Evaluating Riparian Buffers for Nonpoint Source Pollution Control in an Urban Setting Using the Riparian Ecosystem Management Model, REMM
American Society of Agricultural and Biological Engineers , 2006
Allison, B.E., Fatula, S.M., Wolanski, D.P.
Environmental planners recognize the importance of maintaining the integrity of a riparian buffer when land is developed for urban purposes. The state of Delaware requires that 60 percent of the P and 40 percent of the N loadings from new urban land developments be reduced before flowing to surface water. Riparian buffers are effective for treatment of urban storm water runoff, but they are frequently designed using non-specific site criteria for agricultural riparian buffers. The objective of this research was to evaluate the Riparian Ecosystem Management Model (REMM) as a tool for designing urban riparian buffers based on site-specific data. REMM inputs were obtained from published literature and REMM databases. N, P and sediment loadings at the buffer edge were input from SWAT model simulations. A three-zone 15 m and a 30 m riparian buffer were simulated. Results were summarized using five rainfall years (minimum, below average, average, above average and maximum) from the 25-year simulation. Total P was reduced by nearly 60 percent for the 15 m buffer except the low rainfall year. Even though the desired minimum was not reached, the total influx was small and the overall outflow was 0.3 kg P ha-1. Based on these simulation results, the Delaware guidelines for buffer size appear to be too large. Currently, Delaware requires a 30 m forested or vegetation zone for developed areas. Results of this study will be beneficial to individuals who are responsible for nonpoint source permitting and for the control of urban storm water runoff.