FIRST‐YEAR EFFECTS OF CLEARCUTTING AN OAK‐HICKORY WATERSHED ON WATER YIELD¹

Abstract

Two intermittent streams on oak‐hickory watersheds in southern Illinois were gaged with a V‐notch weir and sampled with an automatic water sampler. Baseline data was collected for a period of three years. Flow volume showed large variations between years and watersheds. Water samples were analyzed for Na, K, Ca, Mg, ortho‐P, and NO3‐N. Water quality was consistently high, but there were significant differences between the watersheds during the calibration period. One watershed was clearcut in November 1979. One year of postharvest data has been analyzed. Flow volume increased 95 percent, but there was no evidence of increased sedimentation. There were significant increases in the stream water concentrations of K, Mg, and NO3‐N of 18 percent, 8 percent, and 274 percent, respectively. Nutrient budgets for the site were not adversely affected by the harvest. The clearcutting operation appears to have had a small impact on the watershed due to minimal disturbance during the logging and below normal precipitation the first year following the harvest.

Quality of Runoff From Minnesota Peatlands: Ii. A Method for Assessing Mining Impacts1

“…The paired watershed approach is statistically sound, but also has several drawbacks. Several years are typically required for calibration between a control and treatment watershed and as pointed out by Brozka, et al (1982), even with careful selection of watersheds, significant water quality differences can exist between two natural watersheds. In addition, catastrophes such as fires can ruin a paired watershed study.…”