Potomac Submerged Channel Intake Study

Fact Sheet

What 

• In fall 2002, both County Councils approved in WSSC's capital budget a feasibility study for a submerged Potomac River intake pipe to supply water for its Potomac Water Filtration Plant (WFP).
• WSSC's Potomac WFP produces approximately three-quarters of the water used by its 1.6 million customers in Montgomery and Prince George's Counties.
• The submerged channel intake feasibility study began in summer 2003 and should be complete in spring 2006.
• WSSC is not seeking increased water withdrawals from the river with this submerged channel intake, but is seeking higher quality source water.
• The study will address possible locations, construction methods, costs, environmental impacts and outreach activities.
• If constructed, the intake will be built using environmentally sensitive methods.
• The top of the submerged intake will be a minimum of 2.5 feet below historic low-flow water levels.
• A submerged channel intake will not obstruct recreational river activities or permanently harm aquatic life.

Why

• WSSC's top priority is enhance public health by providing customers with the best possible quality water: a submerged channel intake will provide access to a cleaner, safer, more stable raw water supply.
• At WSSC, we are proud of our efforts to continually produce safe, clean drinking water - water that meets or surpasses strict federal U.S. Environmental Protection Agency (EPA) standards. In fact, WSSC has never had a drinking water quality violation in its history.
• A submerged channel intake will allow WSSC to continue to meet ever-increasing EPA Safe Drinking Water requirements.
• Enhancing the safety and quality of our nation's drinking water supplies was the catalyst for an amendment to EPA's Safe Drinking Water Act that required each state to conduct a Source Water Assessment (SWA) for each drinking water intake.
• Funded by the Maryland Department of the Environment, the SWA for the Potomac Plant was completed in May 2002.
• Key findings of Potomac SWA:
  • A submerged channel intake would allow the Potomac WFP to access a cleaner, more stable source water supply
  • Issues impacting WSSC's existing shoreline intake:
    • Watts Branch causes changes (increased sediment, solids, microorganisms) and instability (pH, alkalinity) in raw water quality particularly after storm events.
    • Occasional clogging from River debris, leaves and ice.
    • Submerged channel intake would mitigate these issues.
• Based on these findings, a main recommendation of the Potomac SWA was that "serious consideration" should be given to a submerged channel intake.
• Other studies (including the Potomac Water Filtration Plant Facility Plan, WSSC, September 2002) also came to the same conclusion.
• A submerged channel intake will reduce treatment and solids handling costs. (Estimated annual cost-savings = $800,000.)While valuable for long-term environmental improvements, best management practices in Watts Branch cannot be relied upon in the near future for significant source water enhancement.
  • It will take decades for improvements in the Watts Branch watershed to impact the raw water at the Plant Intake.

NeXT STEPS 

1. WSSC plans to use briefings, its website, quarterly customer bill inserts, fact sheets and media communications to inform and update officials, customers and other stakeholders about the project.
2. Input will be solicited from all interested parties on an ongoing basis.
3. Following study completion in spring 2006, WSSC will seek concurrence of County Councils on recommendations of feasibility study.