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• 1. [Article] Changes in storm hydrographs due to clear-cut logging of coastal watersheds

  The purpose of this study was to determine the effect of clearcut logging on stormflow by analysis of characteristic parameters of individual storm hydrographs. Parameters considered included height-of-rise, ...

  Citation × Citation Citation Abstract Copy Title: Changes in storm hydrographs due to clear-cut logging of coastal watersheds Author: Harper, Warren Charles The purpose of this study was to determine the effect of clearcut logging on stormflow by analysis of characteristic parameters of individual storm hydrographs. Parameters considered included height-of-rise, peak discharge, volume and time-to-peak. The hydrologic data were derived from experimental watersheds of the Alsea Study located in the Oregon Coast Range. Three clearcut watersheds were selected for study; Deer Creek IV (39 acres) was clearcut, and Needle Branch (175 acres) was clearcut and burned. Both watersheds were compared to Flynn Creek (502 acres), an untreated control, before and after treatment. Change in hydrologic paramaters was determined from differences between pre- and post-logging linear regressions. Statistical techniques were utilized to test for differences in slope or vertical position. Significant increases were found in peak discharge from both Needle Branch and Deer Creek IV following clearcut logging. Larger increases were noted during the fall period than during the winter period. Volume parameters of quick flow, delayed flow, and total flow were increased for Needle Branch. Volume of flow was not shown to increase from Deer Creek IV. This may have been due to the lack of usable storm events for analysis from this watershed. Time-to-peak was not altered in Needle Branch but was decreased for low flows and increased for high flows on Deer Creek IV. The height-of-rise parameter did not prove to be of value for detecting change in this study. Comparison of the burned watershed (Needle Branch) to the unburned watershed (Deer Creek IV) did not produce a noticeable difference in any of the parameters. The observed changes in stormflow were related to clearcut logging and the effect of vegetative removal on watershed response. Title: Changes in storm hydrographs due to clear-cut logging of coastal watersheds Author: Harper, Warren Charles The purpose of this study was to determine the effect of clearcut logging on stormflow by analysis of characteristic parameters of individual storm hydrographs. Parameters considered included height-of-rise, peak discharge, volume and time-to-peak. The hydrologic data were derived from experimental watersheds of the Alsea Study located in the Oregon Coast Range. Three clearcut watersheds were selected for study; Deer Creek IV (39 acres) was clearcut, and Needle Branch (175 acres) was clearcut and burned. Both watersheds were compared to Flynn Creek (502 acres), an untreated control, before and after treatment. Change in hydrologic paramaters was determined from differences between pre- and post-logging linear regressions. Statistical techniques were utilized to test for differences in slope or vertical position. Significant increases were found in peak discharge from both Needle Branch and Deer Creek IV following clearcut logging. Larger increases were noted during the fall period than during the winter period. Volume parameters of quick flow, delayed flow, and total flow were increased for Needle Branch. Volume of flow was not shown to increase from Deer Creek IV. This may have been due to the lack of usable storm events for analysis from this watershed. Time-to-peak was not altered in Needle Branch but was decreased for low flows and increased for high flows on Deer Creek IV. The height-of-rise parameter did not prove to be of value for detecting change in this study. Comparison of the burned watershed (Needle Branch) to the unburned watershed (Deer Creek IV) did not produce a noticeable difference in any of the parameters. The observed changes in stormflow were related to clearcut logging and the effect of vegetative removal on watershed response. Close