Characterization of surface water and groundwater suspended sediment in a West Virginia mixed-use, agro-forested watershed
Abstract
Suspended sediment is an important constituent of freshwater ecosystems that supports biogeochemical, geomorphological, and ecological processes. Excess suspended sediment can act as a physical barrier to sunlight and serve as a transport mechanism for other pollutants, while too little suspended sediment can alter primary productivity and reduce streambed stability. Existing knowledge of suspended sediment is typically based on surface water studies; however, improved understanding of groundwater-surface water suspended sediment dynamics can improve loading estimates and watershed remediation strategies. A study was conducted in a representative mixed-use, agro-forested catchment of the Chesapeake Bay Watershed of the Northeast, USA utilizing a nested-scale experimental watershed design, including eight gauging sites (n = 8) partitioning the catchment into eight sub-watersheds. A hydroclimate station was used to monitor precipitation and 30-minute air temperature data during the study (January 2020 December 2020). Stream water and groundwater grab samples were collected monthly, at each site, for the duration of the study (January 2020 December 2020). Water samples were analyzed for suspended sediment using gravimetric and laser particle defraction methods. Gravimetric results showed that groundwater samples consistently contained higher total suspended solids concentrations. Mean particle sizes were larger in the surface water samples, which contained more sand size particles and smaller calculated particle surface areas. Conversely, groundwater samples contained larger calculated particle surface areas and larger proportions of smaller particle sizes (i.e., silts and clays). Normalized particle size ratios demonstrated that groundwater typically contributed more to fine particle loading relative to the surface water. Results comprise distinct observations of groundwater-surface water suspended sediment source/sink dynamics, thereby improving understanding of pollutant loading regimes and advancing management practices in the Chesapeake Bay Watershed headwaters and similar agro-forested watersheds.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H35O1206G