Published August 18, 2007

This Week's Take

Fixing the problems of stormwater runoff

We frequently hear that the 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 and forests — 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 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 paved surfaces.

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 gardens or bio-retention areas will filter the water from parking lots, removing toxins and providing a recharge for groundwater.

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 implement it.

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

(Revised August 2007)