Stream Restoration in Urban Areas
Crediting Jurisdictions for Pollutant Load Reductions
The Chesapeake Bay Program will credit jurisdictions for reducing pollutant loads to the Bay and
its tidal rivers, resulting from stream restoration in urban areas (including suburban areas). This
document provides guidance to the jurisdictions regarding the stream restoration actions in urban
areas that will be credited in the watershed model.
Stream Restoration in Urban Areas
Land cover changes in the contributing watersheds disrupt the existing natural balance between the
water flow regime and sediment flux, destabilize stream channels, and increase the loadings of
pollutants to downstream areas. The objectives, opportunities, and measures for stream
restoration may differ in urban and rural areas. The objectives for stream restoration in urban
areas 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. Stream restoration activities should result in a
stable stream channel that experiences no net aggradation or degradation over time.
In addition to these in-stream restoration activities, addressing upland sources of stream impacts
(for example, reducing watershed runoff and associated pollutant loads, or encouraging
groundwater recharge) is critical to ensuring the success of stream restoration projects in urban
areas. Projects should be planned in the context of a comprehensive watershed assessment or
inventory, where upland sources of the problem are considered in the project design. Smaller
stream restoration projects on isolated stretches of a stream can be counted as long as upland
sources of impacts are considered in some way. To ensure the success of a stream restoration
project in an urban area, the project must have adequate watershed controls of upstream sources of
urban runoff or be designed to accommodate the current and future urban runoff volume and
velocity from upstream sources.
Just like with other best management practices in the Chesapeake Bay watershed, it is important to
track and monitor the effectiveness of stream restoration projects in urban areas. All projects
should either have a monitoring component or regular inspection and maintenance program to
ensure ongoing stability of the urban stream.
What Types of Projects are Credited as Stream Restoration in Urban Areas?
Pollutant load reductions associated with stream restoration projects in urban areas can be
credited in the Chesapeake Bay Watershed model if they meet the following criteria:
•	Projects must meet multiple objectives of stream restoration in urban areas.
•	Project must be set within the context of a watershed assessment that considers the effect of
upland sources to the viability of the stream restoration project.
•	Project must have a monitoring component and/or regular inspections to demonstrate ongoing
stability of the urban stream.

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The Chesapeake Bay watershed jurisdictions will annually report the number of urban stream
miles restored in each Chesapeake Bay Watershed Model county segment to the Chesapeake Bay
Program Office.
Pollutant Load Reductions Associated with Stream Restoration in Urban Areas
In addition to localized benefits, stream restoration in urban areas can result in reductions of
pollutant loads entering the Bay and its tidal rivers. There is only one known study that quantifies
the pollutant load reductions associated with stream restoration in an urban area. Although data
are lacking, the Chesapeake Bay Program decided it was important to account for load reductions
resulting from stream restoration. The Chesapeake Bay Program will refine these efficiencies as
additional data become available. Reductions in pollutant loads entering the Bay and its tidal
rivers from stream restoration in urban areas will be calculated based on the following pollutant
removal efficiencies (Baltimore County, Maryland, Spring Branch Stream Study, 2002):
•	TN = 0.02 lb/linear foot/year
•	TP = 0.0035 lb/linear foot/year
•	TSS = 2.55 lb/linear foot/year

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