New and redevelopment practices capture and treat stormwater runoff through various physical and biological processes. Examples include wet ponds, bioretention, green roofs, and green streets.  Practices are installed on new development sites to hold pollution levels at pre-development conditions. Alternatively, they can be used at redevelopment sites to reduce pollutant loads below pre-development levels.  The Chesapeake Stormwater Network provides a variety of resources on practices for new and redevelopment projects.

New and redevelopment practices capture and treat stormwater runoff through various physical and biological processes. Examples include wet ponds, bioretention, green roofs, and green streets.  Practices are installed on new development sites to hold pollution levels at pre-development conditions. Alternatively, they can be used at redevelopment sites to reduce pollutant loads below pre-development levels.  The Chesapeake Stormwater Network provides a variety of resources on practices for new and redevelopment projects.

Stormwater retrofits are a diverse group of practices that provide pollution reduction from existing development that is either currently untreated or is inadequately treated by an existing stormwater practice.  Retrofits work by temporarily capturing polluted runoff, reducing flow and improving water quality treatment through physical and biological processes.  Examples of retrofits include wet ponds, swales, permeable pavement, and bioretention.

Stormwater retrofits are a diverse group of practices that provide pollution reduction from existing development that is either currently untreated or is inadequately treated by an existing stormwater practice.  Retrofits work by temporarily capturing polluted runoff, reducing flow and improving water quality treatment through physical and biological processes.  Examples of retrofits include wet ponds, swales, permeable pavement, and bioretention.

This two-page fact sheet lists the nine types of urban BMPs, describes them, and lists the benefits of each type.

MS4s must currently comply with the minimum control measure for illicit discharge detection and elimination (IDDE) in their current stormwater NPDES permits.

Though not typically included in the urban stormwater sector, there are opportunities for communities to achieve pollutant reductions through upgrades to residential septic systems and small wastewater treatment plants.  Residential septic systems, especially older ones, are prone to nitrogen leaks.  Upgrading the pre-treatment tank or making enhancements to the drainfield can be effective nitrogen reduction strategies.  Upgrading wastewater treatment plants is another effective nutrient reduction strategy.

The term "Nutrient Discharges" refers to a wide range of non-stormwater flows polluting urban waters during dry weather due to spills, leaks, and overflows from storm sewers and sanitary sewers. Dry weather nutrient discharges collectively account for as much as 20 to 40% of the annual nutrient load in urban watersheds.  Illicit discharge prevention is the practice of locating, eliminating and preventing non-stormwater entries into storm drain systems.  The Chesapeake Stormwater Network provides a variety of resources on illicit discharge prevention.

Street sweeping can earn communities only a modest pollutant reduction credit.  While street sweepers may reduce trash or toxic contaminants, which are abundant in urban street solids, older technologies that use mechanical broom sweepers do little to reduce nutrients and sediment. While these mechanical sweepers may pick up large particles, they do not pick up the smaller particles that impact water quality.  Upgrading to more effective technologies like Regenerative Air Sweepers and Vacuum Assisted Sweepers can help increase pollution reduction efficiency.

New techniques have been pioneered in the Chesapeake Bay watershed to restore urban streams using diverse approaches such as natural channel design, regenerative stream channel, and removal of legacy sediments.  While each approach is different, they all seek to restore the function of the stream channel by preventing sediment from bank erosion, promoting in stream denitrification, and increasing interaction with the floodplain.  The Chesapeake Stormwater Network provides a variety of resources on urban stream restoration.