Nandita Basu- SENR Seminar Series

Nandita will be presenting Back to the Future:  How Past Land Use Impacts current Water Quality at 4:10P.M. in Kottman 103 on November 15, 2018.
Listen to Nandita's presentation here: carmenconnect.osu.edu/basu

Nandita Basu is an Associate Professor of Ecohydrology and Water Sustainability in the Department of Civil and Environmental Engineering at the University of Waterloo. Her research encompasses a broad range of issues related to water in human-impacted environments, with specific focus on nutrient pollution and legacies in groundwater, rivers, lakes, and coastal waters. 

Abstract:

The last 100 years have seen a more than threefold increase in population accompanied by agricultural intensification and dramatic changes in land use. Human activities have greatly accelerated the nitrogen (N) and phosphorus (P) cycles, with excess N and P leaching into surface water, causing problems of eutrophication, and drinking water contamination. Multiple policies and conservation measures have been adopted to improve water quality; however N and P concentrations of inland and coastal waters are in many cases continuing to increase. Recent work suggests that the lack of success in improving water quality arises from legacy stores of nutrients that have accumulated in landscapes over decades of agricultural intensification. However, current knowledge regarding the magnitudes and distribution of legacy nutrients, as well as the time scales over which they may contribute to elevated nutrient concentrations, remains inadequate. The research from my group aims to fill this critical knowledge gap by providing, for the first time, estimates of legacy N and P accumulated in soils and groundwater in various river basins in North America, and lag times to water quality improvement. Specifically, we have developed a unique modelling approach (ELEMeNT) – which pairs a simulation of soil nutrient dynamics with a travel time-based approach – to reconstruct historic nutrient yields and to model future nutrient loading under a range of scenarios. Our modeling of future scenarios indicates that even if agricultural nutrient use were to become 100% efficient, it would take on the order of decades to meet policy goals for improving water quality.  Our results suggest that significant time lags should be anticipated when aiming to reduce nutrient export, and that both long-term commitment and large-scale changes in agricultural management practices will be necessary to meet such goals.