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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION EFFECTS ASSESSMENT IN THE SOUTH GEORGIA LITTLE RIVER

Location: Southeast Watershed Research

Title: The Evaluation of Conservation Practice Placement in the Little River Experimental Watershed (LREW) Using a GIS Tool

Authors
item Settimi, John -
item Sullivan, Dana -
item STRICKLAND, TIMOTHY

Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 27, 2009
Publication Date: May 1, 2010
Citation: Settimi, J., Sullivan, D.G., Strickland, T.C. 2010. The Evaluation of Conservation Practice Placement in the Little River Experimental Watershed (LREW) Using a GIS Tool. Journal of Soil and Water Conservation Society. 65(3):160-167.

Interpretive Summary: We examined the USDA Natural Resources Conservation Service’s (NRCS) 26 year history of conservation practice placement in the Little River Experimental Watershed (LREW) to evaluate the efficiency of practice location within the landscape. We used a series of currently available geographic information system databases that included: 1) Conservation Practices 2) Soils, 3) Elevation, and 4) Hydrology and evaluated conservation practice placement relative to soil and landscape features such as proximity to a water-body, slope, hydrologic grouping and erosion potential. The conservation practices database contained all fields that participated in NRCS conservation programs between 1980 and 2006 and included nearly 50% of all cropland in the watershed. Sixty-two percent of fields (77% of land area) implemented soil erosion and water erosion quality control practices in high resource concern areas (slope > 2.7 % and low infiltration). Sixty percent of fields within 50 meters of a water body had implemented soil and water erosion control practices. Results suggest that 30 – 40% of the erosion control practices were implemented in areas not considered a high resource concern. When we examined a sub-set of data that included fields where conservation practices were implemented either with or without NRCS assistance, 47% of all fields examined had implemented visible erosion control-specific conservation practices and implementation was linearly related to slope class (r2 = 0.64, p < 0.10). The relationship observed between erosion control practice placement and slope in the sub-watershed database is encouraging and suggests a commitment to good stewardship regardless of participation in federally funded conservation programs.

Technical Abstract: The Conservation Effects Assessment Program – Watershed Assessment Studies is a joint effort between the USDA Natural Resource Conservation Service (NRCS) and the USDA Agricultural Research Service (ARS) to evaluate the effectiveness of federally funded conservation programs. In response to this initiative, a 26 year history of NRCS conservation practice placement has been evaluated for the Little River Experimental Watershed (LREW) in the southeastern Coastal Plain of Georgia. To accomplish this task, a series of currently available geographic information system databases were integrated: 1) Conservation Practices 2) Soils, 3) Elevation, and 4) Hydrology. These data were used to define commonly adopted conservation practices and evaluate their placement relative to soil and landscape features, such as proximity to a water-body, slope, hydrologic grouping and erosion factor. The conservation practices database contained all fields that have participated in USDA NRCS conservation programs between 1980 and 2006. Nearly 50% of all croplands fields in the Little River Experimental Watershed were delineated as having participated in conservation programs. Results showed that 62 % of fields (77% of land area) in the conservation practice data base implemented soil erosion and water erosion quality control practices in high resource concern areas (slope > 2.7 % and low infiltration). When data were queried based on proximity to water feature (field boundary within 50 m), 60 % of fields within the conservation practice database had implemented soil and water erosion control practices. Results suggest that 30 – 40% of the erosion control practice were implemented in areas not considered a high resource concern. Using a sub-watershed database, having complete field coverage of four LREW sub-watersheds (with and without NRCS assistance) GIS databases were queried to evaluate the adoption and placement of erosion control practices. Forty seven percent of all fields in the sub-watershed database had implemented visible erosion control-specific conservation practices and implementation was linearly related to slope class (r2 = 0.64, p < 0.10). The relationship observed between erosion control practice placement and slope in the sub-watershed database is also encouraging and suggests a commitment to good stewardship regardless of participation in federally funded conservation programs.

Last Modified: 9/10/2014