Urban Stormwater Verification Guidance

This 14-page report provides guidance on how to verify the performance of urban BMPs in the Bay watershed.  The guide is organized into 8 parts:

1. The Need for BMP Verification and the Chesapeake Bay Program partners’ Process to Define it

2. Key Verification Definitions

3. Background on Urban BMP Verification

4. Verification Guidance for BMPs Located in MS4 areas

5. Verification Guidance for BMPs Located in non-MS4 areas

6. Verification Guidance for Non-Regulatory BMPs

7. Verification Guidance for Legacy BMPs

Septic System and Minor Wastewater Treatment Facility Upgrades

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.

Nutrient Discharges from Grey Infrastructure

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.

Nutrient Discharges from Grey Infrastructure

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.

Urban Street Sweeping

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.

Urban Street Sweeping

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.

Urban Stream Restoration

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.

Urban Stream Restoration

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.

Urban Forest Management Practices

There are two types of tree planting activities that can earn Bay Pollution Diet credit for your community.  Urban tree canopy expansion includes small-scale residential planting or new street trees. This practice provides pollution reduction credit for every new, individually planted tree in a developed community. Urban forest planting establishes a forest-like condition, and provides credit by meeting state planting density and understory management requirements.

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