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| Area watersheds. Image: DC Water |
The sea change in the city's 20-year timeline for cleaning up area rivers will happen only if DC Water can renegotiate a 2005 federal decree
to build the full tunnel system. That consent decree from the Environmental
Protection Agency emerged out of a lawsuit over DC's management of
runoff in which several environmental groups were plaintiffs.A decision on the future flow of the city's $4.6 billion Clean Rivers Project could come in the next week or so, a spokeswoman with the city's water authority, The District of Columbia Water and Sewer Authority, or DC Water, told DCMud this week.
"It might shift to a more green solution, or it might be a hybrid of the two: green and gray," DC Water spokeswoman Pamela Mooring told DCMud. Green infrastructure, here, refers to infrastructure that absorbs or uses water before it enters the sewer system in the first place. Gray solutions refer to engineering to deal with runoff after it happens - in this case, a massive tunnel infrastructure project to build underground storage tanks for overflow.
The water authority is making efforts to re-focus the Clean Rivers Project for an eight-year pilot "Low-Impact Development" program. The proposal could emphasize infrastructure like rain barrels and rain gardens instead of pipes that have been the mainstay of water channelling. DC Water says that approach - if it proves successful - could render two future pipelines, planned to keep run-off out of the Rock Creek and Potomac waters, obsolete, possibly saving millions of dollars. It notes that other cities including Kansas City and St. Louis have already experimented with similar versions of green infrastructure.
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| Blue Plains Treatment Plant. Image: DC Water |
Old System, Old Problem
Regardless, consensus holds that the city must do something about its dirty water problem. About one third of DC's water system was built in the 1800's, before pipe systems separated storm water, or run-off from non-permeable surfaces, from sewage. That part of the system is called a combined sewer system (CSS), and when heavy rains like those from Hurricane Sandy hit the low-lying city, the CSS can't handle all the water and dumps it - along with sewage - into area watersheds, reducing water oxygen levels and killing wildlife at 53 documented places.
A portion of the pipeline system planned for the Anacostia River is already under construction. In 2011, DC Water awarded a $330 million contract to a joint proposal from Traylor brothers-Skanska-JayDee (TSJD) to build the first part of the system. The pipe, 23 feet in diameter, would be laid 100 feet underground and extend 12,500 feet from southwest DC, along the Potomac and under the Anacostia to about RFK Stadium. Slated for completion in January, 2018, the massive system will hold dirty water from the CSS until it can be piped to the Blue Plains Treatment Plant for processing in dryer weather. Of the scale of the project, DC Water General Manager George Hawkins called it "absolutely huge." "The machine our teams will use to build these tunnels is the size of a football field," and needs to be assembled underground.
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| Image: courtesy Mike Bolinder, @AnacostiaRrkper on Twitter |
Riparian Repair - "Not a Zero Sum Game"
Although he supports a low-impact development approach, Anacostia Riverkeeper Mike Bolinder said it's an approach that he supports in combination with the full, planned tunnel system. "In general I love the idea of green infrastructure, but there is a consent decree in place."
Bolinder said yearly sewage overflow into all three DC watersheds amounts to 2.5 billion gallons.
On the money question, Bolinder said the CSS under the city was built in the time of Abraham Lincoln, so it makes sense that replacing it will cost some money. There is also the cost of maintaining and monitoring the efficacy of low-impact development. "If they don't maintain rain gardens, they stop retaining stormwater," Bolinder said. "Then we have the same system that we had beforehand, with a couple of rain gardens."
Washington D.C. real estate development news
6 comments:
Bravo. Ever since Philadelphia won EPA approval for its green-infrastructure approach to CSO -- a greener, cleaner, and cheaper win/win approach -- I've wondered whether DC and other cities that have yet to sink $billions into now-antiquated big-pipe approaches would be racing to rethink their plans.
It is my understanding the first of these three proposed tunnels will reduce overflows by 98%. It should absolutely be built as planned.
However, the construction of 2 additional tunnels to eliminate the final 2% of overflow seems like overkill (no pun intended). Green roofs and water barrels are nice, but the best thing we can do is mandate the use of permeable pavement for sidewalks and alleyways. Instead of rainwater rushing into the sewer it can soak into the ground instead. Given that many public alleys are in serious need of renovation, this seems like a great opportunity to knock off two projects at once.
A correction for Adam L. The first of the three proposed tunnels, when completed, will reduce 98% of overflows to the Anacostia River. The other two tunnels, when/if completed, would reduce 93% of overflows to the Potomac River and 90% of overflows to Rock Creek, respectively. It's not the case that they would only reduce an additional 2% of overflows. It's just that each tunnel addresses overflows to a different water body.
All of this info is available in the executive summary of DC Water's long-term control plan. http://www.dcwater.com/workzones/projects/pdfs/ltcp/Executive_Summary.pdf
In general, it's hard not to like this proposal. A passive solution is always better than an active, engineered solution--assuming actually works! The devil is in the details, both in the science of the issue and the dollars.
Science: the "riparian" solutions are great, but efforts in DC and elsewhere need to be closely monitored (presumably by someone like university research teams) to verify effectiveness. If they aren't that effective, then we need to re-evaluate.
Dollars: One nice thing about the DCWater tunnel plan is that the costs are spread across practically everyone, in the form of higher water bills. Another bonus is the lack of red-tape to make it happen: DCWater just increases the bills, everyone pays. "Riparian" solutions, I fear, may spread the burden unevenly and/or involve significant new regulations for property owners and developers to deal with. Who pays for these rain barrels, permeable paving, etc, particularly the ones on private properties (and taking into account both installation and ongoing maintenance)? Are we going to load it onto anyone doing new development, while sheltering existing projects (the way that we do with handicap accessibility, affordable housing via "inclusionary zoning," energy code requirements, and a whole host of other things)? Or will DCWater actually subsidize these efforts for both new projects and existing facilities? The latter is much fairer, but either way, we're looking at mountains of new red tape and aggravating citizen-bureaucrat encounters.
The Water Storage Tunnels solution…is just an experiment that gives no definite answer to the city’s overall sewage and storm water overflow problem.
This is the same unproven quick solution that WASA, D.C. Government and the U.S. EPA agreed to do in which to settle a Federal Court lawsuit on storm water and sewage run-offs into the Potomac River. The Federal lawsuit was brought on by several local environmentalist groups.
Water Tunnel Project for Ward 5 Bloomingdale Area
However, if you read that Federal Court agreement those water containers have a 51 day storage restriction period to then be emptied and the stored sewage to be transported to the Blue Plains facility for processing. The McMillan Reservoir is a sand filtration center not a sewage processing plant.
I should believe that those proposed sewage containers on the McMillan Reservoir’s land would also be emptied too. Or, it would be a foul situation for those residents who live in and around the area of the reservoir. However, the Council is always short-sighted when it comes to fully completing or solving any problem in this city.
So citizens will pay for a temporary fix – a $120 million sewage and overflow storage tank facility. Then there will an ongoing cost of [let’s say] $2 million per storm to relocate the stored sewage/overflow from McMillan to the Blue Plains facility for processing. This is now becoming a hefty and generous contract that is predicated upon when it rains and how much it rains... Now D.C. must budget annually for a snow removal program and storage tank waste water removal.
Another problem. If Blue Plains is operating at a 85 to 90% capacity in processing the District’s daily amount of sewage and waste water – when will it find the time and space to process Bloomingdale’s sewage/overflow water stored [for any period of time] in the newly built McMillan storm water tanks. But, if and when the “pending” Federal Court ordered overflow storage tanks are built which of the two tank systems will be emptied to be processed at Blue Plains…with its daily 90% processing workload?
As usual, the Council and the mayor have not put any true thought into this temporary fix. But millions of dollar are now being wasted in this effort with the same mediocre thinking; “…we will have a full and complete solution once we come to that bridge…”
Trusting Citizens…have you had enough of this foolishness from this Council, the Mayor and WASA yet?
Calvin H. Gurley
This "green alternative" comes with an 8 year delay. That's 8 years of raw sewage - somewhere between 10 and 20 BILLION gallons that flow into the Potomac and Chesapeake while we do another study.
To be clear: I embrace green infrastructure. I reject the idea that DC's sewer problem is a zero-sum game where we are forced to chose between green and gray. The answer is "all of the above"
Feel free to reach me - riverkeeper at anacostiariverkeeper dot org.
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