IMPACTS OF URBANIZATION AND STREAM RESTORATION ON CHANNEL MORPHOLOGY AND SEDIMENT FLUX IN THE CHESAPEAKE BAY WATERSHED

Sediment flux from in-channel sources can be difficult to accurately quantify due to localized spatial and temporal conditions. Through data collection over multiple years, we can quantify in-channel sediment storage and erosion in the channel bed and margins, which can advance our understanding of channel evolution. Comparison of the sediment flux in streams with watershed characteristics help to identify how fine sediment residence and transit times are affected by anthropogenic alterations common in the Chesapeake Bay watershed. In this study, we assess the impact of urbanization and stream restoration on in-channel sediment dynamics in two small watersheds.

This study focuses on Difficult Run and Accotink Creek, two neighboring watersheds within the greater Chesapeake Bay watershed. These streams are similar physiographically (watershed size, soil, and bedrock geology) and ecologically (vegetation type and weather patterns) but have different degrees of urbanization, land-use type, and best management practices (BMPs). Accotink Creek has a higher degree of urbanization and increased in-channel stream restoration structures in comparison to Difficult Run. Channel morphology and erosion rates have been monitored by erosion pins and topographic survey data collected at 53 transects along Difficult Run and 15 transects along Accotink Creek since 2010. This study allows us to begin to assess the role of urbanization and land management on in-channel sediment dynamics, which ultimately control water quality, vegetation, habitats, and biodiversity within the Chesapeake Bay.