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Impact of Clean Air Regulations on Nitrogen Fate and Transport in Neuse River Basin
Citation:
Gabriel, M., C. Knightes, E. Cooter, AND R. Dennis. Impact of Clean Air Regulations on Nitrogen Fate and Transport in Neuse River Basin. Presented at 2012 South Carolina Water Resources Conference, Columbia, SC, October 10 - 11, 2012.
Impact/Purpose:
Poster for 2012 South Carolina Water Resources Conference
Description:
We investigated impacts of Clean Air Act (CAA) nitrogen emissions regulations on the fate and transport of nitrogen for two watersheds in the Neuse River Basin. The Soil and Water Assessment Tool (SWAT) and the Community Multi-Scale Air Quality (CMAQ) models were used. Two scenarios were investigated: one that considers CAA emissions controls in CMAQ simulation (with) and a second that does not (without). By 2020, results showed a 70% drop in nitrogen discharge for the Little River watershed and a 50& drop for the Nahunta watershed from 1990 levels under the with scenario. Denitrification and plant nitrogen uptake played important roles in nitrogen discharge from each watershed. Nitrogen response time for Nahunta was twice as long (4 yrs.) as Little River (2 yrs.) which we attribute to a greater concentration and diversity agricultural lands. Agricultural land covers had varied nitrogen response time to changes in atmospheric deposition, particularly for soybean, hay and corn. The studied watersheds demonstrate relatively large nitrogen retention ≥80% of all delivered nitrogen.
