Stream Restoration

Picture of Stream Restoration

The Maryland Department of the Environment, Water and Science Administration, Wetlands and Waterways Program​, reviews proposed projects and issues permits for any activity which impacts tidal and nontidal wetlands and waterways, including 100-year floodplain. One specific type of activity which is gaining in popularity is ecological enhancement of these regulated resources through stream restoration projects.

The recent increase in the number of stream restoration practices being permitted in the State is due to many factors including water quality restoration goals required by Municipal Separate Storm Sewer System (MS4) permits, the Chesapeake Bay Total Maximum Daily Load (TMDL) Watershed Implementation Plans (WIPs), and local TMDLs. See the following data chart for reference numbers of projects in Maryland:


Stream Restoration Statistics 



Why Stream Restoration? 

Stream Restoration has been recognized by the Chesapeake Bay ProgramStoney Run Stream Restoration and the State of Maryland as providing numerous water quality and ecological benefits. The Phase 6 Chesapeake Bay Watershed Model estimates the annual export of nitrogen, phosphorus, and sediment from a stream bed and bank source to the tidal waters of the Chesapeake Bay. This export of pollutants from Maryland’s nontidal streams to the Bay is the result of many different anthropogenic stressors to the State’s nontidal streams and floodplains, over the course of several hundred years. Typical stream restoration techniques aim to stabilize streambeds and banks to prevent erosion and sediment export, promote floodplain reconnection, enhance surface/groundwater interaction, promote nutrient cycling and denitrification, enhance sediment trapping in floodplains, and improve habitat conditions for in-stream aquatic life. These techniques generally improve stream hydraulics and as a result reduce nutrient and sediment loads being delivered downstream. Coupled with improved habitat for in-stream aquatic life, stream restoration projects generally result in overall ecological uplift to a system.

Credits for TMDL Goals and MS4 Permits

Because of many benefits of stream restoration, the Chesapeake Bay Program Partnership and the State
of Maryland allow and encourage local jurisdictions, watershed organizations, and other stakeholders to use stream restoration projects to meet MS4 permit requirements and TMDL goals. MDE follows guidance from the Chesapeake Bay Program on calculating the nutrient and sediment load reductions, qualifying conditions, and verification procedures for stream restoration through Partnership approved Expert Panel reports. As stream restoration has continued to evolve, the Stream Restoration Expert Panel report has evolved as well. New recommendation memos provide updates to the load reduction calculation methodologies, qualifying conditions, etc. outlined in the original expert panel report, which was published in 2013. These memos are based on consensus from the scientific, regulator, non-profit, and practitioner communities. The original stream restoration expert panel report and subsequent, accompanying memos can be found on the Chesapeake Stormwater Network’s website here:

The recommendations from the following reports were incorporated
Image of the Accounting for WLAs and Impervious Acres Treatedinto MDE’s 2020 MS4 Accounting Guidance, which details how nutrient and sediment load reductions are translated into MS4 permit metrics:

  • Recommendations of the Expert Panel to Define Removal Rates for Individual Stream Restoration Projects, 2013
  • Recommendations for Crediting Outfall and Gully Stabilization Projects in the Chesapeake Bay Watershed, 2019
  • Consensus Recommendations for Improving the Application of the Prevented Sediment Protocol for Urban Stream Restoration Projects Built for Pollutant Removal Credit, 2020
  • Consensus Recommendations to Improve Protocols 2 and 3 for Defining Stream Restoration Pollutant Removal Credits, 2019
  • Recommended Methods to Verify Stream Restoration Practices
     Built for Pollutant Crediting in the Chesapeake Bay Watershed, 2019​

Holistic Watershed Restoration

Despite the many benefits of stream restoration, the Department cautions stakeholders in relying solely on this practice to meet water quality goals. MDE encourages and has incentivized holistic approaches to watershed restoration. This includes a combination of both upland and in-stream practices. Upland practices can include a wide array of practices in rural, urban, and suburban watersheds, but generally speaking they include practices such as stormwater management retrofits, reforestation, tree planting, forested and grass stream buffers, urban soil restoration, cover crops, streamside fencing, and many more. Determining what practices are implemented, where they are implemented, and how many practices are implemented should be determined through a comprehensive watershed planning effort that utilizes an adaptive management framework. As it specifically relates to stream restoration, MDE recommends that the practice should not be implemented without prior consideration to other potential stressors upstream of a given project and after evaluating the individual, ecological benefits and costs of any given project. These considerations are reflected in MDE’s project permitting processes.


The Department recognizes that these “restorative” projects are fundamentally different from
development projects in that their intended result is an overall uplift of ecological function. To that end, the Department instituted several measures to ensure that these projects were reviewed differently than development projects. Specifically: having a dedicated team of permit review staff of 2 engineers and a natural resources planner who only handle restorative projects along with producing guidance documents/checklists for restoration applicants to help ensure a complete application submission. The U.S. Army Corps of Engineers also recognizes the importance of such projects.  The Corps has issued the Chesapeake Bay Total Maximum Daily Load Regional General Permit and activated Nationwide Permit #27​ to streamline permitting of qualifying projects in Maryland. The Wetlands and Waterways Program has prepared guidance documents for preparing permit applications of MS4/Chesapeake Bay TMDL/Trust Fund and Restoration Projects. Additionally, the Department recognized that restorative projects, many times, require permit modifications during construction. To assist in the timely review/approval of necessary changes, the Department developed a Tiered Approach to modification approval for restoration projects​.


As restoration techniques and their water quality effects continue to evolve,
the Department continues to engage with the academic and research
community to gain a better understanding of project benefits and shortcomings.Photo of Stream Monitoring
Specifically, MDE continues to review the results of permitted project monitoring and work with partner organizations, such as the Chesapeake Bay Trust’s Pooled Monitoring initiative, to guide research studies intended to help us understand the overall effects of stream restoration. The Chesapeake Bay Trust’s pooled monitoring initiative provides critical research in regards to specific watershed restoration techniques, variable elements of those techniques, and watershed restoration as a whole. One of the primary focuses of these research efforts has been stream restoration. A list of the current research projects funded by the initiative and any applicable results and materials can be found at​.​​

For More Information

For more information about stream restoration projects and permitting, contact:

Wetlands and Waterways Program
Waterway Construction Division
Division Chief

For more information about TMDLs or Credits for TMDL Goals, contact:
Integrated Water Planning Program at