Urban Best Management Practices, or BMPs, are structural, vegetative, or managerial approaches designed to reduce stormwater runoff volume, maximize natural
groundwater recharge, and treat, prevent, or reduce degradation of water quality due to stormwater runoff. Below is a list of Urban BMPs used throughout Carroll County:

Dry Detention Ponds:
These are stormwater design features that provide a gradual release of water in order to increase the settling of pollutants and protect downstream channels from frequent storm events. This type of facility will remain dry between storm events.
Dry Extended Detention Ponds:
Stormwater management structures that provide a gradual release of a specific volume of water in order to increase the settling of pollutants in the pond and to protect downstream channels from frequent storm events. They are often designed with small pools at the inlet and outlet of the pond. These BMPs can also be used to provide flood control by including additional detention storage above the extended-detention level.
ESD and Microscale Treatment Practices: 
A diverse group of on-site techniques that capture, store and partially treat rooftop runoff in residential areas and highly urban landscapes. These practices include drywells, rain barrels, rain gardens, green rooftops, and permeable pavers.
Filtering Practices
BMPs which capture and temporarily store the water quality volume and pass it through a filter of sand, organic matter and vegetation, promoting pollutant treatment and groundwater recharge.
Infiltration Practices
These facilities are used to capture and temporarily store the water quality volume before allowing it to infiltrate into the soil, promoting pollutant treatment and groundwater recharge.
Impervious Surface Reduction
A practice which reduces the total area of impervious cover as well as features that capture stormwater and divert it to a previous area, subsequently encouraging stormwater infiltration.
Riparian Forest Buffer
Riparian forest buffers are areas of trees usually accompanied by other vegetation, that are adjacent to a body of water and which: maintain the integrity of stream channels; reduce the impact of upland pollution sources by trapping, filtering, and converting sediments, nutrients, and other chemicals; and supply food, cover, and thermal protection to fish and other wildlife. The recommended width of riparian forest buffers is 100 feet with a 35-foot minimum.
Stream Restoration
This BMP is used to restore the stream ecosystem by restoring the natural hydrology and landscape of a stream. Stream restoration is used to help improve habitat and water quality conditions in degraded streams. The objectives of using this practice include, but are not limited to, reducing stream channel erosion, promoting physical channel stability, reducing the transport of pollutants downstream, and working towards a stable habitat with a self-sustaining, diverse aquatic community.
Tree Planting
Establishing woody plants by planting seedlings or cuttings, direct seeding, or natural regeneration. This planting is not along a body of water and does not include reforestation areas.
Urban Nutrient Management
A BMP that reduces fertilizer applied to grass lawns and other urban areas. This practice is based on public education and awareness, targeting suburban residences and businesses, with emphasis on reducing excessive fertilizer use.
Wetponds and Wetland Practices
Facilities which collect and increase the settling of pollutants in the structure and protect downstream channels from frequent storm events. Wetponds retain a permanent pool of water.