The Stormwater Facility Maintenance Program is responsible for inspecting and ensuring maintenance of all public and private stormwater management facilities within Montgomery County. The program is paid for by the Water Quality Protection Charge. It is vital that the structures be maintained in working order so they function as intended, providing protection and stormwater management for our parks, schools, and businesses.
Current Maintenance Projects
Lake Whetstone
A public meeting was held on Tuesday evening, December 13th 2011.
Stormwater management facilities are structures that are used to remove pollutants, prevent stream damage and erosion, prevent flooding, and protect public health. The structures can be on the surface (e.g., wet and dry ponds, bioretention basins, sand filters) or underground (e.g., infiltration trenches, oil-grit separators, and underground storage structures). There are more than 4,000 stormwater facilities in the County.
Stormwater facilities have two functions:
They hold stormwater runoff from urban surfaces such as roads, parking lots, and rooftops.
They remove contaminants from the runoff.
These facilities help to slow the stormwater down and clean it before it is allowed to discharge into local streams, and they help to safeguard our waterways. They are vital infrastructure in the urban environment.
Bioretention basins operate by filtering stormwater runoff through densely planted surface vegetation and then percolating the runoff through a prescribed filter medium (such as sand). During percolation, pollutants are retained through fine filtration, adsorption (attaching to other particles), and some biological uptake (e.g., by plants). The runoff is then collected, using perforated pipes, and it flows to downstream waterways or to further storage and treatment sites.
A wet pond is an artificial lake with vegetation around the perimeter, and it includes a permanent pool of water in its design. It is used to manage stormwater runoff from adjacent urban areas.
Wet ponds are designed and constructed to contain stormwater to provide time for pollutants to settle out. They release the stored water gradually to reduce downstream flooding and erosion.
Dry pond
Dry ponds temporarily hold stormwater after a storm, but they remain dry between events. After the storm, the water is slowly discharged to a stream to reduce downstream flooding and erosion.
Filter
Filters treat stormwater runoff by passing it through sand, mulch, soil, or other media. Filters are designed to remove oil, grease, and other pollutants from the stormwater.
Low-Impact Development (LID)
LID structures are vegetated or permeable structures that let water infiltrate into the soil.
Environmental Site Design (ESD)
ESD is a process of designing stormwater features to allow rainwater to infiltrate in a manner similar to natural or undeveloped conditions. Many LID features are used for ESD.
Infiltration trenches
Infiltration trenches capture stormwater runoff to remove pollutants and slowly infiltrate the water into the ground to replenish the groundwater supply.
Hydrodynamic stormwater facilities
Hydrodynamic facilities are underground flow-through
structures that use settling or separation techniques to remove pollutants.
Underground storage
Underground storage structures capture and store stormwater in large underground pipes or other subsurface structures to provide time for pollutants to settle out. The structures release the stored water gradually to reduce downstream flooding and erosion.
Stormwater facilities can become clogged by trash, debris, sediment and mud, or other pollutants. The facilities themselves can develop structural cracks and leaks over time. The Stormwater Facility Maintenance Program has an inspection section that routinely inspects all stormwater facilities in the County every three years. The inspection is used to determine a facility's condition and to identify its need for repair or maintenance. Without proper maintenance, for example, nobody would check regularly to ensure that a stormwater facility is not blocked by a trash clog.
Maintenance also involves cleaning structures that are clogged by oil or other toxic materials. Inspection and maintenance of stormwater facilities are essential to keeping them functioning. When this valuable infrastructure functions well, it:
Prevents flooding in our urban environment
Removes pollution carried by stormwater
Recharges the groundwater supply
Protects local stream banks from highly erosive flows
DEP inspectors have found many unusual items in stormwater management facilities, including:
Shopping carts
Engine blocks
Basketballs
Debris such as tree branches and other yard trim
Trash and recyclable items such as plastic bottles and aluminum cans
Trash and debris affect the functioning of the stormwater facility by blocking inlets and outlets. Grates and racks over inlets help to keep trash from entering stormwater facilities, but vigilance and regular maintenance are necessary to prevent clogs.
Clogged inlets and trash grates do not allow the stormwater structures to function as intended.
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Residential properties: DEP's Stormwater Facility Maintenance Program works with citizens to assume responsibility for structural maintenance for all new residential stormwater facilities and older residential facilities once the property owner has completed the maintenance transfer process. This maintenance responsibility is defined for the owner in a Stormwater Covenant and Easement.
Nonresidential properties: Maintenance for most nonresidential facilities is the responsibility of the owner. This maintenance responsibility is defined for the owner in a Stormwater Covenant and Easement.The property owner may designate another individual to serve as their responsible agent for stormwater facility maintenance. This assignment must be in writing by completing the "Designation of Authorized On-site Representative Form" and the signed form must be sent via e-mail to: mcstormwater@montgomerycountymd.gov.
Nonstructural maintenance: For all facilities, nonstructural maintenance is the responsibility of the owner. This maintenance includes grass cutting, trash removal, and landscaping.
Facility
Maintenance Responsibility
Residential stormwater facility
Nonstructural maintenance: Private owner
Structural maintenance—new facilities and facilities that have completed the transfer process: DEP
Structural maintenance—older facilities that have not completed the transfer process: Private owner
Nonstructural maintenance: DEP
Structural maintenance: DEP
All stormwater facility maintenance contractors working in Montgomery County are required to have a Certificate of Attendance from the Department of Environmental Protection's Stormwater Facility Maintenance Contractor Training.
Stormwater facilities that are functioning as they were designed will not cause mosquito problems. Most facilities, except wet ponds, are designed to drain within 72 hours. For complaints about mosquitoes, contact the Department of Housing and Community Affairs.
How is the stormwater facility maintenance program funded?
button to start the slideshow. To view descriptions of the photos, start the slideshow and enter fullscreen mode by clicking the 
button. Then click the "Show Info" link at the upper right corner of the screen.