The impact of extreme storms on water quality in human-dominated watersheds

Abstract:

Land use and climate variability interact to amplify pulses of carbon, nutrients, and metals in watersheds. These pulses vary across space and time in watersheds as water flows from engineered headwaters to downstream rivers along the watershed continuum. Understanding water pollution pulses across space and time is critical for comprehensively understanding water quality impacts and evaluating recovery after extreme storms. We analyzed pulses of pollution in human-dominated watersheds following Hurricane Sandy, one of the most severe storms in recent U.S. history. We intensively analyzed concentrations and fluxes of over 20 elements including: carbon, nitrogen, base cations (calcium, magnesium, potassium, etc.), trace metals (copper, lead, zinc, etc.) for approximately 1 month following Hurricane Sandy at the Baltimore Long-Term Ecological Research (LTER) site in the Chesapeake Bay watershed. There were large pulses in concentrations of almost all elements, but there were variations in the amplitude and timing of pulses based on watershed position. Our analysis suggests that human-dominated watersheds experience large pulses in water quality in response to extreme storms, and there can be lag times for recovery based on sources and flowpaths of different elements.