1. Quantifying impacts of upstream reservoirs on the Potomac River due to Consumptive Use
Beverly Lanza1, Cherie Schultz2, Celso M. Ferreira3
1Undergraduate Student, Department of Civil, Infrastructure and Environmental Engineering, George Mason University
2Director, CO-OP Operations, Interstate Commission on the Potomac River Basin
3Assistant Professor, Department of Civil, Infrastructure and Environmental Engineering, George Mason University
Introduction
Potomac River Basin Facts
Results
The Potomac River basin is home to more than six million residents and has experienced moderate and severe droughts in the past (e.g., 1930, 1966, 1999, and 2002). With population growth and consequential increasing water demands, net water withdrawals by upstream users can impact the water supplies for downstream populations (Washington Metropolitan Area, WMA) This study focuses on investigating if upstream reservoirs which are not part of the WMA system partially mitigate the impacts of Upstream Consumptive Use (CU) on the Potomac River. Using various parameter a safe yield is calculated for each reservoir.
This information is useful and
must be considered in order to
properly determine the impacts
of upstream reservoirs.
SAFE YIELD Calculations
Step 1: Collect reservoir inflows for historical data record 1960, 1966, 1999, 2002 (worst droughts)
Reservoir inflows were unknown
Streamflow estimation was
conducted
QR = Qg(AR/Ag)
Step 2: Water Balance equation for each reservoir
Step 3: Plot each reservoir
Step 4: Add up all Safe Yield quantities
6.11 Million  Total Potomac River Basin Population
5.1 Million  WMA Population
600 MGD  Total Potomac River Water Withdrawals
500 MGD  WMA Water Withdrawals
Study Upstream Reservoirs
Used Army Corps of Engineer’s Dam Inventory to located all water supply reservoir within the Potomac River Basin and above Little Falls Dam
Chose largest reservoirs with Storage Capacity > 500 ac-ft
Consumptive Use
Water withdrawn that is not filtered back into the basin for future use
Examples:
Natural: Evaporation and transpiration
Manmade: industry, agriculture, water supply, and livestock
This study focused on WATER SUPPLY ONLY.
Objective
This study focused on:
Reservoirs, one of the main water supply sources.
Determining how upstream reservoirs not included in WMA water supply system mitigates consumptive use.
Reason for investigating upstream reservoirs:
Upstream population and withdrawal 
Water Flow Downstream
1) Monie Bay National Estuarine Research Reserve
References
Ahmed, S. N., Bencala, K. R., and Schultz, C. L. (2015) Washington Metropolitan Area Water Supply Study:Demand and Resource Availability Forecast for the Year
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