Download or read book Drivers of Variability in Transpiration and Implications for Stream Flow in Forests of Western Oregon written by Georgianne W. Moore and published by . This book was released on 2003 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: I compared transpiration among different types of forest stands in the western Cascades of Oregon. The three major questions were: 1) How does transpiration compare between a young and old stand and why? 2) Does diversity of overstory trees affect transpiration? and 3) How is transpiration related to stream flow? Transpiration was quantified using thermal dissipation sap flow measurements scaled to a ground-area basis using sapwood surveys for periods during the summer months of 2000, 2001, and 2002, and in a subset of plots, for a full year. I found that a young, rapidly growing stand ([approximately] 40 years since disturbance) used 3.3 times more water during the growing season than an old-growth stand ([approximately] 450 years since disturbance) because the young stand had 2.3 times higher sap flow rates per unit sapwood in Douglas-fir, had a 21% greater total sapwood basal area, and had a larger component of hardwoods that use 1.41 times more water than conifers per unit sapwood. In two-species mixtures of Douglas-fir and red alder, I found evidence that mixtures are less productive and have lower annual transpiration than monocultures of these two species. The observed differences were probably due to altered biomass rather than diversity itself, but diversity likely played a role in altering biomass. Such stand age- and diversity-related differences in transpiration potentially impact stream flow. In a small watershed with a 450-yr-old forest, I examined the role of vegetation in stream flow patterns at hourly, daily, and storm scales. Transpiration apparently controlled stream flow during the summer at hourly scales with lags of at least five hours. In contrast, at daily and storm scales, soil water apparently controlled both stream flow and transpiration during the dry season, but there was no relationship during the wet season. These results indicate that forest management practices that reduce stand age and decrease diversity may lead to increased transpiration and consequently may reduce summer stream flow.
Download or read book Hydrology of Small Forest Streams in Western Oregon written by Robert Dennis Harr and published by . This book was released on 1976 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrology of small forest streams in western Oregon varies by time and space in terms of both streamflow and channel hydraulics. Overland flow rarely occurs on undisturbed soils. Instead, water is transmitted rapidly through soils to stream channels by displacement of stored soil water. Drainage networks expand and contract according to the interaction between precipitation characteristics and soil's capability to store and transmit water. Drainage networks are more extensive in winter than in summer. Streamflow may he 1,000 to 5,000 times greater during winter storms than during summer low flow. A stream's kinetic energy varies along with streamflow. Channel width and depth, heterogeneity of bed materials, and the accumulation of large, organic debris affects the dissipation of kinetic energy. Clearcutting can increase relatively small peak flows, but forest roads and extensive areas of soil compacted by other means may increase larger peak flows. Both roadbuilding and clearcutting can cause soil mass movements, which can drastically alter a stream's channel hydraulics by adding debris or scouring the charnel to bedrock. Removal of naturally occurring organic debris that has become part of a stable channel can accelerate bed and bank erosion.
Download or read book Effects of Forest Practices on Peak Flows and Consequent Channel Response written by Gordon Grant and published by . This book was released on 2008 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a state-of-the-science synthesis of the effects of forest harvest activities on peak flows and channel morphology in the Pacific Northwest, with a specific focus on western Oregon and Washington. We develop a database of relevant studies reporting peak flow data across rain-, transient-, and snow-dominated hydrologic zones, and provide a quantitative comparison of changes in peak flow across both a range of flows and forest practices. Increases in peak flows generally diminish with decreasing intensity of percentage of watershed harvested and lengthening recurrence intervals of flow. Watersheds located in the rain-dominated zone appear to be less sensitive to peak flow changes than those in the transient snow zone; insufficient data limit interpretations for the snow zone. Where present, peak flow effects on channel morphology should be confined to stream reaches where channel gradients are less than approximately 0.02 and streambeds are composed of gravel and finer material. We provide guidance as to how managers might evaluate the potential risk of peak flow increases based on factors such as presence of roads, watershed drainage efficiency, and specific management treatments employed. The magnitude of effects of forest harvest on peak flows in the Pacific Northwest, as represented by the data reported here, are relatively minor in comparison to other anthropogenic changes to streams and watersheds.
Download or read book Forest practices and streamflow in western Oregon written by Robert Dennis Harr and published by . This book was released on 1976 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forest management activities, including roadbuilding, clearcut logging, and broadcast burning, can change certain portions of the forest hydrologic cycle. Watershed studies and other hydrologic research in the Coast and western Cascade Ranges of Oregon have shown that these changes may increase annual water yield up to 62 centimeters, double minimum flows in summer, and increase fall peak flows up to 200 percent and small winter peak flows up to 45 percent in small watersheds. Changes in streamflow resulting from clearcut logging had little effect on either onsite damage to stream channels and hydraulic structures or downstream flooding when yarding caused only light disturbance of soil. By increasing the size of larger peak flows, roadbuilding and soil compaction may cause onsite damage in small, headwater basins. Increases in annual yield and minimum flows may be substantial on small watersheds that are clearcut; under sustained yield forest management, such increases are masked in large, parent watersheds by unaltered streamflow from unlogged watersheds.
Download or read book Effects of Forest Practices on Peak Flows and Consequent Channel Response written by Gordon E. Grant and published by DIANE Publishing. This book was released on 2010-09 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes a database of relevant studies reporting peak flow data across rain-, transient-, and snow-dominated hydrologic zones. Provides a quantitative comparison of changes in peak flow across both a range of flows and forest practices. Increases in peak flows generally diminish with decreasing intensity of percentage of watershed harvested and lengthening recurrence intervals of flow. Peak flow effects on channel morphology should be confined to stream reaches where channel gradients are less than 0.02 and streambeds are composed of gravel and finer material. Managers should evaluate the potential risk of peak flow increases based on factors such as presence of roads, specific mgmt. treatments employed, and watershed drainage efficiency.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Hydrological Sciences written by M. G. Anderson and published by . This book was released on 2005 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bottom up Drivers of Primary Producers and Predator Populations in Oregon Streams written by Matthew J. Kaylor and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humans have drastically altered the physical habitat and food web structure of stream ecosystems. Two major impacts humans have had on Pacific Northwest streams are modification of streamside forests (as a result of agriculture, land development, and timber harvest), and declines in the return of wild anadromous salmon to headwater ecosystems (due to a range of habitat degradation, dams, harvest, and hatcheries). Riparian forest impacts have altered stream light dynamics, while the loss of salmon has led to declines in the delivery of nutrients from the ocean to streams. While the initial impacts of the modifications took place decades or even centuries ago, they can have lasting effects on stream ecosystems and food webs. This dissertation evaluates 1) influences of long-term recovery from historic riparian harvesting on stream light, habitat, and food webs, and 2) how reduced salmon subsidies to streams may be impacting stream productivity and food webs. Today most streams in the Pacific Northwest, and indeed across much of North America, have buffers of riparian forests that are regenerating from earlier land clearing. As stands recover, the trajectories of stand development will affect forest structure, which in turn affects stream light regimes. In the first half of my dissertation, I explore how stand age and structure relates to stream light availability and then how spatial differences and temporal changes in stream light influence stream food webs and higher trophic level biomass in headwater streams. In Chapter 2, I explore how stream light availability differs with the age and stage of riparian forests. I found that stream light flux was generally lower and less variable when bordered by second-growth forests compared to old-growth forests within a stream network and more broadly across forests west of the Cascade Mountains. Numerous studies have evaluated how large differences in light availability (e.g. fully forested compared to complete removal of riparian forests) influence stream food webs, but smaller differences in light availability, such as those found in Chapter 2, have received less consideration. In Chapter 3, I conducted surveys across 18 stream reaches and evaluated how variables associated with stream habitat, light, primary production, and macroinvertebrate biomass account for variability in the biomass of cutthroat trout and total vertebrates (fish and salamanders). Habitat metrics were not well correlated with higher trophic level biomass. In contrast, factors associated with resource availability -- as regulated through bottom-up, autotrophic pathways -- were closely related to the biomass of fish and other consumers. In Chapter 4, I quantified long-term responses of stream biota to the regeneration of riparian forests following clear-cut harvest. I resampled five stream reach pairs that were originally sampled in 1976 shortly after canopy removal. This initial survey showed that periphyton chlorophyll a, predatory invertebrate biomass, and cutthroat trout (Oncorhynchus clarkii clarkii) biomass were elevated in harvested reaches relative to reference reaches. After four decades of riparian regeneration, mean canopy openness, chlorophyll a, predatory invertebrate biomass, and cutthroat trout biomass declined in harvested reaches relative to paired old-growth reference reaches. Changes in canopy cover were consistent with biotic responses and suggest that changes in light availability as stands regenerated exerted control on biota through bottom-up pathways in these streams. While spatial and temporal light dynamics appear as important regulators of stream food webs in small forested streams of western Oregon, other factors may emerge as important constraints on food web productivity across stream networks in other regions. In the second half of my dissertation, I explore bottom-up drivers of fish production in a river network in eastern Oregon where canopies are more open than small western Oregon streams. I focus on nutrient and carbon subsides in this study as the loss of returning anadromous fish has been hypothesized as a key factor contributing to poor recovery of ESA-listed salmonids. In chapter 5, I evaluate network-scale spatial patterns of primary production, potential drivers of primary production, and juvenile salmonid abundance throughout two NE Oregon sub-basins. Primary production rates increased with watershed area and we were able to explain 72% of the variation in primary production across these basins using a combination of fixed-effects (e.g. light, nutrients, and temperature) and spatial autocorrelation. In contrast to other studies, juvenile salmonid abundance was greatest in cool headwaters where nutrient concentrations and rates of primary production were very low. To test the hypothesis that growth of juvenile salmonids and other biota in these low-productivity stream sections may be inhibited by the reduction of returning adult salmon and the associated loss of nutrient subsidies, I conducted a carcasses addition experiment in three locations of the Upper Grand Ronde River. In chapter 6, I focused on the responses of juvenile Chinook (Oncorhynchus tshawytsca) and steelhead (O. mykiss). Chinook and steelhead consumed an abundance of eggs and carcass tissue which resulted in greater growth rates and body condition of fish in treatment reaches relative to controls. To contextualize potential effects of increased growth on Chinook survival, I used an 18 year tagging and detection dataset to evaluate Chinook length-survival relationships. The positive association between length and survival suggests that actions resulting in larger Chinook lead to increased survival rates. In chapter 7, I evaluate carcass addition effects on the broader food web. Periphyton, aquatic invertebrates, and non-salmonid fish assimilated carcass nitrogen, but enrichment was far less than observed in juvenile salmonids. In contrast to salmonids, diet analysis and stable isotope patterns indicated that non-salmonids were not consuming eggs and carcass material, suggesting carcass nitrogen assimilation occurred through bottom-up pathways. These results suggest that salmon subsidies have the potential to broadly impact stream food webs in this region, but that species able to directly consume eggs and carcass material (i.e. juvenile salmonids) clearly benefit more from these subsidies.
Download or read book Forest Practices and Streamflow in Western Oregon written by Robert Dennis Harr and published by . This book was released on 1976 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Low Streamflow Response to Climate Variability and Clearcutting in Snowpack and Rain dominated Forested Watersheds in the Western Oregon Cascades written by Janet S. Choate and published by . This book was released on 2004 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interacting Effects of Climate Forest Dynamics Landforms and River Regulation on Streamflow Trends Since 1950 written by Kendra L. Hatcher and published by . This book was released on 2011 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streamflow patterns are a result of the interaction of many factors, including climate, vegetation, geology, and topography. Analyses indicate that streamflow patterns have changed around the United States over the past century, raising questions about the possible role of climate variability as a driver of water yield. This thesis examines streamflow trends in two separate analyses: a study of streamflow trends and the physical characteristics of large basins in the Willamette River Basin, and a study of streamflow trends in small headwater basins around the United States. In the Willamette River basin, as in much of the western US where summer precipitation is low, declining streamflow will exacerbate the task of water management to meet varying demands for water. Although regional climate warming over the past half-century in the Pacific Northwest is a plausible cause of declining streamflow, climate is only one of several factors that determine the hydrologic regime of the Willamette River basin. This study quantified trends in streamflow from 1950 to 2010 in ten sub-basins of the Willamette, including seven 60-600 km2 predominantly forested sub-basins above dams in the Willamette National Forest, and three gages downstream of dams in urban areas of the Willamette valley (Albany, Salem, and Portland). Trends at the annual, seasonal, and daily time scales were estimated using linear regression with appropriate transformation of variables and the Mann-Kendall non-parametric test. Trends in streamflow and runoff ratios in the Willamette Basin were compared to geology, topography, and changes in forest cover above dams. Data on forest cover by age class were obtained from Willamette National Forest. Up to 29% of area in sub-basins above dams was clearcut since the 1930s. From 1 to 51% of basin area above dams is on young (
Download or read book Forests Water Guidelines written by Great Britain. Forestry Commission and published by . This book was released on 1993 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work advises owners and managers how woodlands and forests influence the freshwater ecosystem, and gives guidance on how operations should be carried out in order to protect and enhance the water environment. The guidelines apply equally to forest enterprises and the private sector.
Download or read book Riparian Areas written by National Research Council and published by National Academies Press. This book was released on 2002-10-10 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Download or read book Forest Hydrology written by Devendra Amatya and published by CABI. This book was released on 2016-09-14 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forests cover approximately 26% of the world's land surface area and represent a distinct biotic community. They interact with water and soil in a variety of ways, providing canopy surfaces which trap precipitation and allow evaporation back into the atmosphere, thus regulating how much water reaches the forest floor as through fall, as well as pull water from the soil for transpiration. The discipline "forest hydrology" has been developed throughout the 20th century. During that time human intervention in natural landscapes has increased, and land use and management practices have intensified. The book will be useful for graduate students, professionals, land managers, practitioners, and researchers with a good understanding of the basic principles of hydrology and hydrologic processes.
Download or read book The Fernow Watershed Acidification Study written by Mary Beth Adams and published by BoD – Books on Demand. This book was released on 2006-04-28 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fernow Watershed Acidification Study is a long-term, paired watershed acidification study. This book describes the responses to chronic N and S amendments by deciduous hardwood forests, one of the few studies to focus on hardwood forest ecosystems. Intensive monitoring of soil solution and stream chemistry, along with measurements of soil chemistry, and vegetation growth and chemistry, provide insights into the acidification process in forested watersheds.
Download or read book Ground water Hydrology of the Upper Deschutes Basin Oregon written by and published by . This book was released on 2001 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Energy and Biogeochemical Budgets written by Mary Jo Baedecker and published by . This book was released on 2000 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
