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What is stormwater management?

• Stormwater management or SWM is the control of stormwater runoff and its impacts.
• Stormwater runoff is rainfall or snowmelt that runs off the ground or impervious surfaces such as buildings and roads and drains into natural or manmade drainage ways.  Runoff picks up debris, oils and other pollutants as it drains.

Why do we need stormwater management?

• To protect the City’s stream valleys from pollutants, trash and stream bank erosion.
• To make our stream valley parks more attractive and more useable.
• Rockville’s streams ultimately drain into the Potomac River and the Chesapeake Bay.  Healthy streams add to the overall health of those bodies of water.
• To comply with State and Federal requirements of the Clean Water Act.

What happens if we don't do stormwater management?

• The City’s streams will continue to erode unchecked, which results in wider, deeper stream channels and more sediment in the stream channels.
• More trees will fall along the eroding stream banks.
• Widened streams endanger nearby sanitary sewer pipes, road crossings and footpaths.
• The City will have to construct more miles of heavy-duty stream stabilization using boulders and gabions.
• The City’s stream habitat for fish and aquatic insects will continue to degrade.
• The City will not be in compliance with the approved terms of its State Municipal Separate Storm Sewer System Permit.
• The City will not meet its residents’ expectations for environmentally sound and effective watershed management.

What are the Challenges in Rockville?

• Much of Rockville was built before SWM was required. This creates a challenge of retrofit.
• Rockville has relatively few places where it has the possibility of putting in SWM facilities. College Gardens Park is one of them. (See below)
• In College Gardens, the challenge is to retrofit a SWM pond in the park and to preserve the park as a recreation facility.

Stormwater Management retrofit facilities have been built or are planned for several other communities in Rockville. 

Some examples include:

Cabin John Watershed - south/central part of the city

• Stoneridge Wetland Marsh - Hungerford community - Completed in 1997
• Tower Oaks Marsh – Tower Oaks Blvd - Partially constructed (currently serving as sediment control)

Rock Creek Watershed - east side of the city

• Northeast Park Wet Pond - Redgate Farms/Maryvale community - Completed in 2006
• Maryvale Wet Pond - in Maryvale Park – currently in design

Watts Branch Watershed - west side of the city

• Aintree Wetland Marsh - Rockshire community - Completed in 1999
• Carnation Drive Dry Pond retrofit - proposed to be constructed this winter