A Good Primer on Run-Off
- View Source[Although directed at issues in the Chesapeake Bay, this short
article by Kincey Potter, a friend of mine, provides insights into
the POLICY and PRACTICES that need to be pursued to keep erosion and
sediment runoff from killing everything in the coastal waters of the
Caribbean. . . bp]
Fixing the problems of stormwater runoff
By Kincey Potter, South River Federation
We frequently hear that the Chesapeake Bay is not getting healthier
because though improvements have been made to decrease pollution,
millions of people are moving into the watershed and increasing
pressures on the Bay.
The population increases by 170,000 every year, and we lose 100 acres
of forest every day. And it's not just population growth but how we
are growing that causes problems.
>From 1990 to 2000, hard surfaces grew five times faster than the population.Most of us have heard about the damage caused by runoff from hard
surfaces in rainstorms.
Stormwater runoff, especially on the Western Shore of Maryland, is
the major source of pollution for our rivers and the bay.
Many of us have seen streams and creeks deteriorate after major
development has taken place nearby.
And some of us are concerned about our wells running dry, partly
because rainwater that previously was absorbed into the earth is now
being immediately piped into the creeks.
So what do we do to protect the bay and still allow development?
Many knowledgeable people including environmentalists, developers and
regulators believe that one significant answer is environmental site
design (ESD), also known as low impact development (LID).
ESD techniques are not new and have been used in Maryland for the
past 15 years.
They combine methods that reduce hard surfaces and preserve landscape
functions that improve the site's ability to absorb the rain.
The most important element is to design the development to fit the
topography of the land so that the natural features of the land -
good soils, forests and coastal wetlands - are used as much as
possible to manage the water flow.
Streets in new subdivisions can be made narrower to reduce hard
surface area, and adjacent swales buffered with grass (or vetiver)
will infiltrate water.
Clustered houses allow preservation of the forest on a development
site and forests can be used to manage water flows from roofs and
Soils that are stripped and compacted during construction can be
treated to absorb more rain. Turf lawns in new developments are
second only to hard surfaces in generating runoff.
In more dense development, such as commercial areas or townhomes,
rain barrels or rain gardens or bio-retention areas will filter the
water from parking lots, removing toxins and providing a recharge for
Vegetated or green roofs on commercial buildings can hold as much as
80 percent of annual rainfall and at the same time reduce heat
reflected from rooftops into the atmosphere.
Prior to this year, laws and regulations allowed, but did not
require, the use of ESD techniques.
Consequently, the use of ESD has not been widespread.
On new development sites we continue to see stormwater ponds that
empty stormwater directly into the creeks, even if more slowly.
This spring of 2007, the Maryland General Assembly passed important
legislation that requires the use of ESD techniques in new
development and redevelopment.
The Stormwater Act of 2007 is arguably the strongest stormwater law
in the country and once again positions Maryland as an environmental
leader and good steward of the bay.
In late July, the Maryland Department of the Environment convened a
meeting of developers, engineers, environmentalists, and state and
local government representatives to discuss the new law and ways to
The meeting was extremely positive and participants, while indicating
that there will be challenges in implementing ESD, generally felt
that it can and should be done.
Prior to that meeting, representatives from more than 25 watershed
associations, waterkeepers and statewide environmental organizations
came together to agree on 11 core principles for implementation of
this important stormwater legislation.
These principles recommend substantially raising the standard for the
volume of water that must be infiltrated on site to recharge
aquifers, thereby reducing the runoff into creeks.
The principles also propose specific limits for nitrogen and
phosphorus, the two pollutants causing the most damage to our rivers
and the bay.
The South River Federation and other members of the Maryland
Stormwater Consortium look forward to working with MDE, the counties
and developers and engineers to achieve regulations that fully
implement the Stormwater Act of 2007.
We have an opportunity to make a real difference in limiting the
damage that future development will cause to our streams and the bay.
We have an opportunity to treat rain as the resource it is, rather
than as a problem to be piped into our creeks.
Kincey Potter is president of the South River Federation and a member
of the Maryland Stormwater Consortium. A full description of
stormwater principles is posted at
President, South River Federation
(H) 410 280-6254 (C) 443 223-6392
''It is no use saying, 'We are doing our best.' You have got to
succeed in doing what is necessary.''
-- Winston Churchill
35 Years of Environmental Service to Small Tropical Islands
Island Resources Foundation Fone 202/265-9712
1718 "P" St NW, # T-4 fax 202/232-0748
Washington, DC 20036 Potter cell: 1-443-454-9044
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