TMDL FULL DELIVERY STREAM RESTORATION

BALTIMORE COUNTY, MD

McCormick Taylor supported the GreenVest, LLC team by performing stream restoration site searches and assisting in the selection of two viable sites for TMDL credit – Long Green Creek and Rolling Ridge.

ENVIRONMENTAL , WATER

THE CHALLENGE

The primary goal of both projects was to improve stream channel stability while effectively mitigating excessive erosion with restoration features that enhance the hydrologic, hydraulic, and ecological functions of the stream systems. Floodplain reconnection, bedform diversity, aquatic habitat enhancement, and riparian buffer restoration were design elements integrated to reduce expected sediment and nutrient reductions and improve water quality within the site and in downstream waters. This includes Maryland Use III waterways associated with sensitive coldwater fish habitat.

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HOW WE HELPED

In addition to supporting the team through stream restoration site searches and the selection of viable sites for TMDL credit, McCormick Taylor also completed a geomorphic assessment and analysis, design, H&H modeling, permitting, construction oversight, and as-built review for these two projects.

 

A process-based design approach was implemented for both projects with hydraulics analysis (HEC RAS modeling) that identified design discharges to maximize floodplain reconnection and promote hydrologic connection to adjacent fringe wetlands. These structures were designed to provide grade control of the channel, while incorporating wood and vegetative components for flow diversity and substrate habitat improvements.

 

In addition, McCormick Taylor successfully secured all necessary permits from Baltimore County Development Management, including a grading permit, approval of forest buffer protection plans, a forest conservation exemption waiver, and stormwater management waiver. Additional permits included erosion and sediment control approval from the Baltimore County Soil Conservation District. We also prepared final construction plans and an engineer’s construction estimate.

 

Later in the project, McCormick Taylor provided construction services for the 5-month construction period. We supplied a design specialist to support Environmental Quality Resources (EQR), ensure design objectives, and adjust to changes in field conditions. McCormick Taylor also prepared certified as-built plans for the projects.

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RESULTS

Two projects were selected for TMDL credit with more than 12,800 LF of stream restoration at Long Green Creek and Rolling Ridge. At these sites and in downstream waters, expected sediment was reduced and water quality was improved.

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