Five-foot-wide storm sewer line Going into the 100 block of Rhode Island Ave NW to help Mitigate Flooding in Bloomingdale

From a press release:

Mayor Vincent C. Gray joined officials from the District Department of Transportation (DDOT) and DC Water today to mark a major step in an ongoing flood-mitigation project in the Bloomingdale and LeDroit Park neighborhoods, and to urge residents to take preventative steps to protect their property in advance of summer storms that may cause flooding.

“Today is another step forward for the Bloomingdale and LeDroit Park neighborhoods, which historically have suffered through significant flooding during large storms,” Mayor Gray said. “We have already implemented several immediate efforts to mitigate the flooding, and are implementing longer-term solutions to ensure that these neighborhoods do not continue experiencing repeated street flooding and property damage due to heavy rainstorms.”

Next week DDOT will begin a construction project to install a five-foot-wide storm sewer line in the median of the 100 block of Rhode Island Avenue NW. This project, which will last three months, will help remove stormwater from the roadway and store it before slowly releasing it into the sewer system.

“When it rains, community members in Bloomingdale and LeDroit Park have historically had to worry about flooding,” said DDOT Director Terry Bellamy. “Today we’re taking a major step forward in addressing this problem.”

Throughout the last century, the historic Bloomingdale and LeDroit Park neighborhoods have experienced occasional street flooding and sewer backups during intense rain storms. Last year, however, four major thunderstorms caused repeated flooding and prompted officials to take a closer look at what District agencies and property owners could do to protect property. Mayor Gray appointed a task force last August to study the problem and recommend solutions.

“Last summer we had more intense rainstorms with flooding than in the previous 10 years combined,” noted DC Water General Manager George S. Hawkins. “We began investigating right away and joined the city task force to investigate creative solutions. This year we want to be sure everyone is aware of both what we are doing and what property owners can do to minimize flooding during heavy rains.”

City Administrator and DC Water Board Chair Allen Y. Lew added, “The ultimate engineering fix is coming in 2022 with the massive Clean Rivers Project, but in the meantime we identified a number of actions that can help these neighborhoods.”

The Mayor’s Task Force on the Prevention of Flooding in Bloomingdale and LeDroit Park issued a final report earlier this year. It found that these neighborhoods, which were developed at the turn of the 20th century when sewage conveyance was a relatively new concept and the population was less dense, were suffering from a sewer system that was simply too small to accommodate today’s needs. The report included 25 recommendations to mitigate flooding, including short-, medium- and long-term solutions in the following categories: engineering, regulatory, code revision and operation and maintenance components.

Short-Term Solutions

Continues after the jump.

DDOT has already installed catch basins (i.e., storm drains) on the 500 to 600 blocks of Florida Avenue NW and the unit block of T Street NW to help divert water from area roadways and alleviate flooding. In addition to the five-foot-wide storm sewer, DDOT will make the following infrastructure improvements in the near future:

Install a new sewer line and double catch basin at the intersection of 2nd Street and Rhode Island Avenue NW to add capacity to the sewer system;
Install permeable pavement near 1st Street NW to reduce runoff; and
Plant a bioretention cell (i.e., rain garden) in the green space at the intersection of T Street and Rhode Island Avenue NW. An inlet will be placed in the rain garden to capture runoff from large storm events and carefully release it into the sewer system.

DC Water continues to offer home engineering consultations for flood-proofing and backup prevention as well as a rebate program for backwater valves — plumbing devices to prevent sewage from backing up into basements. The rebate covers 90 percent of the cost of the device and installation up to $3,000. The District Department of the Environment (DDOE) offers free rain barrels to property owners. In addition, DDOT is investing in a local green infrastructure program to absorb rainwater before it gets into the stormwater and sewer systems.

Medium-Term Solutions

DDOT will invest $10 million over the next five years in green infrastructure stormwater solutions in this area and areas immediately upstream. Some of these improvements include installing permeable paving and rain gardens to capture and redirect stormwater.

DC Water is implementing two significant engineering projects in the medium term. The first transforms two cells of the abandoned sand-filtration facilities at McMillan Reservoir to capture 6 million gallons of stormwater before it can enter the combined sewer system. The sand is being removed now and the cells will be converted to storage tanks to hold the stormwater during intense rains. This will be operational in 2014.

The second installation will serve a similar purpose, storing an additional six million gallons of stormwater. This is a 19’-diameter tunnel to be built under First Street NW, running from Rhode Island and First Street to the southwest corner of the McMillan site. When construction is complete in 2016, this tunnel (called the First Street Tunnel) will hold stormwater during intense rainstorms, after which a temporary pumping station will deliver the stormwater into the sewer system to be treated at DC Water’s Blue Plains facility.

Long-Term Solutions

DC Water began construction on the massive $2.6 billion Clean Rivers Project in 2011 to build large storage tunnels from Blue Plains all the way up to the Northeast Boundary district. The utility is changing the alignment of the system to provide better drainage for the affected area. DC Water has also accelerated project plans to reach the Bloomingdale/LeDroit area sooner than originally scheduled, so that in 2022 the tunnel system to the south will meet up and tie into the First Street Tunnel. At that time the temporary pumping station can be removed, as drainage will be achieved through gravity.

What Can Bloomingdale/LeDroit Residents Do Now to Mitigate Storm Flooding?

If they haven’t already, they should:

Install a backwater valve to keep sewage from backing up into their homes or businesses;
Take steps to prevent overland flooding from entering dwellings. DC Water offers free engineering consultations;
Contact their insurance about a rider covering sewer back-ups;
Request a rain barrel from DDOE; and
Continue to use sandbags as needed during storms.