Soil moisture, precipitation, and streamflow were measured on three watersheds in West Virginia, two deforested and one forested. Water content of barren soil always exceeded that of forest soil throughout the growing season and especially in dry weather. Streamflow increased 10 inches annually on the watersheds that were cleared, most of the increase occurring between July and October. Higher soil moisture was accompanied by large instantaneous peak flows during small storms in the growing season but this peak effect was minor in large stoms and in all storms during the dormant season. With precipitation, streamflow, interception losses, and soil-moisture change estimated to comparable levels of precision, the water balance equation was solved for transpiration with sufiicient sensitivity to demonstrate the effects of tree leaf growth. After tree leaves were fully grown, calculated evaporative losses from the forested watershed somewhat exceeded potential rates as long as unmeasured runoff (leakage) was disre arded. With all components of the water balance quantified, including leakage, estimated soil-moisture loss by transpiration was at rates close to potential. Estimated leakage seemed consistent with observed stream behavior.
Patric, James H. 1973. Deforestation effects on soil moisture, streamflow, and water balance in the central Appalachians. Res. Pap. NE-259. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 12 p.