seen on the boring logs in Appendix C, 1035 sand classifications range from silty sands

(SM) to fairly clean well-graded sand and gravel (SW). Poorly-graded sands (SP), and bothpoorly-graded, and well-graded sands with silt (SP-SM and SW-SM, respectively) also are

represented. Laboratory results of 1035 sand samples from borings C91-4X (SP-SM) and 90-9D

(SM) are included in Table 4-4.

Geotechnical test results on materials from three minor interbeds within the lower till areincluded in Table 4-3. These samples were selected for characterization because they are typicalof minor interbeds that are separately described on the boring logs but are included within thelarger mapping units.

The ML material from boring 91-9Y is representative of what appear to be lacustrine silts,and of silts that have gradational contacts with adjacent sand units. It is also similar to some of

the materials described as glacial backwater deposits (those that are quite uniform in textural


composition and non-plastic or very low in plasticity). Its measured permeability is 1.1 x 10"7

cm/sec.

The SC-SM material from boring 91-9Y is distinguished by its slightly higher percentage

of sand and gravel-sized constituents and slightly lower percentage of clay (compared to typicaltill samples) which contribute to its lower plasticity and higher dry unit weight. Material of this

type usually would be described on the boring logs as "very hard sandy till." Despite itsengineering group classification as a silty or clayey sand, this over-consolidated till has very low

permeability (3.8 x 10"8 cm/sec).

The CL material sampled from 69.7 to 70.7 feet in boring 90-2 differs considerably fromthe lower till surrounding it. It has less sand, almost no gravel, and considerably more clay,when compared to lower till samples. Having a similar but slightly lower plastic limit, its liquidlimit and plasticity index contrast sharply with those of all of the other samples. The high clay

content largely accounts for these differences as well as for the low dry unit weight As mightbe expected, measured permeability is quite low (2.6 x 10"* cm/sec). Material of this type would

be described as sandy clayey silt. It is recognized as being more clayey than the adjacent till,possibly "sticky" in part. This material appears to be part of a lake-fill sequence that was quitevariable in composition. Overlying beds include some with black streaks and laminae that appearto be organic in origin.

4.1.4 Stratified Drift


Below the thick aquitard of ground moraine comprised of the upper till, the inter-till zone,and the lower till, is another thick more-complex sequence of glacial drift that is partly to mostlystratified. This stratified drift consists of silty sand, sand, sand and gravel, sandy silt, clayey silt,silty clay, till, reworked till, and other till-like cohesive materials. In places, the silty sand or

sand zones are weakly cemented. Many of the saturated sands in the deeper borings are


extremely dense. Some of the sand and gravel beds also are cemented. In some borings, beds

that are described as sand and gravel were sufficiently cohesive and dense that they did not

appear to be saturated in spite of the fact that they occurred below the water table. Compact and

knitted are textural terms that have been used on the boring logs to describe materials of this

type.

In most of the site borings, a silty sand, sand, or sand and gravel is found at the base ofthe lower till at a fairly consistent elevation (1010 ±5 feet). In other places, particularly to the

south and east, non-till cohesive materials such as clayey silt or silty clay are present at the baseof the lower till. Often this contact is recognized by a color change from gray to shades of tan,brown or green. In some borings, exact placement of the base of the lower till or the contactwith the stratified drift is difficult. This is particularly the case if sand beds in the stratified driftare few and thin and nearly all of the cohesive materials are till or till-like, and similar inappearance to the lower till.

Below most of the Garkco site, the stratified drift sequence consists mostly of sand orsand and gravel (borings 92-27DD and 92-14DD). However, both till and non-till cohesivematerials are significant interbeds (cross sections A-A' through G-G', Plates 14 through 21). Tothe south and east, however, the thickness ratio of cohesive materials to sand, and sand and

gravel beds increase within the stratified drift sequence. For example, in borings 92-23 and 91-1,non-cohesive beds constitute less than 15% of the total thickness of the stratified drift sequence.


The stratified drift includes all materials from the base of the lower till to bedrock. Thethickness of this sequence ranges from about 58 feet in boring 92-23 to about 114 feet in boring92-2ID. As is the case at boring 92-23, the upper part of the stratified drift sequence has been

truncated by erosion at borings that start below the elevation of the base of the lower till.


Either permeable elastics (sand or sand and gravel) or cohesive materials that may be facies

equivalents (clayey silt or silty clay) appear to be present everywhere beneath the proposedClarkco site, but the thickness of saturated permeable beds decreases significantly to the northeast

(cross sections A-A', B-B', C-CO and pinches out almost entirely to the south (cross section G-

G' and borings 91-1 and 92-23).


Much of the description of the physical properties of the stratified drift sequence will focuson the thick sand and sand and gravel sequence that is regarded as the uppermost aquifer for theClarkco site.

USCS Textural Classification. As seen in Table 4-4, many of the sand or sand and gravel

samples obtained from the stratified drift sequence are classified as a silty sand (SM). This is

particularly true of its upper part. Within the main body of the thick sand and gravel sequence,there appears to be a general trend of coarsening with depth and to the west. The coarser-grained

layers within the sequence often could not be sampled effectively because the coarser gravels and

particularly, the numerous cobbles blocked the sampling devices. As a result, the coarser

classifications such as GP and GW or SP and SW are under-represented in the sieve analysesbecause they could not be retrieved. Drilling indications were used to assign USCSclassifications where sample recovery was lacking. In this way, the boring logs reflect observed

variations in the types of granular materials encountered, and in their textural classifications.

Cohesive materials also are included within the stratified drift. In areas where they are notthe dominant material type, they occur as interbeds of till or re-worked till (mostly CL withlesser amounts of CL-ML), or silt (ML) and as interbeds or laterally-equivalent cohesive

materials that generally are described on the boring logs as alluvial materials. Two examples of

the latter are listed in Table 4-3 (boring C91-3, sample WS-3 and boring C91-4, sample WS-2).The alluvial materials are finer-grained and more uniformly graded than till samples, and all are

classified CL. An example of a till or re-worked till interbed is the 112.0 - 112.5 foot sample


from boring C91-9 listed in Table 4-4. This sample is classified as a CL material of low

plasticity. The 28.2 - 29.7 foot-sample from boring C91-5D is a till sample from the stratified

drift sequence. It also is a CL material (Table 4-4).

Atterberg Limits. The stratified drift sequence underlying most of the Clarkco site consistspredominantly of sand or sand and gravel deposits that generally are non-plastic. However, inmany borings, till or other cohesive units are significant interbeds. Till and/ or low-permeability

alluvial deposits are the predominant material type underlying most of the area at the southwestcorner and south of the proposed landfill. The cohesive materials in the stratified drift sequence

have plasticity characteristics that are in the range of similar materials found in the overlyingground moraine. Stratified drift materials described as till, re-worked till, or glacial backwaterdeposits are expected to have Atterberg limits within the range defined for the upper and lowertills and the inter-till zone (liquid limits 25-18; plastic Limits 16-11, and plasticity indices 11-6,Table 4-3). The 112.0 foot sample from boring C91-9 is an example of a till interbed (Table 4-4). The 28.2 - 29.7 foot sample from boring C91-5D (Table 4-3) is an example of a till sample

from the stratified drift sequence. Stratified drift materials described as alluvial or clayeylacustrine (clayey silts or silty clays) will have liquid limits of about 35-36, plastic limits ranging

from 13-18 and a plasticity index in the range of 17-23 based on lab analyses of the 83.1 - 84.2

foot sample from boring C91-3 and the 56.5 - 57.5 foot sample from boring C91-4. Stratifieddrift beds described as "bull's liver", silt, sandy silt, or silty lacustrine are non-plastic and

classified in the USCS system as an ML material. The 73.0 - 73.5 foot sample from boring C91-1 is an example (Table 4-4). This sample exhibited "bull's liver" consistency and was part of asandy silt and silty sand sequence.

Grain Size Distribution. As might be expected for heterogeneous granular materials, there isconsiderable variation in grain size. For the SM materials, which are more common in the upper

part of the stratified drift, sand percentages are seen to range from 54.4 to 86.1 (Table 4-4).Combined silt and clay percentages range from 12.1 to 30.3. Gravel percentages typically aretrace amounts (less than 10%), but are as high as 33.2 percent in one sample classified as SM.


By definition, the non-cohesive materials that do not fall into the SC, SM, or SM-SC (or

GC, GM, or GM-GC) classifications have combined silt and clay percentages that total less than

12 percent. Six uppermost aquifer samples listed hi Table 4-4 fall into this category. Three arelisted as SP-SM; the others are classified as SW-SM, SP, and GP materials. Nearly all

combinations and gradations of sand and gravel sizes can be found in some part of the sand, and

sand and gravel sequence. Substantial textural variation commonly occurs within each boringand between adjacent borings. The grain-size distribution of cohesive interbeds, although highly

variable, is characteristic of the material type described. (See the preceding discussion of

Atterberg limits; the same comments and examples apply.)

Hydraulic Conductivity, Except for cohesive zones and interbeds, the sand and sand and gravelsequence within the stratified drift generally is highly permeable. The saturated part of this thickclastic sequence (below the well-defined water table at about elevation 985) is considered to be

the uppermost aquifer for the Clarkco site. The unsarurated upper part of this sand, and sand andgravel sequence is considered to be part of the same geologic deposit and has similar physical

properties. As shown on the hydrogeologic cross sections (Plates 14-25) the upper part of this

clastic deposit has been included as part of the uppermost aquifer system, even though it isunsarurated and is not an aquifer. Discussion of the hydraulic conductivity of the uppermostaquifer is in Section 5.3.1 of this report. Laboratory-determined hydraulic conductivities of

cohesive beds that are part of the stratified drift sequence range from approximately 1.4 x 10"7

to 1.8 x 10'9 cm/sec (Table 4-3).

4.1.5 Bedrock


Limestones and dolomites of the middle to lower Silurian system underlie the Clarkco siteand most of German Township (Norris and Fiddler, 1973). Carbonate bedrock was encountered

in all in-site borings that penetrated the entire thickness of the glacial drift.



Reported thicknesses of the carbonate aquifer average about 130 feet. Twelve of the on-siteborings were drilled to the top of bedrock. Carbonate bedrock was encountered in all of these

borings at the following approximate elevations: 955 in PW-1, 925 in PW-2, 926 in PW-3, 916in 91-1, 899 in 92-20D, 904 in 92-21D, 912 in 92-22DD, 924 in 92-23, 934 in 92-27DD, 916

in 92-5DD, and 909 in 92-14DD. On the basis of these borings , the maximum relief on thebedrock surface is about 56 feet in the vicinity of the Clarkco site. The regional carbonateaquifer is present below the Clarkco site and throughout Clark County except where removed by

erosion associated with buried bedrock valleys.


Carbonate bedrock encountered in the Clarkco borings generally is described as light tomedium gray, slightly bluish white or bluish gray, tan, or bluish-tannish gray microcrystalline to

granular dolomite. Hydraulic conductivities for wells completed in the carbonate aquifer

typically range from 2 x 10"3 to 5 x 10"3 cm/sec (Norris and Fidler, 1973).

42 Geomorphology

The proposed Clarkco facility is located in an upland till area that is drained to the north

by Storms Creek and to the south by Chapman Creek. Surface topography within the footprintof the proposed site is mostly gently sloping to gently rolling. Along parts of the exteriorborders of the eastern one half of the footprint, the topography is moderately sloping. Slope issteep in the area associated with the ravine in the southeast corner of the footprint. Most of theconspicuous relief results from headward erosion of surface drainage courses which flow from

the site to the north, south, and east. A small farm pond is present just north of the southernboundary of the proposed footprint (south of boring 89-6).


4.3 Structural Geology

Correlation of the site boring logs indicates that the unconsolidated materials generally areflat-lying and show no indications of structural deformation. Bedrock is not exposed at the site.There are no faults mapped or known at the site.


NORTH SOUTH

GLACIALDRIFT

GROUNDMORAINE

STRATIFIEDDRIFT

THICKNESS58-114'

UPPER TILLTHICKNESS 0-60'

INTER-TILL ZONE I05° SANDTHICKNESS 0-20'

LOWER TILLTHICKNESS -0-40'

SILTY SAND, <T CLAYEY SILTSAND and GRAVEL ^> and SANDYwith SAND and ^v. SILT withCOHESIVE INTERBEDS < SILTY SAND

INTERBEDS->( ALLUVIAL)

TILL and otherCOHESIVE MATERIALS withSAND, SILTY SAND andSAND and GRAVEL INTERBEDS

BEDROCK MIDDLE to LOWER SILURIANDOLOMITES and LIMESTONES

Figure 4-1 Generalized Stratigraphic Column for the Clarkco Site

92-15X

92-2X

1A/07 PRESENT "

\ ^90^^ 92-4X®V ^~- „. \

-5 \ -X192-19X— 92-18 ^X /

92-18X* \

1 090-130/\

\

/

'

)90-8X

090-80

PRESENT /989-6

l>

92-HX 92-14TP-O \

91-9Z 90-9DD '

. /91-9^90-gX I

K

' X

//'

PROPOSEDi LIMIT OFi SOLID WASTE-

) V ";\ /VJ

• C91-7

OC91-2DC92-1X*

C91-1

92-200 o]

92-25YB^92_25XB

89-7« 92-33Y

-3« LEGEND

89-8

092-28X

-+-PW-3

§ 92-290892-29X

1 92-29

Z' 92"31A AC91-4ZZi °92-31X C91~4*fe"-4X4V

f±, QC92-5DD

gl °C91-50

Q_OCt

^^*\ ^ UMfT OF SAND ZONE^^ *^^^

ft 7 THICKNESS OF SANDV (MIH.TPLE NUMBERS

INDICATE INDIVIDUALTHICKNESSES)

1

CL I

1 ' o 200 400

• 89-° 92-21DOl—— ~ ~ - __ SCALE IN FEET

ZONE N FEETIN A COLUMN

BED

_ ———— ——— • ——————— '

Figure 4-2. Thickness and Areal Extent of 1092 Sand

r

<r

1 /---

N

/. \

y M

\

1 -

V

01

CO

\X

ID

I \»

*

^

> /I1

> :/ 1 \ i >' i N ^

__ . NOT PRESENT

PROPOSEDLIMIT OFSOLID WASTE

NOT PRESENTTOPOGRAPHIC CONTOUR OFELEVATION AT WHICH SANDOCCURS (DEFINES OUTCROPAREA WHO?E SANO IS PRESENT)

LIMIT OF SAND ZONE

THICKNESS OF SANO ZONE IN FEET(MULTPLE NUMBERS IN A COLUMNINOCATE INDIVIDUAL BEDTHICKNESSES)



92-24Z 0.3©92-24Y

NOT PRESENT

91-9Z 90-9DD

TOPOGRAPHIC CONTOUR OFQJEVATION AT WHICH SANDOCCURS (DEPNES OUTCROPAREA WHERE SAND IS PRESENT)

LIMIT OF SAND ZONE

THICKNESS OF SANO ZONE IN(MULTPLE NUMBERS IN A COLUMNINDICATE INDIVIDUAL BEDTHICKNESSES)

200 4OO

SCALE IN FZET


UD S zr o'

C/)

(0 a 3 a. a> o m X *-t- a> O m o CO a

Table 4-1SUMMARY OF TEST BORINGS

PROPOSED CLARKCO LANDFILL

Boring/WellNumber

GroundElevation

rftvCompletion

Zone

Depth toM ^pM •

Sand Pack:,:-M^Y

Depth ofScreenedInterval

(ft)

BoringDepth

(ft)

CompletionDate

RECONNAISANGE STUDY

89-189-289-389-489-589-689-789-889-9

8" PRO]

PW-1PW-2PW-3

1106.21109.61111.91077.81071.01087.91081.41082.61055.2

UMAUMAUMAUMAUMAUMAUMAUMAUMA

__— -— —__— —- —— -— —— —

__— -— —— —— —— —— -— —— —

102.0135.5125.5115.0100.0115.0100.5111.080.0

01/10/8912/14/8812/16/8812/29/8801/05/8912/20/8801/03/8912/23/8812/21/88

»0CrnON WEI1£ FOR PIMJS^

1108.71069.31075.0

UMAUMAUMA

87.098.0

115.0

97.0-122.0107.0-117.0120.0-130.0

155.0145.0149.5

03/09/9006/07/9006/08/90

PHASE I CLARKCO HYDROGEOLQOIC INVESTIGATION

90-190-290-390-490-590-6W90-6X90-6Y90-6Z90-6D90-7X90-7Y90-7Z90- 7D90-8X90-8D90-9X

1095.31087.01082.41088.31101.51102.91102.31102.11102.91102.21069.01069.21070.21069.11082.51082.91093.9

UMAUMAUMAUMAUMA

1092 Sand1070 Sand1077 Sand1050 Sand

UMAUMA1

1035 Sand1060 Sand

UMA1060 Sand

UMA1070 Sand

__— -— —— —— —8.1

30.820.552.5

111.5— —

26.86.0

82.021570.019.9

__— —— -— —— —

9.0-14.032.8-35.322.5-27.554.5-59.5

115.8-120.8__

28.8-31.37.3-9.8

87.0-92.024.0-29.072.6-77.622.4-27.4

87.588.085.088.098.515.037.529.063.0

121.059.031.515.593.030.082.028.0

10/24/9011/13/9011/15/9011/08/9011/07/9012/14/9011/29/9012/13/9012/14/9012/19/9012/05/9012/07/9012/10/9011/19/9012/11/9011/27/9012/21/90

- - Indicates borehole was pluggedUMA = Uppermost aquifer

1 Attempt to install well in perched zone above saturated portionof uppermost aquifer, Targeted zone not encountered at boring location.

bornglst.wk3 Page 1 of 4

Table 4-1 (cont'd)SUMMARY OF TEST BORINGS


Boring/WellNumber

91-9Y91 -9Z90-9D90-9DD90-10X90-10Y91-10D90-1190-1290-13D90-14D90-15

GroundElevation

(m1093.81093.71094.11094.11095.71095.71095.61107.01097.41089.81061.71074.4

CompletionZone

1035 Sand1077 Sand

UMAUMA

1050 Sand1077 Sand

UMAUMAUMAUMAUMAUMA

Depth toTop of

Sand Pack(ft)

56.014.575.9

108.245.512.5

118.0— —— —

104.083.5

— —


(ft)

58.0-63.016.8-19.385.3-90.3

110.8-115.847.5-50.014.0-19.0

122.0-127.0— -— -

105.5-110.586.4-91.4

— —

BoringDepthrm67.021.096.5

116.058.021.0

127.098.0

103.0111.093.097.0

CompletionDate

01/25/9101/26/9110/27/9012/14/9011/28/9012/12/9002/26/9111/30/9012/17/9012/11/9012/14/9012/11/90

BORING TO EVALUATE AND CHARACTERIZE UOCAL GEOEOGY

91-1 977.0 Bedrock -- -- 61.1 02/19/91

WiASE H GLARKX:0 HYDROGECtfXDGIC IhTVESTIGAI^ON

C91-1C91-2DC91-3C91-4C91-4XC91-4YC91-4ZC91-5DC91-6C91-7C91-8XC91-8YC91-8DC91-9

1057.91086.81087.21070.51069.51069.81070.41035.41040.41074.21094.61095.01094.91107.8

UMAUMAUMAUMA

1035 Sand1050 Sand1050 Sand

UMAUMAUMA

1050 Sand1070 Sand

UMAUMA

_ _100.0- —--

31.519.012.075.8- —--40.119.0

106.5—~ —

— _105.8-110.8

— ---

33.0-38.023.0-28.014.0-19.078.0-83.0

----

42.5-47.521.1-26.1

110.5-115.5— —

75.5111.0100.0102.039.029.019.584.5

101.790.548.029.0

116.0130.5

07/09/9107/02/9106/21/9106/27/9107/24/9107/24/9107/25/9107/03/9107/11/9107/17/9107/22/9107/23/9106/27/9107/15/91

rLARKf*VHVf>ROGEOLOGIC REPORT SUBMITTED JANUARY 1992

- - Indicates borehole was pluggedUMA = Uppermost aquifer




Boring/WellNumber

GroundElevation

(mCompletion

Zone

f^&to;::if^jp-pr.Sand Pack••mm^1'


(ft)

BoringDepth

(ft)

CompletionDate

PHASE III CLARKCO HYDROGBOLOOKJ INVESTIGATION (JULY 1992 WORKPLAN)BASED ON REPORT RÎEW COMMENTS

WELLS AND BORINGS USEI> 1^ 15BLINEATE AND CHARACTERIZEÂÛKA^Î) 2XM

92-2X92-4X92-11X92-14X92-15XC92-1XC92-9XC92-9Y92-16X92-17XB92-17Y92-18**92-18X**92-19X**92-24Y92-24Z92-25XB92-25YB92-26X92-28X92-2992-29X92-31X92-31Y92-3292-33X92-33Y

1087.11088.21107.81061.71073.91059.01107.71107.71077.91100.31099.81097.61097.61090.11112.01111.61055.11055.41082.31075.71071.81072.11075.81075.41080.41068.91069.9

1035 Sand1035 Sand1050 Sand1035 Sand1035 Sand1035 Sand1050 Sand1070 Sand1035 Sand1035 Sand1050 Sand1035 Sand1050 Sand1035 Sand1050 Sand1092 Sand1035 Sand1050 Sand1060 Sand1050 Sand1035 Sand1050 Sand1035 Sand1050 Sand1035 Sand1035 Sand1050 Sand

îKlTilE TILL SEQUENCE

50.455.555.721.932.819.365.031.439.7— —

50.8— -

48.153.059.815.0— -— —

20.029.0— -15.041.520.0— —26514.0

53.5-58.558.6-63.658.0-63.024.2-29.235.0-40.022.5-27.568.0-73.034.0-39.042.7-47.7

_ _ *54.0-59.0

_ _ **

50.5-56.555.0-60.062.4-67.417.4-22.4

_ _ *

_ _ *

23.0-28.030.9-35.9

- —16.9-21.945.7-48.222.8-27.8

- —28.8-33.816.0-21.0

59.564.064.530.044.029.075.340.048.578.060.473.058.062.069.024.032.010.549.035.936.422.349.728.057.838.023.0

06/03/9206/01/9205/29/9206/29/9205/27/9205/28/9206/16/9206/23/9206/04/9208/10/9208/06/9208/13/9208/17/9208/03/9207/20/9207/21/9207/22/9207/22/9206/30/9209/16/9209/16/9209/17/9209/22/9209/23/9209/23/9209/24/9209/24/92

— — Indicates borehole was pluggedLIMA = Uppermost aquifer

* Targeted formation was not present' ' Scheduled as a boring only




Boring/WellNumber

GroundElevation(m

CompletionZone

Depth toTop of

Sand Pack(ft)


(ft)

BoringDepth

(ft)

CompletionDate

WELLS AND BORINGS USED TO CHARACTERIZE THE UPPERMOSTAQUIFER AND ESTABLISH ITS RELATIONSHIP TO THE LOCAL SETTING

C92-5DD92-14DD92-20D92-21D92-22D92-22DD92-2392-23D92-27DD92-29DB

1035.41061.31064.71056.01002.61002.4982.0982.4

1082.81073.2

UMA (B)UMA (B)UMA (B)UMA (B)

UMAUMA (B)BedrockUMA

UMA (B)UMA

111.1107.8149.7113.023.0743

21.0131.0

1123-117.31103-1153152.9-157.9115.3-120326.0-31.077.0-82.0

24.2-29.2133.0-138.0

123.0155.2167.8152.533.091.560.029.5

151.0102.5

08/05/9207/31/9207/09/9207/23/9208/25/9208/24/9207/15/9207/16/9209/17/9209/25/92

OFF SITE BORINGS

92-3092-3492-35DD

1043.0992.2

1092.7

BedrockBedrock

UMA (B)

Bedrock w— -

134.4

ell installed1

— —138.4-148.4

110.569.0

152.0

09/17/9209/29/9212/08/92

WELLS SCREENED IN GLACIAL TILL FOR IN-SITU PERMEABILITY TESTING

92-7TP92-10TP92-14TPC92-8TP

1069.51095.51061.71094.4

TillTillTillTill

32.077.247.950.0

32.9-36.978.7-83.748.7-53.751.5-56.5

38.584.054.060.0

11/11/9211/18/9211/24/9211/10/92

1 After sampling to 110.5' with an auger rig, a fluid-rotary rig was moved in to ream and deepen the boring in order to installa conventional domestic water well in the bedrock aquifer.

- — Indicates borehole was pluggedUMA = Uppermost aquifer(B) = Drilled to bedrock, but screened in uppermost aquifer.

' Targeted formation was not present* ' Scheduled as a boring only


Table 4-2SUMMARY OF TEST 2-INCH WELLS ARRANGED BY CLUSTER


WellNumber

90-6W90-6Y90-6X90-6Z90-6D

90- 7Z90-7Y92-7TP90-7D

90-8X90-8D

91 -9Z90-9X91-9Y90-9D90-9DD

90-10Y90-10X92-10TP91-10D

90-13D

92-14X92-14TP90-14D92-14DD

C91-2D

C91-4YC91-4ZC91-4X

C91-5DC92-5DD

GroundElevation

cm1102.91102.11102.31102.91102.2

1070.21069.21069.51069.1

1082.51082.9

1093.71093.91093.81094.11094.1

1095.71095.71095.51095.6

1089.8

1061.71061.71061.71061.3

1086.8

1069.81070.41069.5

1035.41035.4

CompletionZone


UMA

1060 Sand1035 Sand

TillUMA

1060 SandUMA


UMAUMA

1077 Sand1050 Sand

TillUMA

UMA

1035 SandTill

UMAUMA (B)

UMA


UMAUMA (B)

Depth toPop of

Sand Pack(K>

8.120.530.852.5

111.5

6.026.832.082.0

21570.0

14.519.956.075.9

108.2

12.545.577.2

118.0

104.0

21.947.983.5

107.8

100.0

19.012.031.5

75.8111.1


(ft)

9.0-14.022.5-27.532.8-35.354.5-59.5

115.8-120.8

7.3-9.828.8-31.332.9-36.987.0-92.0

24.0-29.072.6-77.6

16.8-19.322.4-27.458.0-63.085.3-90.3

110.8-115.8

14.0-19.047.5-50.078.7-83.7

122.0-127.0

105.5-110.5

24.2-29.248.7-53.786.4-91.4

110.3-115.3

105.8-110.8

23.0-28.014.0-19.033.0-38.0

78.0-83.0112.3-117.3

BoringDepth

__mi___15.029.037.563.0

121.0

15.531.538.593.0

30.082.0

21.028.067.096.5

116.0

21.058.084.0

127.0

111.0

30.054.093.0

155.2

111.0

29.019.539.0

84.5123.0

CompletionDate

12/14/9012/13/9011/29/9012/14/9012/19/90

12/10/9012/07/9011/11/9211/19/90

12/11/9011/27/90

01/26/9112/21/9001/25/9110/27/9012/14/90

12/12/9011/28/9011/18/9202/26/91

12/11/90

06/29/9211/24/9212/14/9007/31/92

07/02/91

07/24/9107/25/9107/24/91

07/03/9108/05/92

UMA = Uppermost Aquifer

2inclstr.wk3 Page 1 of 3

Table4-2(cont'd)SUMMARY OF TEST 2-INCH WELLS ARRANGED BY CLUSTER


WeUNumber

C91-8YC91-8XC92-8TPC91-8D

92-2X

92-4X

92-11X

92-15X

C92-1X

C92-9YC92-9X

92-16X

92-17Y

92-18X

92-19X

92-20D

92-21D

92-22D92-22DD

92-23D

92-24Z92-24Y

92-26X

92-27DD

GroundElevation

(ft)

1095.01094.61094.41094.9

1087.1

1088.2

1107.8

1073.9

1059.0

1107.71107.7

1077.9

1099.8

1097.6

1090.1

1064.7

1056.0

1002.61002.4

982.4

1111.61112.0

1082.3

1082.8

CompletionZone

1070 Sand1050 Sand

TillUMA

1035 Sand

1035 Sand

1050 Sand

1035 Sand

1035 Sand

1070 Sand1050 Sand

1035 Sand

1050 Sand

1050 Sand

1035 Sand

UMA(B)

UMA (B)

UMAUMA (B)

UMA

1092 Sand1050 Sand

1060 Sand

UMA(B)

Depth toTop of

Sand Pack(ft)

19.040.150.0

106.5

50.4

55.5

55.7

32.8

19.3

31.465.0

39.7

50.8

48.1

53.0

149.7

113.0

23.074.3

21.0

15.059.8

20.0

131.0


(ft)

21.1-26.142.5-47.551.5-56.5

110.5-115.5

53.5-58.5

58.6-63.6

58.0-63.0

35.0-40.0

22.5-27.5

34.0-39.068.0-73.0

42.7-47.7

54.0-59.0

50.5-56.5

55.0-60.0

152.9-157.9

115.3-120.3

26.0-31.077.0-82.0

24.2-29.2

17.4-22.462.4-67.4

23.0-28.0

133.0-138.0

BoringDepth

(ft)

29.048.060.0

116.0

59.5

64.0

64.5

44.0

29.0

40.075.3

48.5

60.4

58.0

62.0

167.8

152.5

33.091.5

29.5

24.069.0

49.0

151.0

CompletionDate

07/23/9107/22/9111/10/9206/27/91

06/03/92

06/01/92

05/29/92

05/27/92

05/28/92

06/23/9206/16/92

06/04/92

08/06/92

08/17/92

08/03/92

07/09/92

07/23/92

08/25/9208/24/92

07/16/92

07/21/9207/20/92

06/30/92

09/17/92



Table4-2(cont'd)SUMMARY OF TEST 2-INCH WELLS ARRANGED BY CLUSTER


WellNumber

92-28X

92-29X

92-31Y92-31X

92-33Y92-33X

92-35DD

GroundElevation___mi____

1075.7

1072.1

1075.41075.8

1069.91068.9

1092.7

CompletionZone

1050 Sand

1050 Sand

1050 Sand1035 Sand

1050 Sand1035 Sand

UMA (B)

Depth to•Top of

Sand Pack(ft)

29.0

15.0

20.041.5

14.0265

134.4


(ft)

30.9-35.9

16.9-21.9

22.8-27.845.7-48.2

16.0-21.028.8-33.8

138.4-148.4

BoringDepth

__Jft)____

35.9

22.3

28.049.7

23.038.0

152.0

CompletionDate

09/16/92

09/17/92

09/23/9209/22/92

09/24/9209/24/92

12/08/92

UMA - Uppermost Aquifer


Table 4-3GEOTECHNICAL TEST RESULTS FOR UNDISTURBED SAMPLES


BoringSampleType'

SampleInterval

•'-' :':.-ti>sat"^: •?•:Classification

A T T B R B E R G

LiqnWLimit

PlMtlCLimit

PlasticityIndex

NaturalM:<i>'i»tBv£;Content

Dry-UnitWeight

fpcf)

S A N D S I Z E S

Coarse• " ". •':•. '; ' -• • • • ' . • • •

Medium Fine

W ASH G R AD A T I O N

Gravel Sand Silt ClayPermeability

(cm/sec)

UPPER TILL

90-290-490-590 -6X90-6YC91-7C91-990-10X90-10Y90-1590-15

STSTSTSTSTST

WS-1WS-1

STSTST

23.0 - 25.023.0 - 25.018.5 - 20.535.5 - 37.521.0 - 23.015.5 - 17.350.5 - 51.724.0 - 25.014.0 - 15.413.0 - 14.023.0 - 24.5

CLCLCLCLCLCLCL

CL-MLCL-ML

CLCL

i

C91-390-1190-13

WS-1WS-1WS-1

48.3 - 49.567.0 - 68.039.0 - 40.0

CLCLCL

2221212121212320182120

1313121313111313121212

9898810107698

10.611.311.610.311.610.08.012.39.99.011.0

131.46130.02133.86133.60131.71134.33131.06127.65136.99133.83131.83

4.54.14.85.86.34.410.86.49.85.44.8

INTER -TILL ZONE

202121

:-V' ; : ••-;r-::v

121313

888

11.08.79.2

129.43136.52134.24

4.97.04.9

11.09.69.29.89.39.89.710.610.910.111.5

18.617.118.417.015.218.416.618.620.418.622.2

5.05.17.315.713.310.17.56.25.96.93.4

34.130.832.432.630.832.637.135.641.134.138.5

40.944.140.034.437.339.435.340.936.638.739.4

20.020.020.317.318.617.920.117.316.420.418.7

3.034x10"'2.169x10-'2.269x10-'2.258x10-*3.062X10'8

2.382 x 10'8

1.194x10-*6.329x10-*6.326x10-'2.765x10''1.810x10-"

8.611.411.5

18.919.218.9

5.84.95.6

32.437.635.3

40.539.840.1

21.317.719.0

1.337x10-'7.169x 10-'1.539xlO-8

ST = Shclby TubeWS = Waxed Continuous Sampler Sample

undistb.wkS Page 1 of 2

Table4-3(cont'd)GEOTECHNICAL TEST RESULTS FOR UNDISTURBED SAMPLES


... .. , . . . , . . . .Ii

BoringSampleType'

SimpleInterval

usesClassification

A T T E R B E R G

LiquidLimit

PlasticLimit

PlasticityIndex

NaturalMoistureContent

Dry UnitWeight

fpcO

S A N D S I Z E S

Coarse Medium Fine

W A SH G R AD ATI O N

Gravel Sand Silt ClayPermeability

(cm/sec)

.. '-.• : - . • : - -.:::•:: : : • • • . ' ••••.•': :: . : : : ; ." ' -•:- • ' LOWER TILL • V . . ' : : . -: :':^'-< - ' : ' '^ •

C91-190-390-490-4C91-490-5C91-6C91-8D90-1190-1290-1390-14

WS-2WS-3WS-1WS-2WS-1WS-2

STWS-1WS-2

STSTST

50.5 - 52.071.8 - 73.065.0 - 66.076.0 - 77.036.5 - 37.579.5 - 80.520.0 - 22.256.7 - 58.191.2 - 92.183.0 - 84.378.0 - 80.048.0 - 48.7

CLCL

CL-MLCLCLCLCLCLCLCLCLCL

222118202323252221222123

131212121213161312131214

99681110999999

9.59.310.312.911.311.414.19.910.39.811.211.2

129.78134.10131.04128.37127.68132.18123.71133.83127.63133.31131.69131.51

9.05.65.13.13.25.56.05.85.56.16.55.1

10.710.111.79.68.611.011.08.612.010.611.611.6

19.017.520.415.120.319.317.819.417.615.917.819.3

10.116.68.33.41.54.37.27.810.39.45.812.4

38.733.237.227.832.135.834.833.835.132.635.936.0

37.634.738.943.342.041.136.439.237.637.437.937.7

13.615.515.625.524.418.821.719.217.020.620.413.9

4.254x 10"8

1.579x 10"8

2.760 x 10'8

1.285x10-"4.453 JclO'7

1.995x10-'3.285x10-'1.181x10-'1.517x 10"'1.920x10-"1.426x ID'8

3.098 x 10"'

LOWER TILL MINOR INTERBEDS

90-291-9Y91-9Y

WS-1WS-2WS-3

69.7 - 70.753.5 - 54.566.0 - 67.0

CLSC-SM

ML

3419

NP

1012NP

247

NP

19.17.813.7

108.06139.09124.52

0.927.11.0

4.99.85.3

19.815.424.1

0.24.81.2

25.752.330.4

38.531.752.8

35.611.215.6

2.586 x 10"8

3.795x 10-'1.112x10-'

STRATIFIED DRIFT COHESIVE INTBRBEDS

JC91-3C91-4C91-5D

WS-3WS-2WS-1

83.1 - 84.256.5 - 57.528.2 - 29.7

CLCLCL

363524

131813

231711

14.222.810.0

116.25105.94126.91

8.40.26.2

3.40.111.3

18.05.319.9

6.00.05.3

29.85.6

37.4

31.756.636.1

32.537.821.2

1.816x10-'2.562 x 10'8

1.406x 10"7

ST = Shelby TubeWS = Waxed Continuous Sampler Sample

undis ib .wk3 Page 2 of 2

GEOTECHNICALTable 4-4

TEST RESULTS FOR SAMPLES OF GRANULAR MATERIALSPROPOSED CLARKCO LANDFILL

Bo rineSampleType'

SampleInterval

usesClassifi-

cation

NaturalMoistureContent

SAND S I Z E S

Coarse Medium Fine

WAS H G R A D A T I O N

Gravel SandSilt

and ClayPlasticity

Index

SATURATED ZONES ABOVE THE UPPERMOST AQUIFER

C91-1

C91-4X

C91-4Z

90-6W

90 -6X

90-6D

90 -7Z

90-8D

C91-8Y

C91-8D

90-9D

90-10X

cssssssscscssscssscscscs

36-36.5

33.7-34.4

17.0-17.8

11.0-12.0

34.0-34.5

55.8-56.3

8.0-9.6

27.0-27.5

23.0-24.6

42.7-44.1

62.0-63.0

48.4-49.05

SM

SP-SM

SP-SM

SM

SP

SW-SM

SW-SM

SP

SM

SM

SM

SM

13.2

10.9

11.5

12.0

14.6

11.5

11.6

15.0

8.6

8.0

15.1

10.9

2.7

27.7

21.7

16.8

21.0

11.3

22.4

13.5

14.7

19.1

6.6

14.7

37.2

37.6

41.3

25.2

65.6

36.4

38.7

45.5

24.6

31.5

28.4

21.5

44.5

10.8

11.9

22.9

10.8

14.5

10.8

24.9

18.9

21.0

33.3

23.9

0.6

14.1

14.3

20.4

1.6

29.5

19.9

12.5

25.3

15.9

5.1

15.5

84.4

76.1

74.9

64.9

97.4

62.2

71.9

83.9

58.2

71.6

68.3

60.1

15.0

9.7

10.8

14.7

1.0

8.3

8.2

3.6

16.4

12.5

26.6

24.4

NP

NP

NP

NP

NP

NP

NP

NP

NP

NP

NP

NP

* SS = Split SpoonCS = Jar Sample from Continuous Sampler

granmatr.wk3 Page 1 of 2

Table 4-4 (cont'd)GEOTECHNICAL TEST RESULTS FOR SAMPLES OF GRANULAR MATERIALS


BoringSampleType*

SampleInteival

usesClassifi-

cation

NaturalMoistureeontent

SAND S I Z E S

Goainse Medium Fine

W A S H G R A D A T I O N

Gravel SandSilt

and Clay

————————Plasticity

Index

UPPERMOST AQUIFER

C91-1

C91-2D

C91-5D

90-6D

C91-7

90-7D

90-8D

C91-8D

C91-9

C91-9

90-9D

91-10D

91-10D

CS

CS

SS

CS

CS

csVCS \\-cs VCS

CS

CS

CS

CS

73.0-73.5

109.5-110.0

79.0-80.5

93.9-94.5

^S&fr=&*r90D-90.5

CO$$£-79.8

n'JO -riLt33Qflll4.0rVri -$ 'Z- c\rjdjB-rii2.5 'Iji&ty o\o^o

\T^ £-• "O

119.0\- 120.0\ _--—

ML

SP-SM

SP-SM

SP_

gP-SM \

20.9

19.8

13.4

9.1

17.1

@s^c/A i?2^ ,̂̂ ^\ 7.6

•\ sv^swjj^™E^*. \^afcfc

* C^J >23 SM7 ,̂ weCP c'i v

CT5 ?«SM -^ y?•G P %O\ if - •*"2jJ>* '̂

°\ 9'6

f\ 9.2

if^,\ nci -^\ 9-5^.T-H*J \7.0

\.8

""" 13.2

0.1

0.2

7.7

13.4

0.2

0.8

15.9

29.9

5.9

23.8

2.0

9.4

9.2

0.4

47.4

31.3

36.4

51.1

63.0

23.4

34.5

8.6

22.9

44.2

13.3

23.3

31.6

41.2

48.4

13.0

38.0

22.3

15.5

10.8

12.7

7.7

27.0

7.7

28.9

0.1

0.0

1.4

35.1

0.0

1.8

25.9

19.5

6.8

33.2

3.3

66.5

8.3

32.1

88.8

87.4

62.8

89.3

86.1

54.8

75.2

27.2

54.4

73.2

30.4

61.4

67.8

11.2

11.1

2.1

10.7

12.1

19.3

5.3

45.8 & 20.1

12.4

23.5

3.1

30.3

NP

NP

NP

NP

NP

NP

NP

NP

8

NP

NP

NP

NP

————————

* SS = Split SpoonCS = Jar Sample from Continuous Sampler

granmatr.wk3 Page 2 of 2

5.0 SITE HYDROGEOLQGY

5.1 Conceptual Model

Figure 5-1 is a hydrogeologic column for the Clarkco site based on the generalized

stratigraphic column (Figure 4-1) presented in Section 4.0. The lithology and physical properties

of each stratigraphic unit defined at the site are summarized on Figure 5-1 and their

hydrogeologic significance is described. The Upper Till, Inter-Till Zone and Lower Till are all

aquitards which comprise a single confining bed in which minor sand seams are present. The

minor sand seams constitute significant zones of saturation because they are potentially local

migration pathways, but are not sufficiently productive to be considered aquifers. The permeable

sand and gravel zones within the underlying stratified drift constitute the uppermost aquifersystem at the Clarkco site, the upper part of which is unsaturated beneath most of the site. This

uppermost aquifer is a local aquifer that pinches out in several directions. The underlying

bedrock system is a regionally-extensive aquifer. Because of the hydrogeologic similarity of the

tills which collectively make up the confining bed, there are only three hydrostratigraphic units

which constitute the hydrogeologic framework and ground-water flow regime at the Clarkco site.

The conceptual model presented here is an overview of the site characterization that is

presented in this section of the report. Figures 5-2 is a conceptual model illustrating the three

hydrostratigraphic units and the manner in which they control ground-water flow patterns at thesite. Significant zones of saturation within the till confining bed are local pathways for horizontal

migration which discharge at outcrop areas in the ravines or on the hillsides to the north, east,

and south. Recharge to the significant zones of saturation from precipitation occurs through theweathered tills where sand zones are within 20 to 25 feet of the surface. There is a strong

downward hydraulic gradient, but the dominant flow direction is horizontal because the horizontal

permeability of the sand seams is several orders of magnitude greater than the vertical

permeability of the till.


The uppermost aquifer system is unsaturated at the top due to the lack of local recharge

from precipitation through the confining bed. The dominant direction of ground-water flow

within the uppermost aquifer beneath the footprint of the proposed landfill is to the east and

northeast. The potential for ground-water flow in other directions beyond the limits of the

proposed landfill footprint is small by comparison due the lateral gradation to beds of lower

permeability within the stratified drift. The direction of flow within the regional bedrock aquifer

is generally west to east.

5.2 Significant Saturated Zones

The physical properties including hydraulic conductivity of the Upper Till, Inter-Till Zone,

and Lower Till are described in detail in this section. These units constitute a major aquitard as

demonstrated by the summary of physical properties on Figure 5-1, which also shows the

similarity of these units. As a practical matter, these units constitute a single confining bed and

the following detailed description of hydrogeologic characteristics is focused on the sand zones

which occur within it.

In order to fully characterize the hydrogeologic properties of saturated zones within the till

sequence, cluster wells were installed at several locations. Slug tests were performed on most

of these wells to determine the hydraulic conductivity of the sand zones.

Pump tests also were conducted on most of the wells that could not be bailed dry to verify

the slug test results and to determine the potential yield of these water-bearing zones, hi order

to determine whether or not they should be considered to be aquifers. Table 5-1 is a summary

of the results of all of the slug tests and pump tests that have been performed at the Clarkco site.

Results of the pumping tests indicate that none of the sand zones within the confining bed

produce enough water to be classified as an aquifer at this location. Most zones produce

significantly less than one gpm (see Table 5-1). Only wells 92-26X and 90-6Z would produce

more than one gallon per minute and the sustained yield of these wells for 24 hours was

computed to be 1.6 and 1.1 gpm, respectively. Well 90-6Z is located at the extreme northwest


comer of the proposed landfill and well 92-26X is located beyond the landfill footprint about 600

feet to the south.

The information on which the determination of sustained yield is based is summarized in

the "Pumping Test Data" columns on Table 5-1. Graphs and computations for the pumping tests

are presented in Appendix G. Wells which have no available drawdown were not tested, because

a reliable supply could not be developed where water levels are at or below the top of the water

producing zone before pumping. The available drawdown was computed for each well as the

difference between the elevation of the top of the sand zone and the lowest water level observed

to date (Tables 5-2 and 5-3). The sustained yields of wells that were bailed or pumped dry in

a short period of time at rates of less than one gpm, are considered to be much less than the rateat which they were bailed or pumped. Most of the wells fall into these two categories.

A few of the wells could be pumped at rates of 0.9 or 1.0 gpm for more than an hour or

two. Time-drawdown graphs of the test data were analyzed to project the pumping levels out

to 24 hours or until the available drawdown was exceeded. At wells 92-24Z, 92-18X and 92-24Y

the available drawdown was exceeded long before 24 hours. At well 90-9X, the projected

drawdown at the end of 24 hours would have been essentially equal to the available drawdown.

This well might sustain a pumping rate of 1.0 gpm for 24 hours, but no more than that. The

sustained yield for wells 92-26X and 90-6Z was calculated from the test data by multiplying the

test rate by the ratio of the projected 24-hour drawdown to the available drawdown times the test

rate. These are the only wells which potentially are capable of producing more than one gpm.

Only 2 of 38 wells have a calculated sustained yield of 1.0 gpm or more for 24 hours based

on this simple and straight-forward method of analysis. The best well which is outside the

footprint could produce only 1.6 gpm. Considering these meager well capacities and the fact that

all of these thin sand zones have water levels that would be at or near the top of the well screen

and pump intake of a developed supply well, it seems inconceivable that a reputable water-well

contractor would attempt to develop a water supply from them. This is particularly true in view

of the fact that deeper stratified sands potentially yield 10 to 15 gpm. If such a zone is not


encountered, an even greater yield is available from the regional bedrock aquifer. Moreover, the

areal extent of these intra-till sand zones is limited to the Clarkco property, or they crop out just

beyond the property boundaries. Clearly, these intra-till sand zones do not constitute the

uppermost aquifer at the Clarkco site and should be defined only as significant zones of

saturation.

5.2.1 Hydraulic Conductivity

Test results reported in Table 5-1 are grouped by sand zone. The data graphs and

computations are presented in Appendix G in the same sequence as they appear in Table 5-1.

Pump test results on the 1092 sand wells yielded hydraulic conductivities of 1.9 x 10~2 cm/sec

in well 92-24Z and 5.6 x 10~3 cm/sec in well 90-6W. Slug test hydraulic conductivities on the

1077 sand wells ranged from 4.1 x 10'3 cm/sec in well 90-10Y to 8.4 x 105 cm/sec hi well 91-

9Z. Both slug tests and pump tests were performed on two of the 1070 sand wells. Hydraulic

conductivities range from 4.6 x 10"3 cm/sec for the slug test in well 90-9X to 1.3 x 10"* cm/sec

for both the slug test and the pump test hi well 90-6X. Slug and/or pump tests also were

performed on die three 1060 sand wells. Results ranged from 2.8 x 102 cm/sec for the pump test

in well 90-7Z to 9.1 x 10^ cm/sec for the slug test in well 90-8X.

The largest number of in-situ hydraulic conductivity tests were performed on the 1050 sandwells. Hydraulic conductivities for the 1050 sand range from 2.3 x 10'2 cm/sec for the pump test

hi well 90-6Z to 1.7 x 105 cm/sec for the slug test in well 90-10X. The median value for

hydraulic conductivity is 1.1 x 10"3 and the average is 4.5 x 10"3 cm/sec.

Several hydraulic conductivity tests also were run on the 1035 sand wells. Field-

determined hydraulic conductivities ranged from 1.3 x 103 cm/sec for the slug test in well 90-7Y

to 3.6 x 10s cm/sec for the slug test in well 91-9Y. The hydraulic conductivity in the deeper

1035 sand zone is more consistent than in the 1050 sand, with a median value of 2.4 x 10"*

cm/sec. The average of die field-determined hydraulic conductivity values is 4.4 x 10^ cm/sec.


In general, there is good correlation between the results obtained by both testing methods.

In no case is there an order of magnitude difference between the slug-test and pump-test results

for the same well. In fact, few of the results differ by an amount that exceeds half an order of

magnitude. Pump test results are considered the more useful because approximate well yields

were determined from the test rate and time-drawdown data. In many cases, however, wells did

not produce sufficient water to sustain a pump test, even at pumping rates as low as 0.2 gpm.

For this reason, the lowest measured permeabilities for each sand zone necessarily were based

on the slug-test method.

Field hydraulic conductivity tests were not performed on all of the wells listed in Table 5-1.

Several of these wells (92-28X, 29X, 3IX, 31Y, 33X, and 33Y) were installed specifically asmonitoring wells for the 72-hour pumping test of PW-3. Once it was determined that aparticular well could be bailed dry, or broke suction at a pumping rate of one-half gallon per

minute or less, no further attempts to quantify the permeability of the screened zone by collecting

pumping-test data were made. From the additional data listed in Table 5-1, the reason that

additional testing was considered unwarranted is apparent in most cases, particularly when

compared to the results obtained from wells screened hi saturated zones with similar sand

thicknesses and available drawdown.

5.2.2 Ground-Water Level Fluctuations

Ground-water levels have been measured on a monthly basis in all of the wells installedas part of the hydrogeologic investigation of the Clarkco site (Table 5-2). The more-recently

installed wells were added to the circuit as they were completed, hi Table 5-2, PW-1, PW-2, and

PW-3 (the initial installations) are listed first, followed by the 1990 and 1991 well installations.

The 1991 C-prefix wells are listed next. All wells (including 1992 installations) that are part of

a well cluster are grouped in Table 5-2. All of the 1992 wells that were not installed next to an

existing well, are in numerical order at the end of the table.


Hydrographs have been prepared for each well in order to illustrate seasonal water-level

fluctuations. Hydrographs of wells completed in the same sand zone have been grouped in order

to facilitate analysis and discussion of similarities and differences in the patterns of variation.

Figures 5-3 through 5-7 are hydrographs for the 1092 through 1035 sand groups, respectively.

Plate 27 is a composite of hydrographs from wells at both the Clarkco and Tremont properties

which illustrates the range in water-level elevations in the various zones. The downward vertical

gradient is readily apparent from the water-level data presented on Plate 27.

Figure 5-3 illustrates that water levels in both wells developed in the 1092 sand fluctuate

similarly. Figure 5-4 illustrates that the shallower sand zones have a greater range of water-level

fluctuation. The similarity of the hydrographs for wells 91-9Z and 90-9X is because these wells

are located in the same cluster and the zones screened in these wells are separated by only 4.5

feet (see Plate 18). The hydrographs for wells 90-6Y and 90-6X coincide for the same reason.

The vertical separation between the sand zones here is 6.5 feet.

Figure 5-5 illustrates a fairly large range of fluctuation of water levels in wells 90-7Z and

90-8X. Although these wells are developed in the next lower sand zone (the 1060 sand), the

depth of overburden above the top of the sand pack is only 6 feet and 21.5 feet, respectively.

The thin overburden is a function of topography and the relationship is seen again on Figure 5-6

in the next lower 1050 sand, where the depth to the top of the sand pack in wells C91-4Z and

C91-4Y is only 12 feet and 19 feet, respectively. The hydrograph for well C91-4X (see Figure

5-7) developed in the 1035 sand is almost identical to that of well C91-4Y, the next shallower

well in the cluster (see Figure 5-6). The sand packs in these two wells are separated vertically

by about 4 feet and the sand zones are separated vertically by about 8 feet with a sand bed

between them. The similarity of the hydrographs for these wells may indicate an ineffective well

seal in C91-4X or a connection between the 1035 and 1050 sands at this location. However, this

cluster location is more than 1000 feet south of the proposed landfill footprint.


5.2.3 Recharge and Discharge

The fact that water levels in the deeper sand zones fluctuate seasonally, in itself does not

indicate a direct vertical interconnection between sand zones. Water levels in the deeper sands

are confined, for the most part, and respond hydraulically to changes in water levels

downgradient in the same zone. Discharge from all of the saturated zones within the till

sequence is to the ravines or side-slopes that surround the upland area to the north, south, and

east. Near the discharge areas, overburden is much thinner, allowing for local recharge and a

greater range of water-level fluctuation as just described. This causes a corresponding water-level

change upgradient in that zone, whether or not the sand zone receives any direct rechargevertically at that location.

Downward percolation is the primary source of recharge for the saturated zones within the

till sequence. Most of the recharge to each sand zone probably occurs in areas where the sand

zone is less than 20 feet below the ground surface. This conclusion was reached as a result of

studying the hydrographs for each well and for various well groupings and attempting to

categorize the observed patterns of seasonal variation. It was observed that certain wells in each

sand grouping had larger ranges of water-level fluctuations than others and appeared to be

considerably more responsive to seasonal recharge patterns. Table 5-3 summarizes the range of

water-level fluctuations observed, as well as the distance to the outcrop elevations and the depth

to the top of the sand pack for the wells at the Clarkco site. Figure 5-8 is a graph of the

maximum observed water-level fluctuation in a particular well as a function of the distance to

the nearest potential discharge point; and Figure 5-9 is a graph of the maximum observed water-

level fluctuation as a function of the depth to the sand pack of the well screen. Both graphs

show a correlation, and either or both factors may be important in the case of specific wells.

Figure 5-9 suggests that wells that are less than 20 feet deep are likely to be more responsive to

recharge than are deeper wells, hi general, the depth of weathering in the glacial till has been

observed to be about 14-16 feet at the Clarkco site.

Eagon & Associates, Inc. 5-7 • January 1994

5.2.4 Ground-Water Flow

In a general sense, flow in the significant saturated zones within the till sequence is

outward from the upland areas to dissected lowlands that essentially surround the outline of the

proposed landfill. Flow paths and the positions of subsurface drainage divides are dependent

upon the proximity to, and rate of discharge to local surface drainage features. Flow restrictions

and/or a lack of saturated zone continuity may cause flow paths to vary somewhat from

expectations based on topography and geomorphology.

Figure 5-10 is a map illustrating ground-water flow in the 1092 sand. Water-levelelevations in wells 90-6W and 92-24Z for October 5, 1992, indicate a northerly component of

flow. The flow relationship between these two wells is consistent for the period of record

(Figure 5-3). There is no potential for flow to the east or south because the 1092 sand is absent

in borings in these directions. The flow system for the 1092 sand is a simple one. Precipitation

infiltrates the soil zone and selectively infiltrates through the weathered till and into the fairly

permeable 1092 sand. Flow is to one or several discharge points along the ravine to the north

and northwest.

The rate of flow in the 1092 sand can be approximated by a simple velocity calculation

using Darcy's Law in the following form:

v=7.480

where: V = linear velocity, in feet per dayK = hydraulic conductivity, in gpd/ftI = hydraulic gradient, in ft/ft0 = porosity, percent

The apparent gradient, based on the difference in water-level elevation between wells 90-6W and 92-24Z is about 0.004 ft/ft. The average value for hydraulic conductivity determined


from pumping tests on these two wells is about 1.1 x 10~3 cm/sec or 21.2 gpd/ft2. Freeze and

Cherry, 1979, give a range of porosity values for silt between 35 and 50 percent and a range of

porosity values for sand between 25 and 50 percent. Considering that the intra-till sands at the

site are mostly silty sands, an assumed value for porosity of 35 percent seems like a conservative

number for purposes of estimating flow rates. Therefore, the rate of horizontal migration of

ground water in the 1092 sand is estimated as follows:

V = (21-2) x (.004) = Q32 ft/da^ Qr(7.48) x (.35) ' y

Figure 5-11 shows the inferred flow directions for the 1086 sand. Water-level elevations

are not shown because no wells were installed in this sand zone. The 1086 sand occurs in a

fairly narrow band traversing the west central part of the site. In most places, the 1086 sand isless than 10 feet below ground level. In only a few places, it is more than 15 feet below ground

level. Because the 1086 sand is so close to the surface, and of limited areal extent, flow in the

sand is expected to respond rapidly to, and be dominated by infiltration and discharge of

precipitation. Based on the relationship of topography to the area of sand occurrence, three

localized flow systems are envisioned; each of which discharges along the slopes of the ravine

that truncates the sand zone (Figure 5-11). Data are not available for determining flow rates in

the 1086 sand. However, this is of little importance because the 1086 sand will be removed

during excavation for the landfill.

Figure 5-12 is a ground-water flow map for the 1077 sand. Three wells: 90-6Y, 90-10Y,

and 91-9Z are completed in this sand zone. Water-level elevations in these wells on October 5,

1992 are shown on the flow map. The flow in the 1077 sand moves toward the topographically

lower areas and discharges to the ravines to the north, east and south.

Areas of thicker 1077 sand are in the east-southeastern and southwestern parts of the

landfill footprint. Flow in these areas is likely to be quantitatively more significant than in areas

to the north and northwest where little 1077 sand has been encountered. Localized flow systems

that essentially are small scale watersheds that convey runoff and infiltration to numerous


discharge points, collectively constitute the ground-water flow system for the 1077 sand. The

flow system interpretation illustrated in Figure 5-12 takes into account sand thicknesses,

topography, proximity to discharge, and the water-level data.

The hydraulic gradient can be estimated by assuming that the water-level elevation at the

outcrop is the same as the outcrop elevation. Using difference in elevation between water levels

measured in wells screened in the 1077 sand, and the outcrop elevation divided by the distance

from the well to the outcrop, gives gradients ranging from about 0.01 to 0.02 ft/ft. The average

of hydraulic conductivity values determined from slug tests in wells screened in the 1077 sand

is about 1.56 x 10"3 cm/sec or 33.1 gpd/ft2. Again assuming porosity to be 35 percent, the flow

rates are estimated to range as follows:

V = C33-1) * (-01) = -13 ft/day or 46 ft/yr(7.48) x (.35) J y J *

to

V = C33-1) x (-02) = 25 ft/day or 92.3 ft/yr(7.48) x (.35) J 7

Figure 5-13 illustrates the flow system for the 1070 sand. Wells 90-6X, 90-9X, C91-8Y,

and C92-9Y are screened in the 1070 sand and water levels in these wells on October 5, 1992

are shown on the flow map. Of these four wells, only water levels in 90-9X respond in a manner

similar to water levels in the 1077 sand (Figure 5-5). However, as already discussed the sand

pack interval overlaps with that of a shallower well in the cluster. The 1070 sand is found only

in the western and northwestern parts of the proposed landfill footprint. In these areas, the 1070

sand generally is more than 20 feet below ground level and, therefore, is expected to be less

responsive to infiltration.

The gradient from well 90-6X to the outcrop area to the east is about 0.007 ft/ft, based on

the difference in elevations between the October 5, 1992, water level and the outcrop. The

gradient to the south between wells C92-9X and C91-8Y for the same period is about 0.011 (see


Figure 5-13). The average hydraulic conductivity from slug tests and pumping tests in 1070 sand

wells is about 1.6 x 10"3 cm/sec or 33.9 gpd/ft2. Assuming a porosity of 35 percent, the flow

rates are estimated to be as follows:

V - <33-9> * (-007) = .09 ft/day or 32.9 ft/yr(7.48) x (.35) J y

to

V = (33-9) * (-011) = .14 ft/day or 51i9(7.48) x (.35) J

Figure 5-14 illustrates the flow system for the 1060 sand. Wells 90-7Z, 90-8X and 92-26X

are screened in the 1060 sand. The large area of no sand over much of the central part of thesite serves to sub-divide the flow system as does the fact that ravines to the southeast and south

truncate the sand body. Flow patterns that take these factors into account are shown on Figure

5-14. The hydrograph of well 90-8X (which is flashy) and to a lesser extent that of well 90-7Z

(Figure 5-5) illustrate the importance of infiltration of precipitation where the thickness of the

weathered confining layer is about 20 feet thick or less.

Gradients in the 1060 sand between wells in which water-level elevations were measured

on October 5, 1992, and the outcrop areas, calculated as previously described range from 0.004

to 0.016 ft/ft. The average hydraulic conductivity determined from field tests in 1060 sand wells

is 1.5 x 10'2 cm/sec or 318 gpd/ft2. Assuming a porosity of 35 percent, the flow rates are

estimated to be as follows:

V - <318) * (-004) - .49 ft/day or 111 ftlyr(7.48) x (.35) ' ' ' y

to

= (318) x (.016) = 1 94 or 7Q9

(7.48) x (.35)


Figure 5-15 illustrates the flow system for the 1050 sand. Fourteen wells have been

screened across this sand zone. Their hydrographs are grouped in Figure 5-6. Wells C91-4Z and

C91-4Y are cluster wells screened in sand beds that are separated by cohesive beds. Water

levels, however, show that these wells are hydraulically connected and respond in a flashy

manner to infiltration. Only a few months of water-level data is available for wells 92-29X and

92-28X but their pattern of fluctuation suggests that mese wells also are hydraulically connectedand rapidly responsive.

Water levels in C92-9X, 92-17Y, and 92-18X are lower than those in most of thesurrounding wells. Although they may or may not be hydraulically connected with one another,they do not appear to be connected with the other nearby wells because they do not fit anylogical pattern of flow. Water levels in these wells correlate with relative well screen elevations,

suggesting a simple vertical gradient in an isolated saturated zone.

The other six wells in the northern part of the footprint indicate that flow generally is to

the northeast. More-variable localized patterns of flow become dominant wherever the 1050 sandis less than about twenty feet below ground level, particularly in the vicinity of potential

discharge zones. The six wells located to the south of the proposed landfill footprint, show a

pattern of flow generally toward the steep ravine that trends north-south through this group ofwells.

Hydraulic gradients were calculated between wells, and between wells and outcrops, atnumerous places for the 1050 sand based on the data contained on Figure 5-15. The range ofgradient values was found to be between 0.001 and 0.01 ft/ft. Using the median value forhydraulic conductivity determined from field tests in the 1050 sand wells and a porosity of 35percent, the flow rates are estimated to be in the following range:


V = (23-3) * (.001) = Q09 ft/da Qr 3 3 ft(7.48) x (.35) y 3 y

to

K = (23.3) * (.01) = 09 ̂ . 32

(7.48) A: (.35) ' 7

Figure 5-16 illustrates the flow system for the 1035 sand. Hydrographs for the 11 wells

that are screened in the 1035 sand are shown on Figure 5-7. The relatively flat hydrograph of

well 90-7 Y (Figure 5-16) suggests the likelihood that the saturated zone screened in the well isisolated from the flow system. Another possible explanation is that the low water level resultsfrom the proximity of this well to a discharge zone. The hydrograph of well 92-15X is similar.In either case, the low and stable water-level pattern for wells 90-7Y and 92-15X sets them apartfrom the other wells in the 1035 sand group. The water level in C91-4X is anomalously highbecause the 1035 sand in this well is hydraulically connected with the 1050 sand screened in wellC91-4Y at this well cluster location. This may be the result of an ineffective well seal in wellC91-4X rather than a naturally-occurring phenomenon. Comparison of the patterns of water-level

fluctuations in these two wells (Figures 5-6 and 5-7) indicates that the wells are hydraulically

connected and provides an explanation for the flashy response in a well (C91-4X) that would nototherwise by expected to be rapidly responsive to infiltration. However, this well cluster islocated more than 1000 feet south of the proposed landfill.

Three wells (92-4X, 92-14X, and 92-19X) that encountered fairly thick 1035 sand zones(3.2, 3.0, and 3.6 feet, respectively) have maintained similar consistently-high water levels(Figure 5-7). Analysis of the water-level data from the northern part of the site suggests ageneral pattern of flow to the northeast. Water levels in wells 91-9Y and particularly, 92-2X donot fit this flow pattern. It appears that these wells are not hydraulically connected with the other

nearby 1035 sand wells or, at least, are not an integral part of the flow system. The low water

level in well 92-IX is caused by the proximity to a potential discharge point in the ravine to the

southeast of this location.


The 1035 sand screened in the three wells to the south (C91-4X, 92-3 IX and 92-33X)

probably discharges to the large ravine that drains to the south from the southwestern corner of

the proposed landfill, as suggested in Figure 5-16. Well 92-33X, for instance, which is screened

across a thin sand bed that appeared to be wet during drilling, has been dry from the tune that

it was installed.

Gradients in the 1035 sand estimated between wells, and between wells and outcrops, basedon the data contained on Figure 5-16 range from 0.002 to 0.012 ft/ft. Using the median valuefor hydraulic conductivity determined from field tests in the 1035 sand wells, and a porosity of35 percent, the flow rates are estimated to be in the following range:

V = (5) x (.002) = OQ4 ftld^(7.48) x (.35) J y

to

v = (5) x (.012) =(7.48) x (.35)

5.3 Uppermost Aquifer System

Clearly, the sand and gravel sequence within the stratified drift that underlies the Clarkco

site is capable of yielding more than 10 gpm. Therefore, the first zone of saturation encounteredbelow the base of the Lower Till at the site is considered to be the uppermost aquifer.Throughout most of the area of the proposed landfill footprint, a fairly thick unsaturated zoneexists below the base of the Lower Till. The first two wells competed (90-9D and 90-8D) werescreened in the upper part of the uppermost aquifer system, and these resulted in dry holes. Eachwell was screened in what appeared to be the top of the saturated zone. Deeper drilling inseveral borings confirmed the interpretation that the initial dry completions were in localizedzones of saturation that were perched on minor confining beds or resulted from stratification that

was breached in the process of installing the wells. Fortunately, the initial plan of placing the


well screen across the first zone of saturation encountered in the uppermost aquifer sequence wasrecognized as an incorrect and unworkable approach during the initial phases of the field

program.

The first well installation (90-9D) was subsequently pulled, the borehole cleaned out anddeepened, and a well reinstalled with the designation 90-9DD. Well-screen elevations for

subsequent wells were based on the water-level elevation measured in well 90-9DD without

regard to perched saturation conditions that might be encountered in individual boreholes. This

approach proved quite satisfactory. Well 90-8D, which is dry, was left in place as evidence ofthe unsaturated nature of the upper part of the uppermost aquifer.

The unsaturated part of the stratified drift at the Clarkco site is considered to be part of theuppermost aquifer system, because the dry sands beneath the Lower Till are potential pathways

for vertical migration. Plate 26 shows the base of the Lower Till, which actually defines the topof the "uppermost aquifer system", for most of the area of the proposed landfill footprint. In the

area just south of the proposed footprint, the lower till is immediately underlain by lowpermeability alluvial beds of silt and clay which, from a hydrogeologic standpoint, act as part of

the confining bed. The area in which the uppermost aquifer is considered to be confined is

delineated on Figure 5-17 and includes the area to the west of the Clarkco site which

encompasses both the Tremont Landfill and Closed Barrel Fill.

5.3.1 Hydraulic Conductivity

Slug tests attempted on most of the wells screened in the uppermost aquifer ran too fastto provide usable data. This was the case even for wells screened in aquifer materials classifiedSM. Analysis of the slug-test data indicates hydraulic conductivities exceeding 1.5 x 10~l cm/secfor the "cleaner" finer-grained materials. Hydraulic conductivities for the cleanest, coarsest-grained zones of the aquifer are estimated to range between 9.0 x 10~2 and 1.4 x 10"1 cm/sec.


Usable slug-test data was obtained from three of the wells installed in the uppermost

aquifer, giving hydraulic conductivities in cm/sec of 7.6 x 10"2 for well C91-8D, 1.4 x 10"* for

well C91-5D, and 2.0 x KT* for well C91-2D.

Three pumping tests were conducted in 1990 to characterize the hydraulic properties of the

uppermost aquifer at the Clarkco property and to determine whether or not it was capable of

producing well yields of 100 gpm. Three 8-inch test wells were constructed, each in the most

productive sand and gravel zone encountered. The widely-spaced locations of PW-1, PW-2, andPW-3 are shown on Plates 8 and 13. Details of the mernodology used in drilling, wellconstruction, development and testing are described in Section 8.0 of this report. Generally-accepted practices for the construction and development of water wells were employed by theSprowls Drilling Company, an experienced water well contractor, under the supervision of ahydrogeologist on site. The open boreholes were gamma-ray logged prior to the installation of

the well screens primarily to confirm the screen-interval selections. The driller's logs, gamma-raylogs, and tabulated pumping-test data are presented in Appendix H.

Also presented in Appendix H is a representation of the pertinent well construction features

as they relate to the water-bearing zones encountered. PW-1 encountered a significant water-bearing zone of coarse sand and gravel from 94.5 to 118 feet below land surface. This entirezone was screened and developed. The static water level in this well was about 79 feet belowland surface resulting in approximately 15 feet of available drawdown. The static water level

in the water-bearing zone encountered in PW-1 is substantially higher in elevation than thoseencountered in the other two 8- inch wells. The fact that the zone that was developed, was theonly significant water-producing strata at this location is verified by both the gamma-ray log andthe observations of the on-site geologist. PW-1 is located over 1000 feet to the west of theproposed landfill footprint.

At well PW-2, only 5 feet of saturated sand and gravel were logged by the driller, and itwas encountered at a much lower elevation than that in PW-1. This zone had the greatestpotential for producing water of any zone encountered in the PW-2 borehole. The lack of


significant water-bearing materials above the screened zone was confirmed by the nearest test

hole (boring 90-15) which was drilled and sampled continuously. The static water level in PW-2

was 95 feet below land surface, or about 12 feet above the top of the well screen. Available

drawdown was similar to that for PW-1 although both the water-bearing zone and the static level

were encountered at substantially lower elevations. Every effort was made to develop a high-yield producing well at this location as evidenced by the fact that the well screen and gravel pack

were extended above and below the primary water-bearing zone.

The elevation of the water-producing zone developed in PW-3 was comparable to that ofthe developed zone in PW-2. However, the formation encountered in PW-3 is substantiallycleaner and greater in thickness. In addition, the available drawdown was substantially greaterdue to the higher static water level.

Pumping tests of 24-hour duration at a rate of 100 gpm were performed on both PW-1 andPW-3. PW-2 could not produce 100 gpm as the pump broke suction at a rate of 50 gpm duringthe step test. Therefore, a 24-hour pump test was not performed on PW-2. A summary of the

pumping-test results is included in Table 5-4. Interpretation of the pump-test data indicates that

the permeability of the uppermost aquifer in PW-1 and PW-3 is about 2,750 gpd/ft2 and 1,520

gpd/ft2, respectively. The permeability of the zone screened in PW-2 is substantially less, i.e.,

about 184 gpd/ft2. Lower hydraulic conductivity, coupled with the fact that the formation is thinat this location, results in the lower well yield. Although drilled and constructed specificallyto determine hydraulic conductivity and potential well yield, water levels also have beenmeasured routinely in the three pump-test wells and the data are included in Table 5-2.

Analysis of the pumping-test data provides for some additional insights and conclusionsrelative to the hydrogeologic framework of the Clarkco site. A short discussion of the data andits interpretation at each test site follows.

Well PW-1. The time-drawdown data plotted on the semi-log graph (Appendix H) suggest thatrecharge was occurring during the 24-hour pumping test, as shown by the extremely flat slope


of all but the early-time test data, i.e. less than 20 minutes. Analysis of the slope of the early-

time data yields a transmissivity which is consistent with permeability values determined by

various means at the site. If the later-time data were used to determine transmissivity,

unrealistically high values for hydraulic conductivity would result. Therefore, it is concluded thatthe flattened slope of the tune-drawdown data is the result of delayed yield from storage or some

form of leakage between stratified zones at this location.

A likely source of leakage or delayed yield is from materials overlying the producing

formation. This is consistent with the geologic interpretation of this part of the site based on test

borings. In soil boring 89-2, located about 600 feet south of PW-1 (Plate 8), a thick, partly-saturated sand and gravel zone immediately overlies the water-bearing zone developed in PW-1.The elevation at which this zone became saturated in boring 89-2 closely matches the water levelin PW-1. The upper sand and gravel zone identified in boring 89-2 is interpreted to be alenticular deposit (having a north-south orientation) that passes immediately to the west of PW-1.Pumping test data are not sufficient to quantify leakage or slow drainage from materials in thearea.

Well PW-2. The hydraulic conductivity of 184 gpd/ft2 determined for this well is based onthe relationship between transmissivity and specific capacity. The specific capacity of PW-2 wascalculated from data obtained during the step-test for this well. A longer, more extensivepumping test was not performed on PW-2 because it was not possible to stress the aquifer at a

pumping rate of 100 gpm. The PW-2 aquifer characteristics reported in Table 5-4 are consistentwith the geologic interpretation based on borehole data. As seen on cross sections A-A' and B-B', the uppermost aquifer is much thinner and probably pinches out to the northeast.

Well PW-3. The time-drawdown data from the 24-hour pumping test on PW-3 indicates thepresence of a negative boundary condition somewhere in that part of the site. The semi-log plot

(Appendix H) exhibits a steepening of the slope of the time-drawdown data beyond about 220minutes. The transmissivity derived from the early-time data is believed to accurately representthe hydraulic characteristics of the aquifer. The resulting value for hydraulic conductivity seems


realistic based on the aquifer materials encountered and compared to the results of the other tests.

The presence of a negative boundary is consistent with the geologic interpretation of the site

based on test-boring data. Cross sections E-E' and G-G' show that the sand and gravel aquifer

becomes much thinner and appears to pinch out to the south.

The results of the pumping tests demonstrate that the hydrogeologic characteristics of theuppermost aquifer beneath the study area vary considerably from place to place with respect tothickness, permeability, and potential yield. Beneath parts of the property, the sand and gravelaquifer is capable of yielding 100 gpm to individual wells; whereas in other areas of the site,yields of this magnitude are not possible. In the northwestern part of the Clarkco property, inthe vicinity of PW-1, more than 1000 feet from the proposed limit of waste, the aquifer is mostprolific. It is also quite productive in the area of PW-3. The uppermost aquifer thins andbecomes finer-grained to the east, resulting in much lower productivity in the vicinity of PW-2.

The uppermost aquifer also thins and becomes finer-grained to the south as seen by the log of

boring 92-23. Wells which penetrated the full thickness of the uppermost aquifer were drilled

south and southeast of the proposed landfill footprint at 92-20D and 92-2ID. Although laterally-

equivalent sand zones were encountered in these borings, neither of these locations is thought to

have the potential for development of a 100 gpm well based on comparison of the aquifer

materials encountered with those at the other locations.

5.3.2 Ground-Water Level Fluctuations

Hydrographs for wells developed in the uppermost aquifer are included on Plate 27. Mostof the hydrographs are grouped closely together with respect to water-level elevation, showsimilar trends, and fluctuate within a range of about two feet for the period of record. Only threewells at or near the proposed landfill do not fit this pattern. Wells 92-20D and 92-23D havesubstantially lower water levels probably because they are screened in a zone which is physicallyseparated from the uppermost aquifer. The available water-level data indicates a low range offluctuation that suggests a poor connection with surficial materials as is the case with all of thewells in the stratified drift except PW-2.


The hydrograph of PW-2 is unique (see Plate 27). Based on the boring log and water-level

data, this well clearly is developed in a zone that is physically separated from the uppermost

aquifer. However, the range of water-level fluctuation in PW-2 is such that it responds in the

same manner as a well that is only overlain by 20 feet or less of overburden. This is not the

case, because the top of the sand pack in PW-2 is 98 feet below the land surface. The

explanation offered for the magnitude of water-level response in this well to seasonal fluctuations

is that PW-2 is developed in a sand zone isolated from the flow system of the uppermost aquifer,but locally connected to a sand zone that extends off site to the northeast. In this direction, thetopography falls off rapidly, so that the zone occurs near the surface beneath the alluvium in thevalley floor, where response to recharge due to precipitation events is fairly rapid.

On the Tremont site, to the west of the proposed landfill, well TBF-20D responds similarlyto most wells in the uppermost aquifer (see Plate 27). The seemingly erratic scatter of datapoints on the hydrograph most likely is due to the effects of intermittent pumping of the supply

well located nearby, as will be explained in more detail in the discussion of the 72-hour pumpingtest. The hydrographs for PW-1 and TBF-19D fluctuate in a higher elevation range because they

are poorly connected to, and upgradient of, the uppermost aquifer for the Clarkco site.

5.3.3 Recharge and Discharge

Recharge to the uppermost aquifer appears to be primarily from the west and from the

topographically low area south of the proposed landfill as suggested by the flow direction. Inthe vicinity of boring 89-2 (west of the proposed footprint), a shallower aquifer appears tocoalesce with the more extensive sand and gravel aquifer and may be a source of recharge. Also,the uppermost aquifer itself appears to thicken to the west. In wells west of the proposedfootprint (PW-1, BF-19D, and BF-20D), and in the area south of the proposed landfill footprint(PW-3 and C91-5D) the uppermost aquifer is confined. The saturated zone screened in PW-2also is confined. In all of the other wells within or on the periphery of the proposed footprint,the uppermost aquifer is unconfined and flow in this area is under water-table conditions. (Figure5-17).


As evidenced by the observed flow direction and gradient, the uppermost aquifer discharges

to Storms Creek to the northeast and contributes to the base flow of that perennial stream.

5.3.4 Ground-Water Flow

As seen on Plate 27, water-level elevations in PW-1 are consistently higher than the wellslocated within or near the proposed landfill footprint. Water levels in PW-2 are consistently the

lowest with those in 90-7D consistently second lowest. Exceptions to this relationship are wells

92-20D which is screened in a deep isolated sand zone, and 92-23D which is located 3750 feetsouth of the proposed landfill and also is screened in an isolated sand zone. Water-levelelevations measured on February 8, 1993 are contoured on Plate 28 and Figure 5-20 to illustratepotential flow directions. An eastward component of flow is present in the western part of theproposed landfill footprint and a northeastward flow component is indicated for the remainderof the area. The water level hi PW-2 is not contoured because it does not fit the consistentpattern of variation observed in the other wells and represents a different system. Although theaquifer screened in PW-2 is technically the uppermost aquifer at this location and could becorrelated with the zones screened in the other deep wells (cross section A-A'), it also appears

to be isolated from the flow system as illustrated by Figures 5-18 to 20. Plate 27 serves toillustrate that the up- and down-gradient relationships among piezometers within the proposedlandfill footprint are generally consistent over time as water levels fluctuate seasonally. Figures5-19 and 5-20 show the potentiometric surface based on water-level data collected on October5, 1992, and February 8, 1993, respectively. The configuration of water level contours anddirection of flow remain essentially the same as shown by Figure 5-18. The only difference ofnote is the slightly steeper gradient where the aquifer in confined south of the proposed footprint.

During the three periods for which potentiometric maps of the uppermost aquifer wereprepared (Figures 5-18, 5-19 and 5-20) the gradients range from as low as 0.0002 in thenortheastern portion of the proposed landfill to as much as 0.0015 just south of the proposedfootprint. Freeze and Cherry (1979) show that porosity values for sand range from 25 to 50

percent and porosity values for gravel range from 25 to 40 percent. Considering the materials


observed from the uppermost aquifer at the Clarkco site, an assumed value of 30 percent for

porosity seems conservative. The average value for hydraulic conductivity for the uppermost

aquifer as determined from the analysis of the 72-hour pumping test is 1556 gpd/ft2 (see Table

5-4). Therefore, the calculated values for the range of ground-water flow rates to be expected

within the uppermost aquifer are as follows:

v __ (1556) x (.0002) _(7.48) x (.30) J y J *

to

5.4 Interconnections Between Uppermost Aquifer System and Significant Zones ofSaturation

The possibility for interconnection between the intra-till sand zones and the underlying

uppermost aquifer was carefully evaluated using various techniques of investigation. Li addition

to the evaluation of physical features of the geologic materials and the definition of the site

framework, additional hydraulic testing was performed. A 72-hour pumping test was performed

on PW-3 in the area where the uppermost aquifer is under confined conditions, and in-situ

permeability tests were performed on the Lower Till in the area where the upper part of theaquifer system is unsaturated. In addition, tritium testing was performed to determine the relativeage of ground water in various intra-till sand zones and the uppermost aquifer.

5.4.1 72-Hour Pumping Test

A pumping test of 72 hours duration was performed on well PW-3 from 10:30 am onOctober 6 to 10:30 am on October 9, 1992. The purpose of the test was to determine the

hydraulic interconnection, or lack thereof, between the uppermost aquifer and the saturated zones


within the glacial till confining bed above it. A secondary objective of the pumping test was to

evaluate the hydraulic characteristics of the uppermost aquifer. A step test was conducted on

PW-3 three days prior to the 72-hour test to determine the characteristics of the well and to

determine the most appropriate pumping rate for the long test. The maximum capacity of the

pump was found to be about 220 gallons per minute (gpm), so a test rate of 197 gpm was used

for the 72-hour test to insure that a constant rate could be maintained as total-discharge-head

increased as water-levels in the well declined with time.

In all, 53 wells at the Clarkco and Tremont sites were used as observation wells during thetest. Hydrographs plotted from water levels measured in these wells are presented in AppendixI. These wells are listed in Table 5-5 which also identifies the zone in which they are screened,and lists the distance from PW-3 and the method and frequency of water-level measurementduring the test. In order to establish the background trend in water levels, these wells were

measured daily for three days prior to, and four days after, the test. Figure 5-21 is a graphicsummary of the observation wells used for data collection, showing the vertical relationship of

screened intervals and water levels.

5.4.1.1 Test Data

The observation wells can be characterized in several categories. First, there are wellsdeveloped in sand zones within the till. Then there are wells which are screened in the

uppermost aquifer or the other saturated beds in the stratified drift which are laterally equivalentto it. The approximate base of the lower till as shown on Plate 26 and generalized on Figure 5-21 serves to separate these two groups; in reality the base of till ranges from elevation 1020 to1000.

The most important wells for test purposes are the intra-till sand wells located within 700

feet of well PW-3. These are the wells in which a response to pumping in the uppermost aquifer

would be detected if a vertical interconnection were to exist. Each of these wells was equipped

with a transducer in order to obtain a continuous record of water-level fluctuations. The only


exceptions were the two shallower wells at a 3-well cluster (C91-4X, C91-4Y and C91-4Z). Here

a continuous record was obtained in the deepest well and periodic measurements were maderoutinely in the others.

The next important category of observation wells includes those developed within the

uppermost aquifer and located within 2500 feet of PW-3. This includes TBF-19D and 20D at

the Closed Barrel Fill, and the "supply well" at the Tremont Landfill. The purpose of data

collection in these wells was to determine the shape of the cone of depression within theuppermost aquifer in order to identify directional differences in transmissivity, boundaryconditions, and areas more distant from the pumping well where the magnitude of drawdown inthe aquifer might be more likely to cause evidence of a vertical connection due to greater headdifferential. Uppermost aquifer wells within about 1000 feet of PW-3 also were used to collectearly drawdown data for computation of aquifer characteristics. Transducers were installed inwells 92-22D and 22DD and manual water-level measurements were taken frequently in wellsC91-5D, C92-5DD.C91-2D, and 92-21D for the first four hours of the test. Some earlymeasurements also were taken at TBF-19D, TBF-20D and 92-23D. These wells subsequently

were measured on a 4-hour schedule for the remainder of the test. The data collection scheduleis listed on Table 5-5.

The rest of the wells screened in the 1035 and 1050 sands that are located within a radiusof 2000 feet from PW-3 were measured on a 4-hour schedule during the test. The purpose of

including these wells in the network was to insure that all available wells developed in intra-till

sands, where even a remote possibility of a vertical interconnection existed, were observed duringthis test. Four wells developed in the 1070 and 1077 sands also were included because they werelocated at clusters where deeper wells were being measured routinely. It was a fairly simplematter to include them in the schedule.

Wells at the south end of the Tremont Landfill were selected for measurement to determine

whether or not any lateral hydraulic interconnection exists between the uppermost aquifer at the

Clarkco site and the stratified drift at the landfill where ground-water assessment studies have


been performed. Transducers were installed in wells A89-3D and A91-7D, which are typical ofthe two hydrogeologic environments present at the southern end of the Tremont Landfill (Eagon

1992a). Water-level measurements were also taken on a 4-hour schedule in M-3 and A91-9S,

and daily at well M-4.

Finally, several wells at the north end of the Clarkco property were measured for

background purposes. Daily measurements were taken in wells PW-1, 90-6D and 92-27DDwhich are screened in the uppermost aquifer. A strip chart recorder was installed and operatedto obtain a continuous record of water levels in PW-2 and a transducer was installed in well 92-15X.

A continuous record of barometric fluctuations was obtained using a recording barometer

with a strip chart recorder, so that water level fluctuations could be corrected for barometricaffects. The stage of Chapman Creek also was measured routinely during and after the pumpingtest in order to relate river stage to ground-water level changes.

Hydrographs for all of the observation wells monitored during the pumping test are groupedby category, as described above, in Appendix I. Each group of hydrographs is preceded by aheader sheet which explains the logic of the grouping, lists the wells included, and summarizesunique characteristics of the data. Figure 5-22 is the hydrograph for the pumping well (PW-3)

for the data collection period before, during, and after the test. All hydrographs are plotted tothe same scale for both time and water-level elevation to facilitate comparison. Figure 5-23shows the hydrographs for the two closest well pairs screened in the uppermost aquifer, namelyC91-5D and 5DD, and 92-22D and 22DD. Figure 5-24 shows the hydrographs for the twoclosest intra-well sand wells which are 92-28X and 92-29X, located at distances from PW-3 of100 and 75 feet, respectively.


5.4.1.2 Trends and Data Correction

Figure 5-24 includes a plot of the barometric pressure for the data collection period,

converted to feet of water and plotted on an inverted vertical axis so that rising pressure matches

declining ground-water levels. The plots of barometric and water-level fluctuations of wells 92-

28X and 92-29X are almost identical. Based on Figure 5-24, it appears that the only water-level

changes in these two wells during the pumping test were the result of barometric affects.

Conversely, hydrographs of wells in the uppermost aquifer (Figure 5-23) clearly show drawdown

as a result of pumping in PW-3. Some barometric affect is also apparent, causing minor

variations in water levels that vary in amount depending on the barometric efficiency of each

well.

A review of the hydrographs for intra-till sand wells within 700 feet of PW-3 indicate that

there was no drawdown produced in these wells during the 72-hour test period, hi order to

validate this conclusion the hydrographs were corrected for barometric-induced fluctuations by

calculating the barometric efficiency unique to each well and adding or subtracting the

appropriate change values using the beginning of the test as the time reference point. Figure 5-25

is an example of the manner in which the barometric efficiency was determined.

Corrected hydrographs are included in Appendix I for wells 92-28X, 92-29X, C91-4X, C91-

4Z and 91-26X. All of these plots show a straight line, with absolutely no indication of response

to pumping (drawdown) during the test. Most wells show some declining trend during the data

collection period, in varying amounts. Well 92-28X declined about 0.4 foot whereas well 92-29X

was essentially flat. Water levels in wells C91-4Z and 92-26X declined at about the same rate,

about 0.7 foot over the 10 day period. This slight decline is to be expected considering the

season and the lack of substantial precipitation during that period of time. Clearly the declining

trend is natural. It was not necessary to correct the hydrographs for wells 92-31Y and 92-33Y

because there was no barometric affect, probably because the water levels in these wells were


within the sand pack zone (see Figure 5-21). The hydrograph of well 92-3IX also was

essentially featureless and required no correction. Clearly, there was no drawdown in any of

these wells.

A declining trend for the data collection period also is apparent in wells developed in the

uppermost aquifer, the hydrographs of which are grouped together in Appendix I. As seen from

the hydrographs of PW-3 and the C91-5 and 92-22 well pairs, the decline is about 0.6 to 0.7 foot

for the 10-day period. The decline is slightly less in well 92-23D which has a low barometric

efficiency. This well hydrograph requires no correction to conclude that drawdown was not

produced.

Wells C91-2D, C91-8D, 90-9DD, 90-14D, 92-14DD and 92-21D all have hydrographswhich are quite similar. Even though these wells (with the exception of 92-2ID) are developed

in what has been considered to be the unconfined portion of the uppermost aquifer, the water

level fluctuations were not affected by the pumping of PW-3, but appear to be affected by

barometric changes to varying degrees. This is probably due to stratification in the aquifer and

the fact that some have water levels above the top of the sand pack (see Figure 5-21). The

hydrographs for wells C91-2D and 90-9DD were corrected for barometric affects and show a

slight declining trend with no evidence of drawdown.

Well TBF-20D and the supply well both clearly show drawdown as a result of pumping

PW-3. However, it was not possible to keep the supply well shut down during the test and its

on-off cycling is obvious in the hydrographs for both wells. Clearly, TBF-20D is affected by

pumping of the supply well, and both wells are affected by PW-3. The data is too erratic to

determine trends, but it is possible to compute an approximation of the drawdown as a result of

pumping. Drawdown at the supply well and TBF-20D as a result of pumping PW-3 at the end

of the test is estimated to be about 0.70 and 0.65 foot, respectively. Drawdown at TBF-20D as

a result of short-term pumping at the supply well is about 1.1 feet. The supply well itself draws

down about 3 feet when the pump cycles.


The hydrograph for well TBF-19D exhibits the same characteristics as other hydrographs

of wells in the uppermost aquifer which are unaffected by pumping, however, it appears to be

even more responsive to barometric changes. This is consistent with the log of this well which

clearly indicates confined conditions at this location. Hydrographs of PW-1, 90-6D, 90-10D, 90-

13D and 92-27DD are all quite similar and show the same general trends as those which were

corrected. In view of their distance from PW-3, and the fact that corrected hydrographs for

closer wells showed no drawdown, it is concluded that these wells were beyond the radius of

influence of pumping at PW-3.

Wells PW-2 and 92-20D show very minor affects of barometric fluctuations and both

hydrographs exhibit a slight declining trend. PW-2 was considered to be a background well as

it is farthest away (over 3000 feet from PW-3). Clearly there is no drawdown indicated by these

hydrographs.

The next series of hydrographs grouped together in Appendix I are those for intra-till sand

wells located more than 1000 feet from PW-3. All of these wells are located to the north of PW-

3 and all are in the area where the lower till is underlain by a fairly thick unsaturated zone. The

only exceptions are the shallow aquifer wells monitored at the Closed Barrel Fill, namely TBF-

17, 19S and 20S where the uppermost aquifer is confined. A hydraulic response to pumping was

not expected in any of these wells due to their distance from the pumping well and theunderlying unsaturated zone. Nevertheless, they were monitored to insure that the data collection

and test analysis was as comprehensive as possible.

Hydrographs of wells C92-1X, 92-4X, 92-14X, and 92-19X developed in the 1035 sand all

have the same characteristic plots as the barometric record, with slight variations in magnitude

of change due to varying barometric efficiency. As with intra-till wells closer to PW-3, no

change due to pumping was detected. Well 91-9Y is the deepest of the group and appears to be

the most responsive to barometric changes.


Hie hydrographs of 1050 sand wells show similar patterns of barometric fluctuation,although more subdued. The abrupt change in water level on October 8 shown on the

hydrograph of well C91-8X looks like a data collection anomaly because the observed trend

before and after the change matches the other hydrographs. However, the change was real asconfirmed by careful verification by on-site personnel at the time. The change is thought to berelated to the physical conditions in the borehole and sand pack. Perhaps a small airpocket in

a void was released. In any event, the change cannot be attributed to pumping at PW-3. Thiswell is 1440 feet away, and more distant vertically and horizontally than many wells showing no

response. Even if some hydraulic connection were possible, any response would be gradual andnot an abrupt event. This curious change is absolutely unrelated to the pumping test.

The background well in the 1050 sand (92-15X), in which a transducer was installed, has

a low barometric efficiency and the hydrograph shows a fairly level trend. The water level isat or just below the top of the sand pack (see Figure 5-21). This hydrograph is similar to the

other intra-till wells with low barometric efficiency, i.e. like the wells developed in the 1070 and1077 sands. All three intra-till sand wells at the Closed Barrel (TBF-17, 19S, and 20S) havehydrographs that show low barometric efficiency and the characteristic background trend. As

with the closer intra-till sand wells, there is no indication of response to pumping in any of theintra-till sand wells located beyond 1000 feet from PW-3.

The five wells located at the south end of the Tremont Landfill that were monitored duringthe 72-hour pumping test (A89-3D, A91-7D, A91-9S, M-3, and M-4) showed absolutely noresponse to the pumping. The hydrographs are essentially featureless, showing little or no changeresulting from barometric fluctuation and no deviation during the pumping period. Thehydrographs for Chapman Creek shows essentially the same level trend as these wells which are

located in close proximity to it.


5.4.1.3 Evaluation of Vertical Interconnection

As described in the preceding detailed discussion of hydrographs and background trends

in ground-water levels, there was absolutely no evidence of drawdown in any of the intra-till

sand wells during the pumping test. Figure 5-17 shows a general trace of the limit of the area

where confined conditions exist in the uppermost aquifer. In the unconfined area north of this

line there is no physical mechanism for a hydraulic response to be transmitted vertically.

Moreover, there was no drawdown in the uppermost aquifer in that area, as will be discussed in

the next section. Within the confined area, very careful analysis of the water-level data collected

during the test revealed no vertical interconnection between the uppermost aquifer and intra-till

sands within the confining bed above the aquifer.

5.4.1.4 Evaluation of Lateral Interconnection

Figure 5-26 shows the drawdown observed in wells which are developed in the uppermost

aquifer. Essentially all of the wells in the unconfined portion of the aquifer showed no

drawdown. It appears that the cone of depression spread asymmetrically to the northwest,

because drawdown was observed at the supply well and at TBF-20D. However, TBF-19D was

not affected. This was not unexpected, considering that the boring log suggests that well TBF-

19D is developed in a different sand zone that is isolated. The much-higher water-level elevationin TBF-19D also is strong evidence that the well is screened in a zone that is hydraulically

separate from the uppermost aquifer as defined for the Clarkco site. The same rationale applies

at well PW-1. The pumping test confirms this conclusion.

None of the observation wells located at the Tremont Landfill to the southwest of PW-3

were affected by pumping, which in the case of the confined saturated zones, indicates that there

is no lateral interconnection. Wells A91-9S and M-3, for instance, are developed in what are

considered to be local sand lenses within material which is mostly till. Therefore, it was

considered unlikely that a lateral interconnection with these wells existed and the test results

confirm this conclusion. Wells A91-7D, A89-3D, and M-4, however, are developed in effectively


unconfined saturated zones which may be horizontally equivalent to the uppermost aquifer at the

Clarkco site or, more likely, to a discrete aquifer located further to the west. In either case, a

response to pumping at PW-3 would not be expected, and none was observed. This is consistent

with data presented in the Tremont Landfill assessment report (Eagon, 1992a), which describes

a flow system that discharges locally to Chapman Creek.

Well 92-23D, located south of PW-3 along Snyder Domer Road, showed no evidence of

drawdown during the test, which confirms the conclusion that the uppermost aquifer at the

Clarkco site pinches out to the south. There also was no drawdown observed at well 92-2 ID

located only 1025 feet to the southeast of PW-3. The water-level elevation in this well is*

consistent with other wells developed in the uppermost aquifer and it is screened at about the

same elevation as the screen and gravel-pack interval of PW-3. However, there is no evidenceof a lateral interconnection in the pumping test results, which leads to the conclusion that 92-2 ID

is screened in a saturated zone which is hydraulically isolated from the uppermost aquifer. This

serves to illustrate the variable nature of the stratified drift, particularly to the south and southeast

of the proposed landfill footprint.

Well 92-20D is screened in a deeper zone than the other observation wells in the uppermost

aquifer, as shown by the significantly lower water level (see Figure 5-21). The lack of observed

drawdown during the pumping test confirms this conclusion. Whether or not there was any

hydraulic response in the shallower saturated zones at well 92-20D that are closer in elevation

to the aquifer at PW-3 cannot be determined, because only the deep zone is screened at 92-20D.

However, considering that no drawdown was observed at wells C91-2D, 92-14D, and 92-14DD

also located to the northeast of PW-3, it seems doubtful that the hydraulic response would have

been transmitted through the unsaturated portion of the uppermost aquifer to this location, which

is even farther away.

The cone of depression delineated in Figure 5-26 shows the extent of the area in the

uppermost aquifer affected by the pumping of PW-3. Time-drawdown graphs presented in

Appendix I indicate that the wells in which drawdown was observed responded in a manner that


can be characterized as nonieaky artesian conditions. In other words, all of the water pumped

came from storage in the aquifer, rather than some source of recharge such as confining-bed

leakage or streambed infiltration. There does appear to be delayed yield from storage as seen

from log-log plot of the time-drawdown data from well C92-5DD. This is believed to be due

to an imperfect interconnection between zones within the aquifer due to stratification. Evidence

supporting the poor connection is the smaller drawdowns observed in the shallower wells at these

locations, i.e. C91-5D and 92-22D. The delayed response shown by the semi-log graph of the

drawdown in well 92-22D is further evidence of this (see Appendix I).

Negative boundary conditions are indicated by the semi-log plots of drawdown in PW-3

and the affected observation wells. This is consistent with the shape of the cone of influence

delineated on Figure 5-26, and the apparent lack of a lateral interconnection in certain directions

from PW-3.

5.4.1.5 Calculation of Aquifer Characteristics

Aquifer characteristics that were calculated from the pumping-test data from various wells

are summarized in Table 5-4. Well TBF-20D and the supply well could not be used for time-

drawdown computations due to the erratic nature of the data caused by intermittent pumping at

the supply well. Calculated values for transmissivity (T) which are considered to be valid arein die range of 41,800 to 51,100 gpd/ft. Assuming diat the average thickness of the aquifer

within the cone of depression observed is about 30 feet, the average hydraulic conductivity for

the uppermost aquifer based on the pumping test results is 1556 gpd/ft2 or 7.3 x 10~2 cm/sec.

This compares favorably with values determined from slug tests on wells developed in the upper

portion of the uppermost aquifer shown on Table 5-4.

The storativity (S) values determined from the pumping-test data are in the typical artesian

range of 1 x 10"*. This is consistent with confined conditions in the aquifer which exist at PW-3.

However, the distance-drawdown graph plotted from test data (see Appendix I) indicates that

a storativity value of this order of magnitude would cause a very extensive cone of depression.

______._________„__________________________ — _ _ _ - —_______________________.________________„_____.————•———


The transmissivity value determined from the slope of the distance-drawdown graph seems

consistent with drawdowns observed, and T values derived, from time-drawdown methods.

However, the extent of the cone defined by the distance-drawdown plot is much greater than was

actually observed. A value of 1.4 x 10"3 derived from distance-drawdown computations is high

for confined conditions and it seems obvious that the actual S must be higher yet to reconcile the

observed results with the aquifer characteristics derived. The conclusion to be derived from this

analysis is that the cone of depression developed within the confined or partially-confined part

of the aquifer to the south, and spread to the unconfined part to the north. Much of the water

pumped from storage apparently came from the unconfined part of the aquifer where the

storativity may be as high as 0.2. This is the most likely explanation for the limited size of the

cone of depression observed, and the apparent lack of drawdown experienced in the deep wells

to the north of PW-3 where water-table conditions prevail. Again, these results demonstrate thevariable nature of the uppermost aquifer and other units of which the stratified drift is comprised.

The true or average value for S cannot be determined from the test data, but it seems obvious

that it varies with local conditions and becomes larger to the north where there is a transition

from confined to unconfined conditions.

5.4.2 Lower Till In-situ Permeability Tests

Four wells screened in the Lower Till were installed to measure the in-situ permeability of

this material and demonstrate its integrity as a confining layer. Selection of the sites for these

installations was based on several factors. Good spacial distribution over the proposed site was

a primary consideration as was the desirability of installing the till wells at existing cluster well

locations. The lower till was specifically targeted because this natural barrier would be depended

upon to isolate the zone of waste placement from the uppermost aquifer beneath the entirelandfill footprint. Only well-cluster borings in which sand seams and partings were absent over

a lower till thickness of at least ten feet were considered. The ten feet of massive till screening

criterion was necessary to allow for a five-foot well screen and a well point, two feet of sandpack above the well screen, and two and one half feet of effective annular seal above the sand

pack. If sand seams or partings were present in the well screen or sand pack intervals, the slug


test would measure the permeabilities of these horizontal pathways instead of the permeability

of the till.

Based on the above considerations, four installation locations and two back-up locations

were selected. Suitable materials were encountered at the original four installation sites and till

wells were installed in each and given the designations 92-7TP, 92-10TP, 92-14TP, and C91-8TP.

The till wells were installed at the 90-7, 90-10, 90-14, and C91-8 cluster well locations (Plate

13).

A four-foot well screen was installed in 92-7TP because only 6.5 feet of massive till was

encountered in this boring. Well construction tolerances in this boring were such that there was

concern that the results of the slug test on this well might be influenced by an adjacent saturated

zone. They were not.

Slug tests were performed during the period December 21-23, 1992 in each of four till

wells that were installed in November 1992. Time-drawdown plots of the till-well slug tests are

included in Appendix G.

As shown in Table 5-6, in-situ permeabilities ranged narrowly from 1.5 x 10'7 cm/sec to

3.1 x 107 cm/sec. These field determinations of hydraulic conductivity are an order of magnitudegreater than the laboratory-determined permeabilities on the undisturbed samples (Table 4-3).

The difference between the two results is less than the two orders of magnitude that might be

expected due to the fact that the laboratory tests measure permeability in the vertical direction

(perpendicular to clay structure and bedding features, if any) whereas the field tests measure the

path of least resistance (generally horizontal) that may result from sand or silt partings adjacent

to the borehole. Bouwer (1978, p.l 17) states that results yielded by the slug test primarily reflect

permeability in the horizontal direction. Even if no sedimentary features or clay-mineral

orientation resulted from depositional processes; compaction, consolidation, and isostasy resulting

from ice loading and unloading, could be expected to produce a least-principal-stress direction

in the horizontal plane that would be a path of least resistance for fluid migration.


For the reasons discussed, the in-situ tests on the till wells do not duplicate the laboratory

results, but they are well within the range of variation that has been cited in the literature for

differences between horizontal and vertical permeabilities. Because vertical migration through

the till sequence is the primary concern, it is more valid to use laboratory-determined tillpermeabilities in calculations that predict or evaluate vertical rates of migration through the till,

than it is to use in-situ permeability determinations that primarily reflect hydraulic conductivity

in the horizontal direction.

5.4.3 Tritium Age-Dating of Ground-Water Samples

In order to gain additional insight into rates of recharge and movement of ground water at

the Clarkco site, as well as data that might be used to evaluate whether or not there is a directhydraulic connection between various saturated zones hi the glacial drift sequence, ground water

samples from five wells were dated radiometrically using the tritium method. The wells were

selected for testing on the basis of stratigraphy and hydrogeologic environment. Well

installations to which large amounts of water were added during drilling or construction generally

are unsuitable for testing because they are likely to yield ambiguous or inaccurate results. This

is particularly the case for saturated zones with very slow rates of ground-water movement.

Table 5-7 lists the wells that were tested, the saturated zones that the wells are screened

in, the results of the tritium tests, and the interpretation of the test results in terms of rate of

recharge to the zone tested. A copy of the test results from the tritium laboratory is included in

Appendix J.

Tritium is a naturally-occurring hydrogen isotope with a half-life of 12.26 years. Its

concentration is expressed in tritium units (TUs), which is the number of tritium atoms per 1018

atoms of hydrogen. Prior to atmospheric testing of thermonuclear devices in 1954, natural tritium

concentrations in rainfall were about 3 to 20 TUs. Thermonuclear explosions in the atmosphere

caused greatly varying TU values in precipitation worldwide and the permanent entry of man-

made tritium into the hydrologic cycle. TU values in precipitation peaked in 1963-1964 with a


value of 4000 TUs recorded in Chicago. TU values subsequently declined to stable levels of

around 30 to 40 since about 1970.

The apparent age of ground water can be determined by comparing tritium levels in ground

water and rainfall. Tritium concentrations that are very low (about 0.3 TUs) indicate ground

water that is older than 50 years. Low levels of tritium (about 1.0 TUs) indicate ground water

that is younger dian 50 years but prethermonuclear. Higher TU values indicate ground water that

is post-thermonuclear in age.

The tritium results from well 91-9Z, developed in the 1077 sand, indicate that infiltration

of precipitation is rapid in the zone of weathering in the till (to a depth of about 20 feet). The

same conclusion was reached by studying the hydrographs of the various sand zones (Figures 5-3

through 5-7) and Figure 5-9. The 1077 sand screened in well 91-9Z is 17.4 feet below ground

level and the screen pack in this well is only 14.5 feet below ground-level. The high tritium

levels in well 91-9Z suggest that most or all of the water sample originated as precipitation that

percolated downward to the 1077 sand zone within the last few years. The rate of recharge to

the 1077 sand at this location is considered to be rapid because the tritium results indicate that

the ground water is young.

Results of age-dating the ground-water samples as a group, however, (Table 5-7) clearlyindicate dial there is not rapid vertical movement of groundwater through the entire till sequence.

Very low tritium levels were found in the water sampled from well 90-1 OX, which is screened

across the 1050 sand. At this location, the 1050 sand is 48.4 feet below ground level and the

depth to the screen pack in this well is 45.5 feet. The tritium concentration in well 90-10X of

0.35 TUs indicates that ground water in this sand zone is at least 50 years old and that recharge

is very slow.

Very low tritium levels also were found in the ground water sampled from well 92-4X

which is screened in the 1035 sand. The 1035 sand in well 92-4X is 56.0 feet below ground

level and the depth to the screen pack is 55.5 feet. The slightly lower tritium concentration (0.33


TUs) in well 92-4X once again indicates ground water that is at least 50 years old, and that

recharge is very low.

Well 90-9DD is screened just below the water table in the uppermost aquifer. Depth to

the screen pack is 108.2 feet but depth to unsaturated sands that are part of the uppermost aquifer

system is only 75.5 feet. The water sample from well 90-9DD has a low tritium concentration

(1.26 TUs) that indicates slow recharge. (Rainfall with pre-1954 tritium concentrations of less

than 15 TUs would decay to levels of about 1.0 TU in about 30 years.)

Well 92-27DD is screened near the bottom of a thick sand and sand and gravel sequence

that constitutes the uppermost aquifer system. The upper part of the sequence is unsaturated.

Depth to the top of the sequence is 75.0 feet. Depth to the water table is about 99.0 feet. Well92-27DD is screened from 133.0 to 138.0 feet (about 38 feet below the water table) and the depth

to the top of the installed screen pack is 131.0 feet. The water sampled from this well also has

a low tritium concentration (1.00 TUs) indicating that it is pre-1954 in age and somewhat older

than the ground water from well 90-9DD. The tritium data (Table 5-7) suggests that the recharge

to the uppermost aquifer probably takes place laterally (rather than vertically through the till

sequence) because the uppermost aquifer ground water is younger than the ground water in the

1050 and 1035 sand zones that overly it.


LITHOLOGY ANDPHYSICAL PROPERTIES

HYDROGEOLOGICSIGNIFICANCE NORTH SOUTH

UPPER TILLClayey sandy silt with minor clayey silty sand. Soildeveloped in upper 1 to 3 feet. Weathered andoxidized to a depth of 12 to 14 ft. P.L. = 11-13;L.L. = 18-23; P.I. =6-10.Moisture Content =8.0-12.3%. Dry UnitWeight = 127-137lbs/ft3. 34-44% silt; 16-21%Clay. Absent in ravines.

TILL (CL with CL-ML)

AQUITARDK = 1.2xl08to 6.3x10"cm/sec.Includes minor saturated interbedsand localized zones of saturationwithK = 1.9xl02to P.lxlO-'cm/sec.

INTER TILL ZONEPredominately till at most locations. Upper and lower contactsare silt or silly sand as thin beds, seams or partings. Finelyinterbedded silt and fine sand where saturated elastics aremore man 2 ft. thick. Absent in deep ravine cuts. Most of theinter-till zone is till with physical properties like those of theupper and lower tills.________________________

AQUITARDK = l.SxKT'to 7.2x10-*cm/sec, slowlypermeable beds with K~ 1.1x10'cm/sec.and minor saturated zones with K=2.8xlOz

to 1.7xlO'5cm/sec.

LOWER TILLClayey sandy silt with minor sandy clayey silt.P.L. =12-16;L.L. = 18-25; P.I. = 6-11. Moisturecontent = 9.3-14.1%. Dry unit weight = 123-134Ibs/ft'3. 34.7-43.3%silt; 13.6-25.5%clay.Absent only in deepest ravine cuts.

TILL (CL with CL-ML)

AQUITARDK = 1.2xlO-*to 4.5x107. Includesminor saturated interbeds, some ofwhich appear to be isolated, withK = 3.4xl03to 3.6xl05.

STRATIFIED DRIFT

Sand and gravel with cobbles. Some sand, silt,cohesive interbeds, and cemented zones. Gradeslaterally and vertically to silty sand. 2.1 to 30.3%silt plus clay.

(SM, SP-SM, SW-SM, and GMwith minor ML & CL)

Till units have physical properties like those of thelower till. Clayey silt beds and beds described asalluvial materials have more clay and silt, and lesssand and gravel than do till samples. They aremore plastic, have lower dry unit weights, and areas, or more impermeable than till samples.

UPPERMOST AQUIFERSYSTEM

Mostly unconfmed local or sub-regional aquifer. Some perchedzones of saturation in upper part.Yields <25to >100gpm.

Perching layers and aquitards.

. ' _••.»:.'

BEDROCKDolomite and limestone sequence of Silurian age.

REGIONAL AQUIFERYields 10-50 gpm.

Figure 5-1. Hydrogeologic Column for Clarkco Site

t" V-.F:-'./-':.-s* •'•^'•v •-•••-••'̂•{-.v-frv.-r.yrix

.-.TV.-"' V V• • • V-?" *!^-:"••••-•^.-U

::.'l:<l\.r-^:^

c/oU4)E<L>

Ort

-acDo6(-*-<oTDOaa,<uocoU<Ntnaao

CO

NFIN

ING

BED

UPPER

MO

STAQ

UIFERSYSTEM

REGIO

NALAQ

UIFER

pLJJ111U^

zoIUJ

LU_JLJJ

111

UJ

1108

1106

1104

1102

1100

1098

10961-

1094

1092

1090

1088

1086

EAGON & ASSOCIATES INC.

1084

108

T

PROPOSED CLARKCO LANDFILLHYDROGRAPHS FOR WELLS COMPLETED

IN THE 1092 SAND

WELL 9MW

WELL 92-24Z

i i i I i i i i i I i i i I i i i I i i i I i i

171/91 4/1/91 7/1/91 10/1/91 1/1/92 4/1/92 7/1/92 10/1/92

Figure 5-3. Hydrographs for Wells Screened in the 1092 Sand

1/1/93

1108

1106

1104

1102

1100

1098

1096

1094

1092

1090

1088

1086

1084

1082

LLILLJ

oILLJ_lLLJ—1LU

LLJ_lio:LU

1094

1092

1090

1088

1086

1084

1082

1080

1078 -

1076

1074

1072

1070

1068

i — i


IN THE 1070 AND 1077 SAND

1070 SAND

- WELL 90-6X

- WELL 90-9X

- WELL C91-8Y

- WELL C92-9Y

1077 SAND

- WELL 90-6Y

- WELL 91-9Z

- WELL 90-1OY

i——i i——i i791 4/1/91 7/1/91 10/1/91 1/1/92 4/1/92 7/1/92 10/1/92

Figure 5-4. Hydrographs for Wells Screened in the 1077 and 1070 Sand

EAGON & ASSOCIATES INC-i—i—i—i—i—i—i—i——11094

1092

1090

1088

1086

1084

1082

1080

1078

1076

1074

1072

1070

10681/1/93

PLULLJ

iuu_lLLI_lLLJ

LJJ_lccLLJ

1080

1078

1076

1074

1072

1070

1068

1066

1064

1062

1060

1058

1056

1054

EAGON & ASSOCIATES INC.T

PROPOSED CLARKCO LANDFILLHYDROGRAPH FOR WELLS COMPLETED

IN THE 1060 SAND

WELL 90-7Z

WELL 90-8X

WELL C92-26X

i——i——I——i——i——t- J———I———L J———I———I———I———I———I———L.

"1/1/91 4/1/91 7/1/91 10/1/91 1/1/92 4/1/92 7/1/92 10/1/92


I I I1/1/93

1080

1078

1076

1074

1072

1070

1068

1066

1064

1062

1060

1058

1056

1054

1076

LLJLULJL

o1LL1_JUJ_JUJ

LU_JQLLU

1074h

1072

1070

1068

1066

1064

1062

1060

1058

1056

1054

1052

105501/'

-i——i——r n——i——r i——i——r i——r n——i——r i——rEAGON & ASSOCIATES INC.——i——i——i——i——i——i——r

WELL C91-4Y

WELL C91-4Z

WELL 90-6Z

WELL C91-8X

WELL C92-9X

WELL 90-1 OX

WELL 92-11X

WELL 92-17Y

WELL 92-18X

WELL 92-24Y

WELL 92-28X

WELL 92-29X

WELL 92-31Y

WELL 92-33Y


IN THE 1050 SAND

.*•••-........

J———L I i -I——\———L. ' '

1/91 4/1/91 7/1/91 10/1/91 1/1/92 4/1/92 7/1/92 10/1/92


1/1/93

1076

1074

1072

1070

1068

1066

1064

1062

1060

1058

1056

1054

1052

1050

UJLU

g

ILU_lLU_JLU

LU

UJ

Sc

1059

1057

1055

1053

1051

1049

1047

1045

1043

1041

1039

1037

1035

103

i——r T———T I———T "T———I———T

PROPOSED CLARKCO LANDFILLHYDROGRAPHS FOR WELLS

COMPLETED IN THE 1035 SAND

—©— WELLC92-1X

X WELL92-2X

0 WELLC91-4X

+ WELL 92-4X

—•— WELL 90-7Y

D WELL 91-9Y

A WELL92-14X

—-B WELL 92-15X

.....A.... WELL 92-16X

-0 WELL 92-19X

.....£>...... WELL92-31X

I . I ' I ' l l I I ' i I———L -I———I

1/91 4/1/91 7/1/91 10/1/91 1/1/92 4/1/92 7/1/92

EAGON & ASSOCIATES INC.————,1059

1057

1055

1053

1051

1049

1047

1045

1043

1041

1039

1037

1035

103310/1/92 1/1/93


15.0 --.

14.0 4—

13.0 4j"

12.0 -Ij

£11.0 -jUJ -4

^10.0 -IC/5 Ez ~Q 9.0 -j< 4p? 8.0 4O J

3 7 .0^

g 6.0 1UJ J_J :o: 5.0 4UJ E\- ~| 4.0 4

—I

3.0 4—

2.0 -1—-

1.0 2

n n

, , , , , , , , | , , , . I , | , | | , , , | ,, i i | i i | ! 1 1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l_l 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1-1 1-1 1 1 LI 1,1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

PROPOSED CLARKCO LANDFILLCOMPARISON OF WATER - LEVEL FLUCTUATION VS. DISTANCE TO NEAREST

DISCHARGE POINT FOR WELLS ABOVE THE UPPERMOST AQUIFER90-8X

0

90-6Wo

... Q7 90-9X91 -9Z o

90-1 OYo

C91-4Zo

C91-4Yo

C91-4Xo

90-7ZO

92-24ZO

90-6Y0

90-6X 90-1 OXo o

92-29X C92-1X _Q. ov ° 91-9YQ o oy i ~v/^92-28X 92-14X C92Q-9X

0 92-16X

92-31X°°C91"6Y ° 92-2X ^X 92.24Y ° ° 92£™C92-9Y ° ° 92-1 1X

92-31 Y0 o 92-1 5X92-33Y o

EAGON & ASSOCIATES, INC.— • • • • . . T - » i - > T . i i - T t i T - t " T"T't~t T~r n i i i ^T n ITTTI t i i* t rT- i'~r T T t 'T 'T1 i~v T~I — i r1 i i T i T i i i i i i — r r r-i • t i i T i i i > T r-t T 't I~T T T'T1 > i i i i T i i t < f r-^ i i t i T-I -T-T i i < t-v T-> i i . I"T T i i i i i T-V. i •

- 15.0

- 14.0

A f} rt- 13.0

- 12.0

- 11.0

-- 10.0

§- 9.0E-| 8.01—

E- 7.0'-\ 6.0~r

\ 5.0L

E- 4.0E--

j- 3.0~r

\ 2.0^~-

j- 1.0I

- n n

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300DISTANCE TO NEAREST DISCHARGE POINT (FEET)

to Mparpct Onfrror, for Tntr'i-Till <snnr|

13. U -2

-E

14.0 -i-E

13.0 -jJI

12.0 -j-:

t 11-0 ^LLJ -LJL i•—10.0 -.CO~y — •

Q 9.0 -E< -EH 8.0 -I0 jID --u± 7.0 -E_ | -rIII> 6.0 -ELU '-_J I

£T 5.0 -ELU Et- -

| 4.0 -E—.-

3.0 -EI

~

2.0 4—

1.0 4-

n n J

PROPOSED CLARKCO LANDFILLCOMPARISON OF WATER - LEVEL FLUCTUATION VS. DEPTH TO

TOP OF SAND PACK FOR WELLS ABOVE THE UPPERMOST AQUIFER90-8X

o

90-6Wo

a. „ 90-9X91 -9Z oo

90-1 OY0

C91-4ZO

C91-4Yo

C91-4X0

90-7Zo

92-24Zo

90-6Y0

90-6X 90-1 OX90-6Z 91;9Y

92-29X C92-1X „, _.„ °o o 92-28X C91-8X

en tAy C92-9X"" .

^ „ ° 92-1 6XC91Q-8Y 90-7Y o 92-19^2^x

92-26X ° C92-9Y 92-31 X 92-18#2-j7Y ° Q2% 1Xo o o »w o yz*^*+ T„-... 92-2X °9233Y 92-31 Y

92 o Y ° , 92-1 5XO

EAGON & ASSOCIA TES. INC.. -...-,-- , —— . ——— . ——— , ——— . ——— i ——— , ——— , —— i — — T —— r- — T" r-T- —— r —— r——— i ——— I ——— T ——— I —— I —— T ——— T —— -I P i ——— . —, —— 1 ——— . ——— r —— , ——— . ——— . —— • —— ~r~'T"'T' —— I ——— T — ' !"~ T —— ' r™ 1 ——— I —— T —— r t ——— IT- —— F —— T —— ̂ ——— P —— I ——— I ——— T ——— P" — F —— I ——— 1 ——— I —— T —— T ——— I ——— f —— T ——

- ID.U

'-

j- 14.0E-E- 13.0~I

E- 12.0I_

E- 11.0I_

~

E- 10.0I^_~

j- 9.0E-

E- 8.0;

E- 7.0—-

E- 6.0I~

r 5.0:

E- 4.0I_~

E- 3.0:-~

E- 2.0E-z- 1.0;

: n n

10 6020 30 40 50DEPTH TO TOP OF SAND PACK (FEET)

Figure 5-9. Comparison of Water-Level Fluctuation to Top of Sand Pack for Intra-Till Sand Wells

70

c9i-aocwc91_8YIC92^8TP^1_8X \

I "^ | 91-9Z 90-90D )

\ ' .91-9Y~90-9X I

\^.^ \

PROPOSED

i LIMIT OF' SOLID WASTE

-\

//

O C91-20

/C92-1X

C91-1

92-200 O

92-25X8

89-79 92-33Y• Q)

92-32 92-33X• C91-6

C91-3I

O92-28X

I

89-8

92-26XilI

92-29•

92-290992-29X

LEGEND

TOPOGRAPHIC CONTOUR OFELEVATION AT WHICH SANDOCCURS (OCFINES OUTCROPAREA WHERE SAND IS PRESENT)

UMIT OF SAND ZONE

92-31Y

92-31X_C9t-4Z

^C91-4YC91-4X

UJCLO(TD_

QC92-5DD

°C91-50

(,0/3/92)

DIRECTION OFGROUND-WATER FLOW

#69-9 92-210

20O 4OO

SCALE IN FEET

Figure 5-10. Ground-Water Flow in the 1092 Sand

en O 3 c 3 Q. I O c*

(T) 3) o 5' *-»• zr O 00 CD O 3 a.

PRO

PER

TY

LIN

E \

10 c en I o 3 3 CL I O 31 o 0> O O D o.

cs 10 I

——

— ~

< /

Nl

-V

/

?^1

in

A

I

o I 3 Q. I f o •-j o c/> o D Q.


'" i7TP^f / /

/ i/p*-2 ,7 \ / +

TOPOGRAPHIC CONTOUR OFELEVATHDN AT WHICH SANDOCCURS (DEFINES OUTCROPAREA WHERE SANO IS PRESENT)

DIRECTION OFGROUND-WATER FU>«

• 89-9 ) \


PROPOSEDLIMIT OFSOLID WASTE ————— \

f /^ " ~^ '''^^89-4 / / //

92-16X //9°~7^090-7D / /•^ 7^92-TTP / '

92-25YB 92-25X8 \ \* 705J.66 \ ,

89-7* 92_33y ' |

92-3? * ' I92 32 92-33X / 'XMl-a\I 11054.53

92-31Y

92-31XI

CLoa:Q_

I

QC92-5DD°C91-50

C91-3«

1053.81O92-28X

-4-PW-3

•92-29DB92-29X

LEGEND89-8

92-26X

1057.37

TOPOGRAPHIC CONTOUR OFO£VATK>N AT WHICH SANDOCCURS (DEFINES OUTCROPAREA (WHERE SANO IS PRESENT)

UMIT OF SAND ZONE

WATER LEVEL ELEVATION(10/5/92)

DIRECTION OFGROUND-WATER FLOW


92 1(T 092-19X92L1B tnAi^t

92-1400^0-140

PROPOSED, ,. II-T r\ri LIMIT OF

92-25YEI 92-25X8

TOPOGRAPHIC COKTOUR OFELEVATION AT WHICH SANDOCCURS (DEFINES OUTCROPAREA WHERE SAND IS PRESENT]

LIMIT OF SAND ZONE

DIRECTION OfGROUND-WATER FLOW


31 lO c (0 en I --J (V <s c O a v> O O ct Q.

986.08,90-7Y__90-70

^ 92-7JP90-7Z (971.41)

-4-PW-2

986.51O90-13D

C91-9j|C92-9Y

92-9X

986.6892-1400

92-14X 92-14TP957. OJ

C91-80 :9)-8YC92-8TP"C91_8X

986.77OC91-2D

i PROPOSEDi LIMIT OF

SOLID WASTE

0—— POTENTIOMETRIC CONTOUR

1040.31 WATER LEVEL ELEVATION

WATER LEVEL IN BRACKETSNOT CONTOURED

Figure 5-18. Potentiometric Surface of Uppermost Aquifer, August 1991

985.0390-7Y 90-70

985.97 (90-60

-6W90-62 90~6X

90-10Y 90-1 OX "^ 89-5

985.31O90-130

955.4J92-1400 90-14D

C91-8CU^C91-8Y.66

1-8X 985.5991-9Z 90-900QD

90-9X

985.46OC91-2D


92-25YB 92-25X8

Figure 5-19. Potentiometric Surface of Uppermost Aquifer, October 1992

r - t l l O

r- 03 tcoO

1100 -

1090 -

1060-

1050 -

IO40-

1030-

IO20-

KXX> -

990 -

980 -

970 -

960 -

950 -

940 -

930 -

920 - 2

910 -

:>rT>*

Cn<a<

CO

!jfi

i

3•> </5 °0

OJ

B y

•>•>

<5><r•

a

[1

*

Li_ U_ CD >.C D c D T g > - X _ I 01 - l - C M C O C D o O O . H- X

ff-

^-T

Q

„,Mi1

s

r en ^ .T SSI

=

1

|l|

1*-

S enJ 0

0i

2

« ? 6en en

c

?'O^ i

a

1

i

IO

evj

> x*** ro >OJ C\J i

fO

o

1

r*i c' C

"

C

1 [0

lO (Q

<n w'APPROXIMATE BASE

I

SWATER LEVEL ( 10-5 921P^AND PACK

|\CREENED INTERVAL

1 APPROXIMATE LEVEL OF CHAPMAN CREEK

» APPROXIMATE LEVEL OF STORMS CREEK

ogCM (M

CC

a

1

1 CMn en

s -

1III

a>

XCD

< ?

^ Q-VJn

OF

3 2

»

i

\iM >

0C.

o

I

< >-r <

I

S ?> c.

y

iowfv?

I

— S

~

<ri(7)O

O r

Till

\J3>

ff

>

Q O— 0CVJ (.

CSJ '

y

1

s

I

ao

>c0G

X Q Q*T *t TT

C ~ • ~~ OJ OJ OJJ <J> ff> ff*1J

B

*

I

9

2 x Tj T o^ CM ^

O0CM

CMen

i

»

0

s

1

i

2<T>

^

1™

OO

CSJ

CVJ

fi S

Xin

WOf>.

.

1

s,.

t\J

L

hLLL

Cf-

L

L

-IO70

-IO5O

Figure 5-21. Graphic Summary of Observation Wells Used for 72-hour Pumping Test L900

-1030

-IO20

-1010

-1000

-990

-980

ior987.0 -

986.5 -

986.0 -

985.5 -

985.0 -

984.5 -

—, 984.0 -LU£ 983.5 -

g 983.0 -

< 982.5 -_LULTJ 982'° 1LU 981.5 -_LU :

-J 981.0 -

H 980.5 -< ;

^ 980.0 -_

979.5 ^

979.0 -

978.5 -^

978.0 -i

977.5 ^

977.0 -

ior

3/92 10/4/92 10/5/92 10/6/92 10/7/92 10/8/92 10/9/92 10/10/92 10/11/92 10/12/92 10/13/92 10/1

I , , I , I , I , I , I , I ,

~~~— -— __

/- — "X

IN———- ——— s.^ — -^^

f

PROPOSED CLARKCO LANDFILL72-HOUR PUMPING TEST OF PW-3

OBSERVATIONS IN PW-3(PUMP TEST STARTED 1 030 OCT. 6,

ENDED 1030 OCT. 9)—— i | —— i i i i i i i —— | —— i —— | —— i —— | —— i —— | —— i —— | —— , —— , —— , ——5/92 10/4/92 10/5/92 10/6/92 10/7/92 10/8/92 10/9/92 10/10/92 10/11/92 10/12/92 10/13/92 10/1

4/92

r 987.0

r 986.5

r 986.0

r 985.5

r 985.0

r 984.5

r 984.0

r 983.5

'- 983.0

'- 982.5

r 982.0

r 981.5

r 981.0

r 980.5

- 980.0

r 979.5

r 979.0

r 978.5

r 978.0

- 977.5

- 977.0

4/92

Figure 5-22. Pumping Test Hydrograph for Well PW-3

10/3/92 10/4/92 10/5/92 10/6/82 10/7/92 10/8/92 10/9/92 10/10/92 10/11/92 10/12/92 10/13/92 10/14/92

990.0 990.0

< 985.5 -_UJsi 985-° -3

C91-5D

C91-5DD

92-22D

92-22DD

983.0 ^

982.5 -_

982.0 -

981.5 -_

981.0 -j

980.5 -

980.0

PROPOSED CLARKCO LANDFILL72-HOUR PUMPING TEST OF PW-3WELLS IN UPPERMOST AQUIFER

(PUMP TEST STARTED 1030 OCT. 6,ENDED 1030 OCT. 9)

10/3/92 10/4/92 10/5/92 10/6/92 10/7/92 10/8/92 10/9/92 10/10/92

—I—10/11/92

980.0

10/12/92 10/13/92 10/14/92

Figure 5-23. Pumping Test Hydrographs for the Closest Observation Wells in the Uppermost Aquifer

10/3

1063.0 -

1062.5 -_

1062.0 i

1061.5 -_

1061.0 -

1060.5 -_

_-. 1060.0 -tu :UJ 1059.5 -_t- ;

g 1059.0 -m

< 1058.5 -^HI :2J 1058.0 -

UJ 1057.5 -:

-J 1057.0 -^

H 1056.5 ^

> 1056.0 -:

1055.5 -

1055.0 -E

1054.5 -

1054.0 -

1053.5 -

1053.0 -10/

/92 10/4/92 10/5/92

PROPOSED CL72-HOUR PUMPI

(PUMP TEST STAENDED 1

^ »_

^^^^^^

3/92 10/4/92 10/5«2

10/6/92 10/7/92 10/8/92 10/9/92

<\RKCO LANDFILLNG TEST OF PW-3.RTED10300CT.6,030 OCT. 9)

^-+~+~*^*~*~*^

s^~~ ——_^_._±_ts^~*~~*~t^*^

10/6/92 10/7/92 10/8/92 10/9/92

10/10/92 10/11/92 10/12/92 10/13/92 10/1i .i i i i i i i

A 92-28X

—4— 92-29X

—0— BAROMETRIC PRESSURE

^———— ̂ ^^

-%x» -̂(

—^ir~*—

~ £^*~~*—

10/10/92 10/11/92 10/12/92 10/13/92 10/1

4/92

- 31.0

- 31.5

- 32.0

- 32.5

- 33.0

- 33.5

- 34.0 >

- 34.5 §: m- 35.0 ̂ j

- 35.5 -o

"- 36.0 co

- 36.5 §: m- 37.0 "TI: m- 37.5 5: Ir 38.0 8

r 38.5

r 39.0

r 39.5

r 40.0

r 40.5

- 41.04/92

Figure 5-24. Pumping Test Hydrographs for the Closest Observation Wells in the Intra-Till Sand Zones

10/6/9

988.0 -

2-987.5 -CO

u] 987.0 -LU

§986.5 -

I 986.0 -'LU H

Lu 985.5 -

£ 985.0 -LU :

1 984.5 -

32.0 -

^ 32.5 -_

| 33.0 1

£33.5 :Z>COft 34-° -:

BA

RO

ME

TRIC

PR

f.0

CO

CO

CO

3) C

TI

Ol

4.̂

D C

O <

D

01

i i i i

1

i i

t t

1 | i

i

; 1

i i |

208.00 10/6/9220:00 10/7/9208:00 10/7/9220:00 10/8/9208:00 10/8/9220:00 10/9/9208:00

HYDROGRAPH OF 90-9DD

^^~--^-

0.1V

79%

0.14-

0.13'

76%

o.ir

.— — -~

^—~~

~~- ______

80%

—— ,

0.25'

BAROMETRIC RECORD

AVERAGE BAROMETRIC EFFICIENCY = 78 %

PROPOSED CLARKCO LANDFILLILLUSTRATION OF METHOD USED TO DETERMINE BAROMETRIC EFFICIENCY

988.0

'- 987.5

'- 987.0

i- 986.5

1 986.0

985.5

- 985.0

- 984.5

- 32.0

32.5

r 33.0

'- 33.5

'- 34.0

'- 34.5

7 35.0

1 35.5

36.010/6/9208:00 10/6/9220:00 10/7/9208:00 10/7/9220:00 10/8/9208:00 10/8/9220:00 10/9/9208:00

Figure 5-25. Illustration of Method Used to Determine Barometric Efficiency

<£> cn I O) o Q Q.

O * C X)

TD 0> -i 3 o (t) —t Q m Q. o O C C. 3 0)

Table 5-1.FIELD HYDRAULIC CONDUCTIVITY TESTS, FOR INTRA-TILL SAND WELLS


Well

90-6W92-24Z

90-10Y90-6Y91 -9Z

90-6X90-9XC91-8YC92-9Y

90-7Z90 -8X92-26X

90-6Z90-10XC91-4YC91-4ZC91-8X92-11X92-17Y

SandZone

1092 Sand1092 Sand




1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand

SandThidcnessScreened

2.60.8

1.7+0.1 = 1.8.25 +.50=0.75

1.4

2.24.2

2.9+1.0+1.6=5.50.6+1.0=1.6

1.71.7

1.7+6.5=8.2

0.60.7

0.6+0.1+0.8+0.5=2.03.1

0.3+0.1=0.41.6

0.6+0.9+0.7+0.6=2.8

ElevationTop of

1092.91092.8

1080.91078.51076.3

1069.5107031073.21074.2

1062.41059.51062.3

1047.11047.31046.11055.71056.71047.01048.1

Slug Test

5.2 xlO"3

4.1xlO~3

5.1 x 10"4

8.4xlO~5

1.3xlO~4

4.6xlO~3

13 x 10~3

1.8xlO~2

9.1 xlO"6

6.5xlO~3

1.7xlO~5

l . lxKT3

1.5xlO~2

8.4xlO~5

--

Pump Test

5.6xlO~3

1.9 xlO"2

1.3 x 10~4

2.0xlO~3

2.8xlO~2

2.5 xlO"3

2.3 x 10"2

9.1 x 10~4

5.4 xlO"3

3.9 xKT5

PUMPING TEST DATAPumping

fSOmV

1.0

.._ „ _

__

0.7

0.31.0

— —03

——— m-i

0.41.0

0.90.20.40.50.20.30.6

TjestDuration

fniih)

180_ ̂

— —

5.0

9.01440 P

__11.5

__8.0

1440 P

1440 P15.018.0120348.07.0

TestDrawdown

(ft)

7.20

___ _BD

11.02 - BS7.09 - P

— —BD

__BD

6.08 - P

5.18 - P5.75 - BS

12.85 - BS2.73 - BS8.82 - BS

BDBD

AvailableDrawdown

(ft)*

-3.281.56

0.46-0.53

1.28

8.087.03

-2.583.52

-1.631.659.61

5.355.40

12.230.55

-1.887.793.38

SustainedYield(gpm)

<10<1.0

<1.0«1.0«0.7

«0.25

<1.0«0.3

«1.0«0.44

1.6 C

1.1C«0.2«0.4«0.5«1.0«0.3«0.6

Calculated by subtracting the elevation of the top of the sand zone from the lowest water-level observed.Water levels below top of sand are reflected as a negative number

BD = Bailed DryBS = Broke Suction

P = Projected from test data.C = Calculated from test data.

intrhydr.wk3 Page I o f 2

TableS-l.(cont'd)FIELD HYDRAULIC CONDUCTIVITY TESTS, FOR INTRA-TILL SAND WELLS


Well

92-18X

92-24Y

92-28X92-29X92-31Y92-33YC92-9X

90-7Y91-9YC91-4X92-14X92-15X92-16X92-19X92-2X92-31X92-33X92 -4XC92-1X

SandZone

1050 Sand

1050 Sand

1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand

1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand

Sandv/.x— ,':v-ThicknessScreened

0.5+0.2+0.9+0.1 = 1.7

0.5+0.8+0.2=1.5

0.9+1.9+1.1=3.90.9+0.1+0.1=1.1

6.0+1.0=7.00.2+0.3+0.5=1.0

0.5

1.11.00.7

0.8+3.0=3.83.2+0.4=3.6

1.32.3+0.9+0.4=3.6

0.5+1.5=2.01.40.4

1.2+1.3+2.9=5.40.3+0.4+0.3+0.7=1.7

ElevationTtipof

Sand

1046.5

1052.0

1046.21054.81058.41054.31039.3

1039.71034.11036.01038.91038.31033.91034.61031.11029.91037.81032.21036.8

Slug TestK

5.1xlO~3

3.5 x ID'31.5xlO-3

9.6 xKT4

4.6 xlO"5

1.3xlO-3

3.6 xKT5

8.5 x 10~4

_ —2.4 xKT4

3.2xlO~4

--

- —— —

Pump TestK ' - • • . " .

(Bar In)(Bar Out)(Bar In)(Bar Out)

8.8 xlCT4

9.3 x 1(T5

6.1 x 10~5

1.6 xlO'4

--

8.9 xlO'58.0 x 1CT4

PUMPING TEST DATAPumping

.: Rate :';..';'•';-:;.fH>mV

1.0

0.9

0.60.3__0.50.3

0.5— _0.50.30.40.30.30.70.4--0.30.5

'^Tfestr'Duration

i^tiicySji};^--

151

7.0

34.012.0--

20.012.0

5.0— —

20.095.05.0

15.012.03.0

15.0--

95.026.0

TestDrawdown

(ft)

6.39

8.01

11.15 - BSBD--BDBD

BD— _

17.44 - BS13.76 - BS

BDBDBDBDBD--

15.44 - BS6.35 - BS

AvailableDrawdown

(fO*

5.52

3.35

8.891.77

-4.04-0.7511.81

1.08-2.9815.647.192.024.77

12.443.326.68Dry

13.865.89

SustainedYield(EPm)

<1.0

<0.9

«0.2«0.3«1.0«0.5«0.3

«0.5«1.0

<0.5<0.3

«0.4«0.3«0.3«0.7«0.4None<0.3<0.5

Calculated by subtracting the elevation of the top of the sand zone from the lowest water-level observed.Water levels below top of sand are reflected as a negative number

BD = Bailed DryBS = Broke Suction

P = Projected from test data.C = Calculated from test data.

intrhydr.wk3 Page 2 of 2

Table 5-2.GROUND-WATER LEVELS


REFERENCEELEVATION

DATE1/8/911/15/912/25/913/22/914/11/915/22/917/15/918/20/919/20/9110/17/9112/2/911/8/921/10/922/28/923/30/925/12/926/09/926/16/928/10/928/31/9210/5/9211/9/922/8/93

1109.34

PW-11026.401026.501026.491026.691026.381026.81

1025.411024.701023.621022.641022.11

1022.221022.021022.031021.84

1022.591022.441022.311022.121022.87

1071.29r.-:$sS

976.58976.72976.80976.56976.83976.37

971.41970.30969.76969.12

968.86969.23969.80971.67971.57

973.64972.65971.31970.34973.29

107735

:̂1$S988.94988.98988.91988.60988.66988.60

987.46987.01987.02986.92

986.46987.11986.88986.81986.42

987.01986.53986.02986.01987.11

1105.36:::'::":9qi6W;|

1100.681101.141100.801101.261100.411098.27

1092.521091.611090.741089.62

1090.711096.191098.611097.971100.17

1098.271095.081093.511092.971098.76

1104.76Mi&ji:

1081.381081.501081.431081.541081.251080.18

1078.281077.851077.741077.58

1078.001079.121079.651079.991080.67

1079.761078.991078.471078.391079.96

1104.39'•;^9b1-6Y

1082.571082.631082.591082.661082.191081.02

1078.821078.321078.221077.97

1078.351079.801080.411080.811081.53

1080.671079.661079.031078.911080.89

110531^!%i$ea®

1056.041055.521055.341055.361055.191054.37

1052.871052.451052.571052.63

1052.911053.871054.331054.271054.75

1054.021053.421053.091053.021054.36

1104,6*

.̂ iSiS987.48987.40987.63987.72987.42987.89

98730986.89986.97986.82

986.57986.69986.43986.40986.09

986.37986.19985.97985.84986.28

1071.599Q~7Y1042.911041.801041.831041.621041.601041.40

1040.911040.821040.811040.78

1040.871041.511041.571041.571041.55

1041.361041.171041.041041.041041.37

1072.7490- 7Z1066.901067.021066.601066.911066.641063.61

1061.731061.331061.061060.77

1060.901061.961065.541065.461064.46

1065.081063.601062.851062.501065.54

1071.4590-7D986.33986.38986.45986.54986.19986.69

986.08985.64985.74985.63

985.47985.66985.41985.42985.09

985.59985.25985.03984.86985.35

1085.1590-8X1072.171073.071073.271073.471072.751069.14

1063.201062.361061.841061.25

1061.151062.451063.281069.161070.61

1069.181066.341064.811064.191071.19

The reference elevation is the top of the PVC well casing (with well cap removed).

g—\vlevl.wk3 Page 1 of 5

Table 5-2. (cont'd)GROUND-WATER LEVELS


REFERENCEELEVATION

DATE1/8/911/15/912/25/913/22/914/11/915/22/917/15/918/20/919/20/9110/17/9112/2/911/8/921/10/922/28/923/30/925/12/926/09/926/16/928/10/928/31/9210/5/9211/9/922/8/93

1

1085.1990-8D

DRYDRYDRYDRYDRYDRY

DRYDRYDRYDRY

DRYDRYDRYDRYDRY

DRYDRYDRYDRYDRY

1Q9&5890-9X1086.521087.031086.741086.711086.101085.07

1080.611079.261078.531077.33

1077.941083.371085.191085.261085.72

1085.641084.261083.721082.841085.86

:-€ifiiS':^9iim

1039.621039.521033.621036.47

1035.941035.921036.251036.34

1036.251037.391038.011039.061039.47

1036.561037.201036.981037.071038.73

109748;,:;;:9i~9£:

1087.111087.031086.261085.38

1080.931079.561078.791077.58

1078.111083.671085.431085.591086.01

1085.921084.531083.971083.061086.12

10962590^9DD

987.09987.13987.21987.30987.00987.54

986.94986.53986.59986.44

986.17986.36986.00986.01985.67

986.00985.80985.59985.44985.91

1098.3490|lOX1056.501056.621056.471056.421055.961055.80

1053.441052.701052.711052.22

1052.761054.501055.131055.501055.47

1055.651055.001053.911053.461056.05

1098.7490~l6Y1090.121090.301090.361090.451089.311088.01

1083.511082.941082.451081.36

1081.361084.801086.731087.871089.62

1088.461085.751084.061083.511088.73

1QS&989i.«lOii

986.88986.61987.12

986.53986.12986.20986.05

985.84985.98985.73985.71985.40

985.75985.55985.35985.18985.62

'•:• . " . ' '•' '.-.•'•. ' . ".

1091.7390-13D

986.67986.68986.88986.91986.65987.11

986.51986.13986.17986.03

985.81985.97985.67985.67985.35

985.69985.51985.31985.14985.68

1064.8992-14X

1048.171047.451046.621046.091048.76

1065.1790-14D

986.76986.72987.05987.29986.86987.31

986.68986.30986.33986.19

985.94986.09985.78985.77985.47

985.79985.63985.43985.24985.68

1063.9892 -HDD

985.76985.64985.44985.26985.72

* The reference elevation is the top of the PVC well casing (with well cap removed).

g—wlevl.wk3 Page 2 of 5



REFERENCEELEVATION

DATE1/8/911/15/912/25/913/22/914/11/915/22/917/15/918/20/919/20/9110/17/9112/2/911/8/921/10/922/28/923/30/925/12/926/09/926/16/928/10/928/31/9210/5/9211/9/922/8/93

|_ 1061.70C92-1X

1044.021043.831044.121043.161042.271041.691044.98

1089.60C91-2I>

986.94986.77986.39986.42986.13

985.62985.%985.84985.82985.51

985.88985.66985.46985.28985.76

1071 J5y^iiM:

1053.771052.881052.511051.64

1052.201056.291057.111057.001056.14

1058.541057.201057.371056.441057.76

1072.55C91-4Y

1054.721054.041053.691052.23

1052.921057.381058.171058.061056.89

1059.671058.311058.171057.431059.03

1072.91C91-4Z

1058.231057.211056.461055.40

1056.251061.801062.861062.541061.00

1064.441062.601062.391061.591063.34

1037.54C91-5D

988.08987.93987.45987.46987.42

987.24987.40987.17987.34987.31

987.64987.13986.35986.48987.82

1039.26C92-5DD

987.27986.74985.97986.16987.37

ijfee••V:C9p8X:

1055.421054.881054.821055.34

1055.561056.371056.881057.861057.66

1057.731057.271056.721056.101057.93

1098.42C91-8Y

1071.401071.101070.891070.63

1070.621071.301071.771072.431072.78

1072.591072.041071.301071.301072.68

1097.63C91-8D

987.11987.03986.63986.68986.52

986.26986.48986.09986.09985.75

986.07985.86985.66985.59985.98

110939C92-9X

1053.871052.531051.571051.111051.82

1111.36C92-9Y

1079.401078.141077.821077.721078.94


g-wlevl.wk3 Page 3 of 5



REFERENCEELEVATION

DATE1/8/911/15/912/25/913/22/914/11/915/22/917/15/918/20/919/20/9110/17/9112/2/911/8/921/10/922/28/923/30/925/12/926/09/926/16/928/10/928/31/9210/5/9211/9/92

1 2/8/93

1091.0892-2X

1034.851035.901035.551035.441034.801034.421036.04

1092.11:;-.V':'.92|43C:

1047.841047.731047.531046.941046.501046.061048.09

;-;-'::ii<&9*:

SSJiJ

1056.471056.211056.011055.401054.921054.791056.31

1076.37:;::::\92il5X:

1040.631040.671040.891040.801040.521040.321041.03

1080;16isiiiic

1039.421039.291040.111039.691039.141038.671041.02

1103.24:!::92§l?t

1052.321051.771051.481053.25

1099.59•:-92|:18X;

1052.841052.321052.021053.73

W9232;:;j;92ii9x

1049.171047.501047.041048.91

1067.171 92-2QD

959.57959.63959.07958.51959.67

1059.1692-21D

985.75985.58985.35985.15985.74

1005.7292-22D

987.48986.61986.49988.82

1005.4392-22DD

984.99986.03986.15987.52


>-wlevl.wk3 Page 4 of 5


PROPOSED CLARKCO LANDFILLREFERENCEELEVATION

DATE1/8/911/15/912/25/913/22/914/11/915/22/917/15/918/20/919/20/9110/17/9112/2/911/8/921/10/922/28/923/30/925/12/926/09/926/16A>2

1 8/10/928/31/9210/5/9211/9/922/8/93

985.2492-23D

980.02979.44979.10978.96980.32

1114.5092-24Y

1056.691056.041055.621055.351056.90

11143192-24Z

1099.091096.761095.411094.361099.55

1086.1592-26X

1074.041072.701072.511071.911073.74

1084.9392-27DD

985.23985.06985.54

1080.1292-28X

1053.811053.091056.16

1075.7692-29X

1057.491056.571059.84

1079.8692-31X

1036.931036.581038.28

1078.3092-31Y

1054.531054.281055.32

1070.0492-33X

DRYDRYDRY

1073.3992-33Y

1053.761053.551054.47

1094.3392-35DD

1024.10


g-wlevl.wk3 Page 5 of 5

Well

90-6W92-24Z

90-10Y90-6Y91-9Z

90-6X90-9XC91-8YC92-9Y

90 -7Z90-8X92-26X

90-6Z90-10XC91-4YC91-4ZC91-8X92-11X92-17Y

92-18X

92-24Y

SandZone

1092 Sand1092 Sand




1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand1050 Sand

1050 Sand

1050 Sand

. :---!$uSJL^r '••'•-TimelessScreened

2.60.8

1.74-0.1=1.8.25 +.50=0.75

1.4

2.24.2

2.94-1.0+1.6=5.50.6+1.0=1.6

1.71.7

1.7+6.5=8.2

0.60.7

0.6+0.1+0.8+0.5=2.03.1

0.3+0.1=0.41.6

0.6+0.9+0.7+0.6=2.8

0.5+0.2+0.9+0.1=1.7

0.5+0.8+0.2=1.5

ElevationTop ofSand

1092.91092.8

1080.91078.51076.3

1069.51070.31073.21074.2

1062.41059.51062.3

1047.11047.31046.11055.71056.71047.01048.1

1046.5

1052.0

HighestWater*Level

Elevation

1101.261099.55

1090.451082.661087.11

1081.541087.031072.781079.40

1067.021073.471074.04

1056.041056.621059.671064.441057.931056.471053.25

1053.73

1056.90

lowest';'":'Water*;:s;';:;,̂

-• . Level :o • • : ' " ;Elevation

1089.621094.36

1081.361077.971077.58

1077.581077.331070.621077.72

1060.771061.151071.91

1052.451052.701052.231056.251054.821054.791051.48

1052.02

1055.35

Flange of^ater LevelIfliictuation

(ft)

11.645.19

9.094.699.53

3.969.702.161.68

6.2512.322.13

3.593.927.448.193.111.681.77

1.71

1.55

Depth toTop of

Sand Pack(ftV

8.115.0

12.520.514.5

30.819.919.031.4

6.021.520.0

52.545.519.012.040.155.750.8

48.1

59.8

Distanceto

Outcrop(ft)

185490

270475245

540320300255

60165465

720840480500650

13001310

960

1110

Based on record to dale as presented in Table 5-2.

Page 1 of 2

Table 5-3 (cont'd)SUMMARY OF DATA RELATIVE TO WATER LEVEL FLUCTUATIONS, INTRA-TILL SAND WELLS


Well

92-28X92-29X92-31Y92-33YC92-9X

90-7Y91-9YC91-4X92-14X92-15X92-16X92-19X92 -2X92-31X92-33X92 -4XC92-1X

SandZone


1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand1035 Sand

'• '. -r:::.v Sand. :•:.::•; : ,.T^^e :̂.;-;': ' •: :Screened{:::: ' •'•

0.9+1.9+1.1=3.90.9+0.1+0.1 = 1.1

6.0+1.0=7.00.2+0.3+0.5=1.0

0.5

1.11.00.7

0.8+3.0=3.83.2+0.4=3.6

1.32.3+0.9+0.4=3.6

0.5+1.5=2.01.40.4

1.2+1.3+2.9=5.40.3+0.4+0.3+0.7=1.7

ElevationTop of

•.'•.•$Nt&-':-

1046.21054.81058.41054.31039.3

1039.71034.11036.01038.91038.31033.91034.61031.11029.91037.81032.21036.8

Highest. Water*'• •\::;^<Byel::- - . ' : '

Elevation

1056.161059.841055.321054.471053.87

1042.911039.621058.541048.761041.031041.021049.171036.041038.28

Dry1048.091044.98

Lowest,;v-Water* :;•:•:'.'.;.''•'}'l^^ •.'!:•• f'':^

Elevation

1053.091056.571054.281053.551051.11

1040.781035.921051.641046.091040.321038.671047.041034.421036.58

Dry1046.061041.69

Range ofi:\VaterLevelfluctuation

<ttV

3.073.271.040.922.76

2.133.706.902.670.712.352.131.621.70--

2.033.29

Depth toTop of

Sand Pack(ft)

29.015.020.014.065.0

26.856.031.521.932.839.753.050.441.5__

55.519.3

Distanceto

Outcrop(ft)

135110165185

1220

290850530670610750

1250805250285

1150180

* Based on record to date as presented in Table 5-2.

w-Iflucr.wk3 Page 2 of 2

Table 5-4SUMMARY OF HYDRAULIC CONDUCTIVITY TESTS FOR THE UPPERMOST AQUIFER


WellNumber

AvailableDrawdown

• • ' • • • • (ftY

Specific^:;C^p;a t̂y ;̂:::;:.;:^^(l&rrifttHx^

Analytical; • ̂ Tftthod : ; Traiisrnislsiyity

(||)d/ftyStoradvity

AquiferThickness

^•-affite1.-':;;

HydraulicConductivity

.:; (gpd/ft2)

HydraulicConductivity

(cm/sec")Well Yield

1990 PUMPING TEST RESULTS

PW-1PW-2PW-3

241232

51.02.3

20.9

TTT

66,0004,600

43300

_ _- —— —

2425

28.5

2750184

1519

LSxlO"1

8.7xlO~3

7.2xlO~2

100gpm+~25gpm100 gpm+

• : : : . • : • : , '• /-^i^^^ '^^xtm^®^^ :• .;V '.. ' ' ' ; . ' • :.-/r- ' .

91-2D91-5D91-8D

_ _

— —__— —

BBB

____

— —

__- —™ ' —

__- —_ —

4.23.0

1611

2.0xlO~4

1.4xlO"4

7.6xlO~2

__--— —

1992 72-HOUR PUMPING TEST ON PW-3;;

PW-3C92-5DDC91-5DC92-5DDC92-5DDC91-5DC92-22DD

32— _— ______ ___— —

24.3— —— —— —— —— —__— —

TTT

DY(e)DY(1)

NLTD

?5Si:.:V:v' :": ; • ; • " : -;.;?:

77,60049^0044,80041,80045,20049,10045,20051,100

;'*;:;;Si::: ; :•' ••-..':• ';•.'••"••

__

2.8xlO~4

9.5xlO~4

S.lxlO"5

5.4xlO~4

6.0xlO~4

3.5xlO~4

3.2xlO"4

*

3030303030303030

25871650149313931507163715061703

1.2X10'17.8xlO~2

7.0xlO~2

6.6xlO~2

7.1xlO~2

7.7xlO"2

7.1xlO~2

8.0xlO~2

_ —--

— —__— —— —

T = Time-drawdown, semi-log (Cooper & Jacob, 1946)B = (Bower, 1989)

DY(e) = Delayed yield, log-log, early data (Pricket, 1965)DY(1) = Delayed yield, log-log, late data (Pricket, 1965)

NL = Nonleaky artesian, log-log (Theis, 1935)D = Distance-drawdown, semi-log (Cooper & Jacob, 1946)

* Average thickness of aquifer within thearea encompassed by cone of depressionduring test.

hv(hmner.wk3

Table 5-5OBSERVATION WELLS USED DURING 72-HOUR PUMPING TEST


Well No.

92-28X92-29XC91-4XC91-4YC91-4Z92-5DDC91-5D92-33Y91-31X92-31Y92-26XC91-2D92-21D92-22D92-22DD90-9X91-9Y90-9DD91 -9ZSupply WellC92-1X92-14X92- HDD90-14DC91-8XC91-8YC91-8D92-18X92-19X92-20DTBF-20DTBF-20S92-4X

DistancefromPW-3

(feet)

10075

440440440510550595640645690900

102511051120112511251135113511401310140014001410144014501450158016201710177017801780

Zone^iliScreened


UMAUMA


UMAUMAUMAUMA

1070 Sand1035 Sand

UMA1077 Sand

1035 Sand1035 Sand

UMAUMA

1050 Sand1077 Sand

UMA1050 Sand1035 Sand

SDUMA

1050 Sand1035 Sand

||y|p^~«velMeasurementiliiitiiir'::

HHTEEEETHHTE

TTEEEEEEEEEEEEEEEEEE

MeasurementFrequency

CccBBAACCCCAACC4BA4ABBBBB4ABBABBB

Remarks

Pumped intermittently during test.

Affected by supply well

UMA = Uppermost AquiferSD = Stra tified Drift

H = Hermit Transducer with Data LoggerT = Telog TransducerE = Hand Measurement with Electric TapeS = Stevens Strip Chart Recorder

A = Intermittent measurements during 1st 2 hours,then following schedule B.

B = Measurements every 2 hours for24 hours,then at least every 4 hours for remainder of test.

C = Continuous monitoring with pressure transducer.

4 - Measurements every 4 hours.

72hrobsv.wk3 Page I o f 2

Table 5-5 (cont'd)OBSERVATION WELLS USED DURING 72-HOUR PUMPING TEST


Well Nd.

TBF-17TBF-19STBF-19DC92-9X92-17YC92-9YA91-9SA89-3DM-392-23DA91-7D90-8D90-13D90-10DM-4PW-192-27DD90-6D92-15XPW-2Chapman Creek

DistancefromPW-ffeety

17901850185019701980200019802030203021502180212521002280255028902710282030253170

ZoneScreened

1050 Sand1050 Sand

UMA1050 Sand1050 Sand1077 Sand

SDSDSDSD

UMAUMAUMAUMAUMAUMAUMAUMA

1050 SandSD

Water keVelMeasurement

Method

EEEEEEETEETEEEEEEETSE

MeasurementFrequency

BBBBB4B44AC4

DailyDailyDailyDailyDailyDaily

CC4

Remarks

Background wellBackground wellBackground wellBackground well

UMA = Uppermost AquiferSD = Stratified Drift

H = Hermit Transducer with Data LoggerT = Telog TransducerE = Hand Measurement with Electric TapeS = Stevens Strip Chart Recorder

A = Intermittent measurements during 1st 2 hours,then following schedule B.

B = Measurements every 2 hours for 24 hours,then at least every 4 hours for remainder of test.

C = Continuous monitoring with pressure transducer.

4 = Measurements every 4 hours.

72hrobsv.wk3 Page 2 of 2

Table 5-6RESULTS OF SLUG TESTS ON TILL WELLS


Boring/WellNumber

92-7TP92-10TP92-14TPC92-8TP

GroundElevation

at)

1069.51095.51061.71094.4

Top ofSand Pack

32.077.247.950.0

WellScreen

32.9-36.978.7-83.748.7-53.751.5-56.5

BoringDepth

(ft)

38.584.054.060.0

ZqneScreened

Lower TillLower TillLower TillLower Till

Slug TestK

(cm/sec)

2.6 xlO~7

3.1 xKT7

2.1 xlO'71.5xlO~7

————————— |

Water-LevelElevation2/8/93

1039.941018.391016.801055.96

.'-. • : , . . • , • • • . : . .':'.:.: :/: '•'•'•'.'•'•'•.':'.'•'•'•:']•'.•:'• •:>:v;-'-:-X i>x •'.'•:•:•.':•'• ' •'•: 1:'>>.':V;-:j:-:-.'>:-;'::;' :;>;•: :-:;;;;:'i;.-'-.:.-.:X;:;Xv^:";'X':-'-.'X';-:;:;X'X';^i ,'x;.;:;:;/:;:'. ::; :'>;;'^\;.::::':-:':;:;:V;il':;;;::.';:-';t;Y:^:;:;^^^'^-!; !;'•>;•':>:•! ":;^':^; ;;!;.•;•;;';: ;;-'x ; :• ' : : ;.:.-. - • . . " :". • ' • • : • • : . •. - • • • • • , . " . . " . . - • . . . • •

slugtil.wkS

Table 5-7RESULTS OF TRITIUM ANALYSES


Well No.

91 -9Z

90-10X

92-4X

90-9DD

92-27DD

• :;: '• ::V:i ; '" ; ; |SMMi"--.. -' ; :••:•:•: '. :? .vV/'Zone. '• " • ' •.

1077 Sand

1050 Sand

1035 Sand

TopUMA

Base UMA

TritiumUnits(TV)

26.5

0.35

0.33

1.26

1.00

Rate of Recharge

Rapid. Probably <1 Year

Very Slow. > 50 Years

Very Slow. > 50 Years

Slow. > 30 Years; < 50 Years

Slow. > 30 Years; < 50 Years


tritrslt.wkS

PfiOTOSEO CUARKCO LANOHULBBTK——

EASON a ASSOCIATES, INC.

B ASSOCIATES, INC.men STJXZT

WORTHIHfflQN, OHIO 4SOf3

w W

WEST

X

i-w M-OO t4-oo r«-oe M.'OC

LlGiiSD

90-70—— -

.̂1 /

•4-00 W-M W-00 *fr*Q 00*0

SECTION W-WKALI. r>4M>Hr*4O* v EAST

X'

«-00 l-OO B-OO 10-00 t*-O •-00 t»-00 Tt-00 04-00 KM-00

SECTION X - X 1

KALd r-400' N

EAGON a ASSOCIATES, INC

CLiBHCO UWOFlLL CO»W»*T •«..

LOCAL HYDROGEOLOGiCROSS SECTIONS W B>

___^EftMA« Tw^ . a_*H« CO 0^0

EAGON & ASSOCIATES - Records Collections

Documents

Transcript of EAGON & ASSOCIATES - Records Collections