Watering Trough Gulch Mining Project: A Feasibility Study Routt County, Colorado Acknowledgements

Watering Trough Gulch Mining Project:

A Feasibility Study

Routt County, Colorado

Prepared By

Jonathan D. Lindquist

Fort Collins, CO

May 2, 2014

Watering Trough Gulch Feasibility Study (2014)

Acknowledgements

There are a number of people I would like to extend my gratitude

and thanks to for helping me with this thesis. First, I would

like to address the instructors; Dr. John Stednick has helped

immensely improve my thinking as a natural scientist, and pushed

me to develop new time management strategies. His hard work

giving feedback could not be mentioned fully if the help of Dr.

Sunil Kumar and Ph.D. candidate Ryan Webb were left out. Dr.

Kumar and candidate Webb both offered flexibility with questions

and helping me understand my mistakes on the writing assignments.

I would also like to thank my peers in the class for being a

resource when I felt overwhelmed with the other classes being

taken concurrently and believing in me when I did not. Of course

I would also like to express my gratitude towards my brother and

family at home for their support and constant questions about my

work on this thesis. Without all of these people this report

would not exist.


Conversion Factors

This report is reporting units in metric but for future utility

and a different perspective, a conversion table is provided. The

purpose of the conversion table is to provide a convenient way

for readers and users of this report to be able to convert units

to their liking.

U.S. Customary - Metric unitsMultiply By To Obtain

Lengthinch (in.) 25.4 millimeter (mm)inch (in.) 2.54 centimeter (cm)foot (ft) 0.3048 meter (m)mile (mi) 1.609 kilometer (km)Area


acre (ac) 40.47 square meter (m2)acre (ac) 0.0041 Square kilometer (km2)square foot (ft2) 0.0929 square meter (m2)square mile (mi2) 2.59 square kilometer (km2)Massounce (oz) 28.34 grams (g)pounds (lb) .454 kilograms (kg)short ton (ton) .91 metric ton (ton)Volumegallon (gal) 3.785 liter (L)cubic foot (ft3) 0.02832 cubic meter (m3)acre-feet (ac-ft) 0.1234 hectare-meters (ha-m)Flowinch per year (in/yr) 25.4 millimeter per year (mm/yr)foot per year (ft/yr) 0.3048 meter per year (m/yr)cubic foot per second (ft3/s)

0.0283 cubic meter per second (m3/s)

gallon per minute (gal/min) 0.0631 liter per second (L/s)million gallons per day (Mgal/d)


billion gallons per day (Bgal/d)


Densitypounds per cubic foot (lb/ft3)

16.018 kilograms per cubic meter (kg/m3)

TemperatureCelsius °C (°C*1.8)

+32Fahrenheit °F

Yieldtons per acre per year (ton/ac/year)

224170 kilograms per square kilometerper year (kg/km/year)

Short forms and Acronyms


These acronyms, short forms and abbreviations appear throughout

the text. The purpose of this page is to supply the reader with

the meaning of any acronym or short form used in the report

- WTG (Watering Trough Gulch)- SB1 (Subbasin 1)

- BLM (Bureau of Land Management)- CCC (Colorado Climate Center) - COAgMet (Colorado Agricultural Meteorological Network)- DOI (Department of Interior)- EIA (Energy Information Administration)- OSMRE (Office of Surface Mining Reclamation and

Enforcement)- NCDC (National Climatic Data Center) - NLDC (National Land Cover Database)- NOAA (National Oceanic Atmospheric Association)- NRCS (Natural Resource Conservation Service)- SMCRA (Surface Mining Control and Reclamation Act of

1977)- USDA (United States Department of Agriculture)- USGS (United States Geologic Survey)- WSS (Web Soil Survey)

- HEC-HMS (Hydrologic Engineering Center-Hydrologic Modeling System)

- GIS (Geographical Information Systems)- NAD (North American datum)- UTM (Universal Transverse Mercator)- AOI (Area of Interest)- SDB (Sediment detention basin)- SDR (Sediment detention ratio)- AWC (Average water content)


TABLE OF CONTENTS

Acknowledgements...............................................2Conversion Factors............................................3Short forms and Acronyms......................................4

Executive Summary..............................................1Chapter 1 – Introduction.......................................4Chapter 2 – Watershed Description..............................62.1 Introduction..............................................62.2 Methods...................................................6

Data Collection.................................................6Map Making - ArcGIS.............................................7

2.3 Results...................................................82.4 Discussion...............................................10

Chapter 3 – The Water Balance.................................113.1 Introduction.............................................113.3 Methods..................................................113.4 Results..................................................133.5 Discussion...............................................14

Chapter 4 Pre-Mining Condition................................154.1 Purpose..................................................154.2 introduction.............................................15


4.3 Methods..................................................154.4 Results..................................................174.5 Discussion...............................................174.6 Conclusion.....................Error! Bookmark not defined.

Chapter 5 During-Mining Hydrologic Condition..................185.1 Introduction.............................................195.2 Methods..................................................195.3 Results..................................................215.4 Discussion...............................................225.5 Conclusions..............................................225.6 Recommendations..........................................22

chapter 6 – Soil Erosion......................................226.1 Purpose..................................................236.2 Introduction.............................................236.3 Methods..................................................23

Chapter 7 – Sediment Detention / Channel Hydraulics...........247.1 Introduction.............................................247.2 Methods..................................................247.4 Results..................................................27

Chapter 8 – Reclamation/Revegetation..........................288.1 Introduction.............................................288.3 Methods..................................................29Pre-Mining.................................................30Post mining................................................30

8.4 Results..................................................318.5 Discussion...............................................328.6 Conclusion.....................Error! Bookmark not defined.8.7 Recommendations..........................................33

Chapter 9 – Monitoring........................................34


9.1 Introduction.............................................349.2 Methods..................................................34

Conclusion....................................................35Recommendations...............................................35Appendix......................................................37A1. Chapter 1................................................37A2. Chapter 2.................................................1A3. Chapter 3.................................................1A4. Chapter 4.................................................1A5. Chapter 5.................................................1A6. Chapter 6.................................................3A7. Chapter 7.................................................4A8. Chapter 8.................................................5A9. Chapter 9.................................................5A4. Figures........................Error! Bookmark not defined.

Literature Cited...............................................8


Executive Summary

This report, prepared for the Watershed Problem Analysis Capstone

class was completed over the course of the semester under the guidance

of Dr. Stednick. The purpose of this report is to analyze an area –

assigned to us at the start of the semester – for the feasibility of a

potential surface coal mining operation. The feasibility of the mining

operation in Watering Trough Gulch will be determined on the amount of

physical disturbance produced as described in the Surface Mining

Control and Reclamation Act of 1977 (SMCRA). A surface mine operation

in Colorado mines 0.4 km2 annually and the average mine life is 20

years amounting to 2000 total acres mined – this is considered a

baseline for mining to begin.

Watering Trough Gulch has a total area of 6.8 km2 is located in Routt

County, and the area proposed for mining is Subbasin 1. Subbasin 1 has

an area of 0.81 km2 and is dominated by shrub and scrub vegetation at

lower elevations and deciduous forest near the higher elevations. The

subbasin has an average elevation of 2334.7 meters and has an average

slope of 18%. The dominant soil type in both the Watering Trough Gulch

and the subbasin is Foidel Loam – 24% of total area.


Using climate data at a nearby airport, the watershed and its

surrounding area was characterized by a water balance model. An annual

average temperature of 6°C and an annual average precipitation of 35

mm. Cumulative precipitation was found to be 425 mm or 40 cm. This

climate was characterized as semi-arid with scrub and shrub with mixed

forest at higher elevations. Soil types were dominantly loams – 412

acres in Watering Trough Gulch or about 24% of the total area.

An in-depth hydrologic analysis was conducted for the entire watershed

as well as the subbasin considered for mining: both 10-year 24-hour

and 100-year 24-hour storm events were used for modeling purposes. The

goal of the hydrologic analysis for the different land conditions

(pre- and during- mining) in both Watering Trough Gulch and Subbasin 1

was to notice the change in annual soil loss. SMCRA requires the

control of sediment lost to downstream users, to mitigate the effects

of soil loss on the disturbed land it is often that a sediment

detention basin will be designed. The design of the detention basin is

planned to accommodate the capacity of a 10-year 24-hour event as well

as a 24-hour settling rate. Additionally, an emergency spillway will

be designed to accommodate the larger 100-year 24-hour storm event –

this will be designed by a registered engineering company for the

reclamation and monitoring period. Watering Trough Gulch Feasibility Study (2014)

The reclamation of the land would begin, if time and money allow, when

the mine has been operating for at least 6 years. As mining occurs,

the top soil would be saved and seeded with nitrogen-fixing vegetation

to be re-applied at the end of mining each plot. Before the re-

vegetation can being, the area must be returned to its approximate

original contour using backfill of waste rock and overburden- the

stored top soil would be put down once the original contours and

hydrology have been restored. Efficiency and diligence during the

reclamation period must be considered, as re-establishing vegetation

in the Western U.S. takes much longer than the Eastern U.S. Native

grasses and shrubs would be planted using drill seeding on high slopes

while broadcast seeding and mulching on less steep slopes.

An analysis on the pre- and during-mining hydrology is important for

characterizing the “worst case scenario” so that a potential mining

operation may use better judgment in the operation. This plan laid out

in the chapters following, is a desktop-based assessment of the

current and potential conditions given only certain records of data.

With this condition in mind, it may be hard to judge certain variables

in the overall assessment of Watering Trough Gulch and the basin to be

mined, but using historical and spatial references can aid in decision

making. Watering Trough Gulch Feasibility Study (2014)

In conclusion, the mining operation in Watering Trough Gulch is not

feasible at this time. Longer records of data need to exist as well as

a reference site – Watering Trough Gulch is very small in area and has

a number of slopes greater than 30%. I purpose that instead of mining

in this watershed, that it be used as a reference site for adjacent

watersheds permitted to mine. Implementing a meteorological station

within the catchment and activating the stream gauge may be a good

starting point.


Chapter 1 – Introduction

Long ago, about 55 million years ago, Colorado was not so dry and

dinosaurs roamed the plains, there was a shallow sea that extended

from Canada to Mexico. As time passed, the ocean levels slowly receded

and swamps had formed along the coast and peat – an organic-rich soil

material – came as a result of the wetland condition. Over millions of

years, the compaction of the peat over a long period of time produces

the precious coal sought under the ground. Figure 1.2 shows the

different stages of compaction and burial related to the energy

content - the more compaction and heating the peat experience the

higher quality coal is produced (Carroll & Berry, 2005). Anthracite is

this highest quality coal while the lignite coal is of the lowest

quality - the coal found in Colorado is typically bituminous to sub-


bituminous and is low in sulfur content but high in energy content

making it highly desirable (Sanford, 2014). Over 80% of coal in

Colorado is bituminous (Carroll & Berry, 2005).

The state of Colorado is growing in population and a need for more

energy has arisen in response – coal seems to do a good job of

providing cheap clean energy. In Colorado, as well as the entire

United States, coal is a leading source of energy – 50% of electricity

in the United States comes from coal-fired power plants (Carroll &

Berry, 2005). Last year an estimated 30,000 short tons of coal were

produced form Colorado – only 2.8% of the country’s annual coal

production (US Energy Information Administration , 2014). The U.S.

Energy Information Administration (EIA) also reported that each short

ton sold was valued at nearly $40.00 per short ton. With this demand

for coal, mining companies are interested in Colorado coal for its

desired characteristics. Mining cannot occur unless; the miners get a

permit from the Office of Surface Mining Reclamation and Enforcement –

part of a lengthy legal process (Colorado Division of Minerals and

Geology, 1980).


An average surface mine would remove 100 acres/ year – upon being

granted permission to mine. With this permit the mining company agrees

to a list of requirements defined in SMCRA (SMCRA, 2014). Some of the

more important requirements include:

- The entire area is returned to its approximate original

contour (AOC) and that the land is restored to an equal or

better condition once mining has been completed – more

specifics are listed in SMCRA

- Damage and alterations to the hydrologic processes are

prohibited - the normal flows should not be altered, mining

alluvial valley floors is avoided, and minimizes the

disturbances to the water quality and quantity for

downstream users

- Water quality is maintained at state and federal levels –

preventing acid mine drainage and reducing the sediment

yields from the area. Sediment yields from roads and bare

surfaces are considered in the control of erosion.`

The overall analysis on Watering Trough Gulch and the subbasin will be

used in the permitting process and once the permit is accepted a

baseline condition must be established for the following:


- Hydrology and Climatic Data

- Soil losses and annual sediment yields compared to

tolerances

- Reclamation and any implementation of structures (roads,

diversions, settling areas)

- Water quality monitoring

This baseline condition is necessary in returning the area to its

original or better condition as well as determining if the miners will

be awarded their bond for successful reclamation. This report will

explore the process in the obtaining values and basic characteristics

needed to get a mining permit.

Chapter 2 – Watershed Description

2.1 Introduction

To better understand the potential effects a surface mining operation,

it is important to characterize the watershed for baseline parameters.

Since a mining operation has been proposed for the area within

Watering Trough Gulch an analysis of the watershed will be conducted

using several sources of data; from a selection of nearby climate

monitoring stations and a USGS stream gauging station at the mouth of Watering Trough Gulch Feasibility Study (2014)

the watershed, the post-mining period may reference these conditions

in monitoring and reclamation. The mining company, upon completing the

operation, must restore the land to equal or better standing without

disturbing or altering any hydrology (SMCRA, 2014). Using Desktop-

based applications and electronic data acquired from several agencies

websites and databases – characterizing the watershed can be done

remotely and accurately.

2.2 Methods

To get a better understanding of the seasonal and temporal variations

in and around Watering Trough Gulch several websites and agencies were

accessed for spatial and temporal data. This data was imported into

different computer applications for analysis and testing – the ESRI

ArcMap and Microsoft Excel were of major importance in manipulating

and organizing data. Another program that was vital in many of the

calculations was HEC-HMS, free hydrologic modeling software developed

by the Army Corps of Engineers. The major steps in the watershed

characterization will be outlined in the following pages of this

chapter.

Data Collection


From the web – there are a number of ways to access historical and

current climatic and hydrologic datasets. The following points detail

the source and the type of data acquired from the source:

- For this watershed analysis, the USGS historical streamflow

database was accessed to provide a historic record of flows

from the stream gauge (USGS 09244460) located in Watering

Trough Gulch.

- Meteorological data was collected from NOAA’s National

Climatic Data Center database. Data was collected on a

monthly average basis for a period of 105 years from the

Hayden Airport.

- The soils data: Available Water Content (AWC), K & T-

Factors, hydrologic soil group and was collected from the

Web Soil Survey (WSS) and imported into Excel and ArcMap and

area-weighted with land cover.

- Land cover and hydrography were acquired from two different

sources – the USGS Map Viewer Tool (an interactive map) and

the Colorado View database.

- Water quality data was obtained from the COAgMet

Map Making - ArcGIS


The ArcGIS desktop application was used to make a number of maps for

Watering Trough Gulch – maps of slope, aspect, elevation, hydrologic

soil group, stream network, and land cover. The stream gauge in

Watering Trough Gulch was used to delineate the basin as well as

provide a record of streamflow.

2.3 Results

Watering Trough Gulch a smaller catchment located in Routt County and

12 miles south of Hayden, CO is characterized as an arid west

environment. The surrounding climate stations were located at a

similar elevation (Table 2.1).

The mean basin elevation for Watering Trough Gulch was determined to

be 2255 m – the gauging station is located at an elevation of 2117 m

while the highest elevation point is located at 2456 m. The hydraulic

length of the watershed – from the farthest point to the outlet – was Watering Trough Gulch Feasibility Study (2014)

found to be 5.6 km. The area for Watering Trough Gulch was calculated

in both Stream Stats and ArcGIS – 6.35 km2. The average slope for

Watering Trough Gulch was calculated at 21% - greater slopes (Figure

2.1).

The land cover for the basin is dominantly deciduous forest – 69%

followed by scrub and shrub species at 29% of the entire watershed -

the remaining land cover classifications make up the remaining 2% of

land cover (A2-Figure 2.2). The deciduous forest is characterized by

trees generally greater than 5 meters tall, and greater than 20% of

total vegetation cover – more than 75% of vegetation sheds seasonally.

The shrub and scrub are characterized as less than 5 m tall and (Table

2.3).

The dominant soil types were found to be loamy – both Foidel and

Lintim loam make up almost 45% of the soils in Watering Trough Gulch –

just above 42%. 18% of the total area in Watering Trough Gulch

consists of Lintim loam – found on slopes ranging from 3% to 25%.

Foidel loam is found on slopes ranging from 15% to 65% (Figure 2.3).

The streamflow from the USGS gauging station reported a peak on April

30, 1980 with a discharge of 0.1 m3/sec. The streams in watering

trough gulch vary in length and slope, a number of first-order streams


exist in all three basins ranging from; a total 136 channels ranging

from 3 m to 115 m.

The watershed is then split up by the two natural junctions – yielding

three subbasins of similar areas.

Subbasin 1 (SUB1) with an area of 3.1 km2 is furthest to the south and

higher in elevation, the highest point at 2368 m and the lowest at

2169 m – the change in elevation is roughly 200m.The length a drop of

water would have to travel from one end of the subbasin is 3421 m.

Subbasin 2 is located downstream of Subbasin 1 and upstream of the

mouth of Watering trough Gulch making it the middle basin. The area of

Subbasin 2 was determined to be 2.2 km2 and has a similar elevation

change; the highest point being at 2276 m and the lowest at 2123 m is

only a 178 m difference. The hydraulic length of the middle subbasin

was determined to be 1816 m – making this the shortest basin.

The third subbasin or Subbasin 3 is in junction with the middle

subbasin, getting closer to Dry creek and the Yampa it has an area of

1.4 km2. Although the area of the basin is smaller than Subbasin 2 the

hydraulic length is greater being 3026 m long it is 395 km2 less than

the first subbasin and greater than the middle basin by 1200 m. The


highest point in subbasin 3 was 2295 m and the lowest at 2117 m – this

low point is the elevation of the USGS gauging site.

The two reaches in the watershed were also evaluated for physical

traits. The first reach –Reach 1 had a hydraulic length of 1520 m

while Reach 2 closer to the mouth of the watershed had only a 196 m

length. The change in elevation along the first reach was found to be

50 m while the second reach only had a change in 4 m.

2.4 Discussion

Understanding the physical characteristics and naturally occurring

processes that make up the watershed is a vital step in making the

baseline condition. The baseline condition is in a sense is then set

as the goal for the mining operation to meet upon completing their

digs. It is important to understand these physical relationships so

that the best judgment may be used when prescribing different Watering Trough Gulch Feasibility Study (2014)

reclamation and monitoring techniques. For the remainder of this study

the use of Subbasin 1 will be the main scope of analysis.

The stream gauge used to monitor Watering Trough Gulch was active for

only 3 years – September 1979 to July 1981. For hydrologic modeling

standpoint this is not a substantial amount of data or time and

comparing the recorded flows of the watershed to the modeled storms

discussed further in the hydrology chapter.

Chapter 3 – The Water Balance


3.1 Introduction

The purpose of the water balance chapter is to analyze, interpret and

discuss the water balance for the Watering Trough Gulch study site

south of Hayden Colorado. A water balance, in a basic sense, is a

utility for hydrologists to show relationships between the inputs and

outputs of a determined area or system on a time basis (Dunne &

Leopold, Water in Environmental Planning, 1978). Essentially the

water balance equation can be re-arranged until the inputs balance the

outputs.

3.3 Methods

The water balance model can begin with using just temperature and

precipitation values - monthly average temperature and precipitation

values were obtained from an NCDC station located at the Hayden

Airport (Table 2.1). Precipitation of snow and rain are both

considered in the model and a temperature threshold for snow Tsnow <=

3.3°C <= Train was used to determine when snow is accumulating and when

it is raining (EQ 3.1). The precipitation falling on the catchment is

then subject to interception and infiltration losses.

Interception rates may follow a seasonal trend and range from 0 to

1.To determine the interception rates a function of Leaf Area (LAI)


for each land cover classification (Table 2.3) and that land covers

area for the watershed as well as each subbasin.

Snow was calculated as the accumulated snowpack or SWE in millimeters

with interception accounted for. The fraction of snow storage that

melts away is known as the snow melt factor (SMF) and is a function of

mean temperature thresholds and the meltmax (often set to 0.5) (McCabe

& Markstrom, 2007).

With the precipitation defined as snow or rain and temperature

thresholds established, the net inputs have been determined. The

direct runoff (DRO) from the net inputs can be determined next using a

function of the fraction of monthly precipitation as direct runoff

(drofrac) and the monthly precipitation as rain (EQ 3.3). Often the

drofrac is set to 5% (McCabe & Markstrom, 2007) .

PET (potential evapotranspiration) and AET were calculated next: PET

was calculated usign the Thornthwaite method form Dunnne & Leopold

(1978). PET uses the mean monthly air temperature in °C and diveds it

by the annual heat index I found in (EQ 3.5) and raises that ratio

to a power, a - based on the annual heat index .

AET (actual evapotranspiration) is equal to the PET when the net

inputs are greater than PET. Conversely, if PET is greater than net


inputs of the system then AET equals the absoulte value of the change

in soil moisture and the sum of net inputs (Dunne & Leopold, Water in

Environmental Planning, 1978).

To characterize the monthly changes in soil moisture of the system,

rooting depths for each land cover were area weighted in the watershed

with the AWC for each land cover classification. First and accumulated

potential water loss (APWL) must be calculte for eachmonth by

subtracting PET from the net inputs – looking for negative numbers.

Any positive values obtained will be counted as zero (Walter, 2013).

See Water Balance Table (Table 3.1) in Appendix A2.

3.4 Results

The annual average precipitation as snow was determined to be 14 mm

while the average annual precipitation as rain was just 21 mm. The max


annual precipitation as rain was calculated to be 42 mm in April while

the maximum annual precipitation as snow was calculated as 38 mm in

December.

PET exceeded AET levels from May to September indicating a deficit

while the months from October to May indicate a soil moisture surplus

– AET has exceeded PET.

In response changes in soil moisture were observed on an annual scale.

The soil moisture decreased by 26 mm from the months of October to

January and remained at zero until the snow began melting around the

end of March – the change in coil moisture becomes more negative and

between March and April the system loses 28 mm but begins a gradual

incline till July increasing by 5.33 mm per month. In July the soil

moisture levels rise more rapidly at 14.5 mm per month.

Annual temperatures for the region were typical for the area. The

annual maximum temperature ranged from 5.9°C to 28.6°C with a spike in

February – which is typically colder was recorded at 23.4°C. The

average temperature was used for water balance calculations and had a

range of -7.9°C to 19.2°C between January and July. The minimum

temperature had a greater range and increased from -35°C the absolute

minimum of annual temperatures. Minimum temperatures increased to 0°C


for the summer months before dropping back down in September (Figure

3.3)

3.5 Discussion

Temperature thresholds are chosen based on literature but in Colorado

especially the climate regime is always varying. By choosing a 3.3°C

temperature threshold for snow or rain it seems there is a large

window for error when calculating monthly average precipitation

amounts. Snow is and continues to be the more challenging hydrologic

variable to monitor and make seasonal relationships.

Assuming this threshold for temperature will old true for most areas

seems unreasonable for the typical annual climate variability in

Northwestern Colorado. Another assumption regarding snow as

precipitation is the interception rates accounted for by LAI as a

function of land cover and area. The LAI of one plant species is not Watering Trough Gulch Feasibility Study (2014)

going to be the same over an area and as area increases, the accuracy

of the LAI’s ability to predict interception rates decreases. A more

in-depth look at area weighting the land covers in smaller parcels may

help increase the reliability of using the interception rates in the

water balance model. The LAI may also play a role in sublimation rates

and ripening of snow in areas – spatial variability in melting snow

during the spring and fall months. The snowmelt may also be pooling

under the snow surface – either flowing under the snowpack or pooling

and slowly infiltrating down.

Chapter 4 Pre-Mining Condition

4.1 PURPOSE


This chapter will examine the hydrology and land effects in the

Watering Trough Gulch basin for pre-mining condition. The goal of this

chapter is to establish a baseline condition or initial condition of

the land and top soil using two design storms. The chapter should also

illustrate the choice of what area (sub-basin) will be used for the

mining operation and why that choice was appropriate.

4.2 INTRODUCTION

The United States Army Corp of Engineers over several decades have

developed a modeling program for the general public and have been able

to digitize it into a computer model with a graphical user interface.

The HEC-HMS 3.5 program is a modeling program that uses many equations

and functions – these functions need inputs from physical and climatic

data to run the model more accurately (Army Corps of Engineers, 2000).

For this model there are two climatic events of interest: 10-year, 24-

hour and the 100-year, 24-hour storm events. The remainder of the

chapter will look at the methodology, results and issues with running

the model.

4.3 METHODS

This section discusses the methodology for using HEC-HMS and how to go

about operating the program. The following components will outline the


general process of obtaining the desired runoff calculations as well

as the initial steps to get inputs and model parameters. In the header

bar of the program there are different components under the Component

tab, and each component will be detailed below:

1. Basin Model Manager

The first component that should be selected is the Basin Model;

this component will represent either the entire catchment or each

sub-basin depending on the goal of the model. For this model,

there were three sub-basins (delineated in ArcGIS) with two

junctions and four reaches routing the flow from the top to the

bottom of the watershed. For each basin, rout or reach, and

junction different parameters need to define per the desired

function or outcome. Under the basin model manager tab,

adjustments to each reach, junction, and sub-basin area made.

Finding the areas of each basin was done in the ArcGIS as well as

the soil hydrologic groups and their land covers for each basin –

this produces the curve numbers needed to obtain a more


approximate runoff in Watering Trough Gulch. Areas for each soil

type with regard to the land cover can be found in (Table 4.3).

2. Meteorological Model Manager

This is the next component that would be selected for a design

storm and is the basis for the precipitation rates in the

watershed. To analyze the runoff potential in the watershed, two

design storms were established. The 10-year, 24-hour storm and

the 100-year, 24-hour the target for this study and is defined by

certain inputs. These inputs include the precipitation type, for

this model a look at different precipitation types was used to

analyze the comparative magnitude of runoff. Other inputs

involved in the meteorological model can represent the

evapotranspiration, and the snowmelt if desired.

3. Control Specifications

Control specifications define the timeframe of the storm event –

the 10-year event was given a 3 day time period to run. The three

day increment at 1-minute intervals was chosen for the 10-year

event while a ten day increment at 1-minute intervals was

selected for the 100-year event. Preference on the number of days

was chosen to scale the intensity of a typical storm of that typeWatering Trough Gulch Feasibility Study (2014)

for the region Colorado is in (Type II). The 1-minute interval

was chosen to produce the best resolution for the storm event.

Beyond the basic modeling with HEC-HMS, much work in GIS and Excel was

done to determine the parameters and will be presented below in the

results and discussion sections.

4.4 RESULTS

After running the model for both the 10-year and 100-year storm

events, results are still being generated. The storm event that

occurred in October of 1981 over watering trough gulch produced almost

6 cfs for several hours. When running the HEC-HMS model for the pre-

mining condition, the observed flows from the basin were much higher

nearly 18 cfs for the 10-year event and 75 cfs for the 100-year event.

4.5 DISCUSSION

For this model and others there is always a certain level of error

associated with calculating inputs but also the judgment of which

methods to use can influence abstract numbers. The first error

encountered when beginning to calibrate the pre-mining runoff

condition arose in the ArcGIS program. While delineating the sub-

basins, some area was lost in the process – still unsure as to why.

The area given by USGS was approximately 2.65 mi2 while the total areaWatering Trough Gulch Feasibility Study (2014)

after dividing up the sub-basins amounted to 2.57 mi2. This loss

decreases attributing land cover and soil types which can then change

the curve numbers for each basin, but also the areas of each sub-

basin. The next influence on the model was the amount of stream gauge

data to compare to the resulting storm events in the HEC model. With

only three years of record provided from the USGS Surface Water

website, one storm event was observed with a peak of 3 in/hr during

the October 1981 storm.

In conclusion, the look at HEC-HMS and the pre-mining condition show

results that make mining in watering trough gulch feasible. The basin

to be mined would be basin 1 at the southern-most end of the

watershed. This area is the largest and also has the highest frequency

of slopes less than 30%. The dominant vegetative cover in the sub-

basin is scrub and shrub making the initial mining clearing easy.


CHAPTER 5 DURING-MINING HYDROLOGIC CONDITION

5.1 INTRODUCTION

This chapter will examine the during-mining condition of the Watering

Trough Gulch in Basin 1 (B1) (Figure 5.1) for the hydrologic soil

properties and potential runoff for two different design storms; 10-


year 24-hour and the 100-year 24-hour storms for the entire watershed

and the basin selected to be mined. Typically a surface coal mine has

the ability to mine 100 acres per year (Stednick, 2014)

5.2 METHODS

The during-mining condition, similar to the pre-mining or undisturbed

condition a combination of the programs HEC-HMS and ArcMap were

implemented.

To examine the during mining condition and its potential effects on

downstream users and surrounding areas, a baseline condition

(undisturbed) was established in the previous chapter and now will be

compared to the condition of the mine during the mining process. To

accomplish a successful and accurate estimation of the feasibility of

a surface mine under the “worst case scenario” the following steps

were taken using ArcMap:

1. Starting with the Digital Elevation Model (DEM) the slope for the

entire watershed as well as each of the subbasins, the slope (as

a percent rise) was calculated.

2. To determine the area of mineable terrain a conditional statement

using the slopes was created by saying the following: If the

slope is greater than or equal to 35% it shall be assigned a 0


and if the slope is less than 35% give it a 1. Using the

attribute table from the new feature, the data was exported and

added to the map to show the land able for mining.

3. The stream layer was added next and buffered 30 meters. Each

subbasin was clipped to the overall watershed with the new slope

condition to better define the boundaries of each basin. The

visual model in HEC-HMS would later be drawn from the current

map.

4. Finally, the hydrologic soil groups were added to the basin

chosen to be mined (Basin 1) to show where mining would be

accomplished easier as well as provide a baseline for how the

dragline will progress through the mine.

Once the GIS had been wrapped up, the modeling in HEC could begin. The

HEC program was used to determine the peak outflows from the overall

watershed as well as the Basin 1 (B1) selected for the mining

operation. To determine the flows for the now disturbed mined area, as

well as the undisturbed parts the following steps were taken:

1. First under the Components tab the Basin Model Manager option was

chosen and named Watering Trough Gulch, under the Basin Model


Manager the three subbasins were added to the desktop window. The

units were set to metric for this model.

2. Next the Loss Method was set to SCS Curve Number, and similarly

the Transform Method to SCS Unit Hydrograph. The options for the

Baseflow, Canopy, and Surface Methods were not assigned anything

– none. Under the Loss Method, the initial abstraction was not

used but the lag time was calculated using the SCS method (Dunne

& Leopold, 1978). Under the same option, the Curve Number and

the percent impervious area was set to describe the surface mine

after more than 4 years of operation and will be detailed in

the . The Transform Method requires the lag time which was

calculated in the SCS method aforementioned. Repeated this step

for the remaining two subbasins.

3. Once all subbasins characteristics have been filled out, the

reaches were then assigned their parameters – under the Reach tab

for Basin 1 the Junction-1 was selected downstream, the routing

method was selected as Muskingum-Cunge and finally the Loss/Gain

method was selected as none. Next under the Routing tab, the

channel length, channel slope, channel bed width, and side slope

were assigned their respective values. The shape of the channel


was chosen to be trapezoidal. The Options tab was ignored for this

model. Repeated Step 3 for the other reaches.

4. After the Basin Model had been completely filled out, the

Meteorological Model tab was created and two storms could be

defined. The 10-Year 24-Hour and 100-Year 24-hour design storms

parameters could be defined. Under each design storm, the

precipitation type was defined as the SCS storm, leaving the

remaining parameters as none. Moving to the next tab - the basins

were selected to be included. Under each design storm in the

model, the type (Type II) and the depth (mm) were inputted.

5. Finally, select from the Components tab, the Control Specifications

Manager. The number of days and hours for each storm were

inputted – for this model a summer storm setting was chosen and

the month of July was chosen. The number of days was irrelevant

but a 3-day period was selected for the 10-Year 24-Hour storm

while a 5-day period was selected for the 100-Year 24-Hour storm.

Both components were selected to have a 1-minute resolution.

6. Once all the parameters in the Watershed Explorer and Component Editor

had been inputted, running of the model could begin. The results

and discrepancies with the model will be outlined in the

remaining sections of this chapter.


5.3 RESULTS

The during-mining condition compared to the pre-mining condition

produced much higher outflows from each basin. For Basin 1 the total

minable acreage was found to be roughly 2.82 km2 a loss of only .3 km2

– See Figure 1. The hydraulic length for the subbasin was found to be

3.6 km where it meets with the junction of subbasin 2. The Slope of

the channel was roughly 0.06 m/m which contributed to a slightly

higher lag time of 81 minutes. For the entire watershed the peak

outflow for the 10-year 24-hour storm was calculated in HEC-HMS to be

8.4 cms occurring at 1pm. The peak outflow for the subbasin designated

for mining was just under the total basin outflow at 8 cms. For the

100-Year 24-Hour event over the entire watershed the peak outflow was

recorded at 16 cms while the outflow from the subbasin 1 produced a

peak discharge of 13.3 cms.

5.4 DISCUSSION

When running the HEC-HMS there are some sensitive variables that need

to be addressed. First, the Mannings n and the Curve Number influence

the peak discharge greatly. By increasing the curve number and the %

impervious area the peak runoff can increase greatly. Another


influence on differing results can come from the numbers calculated in

ArcMap.

5.5 CONCLUSIONS

The discharge and peak outflow from each basin were considered under

the worst case scenario for the “during-mining” phase – as the mine is

excavated each year (100 acres) the soil is removed as well as the

overburden and replaced every 6 years – this is the process of surface

mining detailed in the SMCRA section. The numbers obtained from both

design storms seem reasonable considering the size and slope of the

watershed as well as the prospective subbasin.

5.6 RECOMMENDATIONS

In the future work with the mining condition – more consideration to

land cover and the actual mining process should be developed. The

numbers obtained in HEC-HMS and ArcMap are reasonable but further

studies within the subbasin should be conducted..

Chapter 6 – Soil Erosion


6.1 Purpose

The purpose of this chapter is to explore the sediment erosion rates in watering trough gulch by means of solving the universal soil loss equation (usle). The goal is to understand the rate and total amount of sediment that runs off the catchment in a pre- during- and post-mining setting.

6.2 Introduction

The amount of soil that leaves a catchment is almost directly related to different

6.3 Methods

To calculate the loss of soil from subbasin 1 in the watering trough

gulch catchment a series of factors from the usle were used and

calculated to determine the annual soil loss.

The soil loss equation is represented by the following parameters: a =

r k l s c p

R-factor

The initial parameter that was calculated was the r-value or rainfall

and runoff factor. To understand the runoff better there were a number

of options available, but for this estimation an isoerodent map was

used as a simple, “cut-and-dry” approach. The r-factor was 10 hundreds

ft-tonf-in(ac'h).

K-factor


The k-factor was found from the natural resource conservation services

(nrcs) webpage under the web soil survey (wss) link. The values for

the k-factor were taken for the pre-mining condition (all the

horizons/layers) as well as the during-mining condition indicating the

top layer was 16 inches below the surface.

The k-factor values for each land condition were imported as .txt

files into the gis program and joined with the soil data from ssurgo.

To determine the average k-factors for the subbasin and overall

watershed the average was taken from each area and land condition and

an average of those was used to determine the during mining runoff

from the watering trough gulch catchment.

Ls-factor

The length-slope factor is determined by the various lengths within

the subbasins of the hydrology as well as the slope for the

corresponding lengths. The accumulation of these values equates to the

length slope factor for a certain area.

Chapter 7 – sediment detention / channel hydraulics

7.1 introduction


The purpose of this chapter is to design a sediment detention basin in

the watering trough gulch catchment as a model to be used during the

mining and reclamation phases of mining.

The sediment runoff of a watershed is important to monitor and control

for most any land-use activity. The amount of sediment that comes off

an area is a function of the precipitation and the existing land

cover. The precipitation intensity, duration and spatial variability

influence the runoff response at a given monitoring gauge. In a mining

setting, there must be a series of sediment detention basins installed

to attenuate the flows from storms due to the lack of friction the

once-covered ground provided. In this chapter a detention basin model

is designed to accommodate the peak flows from a 10-year 24-hour

storm.

7.2 methods

Making the catchment

The subbasin being considered for a feasible mining operation is basin

1. In this basin a smaller catchment was established to help

understand the runoff potential in a during-mining condition. The

catchment area was found using stream stats – state applications to

get an idea of the physical basin characteristics in a timely manner.


Arcmap was used to measure the channel length, basin area, mean slope

by clipping the dem to the catchment raster.

Soil data was found on the web soil survey (wss) on the nrcs webpage.

Under the “physical properties” tab the percent (%) clay, silt, and

sand were found and imported into excel and area weighted for the area

of interest (aoi). In arcmap the soil data was clipped to the land

cover hydrologic soil group raster to determine a new curve number for

the catchment - using the nrcs curve number sheet (nrcs, 2014). From

there the s-value (in.) And initial abstraction (in.) Could be

determined; it would later be used for modeling a design storm in hec-

hms.

In hec-hms the curve number was used as an input in runoff

calculations and to determine the initial abstraction used in the

“basin model manager” tab. Other variables needed include the lag time tl

in minutes, the following equation shows how to calculate the lag time

in hours:

(equation 7.1) lag time is reported in hours and multiplied by 60

minutes to obtain the input for hec-hms. L=channel length in feet,

s=value calculated from the curve number in inches, and s=slope in

percent (%).


There are two important outputs to obtain from hec-hms after a

successful test has been run for the catchment. Looking at the “results”

tab, an executive summary is produced indicating a volume a peak

runoff volume (∀) in inches and the peak discharge (qp) from the

design storm in cubic feet per second (ft3/sec). These values are

important because they determine the sensitivity of the calculated

time of base tbi and peak runoff qpi.

Calculating the sediment detention basin

Using the area-weighted percentages for each soil in the catchment and

each soil type’s unit weight, a weight per cubic foot of soil, was

determined for the aoi. This unit weight would be used for the

remaining calculations of sediment storage

with the new area delineated from arcmap or stream stats, a

sediment detention ratio (sdr) can be calculated using the usda scs

method (1979) where a = square miles (mi2).

The total amount of sediment in pounds per cubic foot (lbs/ft3) for

the mine life can be determined using the following equation where

a=annual soil loss (tons/acres/year), sdr=sediment detention ratio,

w=unit weight found in equation7.1, a=area (acres). The volume of soil

is reported in acre-feet (af).


the peak runoff was calculated using one of the two hec-hms

outputs qp in inches per hour (in/hr). The area of catchment in acres

was used as well to calculate a rate of flow.

using the qpi found in equation 7.4 and the ∀ from hec-hms the

time of base in hours was calculated.

time of recession tri in hours was calculated using time of base -

the value from equation 7.4 and the estimated time to peak tpi from

the hec-hms outputs graph.

Center of mass for the inflow hydrograph was calculated next using the

values obtained in equation 7.5 and the estimated time to peak tpi. The

time to the center of mass for the inflow hydrograph tmi is also in

hours.

Equation (7.8) the detention time tmo, required for a center of

mass outflow hydrograph on the 24-hour scale must be greater than or

equal to 24 hours. Tmo was calculated by adding the center of mass time

(eq 7.8) to the detention time = 24 hours.

the peak outflow qpo was calculated by breaking up and rearranging

equation 7.9 into two parts to obtain values for a quadratic equation


that qpo is defined for. The resulting rate of qpo was produced in

inches per hour and converted to cubic feet per second.

Estimated the storage s volume for the basin is calculated in inches

but converted to acre-feet (af) by multiplying by the area in acres

and converting inches to feet.

The diameter of the outflow pipe in the sediment detention basin can

be calculated by reworking the equation for head on an outflow pipe

(eq 7.11a). Rearranging to solve for dr the inputs needed are the

calculated head in feet (see note below), and the calculated peak

outflow qpo.

The h-value or head is obtained by looking at a stage (ft) vs volume

(af) relationship graph and using the equation produced by the linear

interpolation of the two closest points to the calculated total

storage volume ∀total.

The values for each equation will be reported in the results section.

7.4 Results

The total area of the catchment for this model was determined to be

198 acres or 0.31 mi2. The calculated stream length was 3,394 feet

while the overall basin length was 5,642 feet and an average basin


slope of 18.4%. The curve number used was 88 to represent the worst

case scenario of basin 1 and the catchment together. From there the s-

value and initial abstraction (ia) were calculated. The s-value was

1.4 inches while the initial abstraction was calculated at 0.3 inches.

The estimated weight of storage was determined to be 63 (tons/acre)

per year and for the life of the mine the total storage came to be 967

tons/year or 1 acre-foot annually. (table 7.1)

Time of base tbi was the first component calculated for the sizing of

the detention basin and pipe outflow capacity. Time of base was

estimated to be 1.6 hours. The time to the peak of the inflow

hydrograph tpi occurred at 1.37 hours. The recession tri was 0.25 while

the center of mass of inflow tmi was 1 hour. Next, approximating the

center of mass of outflow hydrograph for a 24-hour detention, tmo

resulted in being 25 hours. (table 7.2)

CHAPTER 8 – RECLAMATION/REVEGETATION

8.1 INTRODUCTION


The purpose and overall goal of this chapter is to address the

concerns with mining reclamation in Watering Trough Gulch and the goal

of the reclamation process for post-mined land in Northern Colorado.

Upon the completion of the mine operation, a process to restore the

land to a better or similar condition than it was prior to the mining

must occur – this process is called reclamation. The reclamation

process can vary in the time and money spent on the project and is a

function of several physical variables.

Revegetation techniques differ by region because they are a function

of the annual and seasonal climate variation for the area. The

revegetation can take place naturally, but with the right funding, it

is typically increased with modern practices and updated machinery.

Compared to the Eastern parts of the United States, where revegetation

may take place naturally or aided in 10 years or less, the Western

states have a much longer revegetation period 10 to 100 years

(Congress, 1986).

Revegetation is a key step and aids other aspects of the reclamation

process – one of the most d important is the sediment yield and the

runoff water quality. With a successful establishment of local


vegetation, and new topsoil placed on top of the filled in land, the

roots should hold the soil in place and reduce the annual sediment

yield from the basin as time goes on.

The reclamation process can be complex and should be taken on by a

series of experts; the general process described is bulleted below

(Paschke, 2014):

1. Determine the restoration goal: The restoration goal can be one

overarching goal or a series of small goals collectively working

together. To build an accurate comparison, the use of a nearby

area with similar physical characteristics can be used to help

compare results.

2. Identify the constraints: There are a number of constraints that

limit restorative efforts from physical and chemical conditions,

a species index and animal patterns, as well as money and time.

3. Prioritize constraints: Some factors in the restoration process

may be accomplished simultaneously to save time and money while

enhancing the condition of the area at

4. Address the constraints in order: Starting with the physical

characteristics, the initial goal is to reduce the runoff by

establishing a vegetation cover over a well-mixed topsoil layer.


Topsoil is the beginning to a successful long-term restoration

followed by vegetative growth and then the introduction of

species. The methods of addressing these different constraints

are discussed further in the Methods section of this chapter.

5. Monitoring: The monitoring of the site will be conducted on the

basis of the physical constraints found in the pre-mining

evaluations and the post-mining reclamation.

6. Maintain the new system: With monitoring efforts in place, the

system may undergo unforeseen changes and flexibility in

management practices may need to be enacted.

With a goal and the important criteria mapped out, the reclamation

process can being during or after the mining operation – typically

the latter is chosen.

8.3 METHODS

There are several main goals of the restoration process that are

considered for a post-mining project, mainly the physical and chemical

characteristics of the soil and runoff water quality. To satisfy a

successful reestablishment of an equal or better ecology in the area,

a pre-mining baseline condition must be fashioned to understand the

goal of the post-mining reclamation process. Watering Trough Gulch Feasibility Study (2014)

PRE-MINING

An account of all the plant species in the area to be designated for

mining must be made prior to mining so that upon completing the mining

operation, a successful growth of vegetation can occur.

A similar account of the animal and other biota living on the premise

may be accounted for using the help of rangeland scientists and

ecologists. The goal is to obtain populations, general habitat

classification and area needed – if larger animals (cattle, bison,

ect.) are present on the land cooperation with the rancher may be

required.

Soil samples will be taken prior to mining to get an idea of the

topsoil and lower layers to determine the soil hydrologic groups –

classifications can be found in Chapter 2. Understanding the

hydrologic soil groups prior to mining will help determine the post

mining soil replacement and revegetation

POST MINING

Once the mining is complete and the heavy machinery has finished the

major operations, new machinery and materials can begin to be moved

into the abandoned mine area, and the restoration plan can be put into

action.


Starting with the stored piles of soil, overburden, interburden and

the tailings from the mining operation – the goal is to make sure

there is no issue with water quality for downstream users. First, the

remaining pits are filled in and the remaining soil can be used

towards putting down new topsoil. To make healthy topsoil it is

important to include a variety of different soil amendments (Paschke,

2014) and many organic elements can be used by mulching any unwanted

vegetation and dead material.

The next step after topsoil has been applied to the area and the

topography has been smoothed back to a similar baseline condition. The

seeding of native plants can begin – to reduce compaction of the new

soil and increase the chance of a successful plant community.

Once basic characteristics of the land have been restored, focus on

managing the chemicals and metals in runoff water quality.

8.4 RESULTS

The findings for the restoration process are categorized into the

highest need to be taken care of first followed by less important or

less time-intensive projects. To understand the importance and order

of these processes or goals in reclaiming a mine site, a sensitivity

analysis may be used to compare the different physical criteria in the


watershed that have the highest potential to affect the environment as

well as the downstream users. The order of restoration will occur in

this order: separate the unusable soil and materials, return area to

original AOC by grading or other method, apply even and well mixed

topsoil over disturbed areas, and begin the revegetation process by

planting and seeding.

When establishing the topsoil there are two options to consider

depending on the mine operations: The storage and upkeep of the local

soil on site, this can be cost effective in the short term, but the

soil may degrade over time affecting long-term success of

revegetation. The other option; Import fresh topsoil from off-site -

this option has been shown to help the long term succession of plants

in the disturbed area (Congress, 1986). For other land cover that once

existed on the site – trees, large shrubs, and crops should be given

special planting instructions and a visual description of the planting

guidelines can be found in Appendix 8.

The succession of a new vegetative cover is a difficult task

especially for the Western US where generally the climate is more

variable and there is a lack of moisture for plants to take in. For

the seeding technique, a spray seeding will not be used due to lower


rates of succession in germination (Congress, 1986). The soil type in

the basin under scope is mostly loam ~ 60-80% of the land cover area.

The loamy soil and potential for metal leeching will be counteracted

using a variety of native grasses and shrubs – some with alkali-

reducing properties. These grasses include: Blue Grama and

Buffalograss (Chapter 12 - Revegetation , 2001).

Considering the hydrology of the disturbed area – and the stream

buffer that was established prior to the mining, post-mining hydrology

can hinder the success of revegetation.

8.5 DISCUSSION

In the reclamation process, the criteria under scope of most

importance and will be taken care of with higher priority than other

processes within the mine site. To have a successful reclamation for

the long-term, it is important to consider the discrepancies with the

methods described above and how they quality can be improved or

reduced in each situation.

When replacing soil it is imperative to have strong Nitrogen-fixers in

the soil, regardless if soil is freshly brought in or stored over the

life of the mine. Nitrogen is a vital chemical for plant growth in

both early and late stages of life (Congress, 1986).


Seeding and planting of the vegetation has the issue of possible weed

growth or an unwanted intrusion of noxious weeds. Weeds grow well in

Colorado, and prevention is a good practice when seeding and

monitoring of the vegetation (Brown & Macklow, 2012). Weeds like

myrtle spurge and houndstongue can be found in many areas near

Watering trough Gulch – monitoring efforts should be placed on the

succession of desirable native plants.

Mine tailings will be placed in an isolated area lined with a liner

and capped with extra overburden. This site shall be monitored for any

runoff of metals after the reclamation process has been underway for

any amount of time. The mine tailings containment can be a difficult

step in the reclamation process but should not be overlooked if the

amount of tailings is not significant (Congress, 1986). If dealt with

improperly, an increase in alkalinity or a change in pH can be

observed downstream of the sub-subbasin.

8.7 RECOMMENDATIONS

When the reclamation process begins it is dependent on the available

money and time as well as temporal and physical variables. These

variables and constraints can influence the choice in reclamation

method for each different project or aspect of the overall reclamation


period. As recommendations, a look at different techniques new and old

could be referenced to the different physical aspects of the disturbed

land to choose the most efficient one.

In the restorative and monitoring phase, an emerging technology in

many industries – Unmanned Aerial Vehicle (UAV) may be implemented to

reduce the amount of man-hours spent driving too and from the site.

These UAV’s are capable of long flight times, mounting hi-resolution

cameras, sensors, and can even carry supplies into the disturbed area.

Drones could be used to aid in the distribution of seed, or be used to

check the progress of the reclamation (Wanless & Katsuris, 2013).

Another recommendation for the reclamation process is to work

diligently and concurrently with the mining process (during mining)

and restore as time goes on.


CHAPTER 9 – MONITORING

9.1 INTRODUCTION

Monitoring is the process of making observations over a time period to

track the progress or levels of a certain variable of interest within

the system. For Watering Trough Gulch, it will be imperative to

monitor prior to the mining operation and long after the mine shuts

down. Monitoring before mining will determine the baseline water

quality levels – referenced in the during- and post-mining stages to

prevent levels exceeding the standard. Water quality is of greatest

concern in the post and pre mining stages

9.2 METHODS

For the monitoring process in Watering Trough Gulch, there will have

been a monitoring and reclamation plan established to monitor prior to

the operation so that any unexpected or unwanted circumstance is

prevented more readily – as designated in SMCRA (SMCRA, 2014).

Monitoring in the pre-mining phase is a key step to establishing

ambient or natural water quality conditions. These conditions can then

be used in the during- and post-mining monitoring efforts. I would


recommend a seasonal or semi-annual monitoring schedule for all

periods of the mining process.

Conclusion

Watering Trough gulch is a smaller watershed that is being considered

for mining use and an initial assessment of the land, water, flora and

fauna must be made to set a standard during the post-mining

reclamation. After interpreting the basic characteristics of the

watershed, the mining process can begin. This watershed is small and

so the remediation of the area can be more easily directed and

controlled compared to other nearby watersheds that are much larger.

In a conclusive look at Watering Trough Gulch, the subbasin chosen to


undergo the mining process will be a highly disturbed area with much

need repair. To make sure the bond is released for the mining company

and their liability for the land freed, the monitoring and initial

restoration efforts must be not only successful but also efficient and

ecologically sustainable for the future. These monitoring efforts will

be discussed in greater detail in the next chapter (CH 9).

Recommendations

CH 2 For this chapter, I plan on going back to my data and checking

for inconsistencies and manipulating any missing data from the cells.

A description of Watering Trough Gulch would be better if the

following occur: An accurate or reasonable water balance calculated

using the Thronwaite model would match temporally with the discharge

and precipitation as rain (Dunne, 1978). There could’ve been adjacent

watersheds to contrast general characteristics of each to understand

how Watering Trough Gulch behaves. Furthermore, it is imperative that

a map of soils and land cover be incorporated in the initial

description of Watering Trough Gulch to show the physical

characteristics of the land better.


APPENDIX

A1. Chapter 1

(Figure 1.1) Diagram shows the relationship between the carbon content (or the time and depth of burial) compared to the heating value.


(Figure1.2) Annual coal mine production in Colorado from 1864-2004 in millions of short tons


A2. Chapter 2

(Table 2.1) Short detail on the stations used in the meteorological and hydrological dataacquisition for Watering Trough Gulch feasibility study

Station Name Operatedby

Period ofRecord

Latitude

Longitude

Elevation(m)

Watering TroughGulch

USGS 1979-1981 40.22 -107.16 2117

Hayden NCDC 1909-2014 40.49 -107.25 1971Hayden COAgMet 2011-2014 40.49 -107.18 1967

(Table 2.2) The Hydrologic soil groups of Watering Trough Gulch are ranked in alphabetical order of hydrologic soil group – ranging from mostly from sandy loams to loam, dominant soil group is B.

Map unit symbol

Soil Characteristic Rating Acres in AOI Percent ofAOI

27A Middlecreek loam, 1 to 10 percent slopes B 104.4 6.10%34E Coutis fine sandy loam, 3 to 25 percent

slopesB 106.1 6.20%

53F Winevada fine sandy loam, 25 to 65 percent slopes

B 0.3 0.00%

66D Foidel loam, 15 to 25 percent slopes B 147.1 8.60%66F Foidel loam, 25 to 65 percent slopes B 251.2 14.80%68C Rabbitears loam, 3 to 12 percent slopes B 12.3 0.70%68D Rabbitears loam, 12 to 25 percent slopes B 34.7 2.00%


80D Foidel loam, 3 to 25 percent slopes B 13.2 0.80%X8D Winevada-Splitro complex, 3 to 25 percent

slopesB 55.3 3.30%

X8F Dunckley-Skyway complex, 25 to 65 percent slopes

B 133.2 7.80%

2E Routtskin loam, 12 to 25 percent slopes C 42.3 2.50%50F Routt loam, warm, 25 to 65 percent slopes C 98.4 5.80%133 Lintim loam, cool, 3 to 25 percent slopes C 310.3 18.20%35D Phippsberg silty clay loam, 12 to 25 percent

slopesD 91.9 5.40%

103 Cryoborolls, cryorthents soils, rock outcrop, 25 to 99 percent slopes

D 177.1 10.40%

120 Phippsberg clay loam, 25 to 65 percent slopes

D 27.8 1.60%

D10 Impass silty clay loam, 12 to 25 percent slopes

D 94.5 5.60%

W Water 1.3 0.10%

(Table 2.3) There are only 5 land cover types found in the watershed found on the NRCS WebSoil Survey webpage. Listed below are the different land cover types and their area of cover as well as the calculated leaf area indexes (LAI), Max Stand Mass and Rooting Depth(Fassnacht S. R., 2013).

VALUE Land Cover Classification Count % of Area Min LAI Max LAI Max StandMass (kg/m2)

Rooting Depth(m) Description

31 Barren Land(Rock/Sand/Clay)

5 0.0007 0 0 0 0 Barren areas of bedrock, desert pavement, scarps, talus, slides, sand dunes, strip mines, gravel pits and other accumulations of earthen material. Generally,


vegetation accounts for less than 15% of total cover.

41 Deciduous Forest 5332 0.6976 0.5 6 20 2

Areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. >75% of vegetation sheds seasonally

42 Evergreen Forest 33 0.0043 1.6 2 25 1

Areas dominated by trees generallygreater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75 percent of the tree species maintain their leaves all year. Canopy is never without green foliage.

52 Shrub/Scrub 2184 0.2858 0.5 4 8 1

Areas dominated by shrubs; less than 5 meters tall with shrub canopy typically greater than 20% of total vegetation. This class includes true shrubs, and young trees in an early successional stage

81 Pasture/Hay 89 0.0116 3 4 1.5 0.2

Areas of grasses, legumes planted for livestock grazing or the production of seed or hay crops, typically on a perennial cycle. Pasture/hay vegetation accounts forgreater than 20 percent of total vegetation.


0.1%

69.8%0.4%

28.6%

1.2%

Land Cover (NLCD)Barren Land (Rock/Sand/Clay)

Deciduous Forest

Evergreen Forest

Shrub/Scrub

Pasture/Hay

(Figure 1.1) A visual and graphical example of percentage land cover for Watering Trough Gulch - retrieved from the National Land Cover Database (NLCD).


(Figure 2.2) Slopes of Watering Trough Gulch with the stream network – slopes were calculated in ArcMap using the Slope tool from the DEM. DEM data was acquired from Colorado View


(Figure 2.3) Land Cover Data retrieved from the NCLD. Watering trough gulch is dominated by deciduous forest and scrub/shrub.


(Figure 2.4) Soils data acquired from SSURGO database. Dominant soils are Foidel Loams and Lintim Loam


A3. Chapter 3

Water Balance Equations

(Equation 3.1)(Wolock & McCabe, 1999)

Psnow=P∙ [ Train−TTrain−Tsnow ]

Psnow is the monthly precipitation-as-snowP is the monthly precipitation

Train is the temperature threshold for rain precipitationT is the mean monthly temperature

Tsnow is the temperature threshold for snow precipitation

(Equation 3.2)(Wolock & McCabe, 1999)

SMF=T−Tsnow

Train−Tsnow∙meltmax

SMF is the fraction of snow storage that melts montlyT is the mean monthly temperature

Tsnow - the temperature threshold for snow precipitationTrain - the temperature threshold for rain precipitation

meltmax is the monthly maximum melt rate

(Equation 3.3)(Dunne & Leopold, 1978)

DRO=Prain∙drofracDRO the monthly direct run off

Prain is the monthly precipitation-as-raindrofrac is fraction of monthly precipitation as direct runoff



Et=1.6[10∙TaI ]a

Et is the monthly potential evapotraspiration (PET)Ta is the monthly average temperature

a is calculated in Equation 3.6I is the monthly heat index


I=∑i=1

12 [ Tai5 ]1.5

I is the monthly heat indexTa is the monthly average temperature


a=0.49+0.0179I−0.0000771I2+0.000000675I3

a is used to calculate Equation 3.4I is the monthly heat index

(Equation 3.7)(Walter, 2013)

AW=AWC×e(APWLAWC

)

AW is the monthly available soil waterAWC is the total available water capacity

APWL is the monthly accumulated potential water loss


(Table 3.1) The annual water balance of Watering Trough Gulch was determined using the series of Equations 3.1-3.7 displayed above using climatic data retrieved from the Hayden Airport in Hayden, Colorado. The water balance was used to characterize the hydrology and climate for the baseline condition.

Annual

Month October November Decembe

rJanuar

yFebruar

y March April May June Jul

y August September Sum Avg

Temperature [C] 7.5 -0.1 -6.3 -8.0 -5.6 -1 5.8 11 16 19 18 14 6Precipitation [mm] 39 33 38 37 31 33 42 38 30 32 35 38 425 35Precipitation as Rain [mm] 39 0 0 0 0 0 42 38 30 32 35 38 254 21

Precipitation as Snow [mm] 0 33 38 37 31 33 0 0 0 0 0 0 172 14

Interception [mm/month] 5 5 6 7 7 6 5 5 5 5 6 6 68

Accumulated snow asSWE [mm] 0 28 60 90 114 141 136 0 0 0 0 0 567

Snowmelt Factor [mm] 0.0 0.0 0 0 0 0 0 0 0 0 0 0

Snowmelt [mm] 0 0 60 90 114 141 68 0 0 0 0 0 471Net Input [mm] 39 32 98 126 145 174 110 38 30 32 35 38 897Direct Runoff 1.9 0 0 0 0 0 2.1 1.9 1.5 1.6 1.8 1.9 13PET [mm/month] 38 0 0 0 0 0 30 56 80 98 93 69 464P-PET [mm] 0 33 38 37 31 33 12 -18 -50 -66 -58 -32Net Input - PET [mm] 0 32 98 126 145 174 80 -18 -50 -66 -58 -32 433

Accumulated potential WL [mm] -18 -50 -66 -58 -32

Actual soil moisture [mm] 214 243 250 250 250 250 222 199 181 169 171 188

Change in SM [mm] 26 29 7 0 0 0 -28 -23 -18 -12 2 17AET [mm/month] 14 11 0 0 0 0 30 56 48 43 37 70 309Deficit [mm] 24 0 0 0 0 0 0 0 32 55 56 -1 167Surplus 14 43 50 50 50 50 22 0 0 0 0 0 279


Total available forrunoff [mm] 25 22 38 37 31 33 12 0 0 0 0 0 197

Detention [mm] 7 22 25 25 25 25 11 0 0 0 0 0 140Total runoff [mm] 12 11 19 18 16 16 6 0 0 0 0 0 99Observed discharge [mm] 0.51 0.53 1.6 25 18 3.7 1 0.26 0.28 0.3

3 0.39 0.41 52.0 4.3


Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct0

20

40

60

80

100

120

-10.0

-5.0

0.0

5.0

10.0

15.0

20.0

25.0Precipitation [mm] PET [mm] AET [mm]Temperature [C]

Month

Depth (mm)

Temperature (C)

Deficit

Soil Moisture Recharge

(Figure 3.1) A water balance was calculated in Chapter 3 to characterize baseline conditions. The monthly water balance indicates relationships between the inputs and outputs and predicts the annual runoff depth from the area.


10/1/1989

11/1/1989

12/1/1989

1/1/1990

2/1/1990

3/1/1990

4/1/1990

5/1/1990

6/1/1990

7/1/1990

8/1/1990

9/1/1990

-40.00

-20.00

0.00

20.00

40.00

60.00

80.00

0.00

10.00

20.00

30.00

40.00

50.00

60.00Soil Moisture

Change in SM [mm] Deficit [mm] Surplus [mm]

Figure (3.2) A monthly water balance was used to determine soil moisture exchanges within the system and to help determine times of deficit and surplus. Soil moisture is both a losing and gaining system through a porous media – soil


0 1 2 3 4 5 6 7 8 9 10 11 12-40.0

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

Avg Temp Max Temp Min Temp

Month

Temperature (C)

(Figure 3.3) Maximum, minimum and average temperatures recorded over a 105 year period recorded at the Hayden Airport – part of the NCDC Climate Observations.


A4. Chapter 4

(Equation 4.1)S=

1000CN

−10

CN is the Curve NumberS is associated with the conditions of the soil and plant-litter-

cover

(Equation 4.2)Ia=0.2×S

Ia represents all losses to the hydrologic systemS is associated with the conditions of the soil and plant-litter-

cover

(Equation 4.3)tL=¿¿¿

tL denotes lag time in hoursY is indicative of channel percent slope

L represents the hydraulic length in feetS is calculated with the CN


Watershed

Areakm2

Highest

Elevation m

Lowest

Elevation m

Hydraulic

Length m

%impervious

CN Slope%

Slopem/m S Ia

Tl (LagTime)hours

Tl (LagTime)min

SubBasin

13.07 2368 2169 3421 1 65.3 6 0.06 5.3 1.06 1.357 81

SubBasin

22.22 2276 2123 1816 1 67.9 5 0.08 4.7 0.95 0.836 50

SubBasin

31.38 2295 2118 3026 1 63.7 6 0.06 5.7 1.14 1.282 77

Reach1 2170 2121 1521 66 3 0.03 5.2 1.05 0.995 60

Reach2 2121 2117 196 66 2 0.02 5.2 1.04 0.236 14

Watering

TroughGulch(complete)

6.67 2456 2117 5,665 66 21 0.06 5.2 1.03 1.056 63

(Table 4.1) A hydrologic modeling program (HEC-HMS) requires several inputs to run accurately and produce valuable results for further analysis. Basic inputs are given in the table below for the pre mining hydrology.


(Table 4.2) The hydrologic soil groups and their associated land cover area weighted for each subbasin in Watering Trough Gulch. Subbasin 1 will be considered for mining in the study.

Basin 1 Basin 2 Basin 3Area = 3.03 km2 Area = 2.23 km2 Area = 1.38 km2

Land Cover Code

B C D B C D B C D

41 0.38 0.11 0.38 0.09 0.04 0.08 0.14 - 0.0342 0.12 0.05 - 0.25 0.27 0.28 0.05 0.04 0.0152 1.02 0.85 0.15 0.60 0.23 0.26 0.72 0.04 0.3081 - - 0.00 - 0.13 0.00 - - 0.05


A5. Chapter 5

(Figure 5.1) Outflow in cubic meters per second (cms) from Subbasin 1 entering Reach 1 for the 100-year 24-hour storm event.Peak at 13 cms.


(Figure 5.3) Total outflows in cubic meters per second (cms) fromWatering Trough Gulch during the 100-Year 24-Hour storm event. Peak at 16 cms.

(Figure 5.4) Outflow in cubic meters per second (cms) from Subbasin 1 entering Reach 1 for the 10-year 24-hour storm event. Peak at 8 cms


(Figure 5.5) Total outflows in cubic meters per second (cms) fromWatering Trough Gulch during the 10-Year 24-Hour storm event. Peak at 8.5 cm

A6. Chapter 6

(Equation 6.1)A=R∙K∙L∙S∙C∙P

A is the estimated average soil loss [tons/acre/year]R is the rainfall-runoff erosivity factor

K is the soil erodibility factorL is the slope length factor

S is the slope steepness factorC is the cover and management factor

P is the erosion control practice factor

(Equation 6.2)(Moore & Burch, 1986)

LS=( [FA ]∙3022.13 )

0.4

∙( sin(S)0.0896)

1.3

LS is the length slope factorFA is the GIS flow accumulation layer

S is the GIS slope layer in degrees


A7. Chapter 7

Clay Sand Silt

Weight when submerged(lbs/ft3) 26 97 70

Percent (%) of Catchment 31.95 31.56667 35.26667

Percent (%) of Catchment 0.32 0.31 0.35 Tons/Mine Life

W (ton/ac/yr) 63 968.6492Table 7.1 The properties of sand silt and clay submerged in waterarea used in the determination of settling times and sediment detention basin size.Watering Trough Gulch Feasibility Study (2014)

Table 7.2 SCS triangular Hydrograph assumptions for Subbasin 1

Area (km2) 0.806CN 88

S (in)1.3636

36

Ia (in) - (mm)6.9272

73

∀s (AF)0.7071

75Annual Soil Loss A (tons/acre/yr) 8.85

SDR0.5801

23Qpi(cms) 5.30Qpi(cfs) 181Qpi (in/hr) .91∀ (mm) - (in) 18.6

Tbi (in)1.6163

49Tpi (Hr) - estimated from HEC chart

1.366667

Tri (hr)0.2496

82

Tmi (hr)0.9943

39

Tmo (hr)24.994

34Qpo (in/hr) 0.079Qpo (cfs) 15.80∀D (in) 5.22∀D (AF) 86Total ∀ (AF) 174Stage Height/Hydraulic Head (ft)

101.9

Pipe Diameter (ft) 0.643309

Pipe Diameter (in) 7.7


A8. Chapter 8

Figure 8.1 Reclaimed lands often have forests and reestablished forestis a victory in surface mine reclamation. Above are basics to replanting young trees – deemed more successful than seeding.


Table 8.1 The mining reclamation process as noted by Dr. Stednick (2014)

Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7

Top Soil Rem oved

Second Year of Reclam ationReclam ation

BeginsTop Soil ReplacedOverburden Replaced

M ining of the Coal

Overburden Rem oved

Reclam ation BeginsTop Soil Replaced

Overburden ReplacedM ining of the Coal

Overburden Rem ovedTop Soil Rem oved

Top Soil Replaced





Parcel 5

Parcel 6

Parcel 7


Concurrent Reclam tion

Top Soil Rem ovedParcel 1

Parcel 2

Parcel 3

Parcel 4

M ining of the Coal



A9. Chapter 9

Table 1: Water Quality in watering trough gulch The red indicatesexceeding the state standard for the water use as posted by the CDPHE 2014

DO pH NO2 NO3 Se As CdJan 9.8 8.0Mar 7.8Apr 10.8 8.2 1.0 1.0May 10.4 7.8 0.0 5.0Jun 12.0 7.8 1.0Jul 8.2 8.2Aug 8.2 8.0 1.0 1.0 0.0Sep 8.2 7.9Oct 8.6 7.6 1.0 2.0Nov 9.6 8.0

Zn Cr Cu Pb Ni Mn TSSJan 400.0 0.0 470.0 48Mar 50.0 35Apr 300.0 4.0 0.0 0.0 0.0 150.0 93May 40.0 49Jun 330.0 107Jul 0.0 0.0 140.0 75Aug 200.0 0.0 0.0 0.0 60.0 34Sep 20.0 48Oct 0.0 30.0 0.0 0.0 100.0 51Nov 60.0 48


LITERATURE CITED

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Congress, U. (1986). Western Surface Mine Permitting and Reclamation. Washington DC: Office of Technology Assessment.

Dunne, T., & Leopold, L. (1978). Water In Environmental Planning. San Francisco: W.H. Freeman.

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Survey.

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Shumate, S. (2013, Aug 22). Office of Surface Mining. (W. F. Practicum, Interviewer)

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Watering Trough Gulch Mining Project: A Feasibility Study Routt County, Colorado Acknowledgements

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