So the category here is just "for your information."
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Posted by Amanda Wilson on 12/13/2012
10:48:00 AM
Billions of dollars in spending set aside for
a massive pipeline project to keep polluted DC water out of area waters could
get delayed and re-channeled to more decentralized infrastructure like rain
gardens, rainwater harvesting, trees and rain barrels - that is, if DC`s
independent water authority gets its way.
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.
DC Water says revising the plan could save
rate-payers millions of dollars and slash $120 from the monthly water bill
increases forecast by the end of the decade.
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.
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.``
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