RiverRenew is a major program in response to a 2017 Virginia law to achieve cleaner, healthier waterways in Alexandria. RiverRenew features a new network of deep tunnels and sewers that will connect to the four combined sewer outfalls in Alexandria. These outfalls currently pollute our waterways on rainy days. The tunnels will capture millions of gallons of sewage mixed with rainwater for treatment at AlexRenew, and the cleaned water will be returned to the Potomac River.
In the oldest portions of Alexandria, sewage and rainwater is collected in one type of sewer system, called a combined sewer system. In a combined sewer system, there is one sewer pipe under each street that collects and transports both sewage and rainwater.
When it's not raining, these combined sewer pipes transport sewage for treatment at AlexRenew's wastewater treatment plant, called the Water Resource Recovery Facility. On rainy days, the capacity of these combined sewer pipes is often exceeded. When the combined sewers are full, the excess sewage mixed with rainwater overflows into Alexandria's waterways via four combined sewer outfalls. Currently, these overflow events occur approximately 60 times per year, resulting in bacteria, trash and other pollutants in local waterways, including Hooffs Run, Hunting Creek and the Potomac River.
In other portions of Alexandria, sewage is collected in a sewer pipe that is separate from the sewer pipe that collects rainwater. This type of sewer system is called a separate sewer system.
In April 2017, Virginia passed a law requiring Alexandria to remediate all four of its combined sewer outfalls by July 1, 2025. The law, Senate Bill 898, introduced by Senator Richard H. Stuart (District 28), lays out the mandates for RiverRenew to meet. The bill requires any combined sewer outfalls in the state, including Alexandria’s, to be brought into compliance with Virginia law, the federal Clean Water Act, and the U.S. Environmental Protection Agency’s Combined Sewer Overflow Control Policy.
To minimize community impact, AlexRenew’s facility will serve as the main construction site for the proposed tunnel system.
Alexandria must meet regulatory requirements to improve water quality in Hooffs Run, Hunting Creek, and the Potomac River. Portions of the City of Alexandria use a combined sewer system that allows untreated sewage to mix with rainwater during rain events. Once the system reaches capacity, the untreated mixture overflows and pollutes our waterways. A Virginia law passed in April 2017 requires that controls be constructed to capture overflows from the combined sewer outfalls by July 1, 2025.
Capital costs related to RiverRenew are estimated between $370 and $555 million. This estimate is based on a conceptual level of design.
Capital costs consist of engineering, management and construction costs.
Revenue for RiverRenew will come from increases in sewer-related fees over the next decade. Efforts are underway to identify other funding sources, including grants through the Commonwealth of Virginia.
Construction for RiverRenew is anticipated to begin in late 2020.
Under the 2017 Virginia law, construction to control combined sewer discharges must be completed by July 1, 2025.
Planning is still underway to determine the exact locations of construction, but a majority of the work is conceptualized to take place at the AlexRenew Water Resource Recovery Facility. Additionally, construction disturbances are anticipated at or near the existing combined sewer outfall locations at Oronoco Bay, Hunting Creek, and Hooffs Run.