Northern Virginia Stream Restoration Bank (NVSRB) – Wetland Success?? Case Study of an Urban Stream Priority 1 Restoration Project Restoring Riparian Wetlands

Wetland Studies and Solutions, Inc. (WSSI), a Davey Company, established the NVSRB in 2006 as the first dedicated stream mitigation bank in Virginia. The approval process began in 2004, culminating in approval of the bank in 2006.  Construction on the first reach began in 2008, with the final reach completed in 2019 (including a 5-year break due to market conditions).  In total, 11.5 miles have been restored, with the majority located within stream valleys owned by the Reston Association.  Streams within the first 2 watersheds (Snakeden Branch, ±20,250 lf) and The Glade (±20,300 lf) have completed their 10th growing season – meeting and exceeding all regulatory requirements.

The priority 1 restoration of these gaining streams was achieved by raising the invert of the severely incised channels, thereby reconnecting them to the floodplain in bankfull events.  We anticipated that groundwater levels would subsequently rise, restoring the adjacent riparian areas that were historically forested wetlands drained by the channel incision caused by uncontrolled stormwater discharges. To determine if our expectations occurred, we conducted a re-delineation and survey of wetlands in the riparian corridors adjacent to both Snakeden Branch and The Glade stream reaches in 2020.

This re-delineation determined that a significant amount of wetland acreage has been restored within the floodplain of both stream valleys.  This presentation will provide a case study of the NVSRB, the results of the wetland restoration that occurred due to the stream restoration, a summary of the on-going studies to document this remarkable success, and how this data can allow scientists and engineers to predict such outcomes using models, such as Wetbud, more precisely.