Effects of Forest Harvest and Planting on Hydrology and Sediment Transport in Headwater Basins Draining the Pelham Escarpment

Abstract

Timber harvesting practices are known to disturb soil and increase bare soil, increase overland flow and peakflow rates, all of which have the potential to increase sediment input to a stream and the erosional power of a stream. These potential water quality issues can have detrimental effects on riparian and aquatic species. Streamside management zones (SMZs) help to reduce the impacts of silvicultural practices. This study is designed to evaluate the hydrologic and sediment transport response during pre-harvest and post harvest periods using a paired watershed approach. Two reference watersheds and two treatment (harvested) watersheds of relatively the same size, shape, geology, and vegetation have been monitored since July 2001. The treatment watersheds will be harvested with the exception of the streamside management zones (SMZs). The SMZs in the will be divided up into upper and lower sections. The upper sections will remain intact and lower sections have undergone partial harvesting in accordance with Georgia forestry best management practices (BMPs). Our results show that there were significant increases in total yield of the treatment watersheds from the pre-harvest to the post harvest period. Peak flows increased slightly in the treatment watersheds after harvest.