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Watershed-scale Restoration in a Highly Urbanized Setting

Max Breslin
GreenVest, LLC
Bowie, Maryland

The Tinkers Creek Stream Restoration Project (Project) is a 40,000+ linear foot stream restoration project designed and constructed for project sponsor Prince George’s County Department of the Environment (PGDOE), which is responsible for the overall project implementation.  The Project goals were stabilization of the stream and its tributaries and providing PGDOE with Impervious Acres Treated Credits for MS4 Permit compliance. At the time of its completion in September 2021, the Project was one of the largest stream restoration projects completed in Maryland. Tinkers Creek and its tributaries Meetinghouse Branch and Paynes Branch represent a drainage area of 2,872 AC, over 40% of which is impervious surface. The flow pressures from this impervious surface, in combination with historic channel straightening, led to accelerated channel erosion as the stream attempted to reach a stable planform. Prior to construction, the main channels exhibited high rates of vertical and lateral instability which resulted in degraded floodplain wetlands, poor bedform diversity, and disconnection from the floodplain. The Project included 51 headwater tributaries, the majority of which were severely degraded and major contributors of sediment loading to Tinkers Creek and Piscataway Creek. Due to the severe and widespread existing condition impairments,  a significant project co-benefit was a design focused on infrastructure repair or protection. Failed stormwater infrastructure, failed slopes, exposed or threatened utility assets, and protection of properties at risk of flooding were all addressed through this comprehensive approach. Due to the expanse of the project and diversity of stream impairments observed, multiple design approaches were developed and implemented, each tailored to address reach-specific impairments and constraints. This approach enabled the GreenVest team to address stream stability, protection of infrastructure, and improvement of wildlife habitat on a case-by-case basis. Examples of this design and implementation approach will be examined in combination with lessons learned. Finally, projects of this scale require intense collaboration with multiple public and private entities. GreenVest will discuss some of the challenges and lessons learned from the implementation of this large-scale urban stream restoration project.