Comparison of the Soil Water Cycle in Clear‐Cut and Forested Sites

Abstract
A study was undertaken to determine the importance of subsurface flow and drainage in a northern Saskatchewan forested basin, and to examine the effect of clear‐cutting on the hydrologic cycle. Components of the soil water cycle were estimated for clear‐cut and forested sites during the spring melt and growing season. Surface runoff was measured using interceptor troughs and tipping‐bucket gauges. Soil water contents were measured using a neutron probe. Soil water fluxes were calculated using Darcy's Law and mass‐balance equations. Creek flow was monitored using a water‐level recorder and still well. Surface runoff was insignificant on all plots during the growing well. Surface runoff was insignificant on all plots during the growing season. Clear‐cutting increased hillslope water yield fivefold during the snowmelt period and doubled drainage during the growing season, compared with the forested site. Stream hydrographs indicated the basin was dominated by subsurface flow. This was consistent with measurement made on the forested plots where calculated drainage values could account for almost all observed streamflow. Hydrograph separation was carried out using mass‐balance calculations of Ca and Mg. The separation was used to identify sources of subsurface water contributing to streamflow.
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