Two recent USGS investigations have measured sedimentation rates along the barely perceptible slope of rivers as they empty into estuaries. The findings could have important implications for the restoration of the Chesapeake Bay and other estuaries.
The studies compared the sedimentation rates found in upriver tidal freshwater swamps (located at the furthest inland reach of tides) to the rate found in brackish water marshes downstream at the lowest reaches of the rivers.
“Sediment trapping in tidal freshwater wetlands is critical for protecting the water quality of estuaries and enhancing the resilience of those wetlands to sea level rise,” said Scott Phillips, USGS science coordinator for the Chesapeake Bay. “These wetlands help reduce nutrients and contaminants from reaching the Bay and also provide critical habitat for waterfowl.”
The new insights about the complexity of sediment, carbon, and nutrient transport from watersheds to estuaries can help water quality managers to more accurately forecast the effects of watershed changes on estuarine water quality and improve adaptive management.