|Tucker, Mike - UNIVERSITY OF GEORGIA|
|Thomas, Dan - UNIVERSITY OF GEORGIA|
|Vellidis, George - UNIVERSITY OF GEORGIA|
Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 2000
Publication Date: June 1, 2001
Citation: TUCKER, M.A., THOMAS, D.L., BOSCH, D.D., VELLIDIS, G. GIS-BASED COUPLING OF GLEAMS AND REMM HYDROLOGY: 2) FIELD TEST RESULTS. TRANSACTIONS OF THE AMERICAN SOCIETY OF AGRICULTURAL ENGINEERS. 43(6):1535-1544. 2001. Interpretive Summary: Farm managers are interested in developing the best overall management systems that meet overall production and environmental goals. To determine these management systems, managers must consider many possible combinations of crop, tillage and chemical applications. Field trials are expensive and time consuming. Computer models that accurately simulate the physical processes occurring in the agriucltural fields are good alternatives to field trials. A computer model that simulates the flow of water from agricultural fields through near stream buffer systems was developed. The model incorporates a well known field scale model with a recently developed riparian buffer model. Testing indicates the model simulates the elevation of the water table well, but does not predict surface runoff as well. However, the model did a good job of simulating the trends expected when land use is changed. The model has the potential of providing a cost effective method for evaluating different management practices. The illustrated methods offer significant cost savings and increased flexibility for land managers.
Technical Abstract: The hydrology component of the GLEAMS and REM models were coupled through a GIS to allow evaluation of agricultural and forest management impacts on water movement. Programs and subroutines were developed to allow delineation of field areas, identification & maintenance of data based on the field map and incorporation of data to the input data format for each model. The model system represented shallow groundwater (SGW) levels from forest management practices of clear-cut, thinned and mature forests in field comparisons with measured values from the site for 27 months of comparision data between 1992-94. Simulated monthly average SGW levels were within 0.14, 0.08 and 0.25 m of measured GW levels for clear-cut, thinned and mature forest treatments. Correlation results for same treatments indicated at least an r*2 of 0.78 for simulated vs measured monthly SGW results. The model system did not respond as well in representing field conditions of total monthly runoff. Average monthly differences in total simulated runoff were 0.73, 1.19 and 0.48 cm lower than measured results for clear-cut, thinned and mature forest management treatments from the site. The model system did, however, indicate runoff trends expected due to changes in forest management. As the number of trees and canopy increased, runoff decreased. The model system has the potential of providing a cost effective method of incorporating multiple model characteristics into management practice evaluations.