Proceedings of the 69th ANNUAL

EASTERN SNOW CONFERENCE

5–7 June 2012

Frost Valley YMCA, Claryville, New York, USA

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ISBN 0-920081-34-7

ISSN: 0424-1932

Proceedings of the Eastern Snow Conference

Printed and Bound in the United States of America

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FOREWARD

his proceedings volume contains papers presented at the 69th Eastern Snow Conference (ESC) held 5–7 June 2012 at the Frost Valley YMCA camp, Claryville, New York, USA. The meeting featured sessions on glaciology, river ice and hydrology, snow and climate,

remote sensing, snowpack properties and hydrochemistry as well as a diverse spectrum of posters. The ESC is a joint United States and Canadian forum for discussing recent work on operational,

applied and scientific issues related to snow and ice. It also retains an increasing interest as a symposium where novel approaches to cryospheric science of international significance are presented. The ESC has published an annual series of proceedings since 1952. Typical topics include studies of snow and ice as materials, snow removal, meteorological forecasting, river ice control, snow hydrology, snow chemistry, glaciology, remote sensing of snow and ice, and snow ecology. Membership in the ESC is open to all interested individuals and corporations. Additional copies of the current proceedings and all back issues can be obtained from the Secretary. Additional information about the Eastern Snow Conference may be found at: http://www.easternsnow.org/.

We continue with an optional review process, and authors may submit extended abstracts or full

papers to the Proceedings. Participants in the Western Snow Conference (WSC—http://www.westernsnowconference.org/) were invited to join the ESC participants in the option to submit papers relevant to winter hydrology to the international journal, Hydrological Processes. These papers went through a formal journal review, revision, and referee process and many appear both in these proceedings and in the journal. John Pomeroy (University of Saskatchewan), Kelly Elder (USFS, Ft. Collins), and Andrew Klein (Texas A&M University) edit this special issue of Hydrological Processes dedicated to ESC/WSC papers.

We thank members of the Library Sciences and Knowledge Transfer (LSKT) Branch, at the

Information Technology Laboratory, Engineering Research and Development Center (ERDC-ITL). Over the years this group has contributed considerable time to this publication and has enhanced the quality of these proceedings. We especially thank Emily Moynihan for her effort on behalf of these proceedings.

The 2012 meeting of the Eastern Snow Conference and these proceedings were made possible

by sponsorship and Corporate Memberships by the following: Campbell Scientific (Canada) Corp. Edmonton, Alberta, CANADA http://www.campbellsci.com/offices/csc.html ERDC-CRREL Hanover, New Hampshire, USA http://www.crrel.usace.army.mil

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GEONOR Milford, Pennsylvania, USA http://www.geonor.com Hoskin Scientific Burlington, Ontario, Canada http://www.hoskin.ca

Bridgewater State University Bridgewater, Massachusetts, USA http://www.bridgew.edu

We look forward to seeing many of you at the 70th Eastern Snow Conference meeting to be held 4–6 June 2013 at the University of Waterloo Summit Centre for the Environment, Huntsville, Ontario, Canada. The general theme of the meeting will be “Snow and Ice under a Changing Climate”

Alex Langois and Susan Frankenstein ESC Proceedings Editors Cartel, Université de Sherbrooke and ERDC-CRREL

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This year’s Eastern Snow Conference Proceedings is dedicated to

Austin William Hogan 1936–2013

ESC Life Member since 1997 US Secretary/Treasurer 1994–2001

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CONTENTS Foreword ...................................................................................................................................................................... iii

Dedication ......................................................................................................................................................................v

Statement of Purpose ................................................................................................................................................... ix

Executives for the 69th Eastern Snow Conference ....................................................................................................... xi

President’s Page ......................................................................................................................................................... xiii

Weisnet Medal for Best Student Paper Putting the Capital “A” in CoCoRaHS: An Experimental Program to Measure Albedo using the Community Collaborative Rain, Hail, and Snow (CoCoRaHS) Network E.A. Burakowski, (C.P. Wake, J.E. Dibb, and M. Stampone) .................................................................................5

David Miller Award for Best Student Poster Satellite and Surface Perspectives of Snow Extent in the Southern Appalachian Mountains J.W. Sugg, (L.B. Perry and D.K. Hall) ................................................................................................................. 21

Campbell Scientific Prize for Best Canadian Student Paper A Simple In-Situ Sensor for Snow Grain Size Measurement A. Kasurak, (R. Kelley and J. King) ...................................................................................................................... 41

Snow Monitoring Networks Developing a Snow Cover Component for the WMO Global Cryosphere Watch R.D. Brown, K. Luojus, and B.E. Goodison .......................................................................................................... 59

Watershed Hydrology: Streamflow Changes in the Timing of Snowmelt and the Seasonality of Nutrient Loading: Can Models Simulate the Impacts on Freshwater Trophic Status? D.C. Pierson, N. Samal, E. Owens, E.M. Schneiderman, and M.S. Zion .............................................................. 65

Effect of Projected Changes in Winter Streamflow on Stream Turbidity, Esopus Creek Watershed in New York, USA R. Mukundan, D.C. Pierson, L. Wang, A.H. Matonse, N.R. Samal, M.S. Zion, and E.M. Schneiderman ............. 75

Potential Effects of Climate Change on Winter Turbidity Levels in the Ashokan Reservoir, NY N.R. Samal, A.H. Matonse, R. Mukundan, D.C. Pierson, R.K. Gelda, M.S. Zion, and E.M. Schneiderman ........ 83

Watershed Hydrology: Precipitation and Snowpack Modeling Past and Future Changes in Frost Day Indices in Catskill Mountain Region of New York A. Anandhi, M.S. Zion, P.H. Gowda, D.C. Pierson, D. Lounsbury, and A. Frei .................................................. 99

Analysis of Rain-on-Snow Runoff Events in New York S.M. Pradhanang, A. Frei, M.S. Zion, E.M. Schneiderman, T.S. Steenhuis, and D. Pierson ............................. 115

Advances in snow measurements and modeling Posters

The Québec/Labrador Peninsula and the Evolution of the Eastern Snow Conference P. Adams, M. Eccelstone, J. Buttle, and C. Taylor ............................................................................................. 129

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Pioneers through Winter in North America: Paleo-Indians and Paleo-Eskimos J. Toupin ............................................................................................................................................................. 137

Modeling Frost Line Soil Penetration Using Freezing Degree-Day Rates, Day Length, and Sun Angle S. Vermette and J. Kanack .................................................................................................................................. 143

Glaciology and Sea-ice Influence of the Recession of the Pasterze Blacier, Austria, on Water Discharge Used for Hydro-power Production K.J. Bayr, D.K. Hall, M. Kelly, and C. Dunn ..................................................................................................... 159

Rising ELA and Expanding Proglacial Lakes Lead to Initiation of Rapid Retreat of Brady Glacier, Alaska M. Pelto, D. Capps, J.J. Clague, and B. Pelto .................................................................................................... 167

Remote Sensing of Snow and Ice: Micro to Watershed Scale

Snow Microwave Emission Modeling of Ice Lenses within the Snowpack Using the Microwave Emission Model for Layered Snowpacks (MEMLS) B. Montpetit, A. Royer, A. Langlois, and C. Derksen ......................................................................................... 183

Estimation of Snow Water Equivalent of Dry Snowpacks Using a Multi-Offset Ground Penetrating Radar System D. Gustafsson, N. Sundström, and A. Lundberg ................................................................................................. 197

Remote Sensing of Snow and Ice: Regional to Hemispheric Scale Posters

Improved Snow Mapping Accuracy with Revised MODIS Snow Algorithm G. Riggs and D.K. Hall ....................................................................................................................................... 209

Sno-Foo Award .......................................................................................................................................................... 215

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STATEMENT OF PURPOSE

The Eastern Snow Conference (ESC) is a joint Canadian/US organization founded in the 1940s, originally with members primarily from eastern North America. Our current members are scientists, snow surveyors, engineers, technicians, professors, students, and operational and maintenance professionals from North America, the United Kingdom, Japan, and Germany. There is a western counterpart to the ESC, the Western Snow Conference (WSC), which also is a joint Canadian/US organization. Every fifth year, the ESC and the WSC hold joint meetings.

The Eastern Snow Conference is a forum that brings the research and operations communities together to discuss recent work on scientific, applied, and operational issues related to snow and ice. The location of the conference alternates yearly between the United States and Canada, and attendees present their work by either giving a talk or presenting a poster. Most resulting papers are reviewed, edited, and published in our yearly Proceedings of the Eastern Snow Conference. In recent years, the ESC meetings have included sessions on snow physics, winter survival of animals, snow and ice loads on structures, river ice, remote sensing of snow and ice, and glacier processes. Volumes of the Proceedings can be found in libraries throughout North America and Europe, and the papers are also available through the National Technical Information Service (NTIS) in the United States and CISTI in Canada.

Le Colloque sur la neige-région est (ESC) est une organisation americain-canadienne fondée dans les années ’40 et

dont les membres provenaient a l’origine surtout de l’est de l’Amérique-du-Nord. Actuellement, les membres, qu’ils soient chercheurs, techniciens en enneigement, ingenieurs, techniciens, professeurs, étudiants, et spécialistes des services d’éxploitation et d’entretien, viennent non seulement d’Amérique-du-Nord, mais aussi du Royaume Uni, du Japon, et d’Allemagne. Le Colloque sur la neige-region ouest (WSC), aussi une organisation americain-canadienne, est l’homologue de l’ESC pour l’ouest nord-americain. Tous les cinq ans, l’ESC et la WSC organisent des réunions en commun.

Le Colloque sur la neige-region est un forum qui rassemble chercheurs et responsables des services d’exploitation pour discuter des travaux récents sur les problemes scientifiques, operationnels, ou autres dus à la neige et à la glace. Le site de cette réunion annuelle alterne entre les États Unis et le Canada. Les participants y présentent les résultats de leurs travaux par des communications orales ou au moyen d’affiches. Ces communications, une fois revues et éditées, sont publiées dans les Annales de l’ESC. Dans les années récentes, les réunions de l’ESC ont inclus des sessions sur la physique de la neige, la survie hivernale de la faune, les forces exercées par la neige et la glace sur les structures et les batiments, la glace de rivière, la télédétection de la neige et de la glace, et les processus glaciaires. Les Annales de l’ESC sont accessibles dans la plupart des bibliothèques scientifiques d’Amerique-du-Nord et d’Europe. Des copies d’articles peuvent être obtenues du National Technical Information Service (NTIS) aux États Unis et son équivalent au Canada, le CISTI.

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EXECUTIVES FOR THE 2011–2012 69th EASTERN SNOW CONFERENCE

PRESIDENT PAST PRESIDENT Jim Buttle Mauri Pelto Peterborough Dudley Ontario, Canada Massachusetts, USA

VICE-PRESIDENT AND PROGRAM CHAIR Robert Hellström

Bridgewater Massachusetts, USA

SECRETARY–TREASURER (Canada) SECRETARY–TREASURER (United States) Miles Ecclestone Derrill Cowing Peterborough Monmouth Ontario, Canada Maine, USA

ESC PROCEEDINGS EDITORS Alex Langlois, Sherbrooke, Quebec, Canada

Susan Frankenstein, Hanover, New Hampshire, USA

ESC WWW Mauri Pelto (Chair)

Dudley Massachusetts, USA

HYDROLOGICAL PROCESSES SPECIAL ISSUE EDITOR

Richard Kelly Waterloo

Ontario, Canada

STEERING COMMITTEE Alex Langlois (Chair)

Sherbrooke Quebec, Canada

Nathasa Neumann Kelowna

British Columbia, Canada

Janet Hardy Hanover

New Hampshire, USA

Baker Perry Elks Park

North Carolina, USA

Stephen Dery Prince George

British Coloumbia, Canada

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Craig Smith Saskatoon

Saskatchewan, Canada

RESEARCH COMMITTEE Allan Frei (Chair)

New York New York, USA

Hans-Peter Marshall Durango

Colorado, USA

Rae Melloh Hanover

New Hampshire, USA

Steve Howell Toranto

Ontario, Canada

Chris Fuhrmann Chapel Hill

North Carolina, USA

Jim Brylawski Milford

Pennsylvania, USA

WEB MASTER Andrew Klein

College Station Texas, USA

LOCAL ARRANGEMENTS (U.S.)

Allan Frei New York

New York, USA

69th ESC 2012 Glenn Horton, New York

Frost Valley YMCA Claryville

New York, USA

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THE PRESIDENT’S PAGE

The 69th annual meeting of the Eastern Snow Conference was held at the Frost Valley YMCA conference facility, near Clareyville, New York, in the beautiful Catskill Mountains. The area also serves as one of the major water supplies for the 9 million people of the City of New York. Thus, it was fitting that a portion of the technical program of this year’s meeting dealt with the characteristics of the New York City water supply and the role of snow in affecting the quantity and quality of water delivered to the system’s reservoirs.

The conference had participants from the United States and Canada, as well as from Europe. We had a very

successful technical program, consisting of 27 oral presentations and 23 poster presentations. As always, one of the highlights of the conference was the large number of excellent student presentations. The following students received awards that were presented at the annual banquet:

• The Don Wiesnet award for the ESC Student Paper competition was given to Elizabeth Burakowski

(University of New Hampshire) for her paper “Putting the Capital ‘A’ in CoCoRAHS: An experimental program to measure albedo using the Community Collaborative Rain Hail and Snow (CoCoRAHS) Network.”

• The Robert Miller Award for Best Poster Presentation was given to Jonathan Sugg (Appalachian State University) for his paper “Satellite and surface perspectives of snow extent in the southern Appalachian Mountains.”

• The Campbell Scientific Canada Award for the paper demonstrating innovative technical expertise in data collection was given to Andrew Kasurak (University of Waterloo) for his paper “A simple in-situ sensor for snow grain size.”

The high quality of these and the other student presentations augurs well for the continued success of the ESC. Thanks to the judges of these awards for their hard work in evaluating a large number of excellent submissions in arriving at their decisions. I also take this opportunity to thank the following for making the 69th ESC such a great success:

• Glen Horton (NY Department of Environmental Protection) and Allan Frei (City University of New York) of the local arrangements committee for their hard work in organizing a great meeting.

• The Frost Valley staff for making our stay there such an enjoyable one. • Robert Hellström (Bridgewater State University) for setting up and running a highly interesting and engaging

technical program. • The ESC secretary-treasurers Miles Ecclestone and Derrill Cowing for their efficient handling of conference

registration and the ESC finances and Mary Jean Cowing for taking the minutes of the pre- and post-conference meetings of the ESC Executive.

• The ESC’s webmaster, Andrew Klein (Texas A&M). • The ESC’s sponsors: Campbell Scientific, Geonor, Bridgewater State University, and the US Army Engineer

Research and Development Center–Cold Regions Research and Engineering Laboratory (ERDC-CRREL). • The editors of the ESC Proceedings (Robert Hellström, Alex Langlois, Susan Frankenstein, Del Levia) and the

editor of ESC Special Issue of Hydrological Processes (Richard Kelly). • Ben Snyder, Director of Natural Resources and Environmental Science at Frost Valley, who conducted the

field trip to the long-term acid and mercury deposition site and the US Geological Survey’s stream gage on Biscuit Brook, which flows through the Frost Valley facility.

• The 2011–2012 ESC Executive for their support and for their dedication to the ESC, particularly Past-President Mauri Pelto.

At the annual ESC banquet, I had the pleasure of announcing that Peter Adams (professor emeritus, Trent

University) was made a lifetime member of the ESC in recognition of his long-standing scientific and administrative contributions to the ESC and particularly his outstanding efforts in fostering student research in snow and ice and their participation in the ESC. ESC Past-President Mauri Pelto presented the coveted Sno-Foo Award to Don Pierson of the New York Department of Environmental Protection (a former graduate student of Peter Adams) for his outstanding efforts in being included in the list of authors on every single paper at the conference that was related to the New York City water suppl, and for his creativity in avoiding completion of a comprehensive examination as part of his PhD studies (namely, doing his PhD in Sweden rather than North America). The highlight of the banquet was the keynote

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talk by David Robinson of Rutgers University and the New Jersey State Climatologist, “Hemispheric to regional dimensions of snow covered extent.” The ESC is very grateful to David for a very entertaining and informative presentation.

On a sadder note, I also took an opportunity at the banquet to dedicate the 69th ESC to Austin Hogan, whose

extensive contributions to the ESC span his initial attendance in at the ESC 1966, when he was at the State University of New York at Albany, through his research while at ERDC-CRREL and into his retirement from that agency. Austin was ill at the time of the meeting, and sadly passed away on January 7, 2013. All of us in the ESC who knew Austin were impressed by the outstanding quality of his research related to snow and ice, by his eagerness to engage in discussions (scientific or otherwise), and by his commitment to the ESC. As someone pointed out to me, Austin made it a habit of always offering to give a presentation in the last session of the technical program (preferably the last presentation). My hope is that the precedent Austin set for us becomes an ESC tradition, such that there will be a fierce competition to give the last presentation on the last day of the conference. Perhaps we can begin the tradition at the 70th annual meeting, to be held at the Waterloo Summit Centre, Huntsville, Ontario, in 2013. I look forward to seeing you there. Jim Buttle

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Eastern Snow Conference Contributions

68th EASTERN SNOW CONFERENCE Frost Valley YMCA, Claryville, New York, USA 2012

Potential Effects of Climate Change on Winter Turbidity Levels in the Ashokan Reservoir, NY NIHAR R. SAMAL1, ADAO. H. MATONSE1, RAJITH MUKUNDAN1, DONALD C. PIERSON2, RAKESH K.

GELDA3, MARK S. ZION2, AND ELLIOT M. SCHNEIDERMAN2

ABSTRACT:

Transport of high concentrations of suspended particles is one of the major water quality concerns for water supply reservoirs, including the New York City water supply system (NYCWSS). Ongoing changes in snowpack accumulation and winter streamflow patterns could potentially lead to increased turbidity levels in early winter and a reduction in turbidity loads at the time of traditional spring runoff. In this study we examine the potential effects of these simulated changes on reservoir turbidity levels. Our analysis focuses on Ashokan Reservoir, which can at times receive significant watershed turbidity inputs mainly from stream channel erosion from the Esopus Creek. Both measured and simulated turbidity loads and climatology are input to CE-QUAL-W2 (W2), a reservoir turbidity transport model that can simulate reservoir turbidity and other water quality parameters. In this study, the W2 model is applied to estimate the effects of hydro-climatology on settling rates and turbidity transport as a result of differences in reservoir thermal structure during summer and winter events. Our results indicate that the two-dimensional hydrodynamic transport model is able to capture summer and winter turbidity processes. Simulations suggest that the settling velocity is substantially lower at low temperatures during winter time. Winter average stream flow is simulated to increase by 12% and 20%, which lead to increases in reservoir turbidity by 11% and 17% for the future period 2046-2065 and 2081-2100, respectively. This analysis is expected to have potential implications for reservoir operations under winter conditions. Key words: stream turbidity; reservoir turbidity; W2 model; climate change; winter settling rate; snowmelt runoff

INTRODUCTION

Intermittent inflows of high concentrations of suspended particles to Catskill system reservoirs is one of the water quality concerns affecting the New York City water supply system (NYCWSS). Turbid water in a reservoir has negative aesthetic and recreational appeal. Mitigating the impacts of high turbidity may require changes in reservoir operations which may increase water delivery and treatment costs. Following high streamflow events when high loads of inorganic particles are transported, elevated turbidity (Tn, NTU) levels with complex spatial ---------------------------------------------------------------------------------------

1Institute for Sustainable Cities, City University of New York, NY 10065, USA 2New York City Department of Environmental Protection, Kingston, NY 12401, USA 3 Upstate Freshwater Institutes, Syracuse, NY 13204, USA Corresponding author: Nihar Samal, Research Associate, City University of New York & Dept. of Civil Engineering, National Institute of Technology Durgapur, M.G. Avenue, West Bengal, INDIA; E-mail: nsamal@hunter.cuny.edu

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pattern in downstream lakes and reservoirs can occur (Effler et al., 2006; Gelda and Effler 2007; Prestigiacomo et al., 2008; Gelda et al., 2012;). Distribution and transport of these particles in lakes and reservoirs are time and space varying (Casamitjana and Schladow, 1993) and are further influenced by the hydro-meteorological forcings. Changes in meteorological forcings can lead to changes in reservoir thermal stratification (Samal et al., 2009; 2012) resulting in changes in the distribution of turbidity. In the unstratified winter period, a reservoir is well mixed and high turbidity levels may be observed due to winter storm events (Lou and Schwab, 2000). Various studies have been undertaken on particle size, particle distribution and transport processes (Casamitjana and Schladow, 1993; MacIntyre et al., 1999; Brach-Papa et al., 2006; Bilotta and Brazier 2008; Chakraborti et al., 2009; Gelda et al., 2009, 2012), but specific mechanisms concerning temperature effects on particle transport following large and small events in a large reservoir system have not been thoroughly addressed, especially effects that would occur during low temperatures and isothermal conditions. The seasonality of streamflow and particle transport may vary under future climate due to changes in winter snowmelt and shifts in seasonality of streamflow in the northeastern region of the U.S (Mukundan et al., 2012; Matonse et al., 2012, 2011). In context of the seasonal variability in streamflow and associated changes in stream turbidity, this investigation is made to document the effects of summer and winter turbidity inputs to the Ashokan reservoir and to assess the turbidity and temperature distributions in the reservoir prior to and after several summer and winter turbidity inputs. The effects of temperature on settling rate in the reservoir following summer and winter events and the potential impact of climate change on future turbidity level in reservoir are examined. Historical simulations The fate and transport of turbidity loads entering the Ashokan Reservoir is determined using W2 model (Cole and Buchak, 1995; Cole and Wells, 2002), which has been adapted, calibrated and rigorously tested for the Ashokan Reservoir (Gelda et al., 1998 and 2009). The simulations presented here are for the West Basin of Ashokan Reservor which is represented in the model by a grid of cells with 28 longitudinal segments and vertical layers of 1 meter thickness (Figure 1). The driving data for the model under historical conditions (1948-2011) include measured time series of daily reservoir inflows with associated stream temperature (T) and turbidity Tn; meteorological data (hourly air temperature, dew point, solar radiation, wind speed and wind direction); and daily records of operational information (withdrawal, spill and release volumes, and reservoir water surface elevation). Model results for in-reservoir water temperature and turbidity for more recent years (2006-2011) were compared with data collected at automated profile buoys located within the reservoir. The two buoys were located at sites about midway longitudinally from the Esopus Creek inflow to the dam (site 1.4) and near the dam (site 3.1). We presented the buoy measurements near the dam (buoy 3.1) for calibration. Data are collected four times a day (6 hour increments) and includes water temperature and turbidity measured from the surface to the bottom of the reservoir at 1 meter depth increments (Gelda et al., 2009). Event-based sampling is also conducted in order to support our modeling study.

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Figure 1. Ashokan Reservoir (West and East Basin): mouth of Esopus Creek and Bush Kill with model segment identification number Future Climate Scenarios Climate scenarios were developed from the output of three GCMs: CGCM3.1, CNRM-CM3 and MRI-CGCM2.3.2. Table 1 summarizes the climate scenarios and time periods used in this study. Scenarios of daily air temperature and precipitation were created by downscaling the different GCMs (Anandhi et al. 2011) and scenarios for the region of study using a 25-bin change factor methodology. Change factors created by this method were applied to historical records of daily meteorological data to develop local future climate scenarios. Table 1. General Circulation Models, emission scenarios and time slices applied in this study. GCM Emission scenario Time Slices GCMs: CGCM3.1 (Canada) A1B, A2, B1 2081-2100

B1 2046-2065 CNRM-CM3 (France) B1 2046-2065, 2081-2100 MRI-CGCM2.3.2 (Japan) B1 2081-2100 For reservoir model application hourly meteorological future climate scenarios were created from the daily climate scenarios. Hourly air temperature was estimated using future simulated daily minimum (Tmin) and maximum (Tmax) air temperatures and the WAVE model as described in Reicosky et al., (1989). The WAVE model uses today’s Tmin and Tmax together with next day Tmin to compute hourly air temperature from today’s sunrise (Rise) to 1400h and from 1400h to sunrise of the next day. Hourly temperature (T(H)) is estimated as

)))/'(cos()( RiseHAmpTaveHT π+= (1) for 0 ≤ H < Rise and 1400h < H ≤ 2400h, and

)))14/()((cos()( RiseRiseHAmpTaveHT −−−= π (2)

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for Rise ≤ H ≤ 1400h ; where H is the time in hours, H’=H+10 if H< Rise, H’=H-14 if H>1400h, Tave = (Tmin +Tmax)/2 and Amp=(Tmax-Tmin)/2. In absence of future sunrise data we used historical regional daily sunrise times. The dew point temperature for W2 climate change simulations is set equal to simulated hourly Tmin, and future wind and solar radiation are set equal to local historical hourly values. Climate change inflows to the West Basin Ashokan Reservoir are simulated on a daily time step using the Generalized Watershed Loading Functions-Variable Source Area (GWLF-VSA) model (Schneiderman et al., 2007; Schneiderman et al., 2002; Haith and Shoemaker, 1987). The GWLF-VSA model was calibrated using historical inputs to simulate streamflow from Esopus Creek at Coldbrook and Bush Kill which contribute to West Basin Ashokan Reservoir inflow. In addition, inflow from ungauged areas draining to the reservoir is estimated using Bush Kill estimates and a ratio between Bush Kill and ungauged drainage areas. A rating curve (Gannett Fleming & Hazen and Sawyer, 2008) developed empirically using historical data is used to estimate turbidity concentration Tn based on simulated Esopus Creek flow QEsp and has the form

2)(log691.0log986.0033.1log EspEsp QQTn +−= (3)

A lower bound Tn = 4.8 is used for QEsp < 5.17 cms. Total daily turbidity is then partitioned into three particle sizes using the following criteria Tn1 = 0.10 * Tn (4a) If QEsp > 40 cms, Tn2 = 0.45 * Tn,

and Tn3 = 0.45 * Tn; else Tn2 = 0.65 * Tn and Tn3 = 0.25 * Tn. (4b)

Future values of Esopus Creek water temperature at hour i (Ti) is calculated in oC using the following regression equation developed by the Upstate Freshwater Institute (UFI) and published in NYC DEP (2007)

4,5322,10 **log** aiSTPEspiairi TaaQaTaaT +++= − (5)

where Tair-2 is the simulated local air temperature of two hours back (in oC), a0 – a5 are the model coefficients calibrated on a monthly basis using historical data, QEsp is the simulated Esopus Creek daily average streamflow in cubic meters per second (cms), and TSTP,i is the Shandaken tunnel portal temperature at the ith hour. Coefficient a5 is 0 when the Shandaken tunnel is off and 1 when the tunnel is on. As part of the NYC water supply operations, water from the nearby Schoharie reservoir can be routed through Shandaken Tunnel to the Esopus Creek that flows into the Ashokan Reservoir. When running future climate scenarios these and other operational flows are obtained from the NYC OASIS model (Operational Analysis and Simulation of Integrated Systems, HydroLogics, Inc., 2007) simulations using similar climate change inflows. For the West Basin Ashokan Reservoir these include the Shandaken Tunnel flows, the gate flows in the dividing weir between the West and East Basins of the Ashokan Reservoir and the release channel withdrawals from West Basin Ashokan. The time series for these flows are obtained from OASIS on a daily time step.

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Figure 2. Modeling frame work: Model connection and data flow Figure 2 illustrates the modeling framework applied for this study. Inputs to W2 model include downscaled GCM/Scenarios climate data, simulated hourly climate developed using various methods based on simulated daily hydrology and climatology, watershed model simulated daily streamflow, daily stream turbidity simulated using a turbidity model that uses simulated streamflow, daily reservoir operations simulated by the OASIS (Hydrologics, Inc., 2007) reservoir system model.

RESULTS AND DISCUSSIONS Evaluation of W2 model performance using historical data The W2 model was previously calibrated and validated for the Ashokan reservoir using volume weighted epilimnetic and hypolimnetic temperature as described in Gelda et al., 2009. For further testing the model was driven with the actual observed streamflow and stream turbidity for the period 2003 to 2011, and evaluated by comparing model versus observed data of: (1) reservoir water surface elevations (June 2003 to September 2011) (Figure 3); (2) reservoir turbidity measured at robotic monitoring site 3.1 for 2006 to 2011 (Figure 4).

Figure 3. Model simulated and observed water surface elevations in Ashokan Reservoir for the period 2003-2011 The model simulates well the fluctuations in water surface elevations both during low and high flow event period except for 11 May 2006 (Figure 3). The three drops in water surface elevations below 174 m are observed on 23 September 2007, 19 October 2008 and 04 September 2010 and

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6/13/2003 10/25/2004 3/9/2006 7/22/2007 12/3/2008 4/17/2010 8/30/2011

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Observed_WSE Simulated_WSE

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are well represented by the model simulation. Sharp rises in water surface elevations correspond to large storm event inputs of water to the reservoir.

Figure 4. Model versus observed turbidity (Tn, NTU) in Ashokan Reservoir, 2006-2011, where the green line represent the model turbidity at segment 28 (Withdrawal point) Figure 4 illustrates how the model simulated reservoir turbidity compares to observed data at buoys 3.1 of the West Basin available for the period 2006-2011. The model simulated turbidity levels are similar to the buoy measured data in all cases except in case of a few high outlying measurements late October and early November. While it is impossible to state the source of these errors, the intermittently high measured data suggests the problem is more likely with the buoy measurements Event sampling from simulated time series In order to evaluate and better understand the seasonal pattern between streamflow, stream turbidity and reservoir turbidity, we sampled the historical model results for two seasons; summer (May-October) and winter (November-April) during more than six decades of historical record (1948-2011). A total of 12 events considering a wide range of streamflows were examined (Table 2). when choosing these events, an average daily streamflow of 146 m3/ was selected as minimum streamflow that caused the average reservoir turbidity to rise above 10 NTU Figure 4 Illustrates summer and winter turbidity response using data from two different storm events Table 2. Same size paired events during summer and winter. * represent turbidity at segment 28 Date of peak streamflow

Summer Date of peak streamflow

Winter Stream-flow (m3/s)

Peak stream turbidity (NTU)

Peak reservoir turbidity (NTU) *

Stream-flow (m3/s)

Peak stream turbidity (NTU)

Peak reservoir turbidity (NTU) *

09-07-1999 191 228 12 11-28-1993 233 283 83 09-18-2004 250 15 12 12-08-1974 240 306 58 10-21-1995 254 351 28 12-2-1996 271 413 92 06-28-2006 322 468 68 11-08-1977 304 557 95 06-28-2006 322 468 68 03-23-2010 350 595 165 10-01-2010 500 1440 138 04-03-2005 500 315 69

0

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Figure 5. Similar size paired summer and winter event; the reservoir turbidity is at segment 28 (Withdrawal point)

Figure 6. Summer and winter settling velocities based on Stoke’s Law For similar streamflow size events the reservoir turbidity was found to be higher in the winter compared to summer, as illustrated by the examples in Figure 5. These results can be explained given the fact that higher temperatures in summer lead to faster settling rates and resulted in lower turbidity (Figure 6). High turbidity events tend to be more frequent during winter. Because of the winter isothermal condition, the turbidity plumes have a longer travel time in the reservoir resulting in overlapping effects between consecutive turbidity events. Event specific temperature-turbidity profiles in Ashokan reservoir Simulated reservoir water temperature and turbidity profiles during summer and winter events are shown in Figure 7 and 8. The reservoir temperature is stratified before the occurrence of an event during summer (Figure 7a) and near isothermal during winter (Figure 8a). During the summer event warmer epilimnetic temperature forms an upper mixed layer and the wind induced

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turbulence energy is not sufficient to establish an isothermal water column (Figure 7a). The warmer epilimnetic temperatures in part reflect higher ambient air temperature during the summer event period. For these two events the summer and winter streamflow events are of similar size (Figure 5a), but summer event turbidity is found to be higher in upper few meters (5-10 m) and lower (< 5 NTU) below the upper mixed layer (Figure 7b). This behavior is related to temperature (density) of input stream water matching temperature of epilimnion and turbidity being concentrated above thermocline and being transported as a plume due to slow settling of clay particles.

Figure 7a. Temperature distribution before, during and after a summer event (06/28/2006)

Figure 7b. Turbidity distribution before, during and after a summer event (06/28/2006) (X-axis: Distance (km) from model segment 28 (0 km) to segment 1 (9 km); Y-axis: Elevation (m) from bottom (133 m) with scale factor 13 meter) Before the winter event (Figure 8), the turbidity appears evenly distributed at about 30-40 NTU throughout the reservoir due to a preceding event. A turbidity plume first appears to be moving from stream mouth (segment 1) to the dividing weir (segment 28,).

Figure 8a. Temperature distribution before, during and after a winter event (03/23/2010)

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Figure 8b. Turbidity distribution before, during and after a winter event (03/23/2010) (X-axis: Distance (km) from model segment 28 (0 km) to segment 1 (9 km); Y-axis: Elevation (m) from bottom (133 m) with scale factor 13 meter)

The location of the plume may be dependent on the ambient stratification regime and the density of the inflow waters, whereas the magnitude of the peak impact may be a function of the loading. However, the major contrast between the two events (Figure 5 and 7) is related to the thermal structure of the reservoir at the time of the event. In the case of the summer event (Figure 7) the reservoir is stratified and turbidity moves as a plume above the thermocline. For the winter event (Figure 8), the reservoir is near isothermal and turbidity is eventually mixed throughout the water column and moves as a plug from upstream to downstream. Driving parameters and reservoir turbidity under future climate We have shown how Ashokan Reservoir experiences elevated turbidity levels following summer and winter events. In figure 9 through 12, we compared boxplots representing simulated average monthly future conditions for 2046-2065 (future_4665) and 2081-2100 (future_8100) time periods against baseline conditions for air temperature, streamflow, stream turbidity, reservoir water surface elevation, water temperature, reservoir turbidity and settling velocity. The boxplots represent the 25th (Q1) and 75th (Q3) quartiles (or the interquartile range) from all six climate change scenarios; for both time slices and baseline, the whiskers represent the lowest and highest data values within the lower (Q-1.5×(Q3-Q1)) and upper (Q3+1.5×(Q3-Q1)) limits; the dark horizontal lines in the box plots represent the median and the asterisks represent outliers.

Figure 9. Average monthly air temperature (0C) for the baseline and simulated future period (2046-2065) and 2081-2100. The air temperature as shown in Figure 9 is projected to increase under future climate conditions with the difference from the baseline being slightly higher for the future_8100 period. The projected average increase in air temperature is +2.0 and +3.5 by future_4665 and future_8100, respectively. The summer and winter season average annual air temperatures is projected to increase by +2.1 and +1.8 by future_4665, whereas it is +3.3 and +3.7 by future_8100 periods. These values are consistent with seasonal trends in historical temperature where average increases in winter temperature are slightly higher than during summer (Hayhoe et al., 2007; Matonse et al., 2011). The higher winter temperature will lead to a reduction in snowpack and may

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cause more precipitation to fall as rain (Matonse et al. 2012). As a result of changes in snow and precipitation early winter streamflow is projected to increase (Figure 10a) under future climate scenarios. The streamflow is projected to decrease during March and April and show minor changes in the following months till October. A similar seasonal pattern is projected for stream turbidity (Figure 10b).

Figure 10 (a) Average monthly inflow (m3/s); (b) Average monthly Stream Turbidity (Tn, NTU) for the baseline and simulated future period (2046-2065) and 2081-2100.

Figure 11. (a) Average monthly water surface elevation (m); (b) Average monthly in-reservoir water temperature (oC) for the baseline and simulated future period 2046-2065 and 2081-2100. Ashokan Reservoir seasonal water surface elevation (Figure 11a) is simulated to increase during the winter period. The reservoir water temperature (Figure 11b), which is a function of atmospheric forcings and inflows, shows a similar seasonal variation as air temperature (Figure 9). On average, the reservoir water temperature is increased by +1.0 (+1.8), +1.4 (+2.4) during summer and +0.6 (+1.3) during winter by future_4665 (and future_8100) periods. This is an indication of stronger stratification during summer but little change in the largely isothermal conditions during winter. The high winter turbidity and low summer turbidity (Figure 12a) under future climate scenarios are results of increased winter turbidity loading associated with increased future winter stream discharge and also to the variation in winter and summer settling rates (Figure 12b) of turbidity causing particles in the reservoir. The increase in future water temperature influences the mobility of suspended particles and consequently the settling rate.

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Figure 12. (a) Average monthly reservoir turbidity (Tn, NTU); (b) Average monthly settling velocity (m/day) for the baseline and simulated future period 2046-2065 and 2081-2100. Under future scenarios, the average annual streamflow is increased by 5% and 7%, which results in an annual increase in reservoir turbidity by 3% and 5% for the future_4665 and future_8100, respectively. However, the average winter reservoir turbidity is increased by 11% and 17% as result of increased in winter stream flow by 12% and 20% for the future_4665 and future_8100, respectively. The climate change scenarios clearly show a shift in timing of streamflow and turbidity loading to the reservoir from a peak in April to earlier in the winter (December-March). This shift in snowmelt driven events causes increased in-reservoir turbidity during December-March, and decreased turbidity in April-May as the peak events of April move to earlier in the year. CONCLUSIONS Our results using historical inputs show that the W2 model accurately simulates reservoir water surface elevation, seasonal and event specific reservoir turbidity. As a result of seasonal differences in thermal stratification the reservoir turbidity generally moves as a plume above the thermocline in summer following a storm event, while in winter turbidity is generally mixed throughout the water column. Simulated future, reservoir turbidity levels are expected to increase during winter due to earlier snowmelt and resulting shifts in streamflow and turbidity load. Winter isothermal conditions are expected to continue in the future and as a result of relatively low water temperature turbidity settling velocity will remain low. ACKNOWLEDGEMENTS The authors are grateful to the New York City Department of Environmental protection (NYCDEP) for providing funding in carrying out this research investigation. Authors acknowledge Ben Wright, Hazen and Sawyer for providing future simulated reservoir operation data. Authors also extend their thanks to David Lounsbury and Donald Kent for their technical support during the preparation of the manuscript. REFERENCES Anandhi A, Frei A, Pierson DC, Schneiderman EM, Zion MS, Lounsbury D, Matonse AH. 2011

Examination of change factor methodologies for climate change impact assessment. Water Resour. Res. 47, W03501, DOI:10. 1029/2010WR009104.

Bilotta GS, Brazier RE. 2008 Understanding the influence of suspended solids on water quality and aquatic biota. Water Research 42: 2849-2861.

Brach-Papa C, Boyer P, Ternat F, Amielh M, Anselmet F. 2006 Settling classes for fine suspended particles. C. R. Mecanique 334: 560-567.

Casamitjana X, Schladow G.1993. Vertical distribution of particles in stratified lake, J. Environ. Eng., 119(3), 443-462.

Chakraborti RK, Atkinson JF, Kaur J. 2009 Effect of mixing on suspended particle-size distribution. J. Environ. Eng., Div. ASCE,135, 5, 306-316.

Cole T, Buchak EM. 1995. Ce-qual-w2: A two-dimensional, laterally averaged, hydrodynamic and water quality model, Version 2.0 (June 1995), User Manual. U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS 39180-6199.

Cole TM, Wells SA. 2002. "CE-QUAL-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamicand Water Quality Model, Version 3.1." Instruction Report EL-2002-1. U.S. Army Engineering and Research Development Center, Vicksburg, MS.

Effler SW, Matthews DA, Kaser J, Prestigiacomo AR, Smith DG. 2006. Runoff event impacts on a water supply reservoir: Suspended sediment loading, turbid plume behavior, and sediment deposition. J. Am. Water Resour. Assoc., 42(6), 1697-1710.

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Gannett Fleming & Hazen and Sawyer. 2008. Catskill turbidity control studies: Phase III Implementation Plan, Prepared for New York City Department of Environmental Protection, Bureau of Engineering Design and Construction

Gelda RK, Owens EM, Effler SW. 1998. Calibration, verification and an application of a two-dimensional hydrothermal model [CE-QUAL-W2(t)] for Cannonsville Reservoir. Lake and Reserv. Manage.,14,186-196.

Gelda RK, Effler SW, Peng F. 2012. Modeling Turbidity and the Effects of Alum Application for a Water Supply Reservoir. J. Environ. Eng., Div. ASCE,138, 1, 38-47.

Gelda RK, Effler SW, Peng F, Owens EM, Pierson DC. 2009. Turbidity model for Ashokan Reservoir, New York: case study. J. Environ. Engrg. Div. ASCE, 135,9, 885-895.

Gelda RK, Effler SW. 2007. Modeling turbidity in a water supply reservoir: Advancements and issues. J. Environ. Engrg. Div. ASCE, 133, 139-148.

Haith DA, Shoemaker LL. 1987. Generalized watershed loading functions for stream flow nutrients, Water Resour. Bull., 23(3):471-478.

Hayhoe K, Wake CP, Huntington TG, Luo L, Schwartz MD, Sheffield J, Wood E, Anderson B, Bradbury J, DeGaetano A, Troy TJ, Wolfe D. 2007. Past and Future Changes in Climate and Hydrological Indicators in the US Northeast. Climate Dynamics 28: 381–407.

Hydrologics Inc. 2007. User Manual for OASIS with OCL, Columbia, MD. Lou J, Schwab DJ. 2000. A model of sediment resuspension and transport dynamics in southern

Lake Michigan, J. of Geophysical Res. Vol.105. no.C3, 6591-6610. MacIntyre S, Flynn KM, Jellison R, Romero JR. 1999. Boundary mixing and nutrient fluxes in

Mono Lake, California. Limnol. Oceanogr., 44(3), 512-529. Matonse AH, Pierson DC, Frei A, Zion MS, Schneiserman EM, Anandhi A, Mukundan R,

Pradhanang SM. 2011. Effects of changes in snow pattern and the timing of run off on NYC water supply system,Hydrological processes. 25. 3278-3288. DOI: 10.1002/hyp.8121.

Matonse AH, Pierson DC, Frei A, Zion MS, Anandhi A, Schneiserman EM, Wright B. 2012. Investigating the impact of climate change on New York City’s primary water supply, Climatic Change. DOI: 10.1007s10584-012-0515-4.

Mukundan, R., S. M. Pradhanang, E. M. Schneiderman, D.C. Pierson, A. Anandhi, M. S. Zion, A. H. Matonse, D. G. Lounsbury, and T. S. Steenhuis. 2012. Suspended Sediment Source Areas and Future Climate Impact on Soil Erosion and Sediment Yield in a New York City Water Supply Watershed, USA. Geomorphology http://dx.doi.org/10.1016/j.geomorph.2012.06.021

NYCDEP. 2007. New York City Water Supply System Reference Guide, NYCDEP Bureau of Water Supply, Valhalla, New York.

Prestigiacomo AR, Effler SW, O’Donnell DM, Smith DG, Pierson DC. 2008. Turbidity and temperature patterns in a reservoir and its primary tributary from robotic monitoring: Implications for managing the quality of withdrawals. Lake and Reserv. Manage., 24:231-243.

Reicosky DC, Winkelman LJ, Baker JM, Baker DG. 1989. Accuracy of hourly air temperatures calculated from daily minima and maxima, Agricultural and Forest Meteorology, 46: 193-209.

Samal NR, Mazumdar A, Joehnk KD, Peeters F. 2009. Assessment of ecosystem health of tropical shallow waterbodies in eastern India using turbulence model. Journal Aquatic Ecosystem Health Management Society 12(2): 215–225.

Samal NR, Pierson DC, Huang Y, Read J, Anandhi A, Owens EM. 2012. Impact of climate change on Cannonsville reservoir thermal structure in the New York City Water Supply. Water Quality Research Journal, Canada 47(3–4): 389–405.

Schneiderman EM, Pierson DC, Lounsbury DG, Zion MS. 2002. Modeling the Hydrochemistry of the Cannonsville Watershed with Generalized Watershed Loading Functions (GWLF). Journal of the American Water Resources Association, 38(5):1323-1347.

Schneiderman EM, Steenhuis TS, Thongs DJ, Easton ZM, Zion MS, Neal AL, Mendoza GF, Walter MT. 2007. Incorporating variable source area hydrology into the curve number based Generalized Watershed Loading Function model. Hydrological Processes 21, 3420–3430.

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TO ERR IS HUMAN, TO FORGET IT WOULD BE DIVINE.

SNO-FOO 2012—Don Pierson

Don Pierson was an author on seven consecutive papers today. This suggests a bloom of sorts from post-doc loading. He ranges from first to seventh author in seemingly random order. That is unless you convert the author order to represent the word in the abstract that matches author position, this yields a subliminal message, “Analysis period explained historical important runoff associated NYC Bias.” Bias indeed. In pursuing a doctorate degree, Don had one criteria that stood out above all others: how can I do this without taking comprehensives? This seems at odds with the practice of overworking his current grad and post grads.

But back in time for Don’s choice of college: Canadian Universities required comprehensives. US universities required comprehensives. Finnish universities were too tough. French universities took too long. Sweden, Uppsala, just right for a doctorate. This goes to show that just because you are looking for an easier path, and finding it, does not mean this path is not the correct one. In this case, one that would lead to the generation of much fine science and apparently devoted post-grads.