Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2006
Publication Date: 4/1/2006
Citation: Bosch, D.D., Sullivan, D.G., Sheridan, J.M. 2006. Hydrologic impacts of land-use changes in coastal plain watersheds. Transactions of the American Society of Agricultural and Biological Engineers. 49(2):423-432. Interpretive Summary: Over the past 20 years, conservation programs developed and implemented by the U.S. Department of Agricultural have led to major land-use changes throughout the U.S. Through the Conservation Reserve Program (CRP) alone, over 13 million ha (34 million acres) of highly erodible and environmentally sensitive cropland have been converted into non-tilled land since 1985. The overall impact of these conservation programs can be a fairly dramatic change in land-use within many watersheds, resulting in significant hydrologic changes, the extent and impact of which is largely unknown. This impact was examined using data collected for the Little River Watershed in South-Central Georgia. The results of this analysis indicate that to date, the conservation programs have not dramatically impacted land-use within the watershed. In addition, there is little indication from the collected flow data that any land-use changes that have been implemented within Little River Watershed since 1975 have impacted the flow. Annual total precipitation and seasonal variability in precipitation appear to have the greatest overall impact on streamflow.
Technical Abstract: Conservation programs developed and implemented by the U.S. Department of Agriculture have led to land-use changes of large areas throughout the U.S. Different evapotranspiration and infiltration characteristics of these areas may cause dramatic hydrologic differences to be observed on watersheds where the changes are implemented. This impact was examined using observed data for the Little River Watershed in South-Central Georgia. Examination of satellite images collected from 1975 to 2003 indicates small decreases in fallow acreage and increases in row-crop and pasture acreage. However, from this analysis it does not appear that conservation programs have altered forested acreage or dramatically impacted overall land-use within the watershed. Over a 33 year hydrologic observation period there has been no discernable change in the ratio of the annual flow to the annual precipitation for this watershed. This ratio has remained stable at approximately 0.27. There is little indication from the collected flow data that any land-use changes that have been implemented with Little River Watershed have impacted the flow. Annual total precipitation and seasonal variability in precipitation appear to have the greatest overall impact on streamflow. It is not known if greater changes in land-use would have more significant impacts on the hydrology.