Interstate Commission on the Potomac River Basin
Washington Metropolitan Area Water Supply Alternatives
This study assesses a range of solutions to increase the capacity of the region’s water supply, which may not under all conditions meet unrestricted demands by 2040. The Washington Metropolitan Area Water Supply Alternatives Study provides information on alternatives out to 2085 to help ensure strategic options are available over that planning horizon. Alternatives were evaluated by their abilities to maintain reliability in the face of growing metropolitan area water demand, decreasing river flows due to upstream use, and the potential impacts of climate change. In January 2018, the ICPRB Commissioners adopted a resolution encouraging action on the study results.
Evaluation of Travilah Quarry for Water Supply Storage
Water Supply Reliability Studies
Every five years since 1990, CO-OP has conducted a water demand and resource availability forecast for the Washington, D.C., metropolitan area. These studies assess whether or not the current water supply system will be able to meet the needs of the region 20 or more years in the future.
2020 Washington Metropolitan Area Water Supply Reliability Study: Demand and Resource Availability Forecast for the Year 2050
This is the seventh edition in the series. The objective of the current study is to provide decision-makers with the following:
- forecasts of water demands for the WMA throughout the planning horizon, 2050, taking into account projected demographic and societal changes that may affect future water use,
- forecasts of water availability, considering the potential impact of changes in climate and upstream water use on system resources, and
- an evaluation of the ability of current and planned system resources to meet the forecasted demands.
The current study has a fourth objective, and that is to assess the effectiveness of several options for enhancing the current system that were recommended in a special study conducted in 2017 (Schultz et al., 2017). This special study, which will be referred to as the 2017 alternatives study, evaluated and compared the ability of 10 proposed changes and additions to the WMA water supply system to meet the challenges of growing regional demand for water and the potential impacts of climate change.
2015 Washington Metropolitan Area Water Supply Reliability Study: Demand and Resource Availability Forecast for the Year 2040
The 2015 iteration of the Washington Metropolitan Area Water Supply Study indicates that by 2035, the current water supply system could experience considerable stress during a severe drought, not accounting for the impacts of climate change. Managing water supply in that event would require mandatory water use restrictions. By 2040, in the event of a severe drought, there would be a chance that storage in Little Seneca Reservoir would be depleted and that flow in the Potomac River would drop below the minimum environmental flow level of 100 million gallons per day at Little Falls dam, though only by a small amount. When climate change is considered, a wide range of outcomes is predicted, from the depletion of most reservoirs in the system to there being no issues meeting unrestricted demand.
2010 Washington Metropolitan Area Water Supply Reliability Study Part 1: Demand and Resource Availability Forecast for the Year 2040
Part 1 of the 2010 study indicates that the current water supply system will likely be adequate in 2030, but might become strained by 2040. If in 2040 the region were to experience conditions similar to the worst drought on record (1930) mandatory water use restrictions would likely be required. (See figure 1 for a comparison of Washington metropolitan area average annual demand forecasts with current and past studies.)
2010 Washington Metropolitan Area Water Supply Reliability Study Part 2: Potential Impacts of Climate Change
Projected impacts of climate change on regional water supplies range from minor to major. In worst-case scenarios, with no changes to the current water supply system, a moderate drought in 2040 could cause:
- Mandatory restrictions on water use,
- Depleted reservoirs, and/or
- Inability to maintain environmental flow-bys.
Water Supply Reliability Forecast for the Washington Metropolitan Area, Year 2025
Ani Kame’enui, Erik R. Hagen, and Julie E. Kiang, ICPRB-05-06, 2005
Year 2000 Twenty-Year Water Demand Forecast and Resource Availability Analysis for the Washington Metropolitan Area
Erik Hagen and Roland C. Steiner, ICPRB-00-6, 2000
1995 Water Demand Forecast and Resource Availability Analysis for the Washington Metropolitan Area
Mary G. Mullusky, Stuart S. Schwartz, and Roland C. Steiner, ICPRB-95-6, 1995
20-Year Water Demand Forecast and Resource Availability Analysis for the Washington Metropolitan
John Holmes and Roland C. Steiner, ICPRB-90-5, 1990