Variability of sediment transport at a tidal wetland restoration site: Prime Hook National Wildlife Refuge, Delaware
| Author(s) | Runion, Kyle D. | |
| Date Accessioned | 2020-04-10T12:23:32Z | |
| Date Available | 2020-04-10T12:23:32Z | |
| Publication Date | 2019 | |
| SWORD Update | 2020-02-06T17:01:01Z | |
| Abstract | Prime Hook National Wildlife Refuge in Delaware contains over 10,000 acres of tidal wetlands along the coast of lower Delaware Bay. The refuge formerly contained two managed freshwater wetland impoundments, but starting in 2009 a series of coastal storms breached the coastal barrier and threatened the ecological integrity of the wetland complex. A restoration project was completed in 2016 to close the breaches and reintroduce regular tidal flow for the first time in decades. Sediment transport and accumulation are critical to maintain newly created tidal flats and stabilize reestablishing salt marsh vegetation. An observational study of sediment flux was conducted to develop a conceptual model of suspended sediment transport and inform ongoing restoration efforts. Time series of continuous flow and sediment concentration data obtained at four tidal channel locations and nearby meteorological (wind, precipitation) data were analyzed to identify mechanisms of sediment flux related to tides, wind stress, wave resuspension, and freshwater discharge. Analysis revealed that the post-restoration refuge behaves as a tidally choked coastal lagoon impacted by local and remote winds. Average suspended sediment concentrations (SSC) were high (80-130 mg/L) compared to typical tidal wetlands in the region (10-40m mg/L), perhaps due to resuspension of material from unvegetated tidal flats. High wind speeds generate high SSCs, and both wind speed and tidal action influence the discharge of water. Freshwater discharge from local creeks drove a net export of water, causing a net export in the sediment flux in fair weather conditions. Storm events created both import and export events, but export events were more prevalent. Storms accounted for 20% of the net sediment flux but 44% of the gross sediment flux, indicating that they are not the dominant mechanism but have a high potential for sediment transport considering climate change projections predict an increase in storm intensity and frequency. Northerly or easterly winds and storm surge contributed to the import of water and sediment while southerly or westerly winds and fair weather conditions contributed to the export. Overall, the measured sediment flux for the refuge was an export of 5,296 ± 112 metric tons per year. | en_US |
| Advisor | Sommerfield, Christopher K. | |
| Degree | M.S. | |
| Department | University of Delaware, School of Marine Science and Policy | |
| Unique Identifier | 1149922677 | |
| URL | http://udspace.udel.edu/handle/19716/25568 | |
| Language | en | |
| Publisher | University of Delaware | en_US |
| URI | https://search.proquest.com/docview/2383147254?accountid=10457 | |
| Title | Variability of sediment transport at a tidal wetland restoration site: Prime Hook National Wildlife Refuge, Delaware | en_US |
| Type | Thesis | en_US |