Excerpt from Changes in Streamflow Following Timber Harvest in Southwestern Oregon Changes in size of annual and seasonal yields and instantaneous peak flows were determined on three small, experimental watersheds following three silvicultural methods of timber harvest. Changes are related to changes in forest hydrologic system. Keywords: Streamflow - )forestry methods, water supply, logging -hydrology, runoff - )vegetation. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Excerpt from Streamflow After Patch Logging in Small Drainages Within the Bull Run Municipal Watershed, Oregon Changes in annual water yield, mini mum streamflow, and instantaneous peak flow (the maximum rate of streamflow caused by a rain or snow melt event) are all important in municipal watershed management. If timber cutting can increase water yield, then a municipal watershed might be made to yield more water, particularly during the summer period of low flow. Increased size of peak flows as a result of timber harvest might be associated with not only overland flow and attendant surface erosion but also erosion of stream channels. Both factors could adversely affect water quality. In 1955, the usda Forest Service and the City of Portland, Oregon, began a cooperative study to determine effects of timber harvest on water yield and timing of runoff and the quality of streamflow in three small watersheds within the Bull Run Municipal Watershed. This report deals only with changes in quantity and timing of streamflow. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Stream temperature is a water quality parameter that directly influences the quality of aquatic habitat, particularly for cold-water species such as Pacific salmonids. Forest harvesting adjacent to a stream can increase the amount of solar radiation the stream receives, which can elevate stream temperatures and impair aquatic habitat. Oregon Forest Practice Rules mandate that forest operators leave Riparian Management Areas (RMAs) adjacent to streams in order to minimize the water quality impacts from forest harvesting. However, RMAs that contain overstory merchantable conifers are not required for small non-fish-bearing streams in Oregon, thus there is potential for increases in stream temperature to occur in headwater streams after harvesting. There is concern that increases in stream temperatures and changes to onsite processes in non-fish-bearing, headwater streams may propagate downstream and impair habitat in fish-bearing streams. The objectives of the following work are to assess the effects of contemporary forest management practices on stream temperatures of small non-fish-bearing headwater streams and to develop new knowledge regarding the physical processes that control reach-level stream temperature patterns. Summer stream temperatures were measured for five years in six headwater streams in the Hinkle Creek basin in southern Oregon. After four years, four of the streams were harvested and vegetated RMAs were not left between the streams and harvest units. The watersheds of the two remaining streams were not disturbed. Post-harvest stream temperatures were monitored for one year in all six streams. Each harvested stream was paired with one unharvested stream and regression relationships for maximum, minimum and mean daily stream temperatures were developed. Changes to temperatures of harvested streams were detected by comparing the mean pre-harvest regression relationship to the mean post-harvest relationship. Change detection analyses that considered the mean response among all four harvested streams indicated that maximum daily stream temperatures did not increase after harvesting, but that minimum and mean daily temperatures decreased significantly after harvesting. Additionally, diel stream temperature fluctuations were significantly greater one year after harvesting. Pre- and post-harvest surveys of canopy closure in the harvested and unharvested streams were completed in order to compare levels of stream shading before and after harvest. The post-harvest survey quantified canopy closure from remaining overstory vegetation as well as from logging slash that partially covered the harvested streams. The surveys indicated that mean overstory canopy closure in the harvested streams decreased by 84% as a result of the harvest, but as the logging slash provided considerable cover, total canopy closure decreased by only 20%. It is possible that the logging slash effectively attenuated solar radiation and prevented extreme temperature increases in the harvested streams. However, it is likely that streamflow increased after harvesting and that the increased streamflow also prevented increases to maximum temperatures and contributed to lower minimum and mean stream temperatures.

Excerpt from Stream Channel Adjustments Following Logging Road Removal in Redwood National Park When roads are constructed across streams, a large amount of fill material (soil) is bulldozed into the stream channel to build the road bed up to grade. A major part of the ongoing watershed restoration program includes the removal of this road fill material from skid trail and haul road stream crossings (figure Excavation of road fill from stream crossings is given high priority because of the relatively high potential for significant erosional damage. For example, during extreme runoff events, plugged culverts may divert streamflow and cause gullying of hillslopes and road beds while saturated stream crossings can fail as destructive debris torrents. Figure 1. Location map of lower Redwood Creek showing Redwood National Park lands in the lower one-third of the basin. Figure 2. Logging road stream crossing before (a) and after (b) excavation. Excavation has uncovered cobbles and boulders that composed the original stream bed. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.