Forest Harvest and Site Preparation Effects on Stormflow and Peakflow of Ephemeral Streams in the Ouachita Mountains

Abstract

AbstractStormflow and peakflow response to three silvicultural treatments—clearcutting, selection cutting and no disturbance (control)—were compared in a replicated small watershed study in the Ouachita Mountains of Arkansas. Watersheds were blocked according to aspect, location, soils, and geology in a randomized complete block design to test effects of treatments. Soils on the watersheds are shallow and were derived from sandstones and shale parent materials. Annual precipitation totals ranged from 72 to 142% of the long‐term average (131.7 cm) during the study and a single rainstorm exceeding the 100‐yr, 24‐h event occurred the second year following harvest treatments. Overall, stormflow water yields did not increase significantly due to forest harvest treatments apparently because permeable soils and subsurface geology allowed deep seepage at the expense of Stormflow. However, a treatment response was observed within one block and there was clearly a difference in Stormflow response between blocks of watersheds. Annual stormflow as a percentage of precipitation ranged from 2 to 59% across watersheds and years. Overall peakflows did not increase significantly due to treatment, but a treatment response was obseved within one block of watersheds and there was a significant difference in peakflows between blocks. Treatment differences in Stormflow and peakflow for the 100‐yr event were not significant. Stormflow to precipitation ratios for this event ranged from 0.63 to 0.81.