|Williams, Randall - Randy|
Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/1999
Publication Date: N/A
Citation: INAMDAR, S.P., LOWRANCE, R.R., ALTIER, L.S., WILLIAMS, R.G., HUBBARD, R.K. RIPARIAN ECOSYSTEM MANAGEMENT MODEL (REMM): II. TESTING OF THE WATER QUALITY AND NUTRIENT CYCLING COMPONENT FOR A COASTAL PLAIN RIPARIAN SYSTEM. TRANSACTIONS OF THE AMERICAN SOCIETY OF AGRICULTURAL ENGINEERS. 42(6):1691-1707. 1999. Interpretive Summary: Although it is generally recognized that riparian (streamside) buffers are an effective Best Management Practice for controlling nonpoint source pollution from agriculture there are only a few studies to provide field experimental data for limited sets of conditions. Yet, USDA programs such as the Conservation Buffer Initiative, continuous signup of the Conservation Reserve Enhancement Program and many state/USDA partnerships formed as Conservation Reserve Enhancement Programs all stress use of riparian buffers. These efforts are part of USDA's plan to install two million miles of buffers on US farmland by 2002. Between 1996-2002 USDA and state partners will spend hundreds of millions of dollars on cost-share and rental payments for riparian ecosystem buffers on farms. The Riparian Ecosystem Management Model (REMM) developed by ARS and university coopera- tors is the only tool available for examining effects of riparian ecosystem mbuffers on nonpoint source pollution. REMM has been tested by comparing model output results to field data for Coastal Plain riparian systems. Comparison of field and simulated data showed that REMM gave results that were consistent with 5 year averages of field data. Simulated and observed concentrations of nutrients in groundwater were similar. REMM also gave results that matched some of the seasonal patterns of nutrient concentra- tions in groundwater. Results show that REMM will provide useful results for examining the nonpoint source pollution control functions of riparian buffers in parts of the country where test data are available for a specific set of conditions.
Technical Abstract: The Riparian Ecosystem Management Model (REMM) was used to simulate nitrogen (N), phosphorus (P) and carbon (C) cycling and transport in a Coastal Plain riparian buffer system near Tifton, GA. The riparian buffer consisted of zone 3 (grass next to row crop field); zone 2 (mature pine forest downslope from zone 3); and zone 1 (hardwood forest doewnslope from zone 2, adjacent to stream). Uncalibrated simulation results for a 5-year period were compared to measured values for the same time period at the research site. Generally, REMM simulations were within one standard devia- tion of observed values on an annual basis. The exception to this was REMM tended to overestimate amount of N removed from surface runoff in zones 3 and 2 of the riparian ecosystem. REMM simulations also overestimated amount of N lost by denitrification although differences were not large. Although some of the runoff differences (observed vs simulated) were large in rela- tive terms, overall trends within actual riparian buffer were generally well represented and differences were not large in absolute terms. Simulation results of groundwater nutrient concentrations agreed closely with observations. Much of the temporal dynamics of observed data were also captured in REMM simulations. Certain constraints of the model use are discussed, but REMM appears to be useful for representing many of the specific processes and general trends in riparian ecosystem buffers. The model will be used to help in the design of buffer systems to control non- point source pollution from agriculture.