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281. [Article] Infiltration capacities and surface erodibility associated with forest harvesting activities in the Oregon Cascades
An infiltration capacity and surface erodibility study was conducted six years after forest harvesting in the Oregon Cascades. A portable rainfall simulator was utilized to obtain field measurements on ...Citation Citation
- Title:
- Infiltration capacities and surface erodibility associated with forest harvesting activities in the Oregon Cascades
- Author:
- Johnson, Michael G.
An infiltration capacity and surface erodibility study was conducted six years after forest harvesting in the Oregon Cascades. A portable rainfall simulator was utilized to obtain field measurements on the Coyote Creek and Hi-15 Watersheds during summer and fall, 1977. Seasonal variations were found to occur in infiltration capacities and surface erodibility. Infiltration capacities increased by 1.4 times from summer to fall, while surface erodibility characteristics, suspended sediment concentration and sediment yield, decreased from summer to fall. Surface limiting conditions during the summer and soil profile controlled conditions in the fall were hypothesized to explain this seasonal variation. Nearly all timber harvesting treatments for each study area had statistically equal summer infiltration capacities in comparison with adjacent unlogged areas. In addition, summer surface erodibility characteristics on treated areas were typically less than those found on undisturbed areas. Only certain skid trails, cable log paths and severely disturbed sites such as tractor windrowed and burned areas had substantially reduced infiltration capacities and increased surface erodibility. However, all areas, including the most severely disturbed, had fall infiltration capacities that exceeded usual and maximum fall precipitation intensities. Many skid trails and other highly disturbed and compacted areas at Coyote Creek appeared to have greatly recovered since logging six years ago. Freezing/thawing, biological activity, and shrinking and swelling of soils may account for this recovery in infiltration capacities, surface erodibility and soil properties. Skid trails and severely disturbed areas may partially account for peak flow increases and minor sedimentation the first few years after logging. However, data from this study collected six years following timber harvesting do not support the premise that continued increases in peak flows are caused by changes in infiltration capacities, except perhaps for a tractor windrowed and burned area. Predictive models for infiltration capacity (normally distributed) and surface erodibility characteristics (requiring normalizing transformations) were not found using regression techniques because of large amounts of variance. Variation in estimates of infiltration capacities and surface erodibility for individual plots and between study areas was identified.
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282. [Article] Cape Scene & the path to a conscientious tourism product
Many countries around the world are looking to tourism as a sustainable solution for economic development and many individuals seek business opportunities in the tourism industry. Researchers in the field ...Citation Citation
- Title:
- Cape Scene & the path to a conscientious tourism product
- Author:
- Sykes, Kimberly M.
Many countries around the world are looking to tourism as a sustainable solution for economic development and many individuals seek business opportunities in the tourism industry. Researchers in the field of anthropology and other disciplines alike have recorded findings of the environmental, economic and cultural impacts of tourism development that are useful both to tourism promoters and new business developers. While there are a number of negative examples of environmental degradation, economic dependency and cultural exploitation resulting from tourism, there are so few positive models that scholars are now questioning whether tourism is a truly sustainable strategy for prosperity. In particular, ecotourism and nature-based tourism have burgeoned from a perceived prospect of increased environmental, economic and cultural sensitivity, but a watershed of criticism has followed in the wake of their emergence. Critics claim that what is touted as eco-sensitive is just another marketing strategy to attract more people to areas of the world vulnerable to hosting a growing number of guests. Overuse of the term ecotourism has parties involved at all levels of tourism development from host communities, to tourism planners, to scholars questioning what is sustainable ecotourism. Due to this ambiguity, a new term, conscientious tourism, is suggested as a euphemism in order to clarify what type of tourism most contributes to sustainability. Cape Scene magazine has evolved as a conscientious tourism product informing guests visiting South Africa how best to interact with the wildlife, environment and local people. The magazine has coupled interesting feature stories and helpful information on navigating around the Western Cape and Cape Town and includes a useful fold out map. The magazine reaches a broad audience of mass tourists, small group tourists and individuals and groups interested in nature, wildlife and cultural experiences. The magazine also informs readers of local conservation and community development projects ongoing in South Africa. This emphasis has created a conscientious tourism product that informs tourists of the country they are visiting while promoting conservation and social development causes that can be benefited by overseas awareness. As mass tourism will never completely give way to smaller conservation minded guided tour groups, the magazine helps to propel conscientious tourism by reaching out to even the most undiscerning holiday maker. The magazine was created by drawing on graduate internship experiences from coastal Oregon, the Micronesian island of Kosrae and Costa Rica. These internships give insights on how conservation, economic and cultural concerns have been and can be better addressed by local people and local businesses in an effort to work towards conscientious tourism and sustainable development. This thesis explores several ecotourism related projects encountered on the way to developing a conscientious tourism product, Cape Scene magazine. The existing body of tourism literature is considered in relation to the projects encountered and current work with Cape Scene magazine.
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Storage of water for water quality control is one of the alternative means of achieving water quality objectives. Authorities in the field of water quality management disagree regarding the use of precious ...
Citation Citation
- Title:
- An investigation of alternative means of achieving water quality objectives
- Author:
- Kerri, Kenneth Donald
Storage of water for water quality control is one of the alternative means of achieving water quality objectives. Authorities in the field of water quality management disagree regarding the use of precious water for the dilution of wastes. The costs of achieving water quality objectives by treatment of wastes at their source or by a combination of waste treatment and storage of water for waste dilution are investigated. Water quality objectives studied are dissolved oxygen and coliform bacteria. Different levels of water quality and fluctuating flows of the Willamette River in Oregon during the 1963 summer low flow period are examined. To ascertain the minimum cost of achieving a water quality objective in a complex river basin, an analytical model is developed to examine the costs of waste treatment and the response of the receiving waters to the wastes discharged. A minimum cost solution to achieve a water quality objective is obtained employing nonlinear programming techniques which analyze the assimilative capacity of the receiving waters and the economics of waste treatment. The response of the receiving waters is indicated by systems analysis methods. Final results include the degree of treatment required of each discharger. Regulated flows under full development of the Willamette River Basin System of the Corps of Engineers do not follow typical statistical distributions. Distribution free or nonparametric methods are employed to determine the quantities of water required for low flow augmentation. Costs of storage are calculated on the basis of analysis of the costs of the three remaining authorized reservoirs in the Willamette Valley that are not under construction at this time. Conditions under which the storage of water for dilution is favorable, in lieu of waste treatment, are summarized. Generally water can be stored for water quality control in the Willamette River Basin to achieve high levels of quality by augmenting low flow levels of a short duration. Methods for selecting optimal water quality objectives and design periods for the storage of water for water quality control are presented in graphical form and expressed mathematically, These methods are based on the assumption that it is possible to measure the reduction in costs to society resulting from water quality management programs. This dissertation does not attempt to measure the reduction in damage costs because the data are not readily available at this time. An analytical model is used to illustrate the impact of different water quality management alternatives on the economy of a river basin in terms of waste treatment costs. This model produces some interesting results under different management policies to achieve the same water quality objective. The response of the receiving waters and the economic impact of stream standards and effluent standards are revealed by the model. Examination of the costs of different discharge policies indicates to the administrator the consequences of alternative policies. Computed results can be compared with the costs of administering and enforcing different water quality management policies. Recommendations for implementation of the model are offered. These recommendations contain provisions for future growth and expansion, including the entrance of new firms into the basin, and a program based on industrial cooperation to achieve water quality objectives at a minimum cost to the industries situated in a particular basin. The methods developed and the results obtained should prove helpful to persons planning or administering water quality management programs. They furnish a strong justification for an adequate stream sampling program and indicate areas requiring additional research.
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It is no longer possible in any area of the United States to formulate water resources plans for single purpose projects as has been done in past years. No longer can one of our greatest natural resources, water, ...
Citation Citation
- Title:
- An evaluation of planning for water quality control in the Willamette River Basin
- Author:
- Kirkpatrick, Kenton
It is no longer possible in any area of the United States to formulate water resources plans for single purpose projects as has been done in past years. No longer can one of our greatest natural resources, water, be used solely for navigation, power generation, irrigation, or controlled for reducing floods. This resource must now serve a multitude of purposes in our society. Determining the present status of our water resources, what the future requirements will be, how to plan for these future needs, and implementation of these plans represents a major undertaking of local, State, and Federal authorities having interests in this field. In the Pacific Northwest, the Willamette Basin Task Force, acting under the auspices of the Columbia Basin Inter-Agency Committee, has been created to provide the coordinating mechanism for the prosecution of a comprehensive study for the management and development of the water and related land resources of the Willamette River Basin. This study is presently underway. In this thesis, information was collected from individuals associated with the Task Force, from minutes of meetings, and from other publications not readily available, to provide a single document giving the organization and objectives of the Task Force. The National comprehensive planning mechanism was studied to provide background information relating to the evolution of the Task Force and its operation. Water quality control is one of the areas of investigation of the Willamette Basin Task Force. It is directly related to and influenced by the several other multiple-purpose uses of the basin's water resources. It is this aspect of the comprehensive planning mechanism that has been considered in this thesis to evaluate what progress is being made in planning for present and future water quality control requirements for the basin. The results of this study indicate that additional study will be necessary, after further progress has been made by the Task Force, to fully evaluate the planning procedures and accomplishments of the Task Force. Conclusions indicate problems that have been encountered using this particular approach to water resources comprehensive planning. Various problems in the water pollution phase of the study are discussed. Several research study areas are suggested as a means of solving water quality problems which exist now in the Willamette River Basin and those water quality problems which are anticipated in the future as greater demands are placed on this resource.
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The analysis of material and energy exchange between the marine and terrestrial components of island ecosystems enables research into the impact of human population and land use on the health of coral ...
Citation Citation
- Title:
- Derivation of near-shore bathymetry from multispectral satellite imagery used in a coastal terrain model for the topographic analysis of human influence on coral reefs
- Author:
- Hogrefe, Kyle Richard
The analysis of material and energy exchange between the marine and terrestrial components of island ecosystems enables research into the impact of human population and land use on the health of coral reef habitat. Satellite and acoustic remote sensing technologies enable the collection of data to produce high resolution bathymetry for integration with terrestrial digital elevation models (DEMs) into coastal terrain models. An integrated terrain surface that incorporates the land-sea interface, grounded by a geographic information system, is a powerful analytical tool for geomorphic studies of watersheds and coastal processes. The island of Tutuila, American Samoa is an ideal case study due to its high relief terrain, data availability and local interest in impacts to coral reef resources. The Tutuila model integrates a USGS DEM, multibeam bathymetry from 15 to 500 m and near shore bathymetric data from 0 to 15 m derived from IKONOS satellite imagery. The high spatial resolution of IKONOS imagery is suitable for detection of features with subtle relief and intricate structure. Shallow water bathymetry is derived by quantifying the relative attenuation of blue and green spectral band radiance as a function of depth. The procedure used to derive bathymetry, Lyzenga (1985), is identified as the most effective of several proposed in the recent literature. The product is error-checked using control points extracted from multibeam sonar data and collected during recent field surveys, as well as terrain profiles. The coastal terrain model provides morphological detail of fine resolution and high accuracy for terrain and land use analysis to enhance the study of ecosystem interconnectivity and the effects of anthropogenic inputs to coral reef habitats. Subsequent topographic analyses of the Tutuila model use drainage patterns to identify contiguous marine/terrestrial basins within which the marine environment is most directly impacted by land use through freshwater inputs from affiliated catchments. Human population density serves as an indicator of intensified land use and urbanization, which has been shown to increase pathogen and sediment loads in runoff, while percent coral cover, coral colony density and coral genera diversity are used as indicators of reef health. Spatiotemporal correlation analyses of population density against the three reef health indices within each of the marine/terrestrial basins reveal a decline in reef health associated with increased population density. This paper integrates and builds upon established methods of satellite imagery analysis and terrain modeling to create the Tutuila coastal terrain model and uses it to refine the scale of other studies linking human terrestrial activities to the physical condition of coral reefs.
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286. [Article] Headwater stream characterization : an energy and physical approach to stream temperature using distributed temperature sensing
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing ...Citation Citation
- Title:
- Headwater stream characterization : an energy and physical approach to stream temperature using distributed temperature sensing
- Author:
- Roth, Travis R.
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing downstream reaches with important constituents such as sediment and woody debris. Small headwater streams are particularly susceptible to anthropogenic and natural disturbances that affect their runoff production, chemical make-up, and thermal regime. Based on their position in the drainage basin and contribution to stream flow, heat energy transfer within a small mountain stream helps establish the thermal regime of the downstream lower order streams. However, headwater catchment thermal function remains poorly understood. Stream temperature is a manifestation of the environment through which it flows and the mechanisms by which it reaches the stream. Subsurface process controls, such as local soil properties, bedrock topography, and lateral flow discharge play an important role in headwater stream generation. Study outcomes are a result of vigorous field experimental work at the Watershed 07 (WS07) stream at the H.J. Andrews Experimental Forest (HJA) located in the Western Cascades, Oregon. Bedrock Topography was delineated through the use of a dynamic cone penetrometer, local lateral inflow sources were identified and quantified through the application of a salt tracer, and the energy budget was characterized through the use of Distributed Temperature Sensing (DTS) technology. High gradient, low volume streams such as WS07 provide unique challenges for DTS deployment which require extensive post-calibration data analysis. An automated cable submersion identification process was developed and was carried out on the collected temperature data with 32.8 % (379 of 1155) of measured temperature points identified as "in-water". Uncertainty propagation analysis associated with DTS measurement was calculated to be 0.21 °C. Salt tracer application found that 2 localized lateral inflow discharge to the stream accounted for 15% and 16% of total discharge in the upper section of the stream. Downstream lateral inflows exhibited incremental additions to stream discharge on the order of 5%. Stream discharge increased by 1.13 l/s from the upper section to the start of the lower section, an increase of 45%. Substantial lateral inflows provided reduction of stream temperatures in the lower section. Using DTS technology we measured stream temperature as a validation method for a physically based energy balance stream temperature model to characterize energy controls on stream temperature. Analysis of model performance was determined through root mean square error with reported values of 0.38 °C and 0.32 °C for the upper and lower section, respectively. Total energy inputs into the upper and lower sections of the stream were 302 W/m² and 210 W/m². Primary energy balance components were found to be solar radiation, atmospheric longwave radiation, and bed conduction. Solar radiation accounted for 63% of total energy flux into the stream in the upper section and 28% in the lower section. This is primarily a result of the distinct vegetation differences between the two reaches. Atmospheric longwave radiation contributed 27% and 26% of total energy flux in the upper and lower sections, respectively. While bed conduction made up 11% and 24% of the total flux in the upper and lower sections.
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287. [Article] Subsurface geology of the southeastern Cuyama Valley, southern Coast Ranges, California
The southeastern Cuyama Valley is located in the southern Coast Ranges, west of Bakersfield, California. Subsurface geologic mapping using data from 62 prospect wells was integrated with surface mapping to ...Citation Citation
- Title:
- Subsurface geology of the southeastern Cuyama Valley, southern Coast Ranges, California
- Author:
- Spitz, Herbert M.
The southeastern Cuyama Valley is located in the southern Coast Ranges, west of Bakersfield, California. Subsurface geologic mapping using data from 62 prospect wells was integrated with surface mapping to determine the depositional and deformational history of this part of the Neogene Cuyama basin. The northwest-trending Russell fault system was active from late Oligocene to Pliocene time. Deformation along this major wrench system began during deposition of the late Oligocene to early Miocene Soda Lake Shale Member of the Vaqueros Formation and ended prior to deposition of the Plio-Pleistocene Morales Formation. The southern extension of this fault system remains uncertain, but it probably joins the Ozena fault southeast of the South Cuyama oil field. Removal of 16 to 18 miles of right-lateral offset on the Russell fault system restores the Ozena fault to a position directly east of the La Panza fault. These two faults were probably a single fault, designated the La Panza-Ozena fault, which was active, north-side down, during the Oligocene. Nonmarine conglomerates of the Simmler and lower Caliente formations were deposited north of this fault during the Oligocene, prior to the initiation of notion on the Russell fault system. Three major faults of the Cox fault zone on the west and the Lundstrom-Becker and Becker-Heller faults on the east define the margins of the Cox trough, a complex north- to northeast-trending graben north of the Russell fault which was active from Saucesian through Relizian time (early Miocene). The Saltos Shale Member of the Monterey Formation increases in thickness by 3 to 7 times across the margins of the trough. Growth faulting associated with the Cox trough ended prior to deposition of the middle Johnston sand on all faults except the Cox 46-5 fault, which was active through deposition of the Branch Canyon Sandstone. Post-Pliocene tectonism in the Cuyama basin was limited to folding and reverse-faulting in response to regional north-south compression. The Central Cuyama dome and associated north-dipping reverse faults formed during an early episode of this deformation. Subsequent deformation occurred on the Morales fault, the South Cuyama fault, and the rejuvenated Ozena fault. This Quaternary thrusting obscured the structures of the older wrench-tectonic regime and resulted in the formation of the Caliente and Sierra Madre Ranges and the present-day Cuyama Valley.
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288. [Article] Abundance Monitoring of Juvenile Salmonids In Coastal Oregon and Lower Columbia Streams, 2008 Report Number: OPSW-ODFW-2009-1
Abstract -- As part of the Oregon Plan for Salmon and Watersheds, the Oregon Department of Fish and Wildlife (ODFW) initiated this project in 1998 to monitor the status and trend in abundance and distribution ...Citation Citation
- Title:
- Abundance Monitoring of Juvenile Salmonids In Coastal Oregon and Lower Columbia Streams, 2008 Report Number: OPSW-ODFW-2009-1
Abstract -- As part of the Oregon Plan for Salmon and Watersheds, the Oregon Department of Fish and Wildlife (ODFW) initiated this project in 1998 to monitor the status and trend in abundance and distribution of juvenile coho salmon (Oncorhynchus kisutch) in coastal Oregon streams. This report summarizes the data collected during the summer of 2008 and, for coho salmon, compares it to data previously collected. The project originally surveyed only 1st-3rd order (tributary) streams but was expanded in 2002 to include juvenile steelhead (Oncorhynchus mykiss) and 4th-6th order (mainstem) rearing areas and in 2006 to the Oregon portion of the Lower Columbia River coho evolutionarily significant unit (ESU) (Figure 1). The sampling frame is intended to encompass all non-tidal coho and steelhead rearing habitat. The original 100k stream layer frame was replaced by a 24k frame in 2007. A Generalized Random Tessellation Stratified design (GRTS) (Stevens 2002) was used to create a spatially balanced, random point distribution. Sites were stratified by Monitoring Area (MA) and stream order (Table 1). A detailed description of the sampling frames and survey designs are found in Jepsen and Rodgers (2004) and Jepsen and Leader (2007). Field crews snorkeled all pools meeting the size criteria (6 m2 in surface area and 40 cm in maximum depth) in one kilometer of stream encompassing the GRTS point. Snorkeling was conducted during the minimum flow period from July to September using a single pass of one to four snorkelers, depending on stream width. In each pool counts were made of juvenile coho, Chinook, steelhead 90 mm, and cutthroat 90 mm. Presence was noted for dace, shiners, and trout < 90 mm. Sites with poor water clarity or quality were electrofished using a single pass without block nets to determine presence for coho, steelhead and cutthroat in each pool. To assess repeatability and quality control supervisory staff resurveyed 10% of tributary sites in each MA. Data were summarized by MA and stream order for analyses. Average pool density and percent pool occupancy for each site was averaged by MA. The percent of sites with at least one fish and with >0.7 coho/m2 are reported for each MA. 0.7 coho/m2 is regarded as full seeding after Nickelson et al. (1992) who reported full seeding based on electrofishing as 1.0 coho/m2 and Rodgers et al. (1992) who found that snorkelers observed 70% of the coho counted by electrofishing. CDFs, variances, and confidence intervals were created using tools developed by the EMAP Design and Analysis Team (EPA 2009).
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289. [Article] Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced ...Citation Citation
- Title:
- Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced salmon have resulted in substantial changes in many hatchery programs. In 2007 the Oregon Department of Fish and Wildlife terminated a 30-year artificial propagation program for coho salmon in the Salmon River basin after a status assessment concluded that wild population viability was threatened by hatchery effects on salmon productivity (Chilcote et al. 2005). Hatchery-reared coho comprised 50-100% of the naturally spawning population in recent years. Low productivity was reflected in a low spawner to recruit ratio, and life-stage specific survival was lower than that of nearby populations. The temporal distribution of adult spawning in the basin was truncated and peaked 1.5 months earlier relative to the pre-hatchery period and adjacent coastal populations. The cessation of hatchery releases into Salmon River not only removed the primary factor believed to limit productivity of the local population, it also constituted a rare management experiment to test whether a naturally-spawning population can recover from a prolonged period of low abundance after interactions with hatchery-produced coho salmon are eliminated. This report summarizes the results of coho population studies at Salmon River for the first three years after the hatchery program was discontinued. The study in Salmon River is timely because ecological interactions between hatchery and wild fish have been implicated in the reduced survival and decreased productivity of wild coho and other salmonid populations (Nickelson 2003, Buhle et al. 2009, Chilcote et al. 2011). Recent studies involving a diversity of salmonid species and watersheds have shown a negative relationship between hatchery spawner abundance and wild population productivity regardless of the duration of hatchery influence (Chilcote et al. 2011). Yet neither the mechanisms of these productivity declines nor their potential reversibility have been investigated. Recent management changes at Salmon River provide an opportunity to experimentally evaluate coho salmon survival and productivity following the elimination of a decades-long hatchery program. The results will provide new insights into the reversibility of hatchery effects and the rate, mechanisms, and trajectory of response by a naturally spawning coho salmon population. Hatchery programs have been shown to change the timing and distribution of naturally spawning adults, but ecological and genetic influences on the spatial structure and life history diversity of juvenile populations are poorly understood. Conventional understanding of the life history of juvenile coho has presumed a relatively fixed pattern of rearing and migration. However, recent studies have found much greater variation in juvenile life history and habitat-use patterns than previously expected (Miller and Sadro 2003, Koski 2009), including evidence that estuaries may play a prominent role in the life histories of some coho salmon populations. A recent study in the Salmon River basin found considerable diversity in the life histories of juvenile Chinook salmon, including extended rearing by fry and other subyearling migrants within the complex network of natural and restored estuarine wetlands (Bottom et al. 2005). Unfortunately, interpretation of juvenile life history variations at Salmon River was confounded by the Chinook hatchery program, which has concentrated spawning activity in the lower river near the hatchery and may directly influence juvenile migration and rearing patterns. Discontinuation of the coho hatchery program at Salmon River provides an opportunity to quantify changes in juvenile life history following the elimination of all hatchery-fish interactions with the naturally spawning population. Such responses may provide important insights into the mechanisms of hatchery influence on wild salmon productivity and population resilience. Our research integrates adult and juvenile life stages, examines linkages to physical habitat conditions in fresh water and the estuary, and describes variability between juvenile performance and adult returns. It also monitors the coho salmon population across habitat types and life history stages to identify population responses at a landscape scale. We will determine productivity and survival at each salmon life stage and monitor the response of the adult population following the cessation of the coho salmon hatchery program. From these indicators, we will determine the potential resiliency of the coho salmon population, and evaluate the biological benefits or tradeoffs of returning the ecosystem to natural salmon production. Our study design encompasses four population phases: (1) pre-hatchery conditions (Mullen 1979), (2) dominance by hatchery-reared spawners (2008), (3) first generation naturally produced juveniles (2009-2011), and (4) second generation naturally produced juveniles (starting in 2012). This research will validate assumptions about factors limiting coho recovery and determine whether recovery actions have been effective. Here, we report on findings from 2008-2010 to address four principal objectives: 1. Quantify life stage specific survival and recruits per spawner ratio of the coho salmon population before and after hatchery coho salmon are removed from Salmon River. 2. Assess whether the Salmon River coho population is limited by capacity and complexity of stream habitat. 3. Describe the diversity of juvenile and adult life histories of coho salmon in the Salmon River basin, and estimate the relative contributions of various juvenile life histories to adult returns. 4. Determine seasonal use of the Salmon River estuary and its tidally-inundated wetlands by juvenile coho salmon. The field sampling that supported the study on coho salmon also captured Chinook salmon and steelhead and cutthroat trout during routine sampling in the watershed and estuary. This report emphasizes coho salmon results, but also summarizes catch, distribution, and migration data for other salmonids to compare densities and abundances in freshwater and the estuary. Additional results for Chinook, steelhead, and cutthroat are presented in Appendix A. See Stein et al. (2011) for more detailed information on life history diversity, migration patterns, habitat use, and abundance of cutthroat trout.
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290. [Article] Historical change in channel form and riparian vegetation of the McKenzie River, Oregon
This study examined channel structure and position and riparian vegetation and land use on the upper 70 km of the McKenzie River, Oregon in the 1940s, compared the 1940s conditions to present conditions, ...Citation Citation
- Title:
- Historical change in channel form and riparian vegetation of the McKenzie River, Oregon
- Author:
- Minear, Paula J.
This study examined channel structure and position and riparian vegetation and land use on the upper 70 km of the McKenzie River, Oregon in the 1940s, compared the 1940s conditions to present conditions, and explored the processes driving change in this system and the implications for aquatic habitat. The hydrologic record was analyzed, and field surveys were conducted and compared to historical habitat surveys. Riparian characteristics and channel features were digitized from aerial photographs from 1945/49 and 1986 and imported into Arcinfo GIS for analysis. Types of data digitized from the aerial photos included locations and length or area of wetted channel, active channel, tributaries, side channels, large woody debris, exposed gravel bars, roads, and dominant vegetation or land use within 200 m of the active channel. Construction of dams on the mainstem Mckenzie River and two major tributaries, Blue River and South Fork, in the 1960s has altered the flow regime and sediment supply to the mainstem Mckenzie, decreasing the frequency, mean and variation of peak flows, reducing the competence of flows to move existing bedload, and cutting off sediment from over half of the drainage area. Mean peak flows decreased 44% and competence of peak flows with a 2-yr recurrence interval declined approximately 29% after dams were constructed upriver. Adjustments to reduced sediment supply and flow alteration by dams in this system included 57% decrease in exposed gravel bars, 40% decrease in side channel length, and possible substrate coarsening (as compared to historical estimates). Channel straightening occurred in each of three instances of channel change during the study period, and sinuosity decreased one half of the amount needed to produce a straight channel in the most susceptible, unconstrained reach. Human actions prior to high flow events played a role in the direction of channel change in each case. Over the entire study area, 7% of the main channel changed position by 30 m or more and little or no change in channel position was noted in reaches constrained by valley floors. Additional channel constraint has been produced by road construction near the channel and riprapping for roads, bridges, and residences. Less large woody debris was observed in the 1986 channel than in the 1949 channel, indicating a reduction in pool-forming agents and channel roughness elements. Frequency of large pools ([greater than or equal to] 2 m depth and >40 m² area) decreased 19% over the study area. The greatest loss in pools (73%) was noted in the unconstrained reach that exhibited two areas of channel change and an increase in exposed gravel bars. Increased human use of the riparian area for roads and residential purposes has led to an increased fragmentation of the riparian landscape. Density of residential or developed patches within the riparian area has increased 215% as more and smaller areas are converted from natural vegetation to human use. Riparian area devoted to roads and residential uses has nearly doubled since the 1940s. Mean vegetation or land-use patch size has decreased from 2.2 ha to 1.6 ha as larger patches have been sub-divided, and patch and edge densities have increased. Agriculture and clearcuts for timber removal have decreased within the riparian area while continuing upslope. Riparian area in mature conifers has decreased 44% from levels in the 1940s while hardwoods have increased 45% in the riparian area. Future wood loading to the channel is reduced by a decline in mature riparian vegetation, especially mature conifers. Channel and riparian changes noted in this study have implications for fish populations. Channel straightening, reduction in side channels, and loss of pool-forming agents reduce habitat heterogeneity and off-channel refugia. Ecosystem management of watersheds requires evaluation of conditions across scales of time and space. The use of GIS in this study made it possible to detect changes in channel form and riparian conditions during four decades, along a 70-m channel and 90-m riparian area and to analyze the large data sets relevant to understanding functions and change in channels and riparian areas.