Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Proceedings
Publication Acceptance Date: 4/8/2006
Publication Date: 4/8/2006
Citation: Bosch, D.D., Sheridan, J.M., Lowrance, R.R., Sullivan, D.G. 2006. Impact of forestation within coastal plain watersheds. American Society of Agricultural Engineers Special Meetings and Conferences Papers. International Conference on Hydrology and Management of Forested Wetlands; April 8-12, 2006, New Bern, NC. 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 have impacted the flow. Annual total precipitation and seasonal variability in precipitation appear to have the greatest overall impact on streamflow.
Technical Abstract: A common conservation practice occurring throughout the Coastal Plain is the conversion of marginal crop-land from row-crop to upland forests. This conversion is supported by conservation programs implemented by the U.S. Department of Agricultural. Differences between the evaporative demands of these crops as well as infiltration differences may cause significant hydrologic differences to be observed on watersheds where the forestation occurs. The impact of these changes was examined using observed land-use and hydrologic data for the Little River Watershed in South Central Georgia. Examination of satellite images collected from 1975 to 2003 indicates decreases in fallow acreage and increases in row-crop and pasture acreage. No statistically significant changes in forest acreage within the watershed were detectable from the satellite imagery used. Hydrologic data collected from this watershed do not indicate significant changes in hydrology that can be attributed to the minor changes in land-use observed. The average ratio of the annual flow to the annual precipitation for this watershed was 0.27. Year to year variation of the ratio varied from a high of 0.41 observed during a year with above normal winter rainfall to 0.06 observed during a year with very low annual rainfall. Stream flow patterns within the watershed are dominated by annual and seasonal precipitation patterns.