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• 11. [Image] Natural flow estimates for streams in the Klamath Basin

  	"Open file report SW 04-001"
  	Citation × Citation Citation Abstract Copy Title: Natural flow estimates for streams in the Klamath Basin Author: Cooper, Richard M. Year: 2004, 2005 "Open file report SW 04-001" Title: Natural flow estimates for streams in the Klamath Basin Author: Cooper, Richard M. Year: 2004, 2005 "Open file report SW 04-001" Close

• 12. [Image] Determining surface water availability in Oregon : open file report SW 02-002

  	Determining Surface Water Availability in Oregon By Richard M. Cooper, PE Abstract The Oregon Water Resources Department (Department or OWRD) limits appropriation from Oregon streams to assure new applicants ...
  	Citation × Citation Citation Abstract Copy Title: Determining surface water availability in Oregon : open file report SW 02-002 Author: Oregon. Water Resources Dept. Year: 2002, 2005 Determining Surface Water Availability in Oregon By Richard M. Cooper, PE Abstract The Oregon Water Resources Department (Department or OWRD) limits appropriation from Oregon streams to assure new applicants use of surface water a reasonable amount of time and to minimize regulatory conflict. The standards for new appropriation of water are: (1) consumptive use from allocations for out-of-stream uses can total no more than the 80-percent ex-ceedance natural stream flow, and (2) allocations for in-stream flows can be no more than the 50-percent exceedance natural stream flow. OWRD has created and maintains a database of the amount of surface water available for appropriation for most waters in the state. This database is used to evaluate applications for new uses of water. Water availability (WA) is obtained from natural stream flow (QNSF) by subtracting existing storage (ST), out-of-stream consumptive uses (CU) and in-stream demands (IS). WA = QN -ST-CU-IS Ideally, water availability would be calculated for every watershed above a point of diversion or in-stream demand. Practically, the number of watersheds must be limited. The watersheds selected for analysis are called Water Availability Basins (WABs). Stream flow can be highly variable, and it is useful to characterize it in some way, usually by a statistic, e.g., a monthly or annual mean. For water availability, it is important to know how often water is available. The appropriate statistic in this case is exceedance stream flow. This statistic tells us how often to expect a given rate of stream flow to occur. Exceedance stream flows are determined directly from gage records, or for ungaged streams, by estimation through modeling. When determined from gage records, the exceedance flows must be corrected to a common base period, and then, to natural stream flow. When determined through modeling, the exceedance flows are estimated from statistical models that relate watershed characteristics to natural stream flow. The models are derived by multiple linear regression. Storage is water retained in a reservoir. It is debited from water availability when the water is stored. It diminishes availability both upstream and downstream of the point of diversion. Consumptive use is divided into three major categories: irrigation, municipal, and all others e.g., domestic, livestock. These uses are less than 100 percent consumptive. It is assumed the non-consumed part of a diversion is returned to the stream from which it was diverted. Consumptive use from irrigation is from estimates made by the US Geological Survey (Portland). Consumption from other uses is based on the associated water rights. In these cases, consumptive use is obtained by multiplying the maximum diversion rate allowed for the water right by a consumptive use coefficient. Consumptive use diminishes availability both upstream and downstream of the point of diversion. There are two types of in-stream demands: in-stream water rights and scenic waterway flows. In-stream demands diminish availability upstream only. Because they are non-consumptive, they do not diminish stream flow downstream as do consumptive uses. Water availability has been calculated for over 2500 WABs. In general, the calculation of water availability at one WAB cannot be considered in isolation from other WABs in the same stream system. For water to be available at any given upstream point, it must be available at all points of calculation downstream. Title: Determining surface water availability in Oregon : open file report SW 02-002 Author: Oregon. Water Resources Dept. Year: 2002, 2005 Determining Surface Water Availability in Oregon By Richard M. Cooper, PE Abstract The Oregon Water Resources Department (Department or OWRD) limits appropriation from Oregon streams to assure new applicants use of surface water a reasonable amount of time and to minimize regulatory conflict. The standards for new appropriation of water are: (1) consumptive use from allocations for out-of-stream uses can total no more than the 80-percent ex-ceedance natural stream flow, and (2) allocations for in-stream flows can be no more than the 50-percent exceedance natural stream flow. OWRD has created and maintains a database of the amount of surface water available for appropriation for most waters in the state. This database is used to evaluate applications for new uses of water. Water availability (WA) is obtained from natural stream flow (QNSF) by subtracting existing storage (ST), out-of-stream consumptive uses (CU) and in-stream demands (IS). WA = QN -ST-CU-IS Ideally, water availability would be calculated for every watershed above a point of diversion or in-stream demand. Practically, the number of watersheds must be limited. The watersheds selected for analysis are called Water Availability Basins (WABs). Stream flow can be highly variable, and it is useful to characterize it in some way, usually by a statistic, e.g., a monthly or annual mean. For water availability, it is important to know how often water is available. The appropriate statistic in this case is exceedance stream flow. This statistic tells us how often to expect a given rate of stream flow to occur. Exceedance stream flows are determined directly from gage records, or for ungaged streams, by estimation through modeling. When determined from gage records, the exceedance flows must be corrected to a common base period, and then, to natural stream flow. When determined through modeling, the exceedance flows are estimated from statistical models that relate watershed characteristics to natural stream flow. The models are derived by multiple linear regression. Storage is water retained in a reservoir. It is debited from water availability when the water is stored. It diminishes availability both upstream and downstream of the point of diversion. Consumptive use is divided into three major categories: irrigation, municipal, and all others e.g., domestic, livestock. These uses are less than 100 percent consumptive. It is assumed the non-consumed part of a diversion is returned to the stream from which it was diverted. Consumptive use from irrigation is from estimates made by the US Geological Survey (Portland). Consumption from other uses is based on the associated water rights. In these cases, consumptive use is obtained by multiplying the maximum diversion rate allowed for the water right by a consumptive use coefficient. Consumptive use diminishes availability both upstream and downstream of the point of diversion. There are two types of in-stream demands: in-stream water rights and scenic waterway flows. In-stream demands diminish availability upstream only. Because they are non-consumptive, they do not diminish stream flow downstream as do consumptive uses. Water availability has been calculated for over 2500 WABs. In general, the calculation of water availability at one WAB cannot be considered in isolation from other WABs in the same stream system. For water to be available at any given upstream point, it must be available at all points of calculation downstream. Close

• 13. [Image] Oregon Plan for Salmon and Watersheds biennial report, 2001-2003

  	A GUIDE TO PART I - ESTABLISHING COMMON BASINS A GUIDE TO PART II - THE FOUR ELEMENTS OF THE OREGON PLAN THE OREGON PLAN - BASIN BY BASIN KEY TO BASIN LAYOUTS BASIN REPORTS North Coast Umpqua South Coast ...
  	Citation × Citation Citation Abstract Copy Title: Oregon Plan for Salmon and Watersheds biennial report, 2001-2003 Author: Oregon Watershed Enhancement Board Year: 2003, 2005, 2004 A GUIDE TO PART I - ESTABLISHING COMMON BASINS A GUIDE TO PART II - THE FOUR ELEMENTS OF THE OREGON PLAN THE OREGON PLAN - BASIN BY BASIN KEY TO BASIN LAYOUTS BASIN REPORTS North Coast Umpqua South Coast Rogue Klamath Lakes Basin Owyhee-Malheur Powder Grande Ronde Umatilla John Day Deschutes Hood Lower Columbia Willamette FEDERAL CONSERVATION AND RESTORATION DATA THE OREGON PLAN - FOUR ELEMENTS AGENCY ACTIONS VOLUNTARY RESTORATION ACTIONS BY OREGONIANS MONITORING SCIENCE OVERSIGHT HI. THE OREGON PLAN-OBSERVATIONS and RECOMMENDATIONS OF THE OWEB BOARD DATA SOURCES and CREDITS Title: Oregon Plan for Salmon and Watersheds biennial report, 2001-2003 Author: Oregon Watershed Enhancement Board Year: 2003, 2005, 2004 A GUIDE TO PART I - ESTABLISHING COMMON BASINS A GUIDE TO PART II - THE FOUR ELEMENTS OF THE OREGON PLAN THE OREGON PLAN - BASIN BY BASIN KEY TO BASIN LAYOUTS BASIN REPORTS North Coast Umpqua South Coast Rogue Klamath Lakes Basin Owyhee-Malheur Powder Grande Ronde Umatilla John Day Deschutes Hood Lower Columbia Willamette FEDERAL CONSERVATION AND RESTORATION DATA THE OREGON PLAN - FOUR ELEMENTS AGENCY ACTIONS VOLUNTARY RESTORATION ACTIONS BY OREGONIANS MONITORING SCIENCE OVERSIGHT HI. THE OREGON PLAN-OBSERVATIONS and RECOMMENDATIONS OF THE OWEB BOARD DATA SOURCES and CREDITS Close

• 14. [Image] Water quality monitoring : technical guide book

  	"July 1999."
  	Citation × Citation Citation Abstract Copy Title: Water quality monitoring : technical guide book Author: Oregon. Governor's Watershed Enhancement Board Year: 1999, 2005, 2004 "July 1999." Title: Water quality monitoring : technical guide book Author: Oregon. Governor's Watershed Enhancement Board Year: 1999, 2005, 2004 "July 1999." Close

• 15. [Image] Preliminary report on the ground-water resources of the Klamath River Basin, Oregon

  	The Klamath River basin, including the adjacent Lost River basin, includes about ?,5>OO square miles of plateaus, mountain-slopes and valley plains in south-central Oregon* The valley plains range in altitude ...
  	Citation × Citation Citation Abstract Copy Title: Preliminary report on the ground-water resources of the Klamath River Basin, Oregon Author: Newcomb, Reuben Clair Year: 1958, 2005 The Klamath River basin, including the adjacent Lost River basin, includes about ?,5>OO square miles of plateaus, mountain-slopes and valley plains in south-central Oregon* The valley plains range in altitude from about U,100 feet in the south to more than li,500 feet at the northern end; the mountain and plateau lands rise to an average altitude of 6,000 feet at the drainage divide, some peaks rising above 9*000 feet. The western quarter of the ba3in is on the eastern slope of the Cascade Range and the remainder consists of plateaus, mountains, and valleys of the basin-and-range type* The rocks of the Klamath River basin range in age from Recent to Mesozoic* At the southwest side of the basin in Oregon, pre~Tertiary metamorphic, igneous, and sedimentary rocks, which form extensive areas farther west, are overlain by sedimentary rocks of Eocene age and volcanic rocks of Eocene and Oligocene age* These early Tertiary rocks dip east toward the central part of the Klamath River basin. The complex "volcanic rocks of high Cascades" include three units: The lowest unit consists of a sequence of basaltic lava flows about 800 feet thick5 the medial unit is composed of volcanic-sedimentary and sedimentary rocks?the Tonna formation-200 to 2,000 feet thick; the uppermost unit is a sequence of basaltic lava flows commonly about 200 feet thick. These rocks dip east from the Cascade Unpublished records subject to revision 2 Range and are the main bedrock formations beneath most of the basin. Extensive pumice deposits, which emanated ^?^ ancestral Mount Mazaraa, cover large areas in the northwestern part of the basin* The basin has an overall synclinal structure open to the south at the California boundary where it continues as the Klamath Lake basin in California* The older rocks dip into the basin in monoclinal fashion from the adjoining drainage basins* The rocks are broken along rudely rectangular nets of closely spaced normal faults* the most prominent set of which trends northwest* The network of fault displacements includes two main grabens, the Klamath and the Langell, which were downthrown approximately ?00 and 1,000 fast, respectively* The average annual precipitation varies with the altitude, the higher parts of the Cascade Range getting more than 60 inches, and the semierid valley plains receive as little as 13 inches in some places* Most precipitation occurs in the winter. \ The principal tributaries, Williamson and Sprague Rivers, rise near the higher parts of the eastern rim of the basin, flow through narrow valley plains to the western part, and discharge into Upper Klamath Lake* Wood River and associated creeks also empty into Upper Klamath Lake after draining southward along the eastern foot of the Cascade Range* The Klamath River receives the outflow from Upper Klamath Lake, via Lifak River and Lake Ewauna, and flows southwestward through Keno Gap and hence through a youthful canyon, to its lower valley in California* The ground water occurs largely in an unconfined, or water-table, condition, though areas of local confinement are present* The regional Unpublished records subject to revis&oa is graded to water table / a base level about equal to that of the major drainage* where water is confined, on the valley plains. The slope of the water tafele, ~ of/the piezomstric surface is downstream at about the same grade as that "of the surface drainage in each of the larger valleys, attd groufid*water divides occur between the upper parts of adjacent major valleys* The principal water-bearipg units are.the'lower lava rocks and upper lava rocks of the "volcanic rocks of high Cascades,* the pumice of Quaternaryage, and the allusriTuju In places layers of coarse flagmental material in the Tonna formation (Newcorub, 1958) also transmit water* The water-bearing units, especially the breccia layers of the lava rocks and the pumice, yield large amounts of water to wells and provide natural discharge outlets for the ground water. The spring outflows to the Williamson and Wood Rivers-Crooked Creek drainage, measured in September and October 1955, were at a rate equivalent to about 700,000 acre-feet per year. The spring outflows into the Sprague River were at a rate equal to 2l;5>000 apre-feet per year* Large springs occur along the edges of Upper Klamath Lake but their discharges could not be measured, and the known spring discharge from the lower lava rocks in the river canyon below Keno was not measured. The spring discharge into Lost River in the reach ?rom Bonanza to Harpold Bridge was at a rate equivalent to 75,000 acre-feet per year. Much of the water discharged from springs is used for irrigation during the growing season, but ground water has not been extensively Unpublished records subject to revision developed by means of wells except in the'Yonna Valley and other local areas. The total withdrawal of ground water from wells in 1951? was only about 30,000 acre-feet, of which 27,000 was used for irrigation* The ground water is of excellent quality in general, but sodium sulfate water occurs in the belts of warm rock along some faults and alkali bicarbonate water is present in the main evapotranspiration basins. Unpublished records subject to revision Title: Preliminary report on the ground-water resources of the Klamath River Basin, Oregon Author: Newcomb, Reuben Clair Year: 1958, 2005 The Klamath River basin, including the adjacent Lost River basin, includes about ?,5>OO square miles of plateaus, mountain-slopes and valley plains in south-central Oregon* The valley plains range in altitude from about U,100 feet in the south to more than li,500 feet at the northern end; the mountain and plateau lands rise to an average altitude of 6,000 feet at the drainage divide, some peaks rising above 9*000 feet. The western quarter of the ba3in is on the eastern slope of the Cascade Range and the remainder consists of plateaus, mountains, and valleys of the basin-and-range type* The rocks of the Klamath River basin range in age from Recent to Mesozoic* At the southwest side of the basin in Oregon, pre~Tertiary metamorphic, igneous, and sedimentary rocks, which form extensive areas farther west, are overlain by sedimentary rocks of Eocene age and volcanic rocks of Eocene and Oligocene age* These early Tertiary rocks dip east toward the central part of the Klamath River basin. The complex "volcanic rocks of high Cascades" include three units: The lowest unit consists of a sequence of basaltic lava flows about 800 feet thick5 the medial unit is composed of volcanic-sedimentary and sedimentary rocks?the Tonna formation-200 to 2,000 feet thick; the uppermost unit is a sequence of basaltic lava flows commonly about 200 feet thick. These rocks dip east from the Cascade Unpublished records subject to revision 2 Range and are the main bedrock formations beneath most of the basin. Extensive pumice deposits, which emanated ^?^ ancestral Mount Mazaraa, cover large areas in the northwestern part of the basin* The basin has an overall synclinal structure open to the south at the California boundary where it continues as the Klamath Lake basin in California* The older rocks dip into the basin in monoclinal fashion from the adjoining drainage basins* The rocks are broken along rudely rectangular nets of closely spaced normal faults* the most prominent set of which trends northwest* The network of fault displacements includes two main grabens, the Klamath and the Langell, which were downthrown approximately ?00 and 1,000 fast, respectively* The average annual precipitation varies with the altitude, the higher parts of the Cascade Range getting more than 60 inches, and the semierid valley plains receive as little as 13 inches in some places* Most precipitation occurs in the winter. \ The principal tributaries, Williamson and Sprague Rivers, rise near the higher parts of the eastern rim of the basin, flow through narrow valley plains to the western part, and discharge into Upper Klamath Lake* Wood River and associated creeks also empty into Upper Klamath Lake after draining southward along the eastern foot of the Cascade Range* The Klamath River receives the outflow from Upper Klamath Lake, via Lifak River and Lake Ewauna, and flows southwestward through Keno Gap and hence through a youthful canyon, to its lower valley in California* The ground water occurs largely in an unconfined, or water-table, condition, though areas of local confinement are present* The regional Unpublished records subject to revis&oa is graded to water table / a base level about equal to that of the major drainage* where water is confined, on the valley plains. The slope of the water tafele, ~ of/the piezomstric surface is downstream at about the same grade as that "of the surface drainage in each of the larger valleys, attd groufid*water divides occur between the upper parts of adjacent major valleys* The principal water-bearipg units are.the'lower lava rocks and upper lava rocks of the "volcanic rocks of high Cascades,* the pumice of Quaternaryage, and the allusriTuju In places layers of coarse flagmental material in the Tonna formation (Newcorub, 1958) also transmit water* The water-bearing units, especially the breccia layers of the lava rocks and the pumice, yield large amounts of water to wells and provide natural discharge outlets for the ground water. The spring outflows to the Williamson and Wood Rivers-Crooked Creek drainage, measured in September and October 1955, were at a rate equivalent to about 700,000 acre-feet per year. The spring outflows into the Sprague River were at a rate equal to 2l;5>000 apre-feet per year* Large springs occur along the edges of Upper Klamath Lake but their discharges could not be measured, and the known spring discharge from the lower lava rocks in the river canyon below Keno was not measured. The spring discharge into Lost River in the reach ?rom Bonanza to Harpold Bridge was at a rate equivalent to 75,000 acre-feet per year. Much of the water discharged from springs is used for irrigation during the growing season, but ground water has not been extensively Unpublished records subject to revision developed by means of wells except in the'Yonna Valley and other local areas. The total withdrawal of ground water from wells in 1951? was only about 30,000 acre-feet, of which 27,000 was used for irrigation* The ground water is of excellent quality in general, but sodium sulfate water occurs in the belts of warm rock along some faults and alkali bicarbonate water is present in the main evapotranspiration basins. Unpublished records subject to revision Close

• 16. [Image] Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels

  	"December 10, 1998."
  	Citation × Citation Citation Abstract Copy Title: Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 10, 1998." Title: Review of the hatchery measures in the Oregon plan for salmon and watersheds. Part I, Consistency of the Oregon plan with recommendations from recent scientific review panels Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 10, 1998." Close

• 17. [Image] Recovery of wild salmonids in western Oregon forests : Oregon Forest Practices Act rules and the measures in the Oregon plan for salmon and watersheds

  	"September 8, 1999."
  	Citation × Citation Citation Abstract Copy Title: Recovery of wild salmonids in western Oregon forests : Oregon Forest Practices Act rules and the measures in the Oregon plan for salmon and watersheds Author: Independent Multidisciplinary Science Team (Or.) Year: 1999, 2005 "September 8, 1999." Title: Recovery of wild salmonids in western Oregon forests : Oregon Forest Practices Act rules and the measures in the Oregon plan for salmon and watersheds Author: Independent Multidisciplinary Science Team (Or.) Year: 1999, 2005 "September 8, 1999." Close

• 18. [Image] Pinniped and seabird predation : implications for recovery of threatened stocks of salmonids in Oregon under the Oregon Plan for Salmon and Watersheds

  	"December 22, 1998."
  	Citation × Citation Citation Abstract Copy Title: Pinniped and seabird predation : implications for recovery of threatened stocks of salmonids in Oregon under the Oregon Plan for Salmon and Watersheds Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 22, 1998." Title: Pinniped and seabird predation : implications for recovery of threatened stocks of salmonids in Oregon under the Oregon Plan for Salmon and Watersheds Author: Independent Multidisciplinary Science Team (Or.) Year: 1998, 2005 "December 22, 1998." Close

• 19. [Image] Natural flow of the upper Klamath River

  	Executive Summary Executive Summary This report presents details of the investigation and results in estimating the natural flow of the upper Klamath River at Keno, Oregon. The area investigated includes ...
  	Citation × Citation Citation Abstract Copy Title: Natural flow of the upper Klamath River Author: United States. Bureau of Reclamation. Klamath Basin Area Office Year: 2005, 2008 Executive Summary Executive Summary This report presents details of the investigation and results in estimating the natural flow of the upper Klamath River at Keno, Oregon. The area investigated includes the Klamath River Basin above Keno, Oregon, primarily in Klamath County, with some areas of Siskiyou and Modoc Counties in California. The study area includes the Sprague, Williamson, and Wood River basins, as well as Upper Klamath and Lower Klamath Lakes. Objectives The current purpose of this study is to provide an estimate of the monthly natural flows in the upper Klamath River at Keno. This estimate of the natural flow represents typical flow without agricultural development in the Upper Klamath River Basin, including its tributaries. Study Approach This study used a water budget approach to assess the agricultural depletions and alterations to the natural flow. The approach was to evaluate the changes of agriculture from predevelopment conditions, estimate the effects of these changes, and restore the water budget to natural conditions by reversing the effects of agricultural development. Records used in this empirical assessment were derived from both stream gaging flow histories and from climatological records for stations within and adjacent to the study area. Water Budget Description The water budget assessment of the watershed as a natural system includes an evaluation of hydrological changes related to agricultural development above the Keno gage. The water budget assessment includes: ? Natural inflow from the Sprague, Williamson, and Wood Rivers to Upper Klamath Lake ? Predevelopment evapotranspiration losses from marshes surrounding Upper Klamath Lake ? Predevelopment evaporation losses of the Upper Klamath Lake ? Natural flow at the outlet of Upper Klamath Lake into the Link River at Klamath Falls ? Resulting natural flow at Keno The processes developed in the water budget to evaluate the natural outflow of Upper Klamath Lake accounts for factors related to water resources developments XI Natural Flow of the Upper Klamath River in the watershed that have affected inflow to the lake, and for losses due to natural condition of the lake. The water budget assessment of the watershed as a natural system includes an evaluation of hydrological changes related to agricultural development above the Keno gage. The results of the water budget assessment are given as average annual flows for two important stream gages, one located on the Link River at Klamath Falls and the other on the Klamath River at Keno. Evaluation of Predevelopment Conditions An evaluation of predevelopment conditions included an evaluation of changes to Upper Klamath Lake, agricultural developments in the Wood River, Sprague River, and Williamson River watersheds. Several basic elements were considered in this study: ? How had development changed the system ? Was information available about conditions before the changes occurred ? Were data available to assist in estimating changes to the natural system Evaluation of Current Conditions Period of Record The period of record considered in this investigation is the 52 years from 1949 to 2000. This period of record was chosen because hydrologic and climatological data were limited for the pre-1949 period and data beyond 2000 were not available when the study began. The water year convention (October through September) is used in this report. Crop and Marshland Evapotranspiration Analysis The modified Blaney-Criddle method was used to determine potential net evapotranspiration (ET) from crops, marshlands, and riparian zones. The method is empirical and the calculated values were adjusted based on other recent study findings and water limiting considerations. To estimate net ET water consumption by this method requires the following data: ? Location of irrigated lands, marshlands, and riparian zones ? Types of crops and number of acres for each crop ? Types and acreages of marshland and riparian vegetation, both existing and predevelopment ? Monthly precipitation and monthly average temperature for the period of record for each area Methods to Estimate Natural Flows Natural streamflow development included adjustment of gaged streamflow to natural flow, restoration of missing streamflow and climate data, making natural streamflow estimates in ungaged watersheds, assessing groundwater XII Executive Summary contributions, and estimating transit losses. Not all of these procedures were appropriate or possible in all subbasins of the study area. Records of historic flow may be adjusted to natural flow using crop net consumptive use and marshland evapotranspiration: natural flow = gaged flow + crop net consumptive use - reclaimed natural marshland net evapotranspiration Correlation analysis was used to restore missing values from monthly-value data records used in this study. The method is different from linear least-squares regression estimation. Data records used in this study include precipitation and average temperature histories, in addition to hydrologic records of streamflow and lake stage. Also, natural streamflow histories are required in ungaged watersheds to assess the natural inflow to Upper Klamath Lake. Sparse monthly flow records for streams heading on the east flank of the Cascades and flowing into the Wood River Valley or Pelican Bay area of Upper Klamath Lake required estimation techniques that used gaged histories from nearby river basins. These data were evaluated in statistical applications to yield natural flow estimates for these ungaged portions of the Klamath Basin. In a similar vein, groundwater contributions required temporal adjustments attributable to the climate signature evident in longer term records for similar groundwater discharges in neighboring watersheds. Transit losses for both surface water and groundwater contributions were also estimated in this study. Natural Lake Simulations Implementation of a water budget for Upper Klamath Lake required developing information about (1) the storage and inundation surface area characteristics of the lake, and (2) the discharge characteristics at the outflow point of the lake. These characteristics were evaluated in relation to the elevation, or stage, of the water surface of the lake. Additionally, discharge from the lake was also related to the stage. Estimating the outflow of a natural lake is accomplished using a water budget approach. A monthly summation of all elements in the water budget may be stated by the general form of the hydrologic equation: i = o + As where i = inflow to the lake o = outflow from the lake and As = change in storage of the lake XIII Natural Flow of the Upper Klamath River For Upper Klamath Lake, the month-to-month water budget accounts for natural inflow, storage of water within each lake, resulting estimated lake stage, and discharge from each lake. In addition, open water surface evaporation and groundwater discharge to the lake from the regional aquifer were estimated. The water budget assessment was designed to simulate the lake as a natural water body. Materials and Data Researched and Used Data Sources Records used in this analysis were derived from both stream gaging flow histories and from climatological records for stations within and adjacent to the study area. Information was also developed from published reports, file documents, and maps. Supporting information included documents from: ? Archives of the Bureau of Reclamation Klamath Basin Area Office ? Numerous U.S. Geological Survey (USGS) Water Supply Papers regarding stream gaging records ? Compact disk databases containing digital records of gaged flow, lake stage records, and meteorological data Anecdotal items from newspaper articles or clipped from magazines were also reviewed. These sources consisted of narratives of past events or conditions, transcripts of interviews, newspaper accounts, books, diaries, and historical journals. These provided an impression of predevelopment conditions that can be compared to the empirical and scientific information gleaned from other sources. Other reviewed materials included unpublished and out-of-print scientific reports, historical maps, letters, books, journals, and photographs. Modeling Tools Results of the water budget assessment were accomplished using Excel?, a sophisticated spreadsheet available in the Microsoft Office for Windows software package. This model was chosen over other models because this study is unique. The computational modules built as the study developed represent a custom application of Excel? to the solution of estimating the natural flow conditions in the Upper Klamath River Basin. Klamath River at Keno Gaging Station For the simulation period, 1949 to 2000, the water balance for the Upper Klamath River Basin at Keno is described below. The natural outflow (discharge) from Upper Klamath Lake at Link River was computed in the water balance. Discharge at Keno was then calculated using a correlation relationship developed between historic measured Link River and Keno flows. Table S-l presents the estimated water balance and outflow developed for the Link River and Keno gages. XIV Executive Summary Table S-1. Estimated inflow and outflow developed for Link River and Keno gages Upper Klamath Lake Acre-feet Average annual natural inflow Average annual natural net loss 1,605,000 210,000 Resulting average annual natural outflow 1,395,000 Link River to Keno Average annual natural inflow 1,485,000 Resulting average annual natural outflow at Keno gage 1,306,000 Other Factors Considered The focus of this study is agricultural development in the Upper Klamath River Basin and its effects on natural flow conditions. Other watershed factors have changed since predevelopment. Some of these factors were considered, but are unaccounted-for in the assessment, such as changes in forest conditions or an extension of the flow histories before 1949. Model Review and Sensitivity Analysis Although this study uses best available hydrologic methods and data to either measure or estimate all inflows and outflows to the system, additional concerns have arisen in completing the work. Relationships regarding the significance of uncertainty are likely to be spatially and temporally variable. The key factor is the relative importance of each module in the transit losses suffered by inflows to the natural system. The significance of these influences to model sensitivity is related to time of year or length of time over which flows are evaluated. Model sensitivity is related to uncertainty in data regarding the most significant transit losses; namely, marsh evapotranspiration and open water evaporation. The natural flows developed at Keno are realized, in part, through a statistical rule based model rather than a physically based model. This construct within the model is for the segment from the Link River gage below Upper Klamath Lake, to the Keno gage below Lower Klamath Lake. Thus, sensitivity in testing the spatial and temporal variables within the Link River to Keno reach that affect the flow at Keno is problematic. xv Natural Flow of the Upper Klamath River Summary Development of the natural flows at the Keno gage was accomplished using a spreadsheet modeling approach to resolve the water budget for the Upper Klamath River Basin under undeveloped watershed conditions. The resulting flow duration for simulated natural average monthly flows for Keno gage are described in Table S-2. The percentiles represent the flow exceedence ranges in monthly natural flow estimates at Keno solely due to record length. These percentiles are estimates for modeled baseline conditions and do not reflect data uncertainties for possible changes in evaporation, evapotranspiration, or other factors. Table S-2. Summary of simulated monthly flows at Keno in cfs % Time <= Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sept Annual % Time >= 10 648 1088 1216 1408 1647 1577 1670 1408 1168 631 520 560 1188 90 20 769 1159 1352 1472 1767 1689 2017 1721 1358 822 578 616 1429 80 30 857 1255 1453 1667 1925 1907 2125 2051 1664 964 706 720 1528 70 40 974 1342 1625 1845 2016 2040 2477 2280 1890 1228 767 746 1607 60 50 1033 1455 1698 1964 2343 2133 2595 2649 2039 1349 873 854 1773 50 60 1131 1523 1803 2072 2410 2360 3009 2827 2388 1478 998 955 1903 40 70 1224 1576 1984 2196 2615 2703 3146 3131 2657 1706 1154 1049 2169 30 80 1304 1739 2049 2399 2829 3115 3615 3385 3104 2210 1351 1210 2347 20 90 1488 1815 2319 2659 3294 3367 3877 3707 3460 2923 1684 1412 2511 10 A simplified flowchart depicting the overall sources of included inflow and outflow variables has been completed as figure S-l, with average annual values shown from each source. XVI Title: Natural flow of the upper Klamath River Author: United States. Bureau of Reclamation. Klamath Basin Area Office Year: 2005, 2008 Executive Summary Executive Summary This report presents details of the investigation and results in estimating the natural flow of the upper Klamath River at Keno, Oregon. The area investigated includes the Klamath River Basin above Keno, Oregon, primarily in Klamath County, with some areas of Siskiyou and Modoc Counties in California. The study area includes the Sprague, Williamson, and Wood River basins, as well as Upper Klamath and Lower Klamath Lakes. Objectives The current purpose of this study is to provide an estimate of the monthly natural flows in the upper Klamath River at Keno. This estimate of the natural flow represents typical flow without agricultural development in the Upper Klamath River Basin, including its tributaries. Study Approach This study used a water budget approach to assess the agricultural depletions and alterations to the natural flow. The approach was to evaluate the changes of agriculture from predevelopment conditions, estimate the effects of these changes, and restore the water budget to natural conditions by reversing the effects of agricultural development. Records used in this empirical assessment were derived from both stream gaging flow histories and from climatological records for stations within and adjacent to the study area. Water Budget Description The water budget assessment of the watershed as a natural system includes an evaluation of hydrological changes related to agricultural development above the Keno gage. The water budget assessment includes: ? Natural inflow from the Sprague, Williamson, and Wood Rivers to Upper Klamath Lake ? Predevelopment evapotranspiration losses from marshes surrounding Upper Klamath Lake ? Predevelopment evaporation losses of the Upper Klamath Lake ? Natural flow at the outlet of Upper Klamath Lake into the Link River at Klamath Falls ? Resulting natural flow at Keno The processes developed in the water budget to evaluate the natural outflow of Upper Klamath Lake accounts for factors related to water resources developments XI Natural Flow of the Upper Klamath River in the watershed that have affected inflow to the lake, and for losses due to natural condition of the lake. The water budget assessment of the watershed as a natural system includes an evaluation of hydrological changes related to agricultural development above the Keno gage. The results of the water budget assessment are given as average annual flows for two important stream gages, one located on the Link River at Klamath Falls and the other on the Klamath River at Keno. Evaluation of Predevelopment Conditions An evaluation of predevelopment conditions included an evaluation of changes to Upper Klamath Lake, agricultural developments in the Wood River, Sprague River, and Williamson River watersheds. Several basic elements were considered in this study: ? How had development changed the system ? Was information available about conditions before the changes occurred ? Were data available to assist in estimating changes to the natural system Evaluation of Current Conditions Period of Record The period of record considered in this investigation is the 52 years from 1949 to 2000. This period of record was chosen because hydrologic and climatological data were limited for the pre-1949 period and data beyond 2000 were not available when the study began. The water year convention (October through September) is used in this report. Crop and Marshland Evapotranspiration Analysis The modified Blaney-Criddle method was used to determine potential net evapotranspiration (ET) from crops, marshlands, and riparian zones. The method is empirical and the calculated values were adjusted based on other recent study findings and water limiting considerations. To estimate net ET water consumption by this method requires the following data: ? Location of irrigated lands, marshlands, and riparian zones ? Types of crops and number of acres for each crop ? Types and acreages of marshland and riparian vegetation, both existing and predevelopment ? Monthly precipitation and monthly average temperature for the period of record for each area Methods to Estimate Natural Flows Natural streamflow development included adjustment of gaged streamflow to natural flow, restoration of missing streamflow and climate data, making natural streamflow estimates in ungaged watersheds, assessing groundwater XII Executive Summary contributions, and estimating transit losses. Not all of these procedures were appropriate or possible in all subbasins of the study area. Records of historic flow may be adjusted to natural flow using crop net consumptive use and marshland evapotranspiration: natural flow = gaged flow + crop net consumptive use - reclaimed natural marshland net evapotranspiration Correlation analysis was used to restore missing values from monthly-value data records used in this study. The method is different from linear least-squares regression estimation. Data records used in this study include precipitation and average temperature histories, in addition to hydrologic records of streamflow and lake stage. Also, natural streamflow histories are required in ungaged watersheds to assess the natural inflow to Upper Klamath Lake. Sparse monthly flow records for streams heading on the east flank of the Cascades and flowing into the Wood River Valley or Pelican Bay area of Upper Klamath Lake required estimation techniques that used gaged histories from nearby river basins. These data were evaluated in statistical applications to yield natural flow estimates for these ungaged portions of the Klamath Basin. In a similar vein, groundwater contributions required temporal adjustments attributable to the climate signature evident in longer term records for similar groundwater discharges in neighboring watersheds. Transit losses for both surface water and groundwater contributions were also estimated in this study. Natural Lake Simulations Implementation of a water budget for Upper Klamath Lake required developing information about (1) the storage and inundation surface area characteristics of the lake, and (2) the discharge characteristics at the outflow point of the lake. These characteristics were evaluated in relation to the elevation, or stage, of the water surface of the lake. Additionally, discharge from the lake was also related to the stage. Estimating the outflow of a natural lake is accomplished using a water budget approach. A monthly summation of all elements in the water budget may be stated by the general form of the hydrologic equation: i = o + As where i = inflow to the lake o = outflow from the lake and As = change in storage of the lake XIII Natural Flow of the Upper Klamath River For Upper Klamath Lake, the month-to-month water budget accounts for natural inflow, storage of water within each lake, resulting estimated lake stage, and discharge from each lake. In addition, open water surface evaporation and groundwater discharge to the lake from the regional aquifer were estimated. The water budget assessment was designed to simulate the lake as a natural water body. Materials and Data Researched and Used Data Sources Records used in this analysis were derived from both stream gaging flow histories and from climatological records for stations within and adjacent to the study area. Information was also developed from published reports, file documents, and maps. Supporting information included documents from: ? Archives of the Bureau of Reclamation Klamath Basin Area Office ? Numerous U.S. Geological Survey (USGS) Water Supply Papers regarding stream gaging records ? Compact disk databases containing digital records of gaged flow, lake stage records, and meteorological data Anecdotal items from newspaper articles or clipped from magazines were also reviewed. These sources consisted of narratives of past events or conditions, transcripts of interviews, newspaper accounts, books, diaries, and historical journals. These provided an impression of predevelopment conditions that can be compared to the empirical and scientific information gleaned from other sources. Other reviewed materials included unpublished and out-of-print scientific reports, historical maps, letters, books, journals, and photographs. Modeling Tools Results of the water budget assessment were accomplished using Excel?, a sophisticated spreadsheet available in the Microsoft Office for Windows software package. This model was chosen over other models because this study is unique. The computational modules built as the study developed represent a custom application of Excel? to the solution of estimating the natural flow conditions in the Upper Klamath River Basin. Klamath River at Keno Gaging Station For the simulation period, 1949 to 2000, the water balance for the Upper Klamath River Basin at Keno is described below. The natural outflow (discharge) from Upper Klamath Lake at Link River was computed in the water balance. Discharge at Keno was then calculated using a correlation relationship developed between historic measured Link River and Keno flows. Table S-l presents the estimated water balance and outflow developed for the Link River and Keno gages. XIV Executive Summary Table S-1. Estimated inflow and outflow developed for Link River and Keno gages Upper Klamath Lake Acre-feet Average annual natural inflow Average annual natural net loss 1,605,000 210,000 Resulting average annual natural outflow 1,395,000 Link River to Keno Average annual natural inflow 1,485,000 Resulting average annual natural outflow at Keno gage 1,306,000 Other Factors Considered The focus of this study is agricultural development in the Upper Klamath River Basin and its effects on natural flow conditions. Other watershed factors have changed since predevelopment. Some of these factors were considered, but are unaccounted-for in the assessment, such as changes in forest conditions or an extension of the flow histories before 1949. Model Review and Sensitivity Analysis Although this study uses best available hydrologic methods and data to either measure or estimate all inflows and outflows to the system, additional concerns have arisen in completing the work. Relationships regarding the significance of uncertainty are likely to be spatially and temporally variable. The key factor is the relative importance of each module in the transit losses suffered by inflows to the natural system. The significance of these influences to model sensitivity is related to time of year or length of time over which flows are evaluated. Model sensitivity is related to uncertainty in data regarding the most significant transit losses; namely, marsh evapotranspiration and open water evaporation. The natural flows developed at Keno are realized, in part, through a statistical rule based model rather than a physically based model. This construct within the model is for the segment from the Link River gage below Upper Klamath Lake, to the Keno gage below Lower Klamath Lake. Thus, sensitivity in testing the spatial and temporal variables within the Link River to Keno reach that affect the flow at Keno is problematic. xv Natural Flow of the Upper Klamath River Summary Development of the natural flows at the Keno gage was accomplished using a spreadsheet modeling approach to resolve the water budget for the Upper Klamath River Basin under undeveloped watershed conditions. The resulting flow duration for simulated natural average monthly flows for Keno gage are described in Table S-2. The percentiles represent the flow exceedence ranges in monthly natural flow estimates at Keno solely due to record length. These percentiles are estimates for modeled baseline conditions and do not reflect data uncertainties for possible changes in evaporation, evapotranspiration, or other factors. Table S-2. Summary of simulated monthly flows at Keno in cfs % Time <= Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sept Annual % Time >= 10 648 1088 1216 1408 1647 1577 1670 1408 1168 631 520 560 1188 90 20 769 1159 1352 1472 1767 1689 2017 1721 1358 822 578 616 1429 80 30 857 1255 1453 1667 1925 1907 2125 2051 1664 964 706 720 1528 70 40 974 1342 1625 1845 2016 2040 2477 2280 1890 1228 767 746 1607 60 50 1033 1455 1698 1964 2343 2133 2595 2649 2039 1349 873 854 1773 50 60 1131 1523 1803 2072 2410 2360 3009 2827 2388 1478 998 955 1903 40 70 1224 1576 1984 2196 2615 2703 3146 3131 2657 1706 1154 1049 2169 30 80 1304 1739 2049 2399 2829 3115 3615 3385 3104 2210 1351 1210 2347 20 90 1488 1815 2319 2659 3294 3367 3877 3707 3460 2923 1684 1412 2511 10 A simplified flowchart depicting the overall sources of included inflow and outflow variables has been completed as figure S-l, with average annual values shown from each source. XVI Close

• 20. [Image] Influences of human activity on stream temperatures and existence of cold-water fish in streams with elevated temperature: report of a workshop: Independent Multidisciplinary Science Team, Corvallis, OR, October 5-6, 2000

  	Executive Summary The Independent Multidisciplinary Science Team (IMST) convened a panel of experts on stream temperature and fish ecology on October 5-6, 2000 for a scientific workshop on human influences ...
  	Citation × Citation Citation Abstract Copy Title: Influences of human activity on stream temperatures and existence of cold-water fish in streams with elevated temperature: report of a workshop: Independent Multidisciplinary Science Team, Corvallis, OR, October 5-6, 2000 Author: Independent Multidisciplinary Science Team (Oregon) Year: 2000, 2008, 2005 Executive Summary The Independent Multidisciplinary Science Team (IMST) convened a panel of experts on stream temperature and fish ecology on October 5-6, 2000 for a scientific workshop on human influences on stream temperature and responses by salmonids. The workshop was designed to review and discuss scientifically credible data and publications about 1) factors related to human activity that influence stream temperature and 2) behavioral, physical, and ecological mechanisms of cold water fish species for existing in streams with elevated temperatures. The goal of the workshop was to review empirical evidence and to identify points of agreement, disagreement, and knowledge gaps within the scientific community concerning the factors that influence stream temperature and fish responses to elevated temperatures. This information will assist the IMST in preparing a broader temperature report on Oregon's stream temperature water quality standards and their implementation. This report is prepared by the IMST. It was reviewed by workshop participants and revised by the IMST accordingly. The report includes abstracts of plenary presentations on factors that influence stream temperatures and fish responses, and the results of group discussions. The workshop participants focused on three main questions and were asked to list statements of agreement and disagreement, and to identify gaps in the scientific knowledge related to each question: ? How and where does riparian vegetation influence stream temperature? ? Do other changes in streams cause increases in stream temperature? ? How can apparently healthy fish populations exist in streams with temperatures higher than laboratory and field studies would indicate as healthy? The workshop participants provided answers to the questions in the form of bullets. The answers below represent the IMST's summation of the workshop findings and were reviewed by the participants. Several gaps in the scientific basis for specific questions or relationships were identified. The participants found no areas of disagreement for which technical information was available. They noted that any disagreements were not related to scientific interpretation, but were based on concerns or opinions about application, regulation, and management. How and where does riparian vegetation influence stream temperature? The influence of riparian vegetation on stream temperature is cumulative and complex, varying by site, over time, and across regions. Riparian vegetation can directly affect stream temperature by intercepting solar radiation and reducing stream heating. The influence of riparian shade in controlling temperature declines as streams widen in downstream reaches, but the role of riparian vegetation in providing water quality and fish habitat benefits continues to be important. Besides providing shade, riparian vegetation can also indirectly affect stream temperature by influencing microclimate, affecting channel morphology, affecting stream flow, influencing wind speed, affecting humidity, affecting soil temperature, using water, influencing air temperature, enhancing infiltration, and influencing thermal radiation. It is critical to know the site potential to understand what vegetation a site can support. There is not a good scientific understanding of how much vegetation shading is required to affect stream temperature. 1 This lack of understanding may be due to the spatial and temporal variability in landscape components, and the resulting variability in both the direct and indirect influences of vegetation on stream temperature. Therefore, it is difficult to generalize about the effects of vegetation on stream temperature. Do other changes in streams cause increases in stream temperature? The answer to this question is yes, other physical changes in the stream system can modify stream temperatures. Stream temperature is a product of complex interactions between geomorphology, soil, hydrology, vegetation, and climate within a watershed. Changes in these factors will result in changes in stream temperature. Human activities influence stream temperature by affecting one or more of four major components: riparian vegetation, channel morphology, hydrology, and surface/subsurface interactions. Stream systems vary substantially across the landscape, and site-specific information is critical to understanding stream temperature responses to human activities. How can apparently healthy fish populations exist in streams with temperatures higher than laboratory and field studies would indicate as healthy? Workshop participants identified several mechanisms that might explain the ability of fish populations to exist at higher than expected temperatures. The first mechanism was that the fish may have physiological adaptations to survive exposures to high temperatures. A second possibility was that stream habitats may contain cooler microhabitats that fish can occupy as refuge from higher temperatures. A third consideration is that ecological interactions may be different under differing thermal conditions resulting, for example, in changes in disease virulence or cumulative effects of stressors. Finally, since substantial differences exist between laboratory and field studies, it is difficult to apply results of laboratory studies to fish responses in the field. It is important to note that these proposed mechanisms are speculative and, as the list of gaps indicates, substantial experimental work is required to establish their influences on fish in different stream systems. Workshop Summaiy Workshop participants recognized gaps in the available science. Additional knowledge about human influences on stream temperatures and, consequently, influences on cold-water fish populations, will improve our ability to prevent further degradation of stream habitat and will enhance efforts geared towards the recovery of depressed fish populations. Even with these gaps, there was enough agreement on factors that influence stream temperature to indicate information is available to start developing and implementing management practices that are designed to reduce stream warming. It was suggested that managers should consider riparian vegetation, channel morphology, and hydrology, and should account for site differences. Title: Influences of human activity on stream temperatures and existence of cold-water fish in streams with elevated temperature: report of a workshop: Independent Multidisciplinary Science Team, Corvallis, OR, October 5-6, 2000 Author: Independent Multidisciplinary Science Team (Oregon) Year: 2000, 2008, 2005 Executive Summary The Independent Multidisciplinary Science Team (IMST) convened a panel of experts on stream temperature and fish ecology on October 5-6, 2000 for a scientific workshop on human influences on stream temperature and responses by salmonids. The workshop was designed to review and discuss scientifically credible data and publications about 1) factors related to human activity that influence stream temperature and 2) behavioral, physical, and ecological mechanisms of cold water fish species for existing in streams with elevated temperatures. The goal of the workshop was to review empirical evidence and to identify points of agreement, disagreement, and knowledge gaps within the scientific community concerning the factors that influence stream temperature and fish responses to elevated temperatures. This information will assist the IMST in preparing a broader temperature report on Oregon's stream temperature water quality standards and their implementation. This report is prepared by the IMST. It was reviewed by workshop participants and revised by the IMST accordingly. The report includes abstracts of plenary presentations on factors that influence stream temperatures and fish responses, and the results of group discussions. The workshop participants focused on three main questions and were asked to list statements of agreement and disagreement, and to identify gaps in the scientific knowledge related to each question: ? How and where does riparian vegetation influence stream temperature? ? Do other changes in streams cause increases in stream temperature? ? How can apparently healthy fish populations exist in streams with temperatures higher than laboratory and field studies would indicate as healthy? The workshop participants provided answers to the questions in the form of bullets. The answers below represent the IMST's summation of the workshop findings and were reviewed by the participants. Several gaps in the scientific basis for specific questions or relationships were identified. The participants found no areas of disagreement for which technical information was available. They noted that any disagreements were not related to scientific interpretation, but were based on concerns or opinions about application, regulation, and management. How and where does riparian vegetation influence stream temperature? The influence of riparian vegetation on stream temperature is cumulative and complex, varying by site, over time, and across regions. Riparian vegetation can directly affect stream temperature by intercepting solar radiation and reducing stream heating. The influence of riparian shade in controlling temperature declines as streams widen in downstream reaches, but the role of riparian vegetation in providing water quality and fish habitat benefits continues to be important. Besides providing shade, riparian vegetation can also indirectly affect stream temperature by influencing microclimate, affecting channel morphology, affecting stream flow, influencing wind speed, affecting humidity, affecting soil temperature, using water, influencing air temperature, enhancing infiltration, and influencing thermal radiation. It is critical to know the site potential to understand what vegetation a site can support. There is not a good scientific understanding of how much vegetation shading is required to affect stream temperature. 1 This lack of understanding may be due to the spatial and temporal variability in landscape components, and the resulting variability in both the direct and indirect influences of vegetation on stream temperature. Therefore, it is difficult to generalize about the effects of vegetation on stream temperature. Do other changes in streams cause increases in stream temperature? The answer to this question is yes, other physical changes in the stream system can modify stream temperatures. Stream temperature is a product of complex interactions between geomorphology, soil, hydrology, vegetation, and climate within a watershed. Changes in these factors will result in changes in stream temperature. Human activities influence stream temperature by affecting one or more of four major components: riparian vegetation, channel morphology, hydrology, and surface/subsurface interactions. Stream systems vary substantially across the landscape, and site-specific information is critical to understanding stream temperature responses to human activities. How can apparently healthy fish populations exist in streams with temperatures higher than laboratory and field studies would indicate as healthy? Workshop participants identified several mechanisms that might explain the ability of fish populations to exist at higher than expected temperatures. The first mechanism was that the fish may have physiological adaptations to survive exposures to high temperatures. A second possibility was that stream habitats may contain cooler microhabitats that fish can occupy as refuge from higher temperatures. A third consideration is that ecological interactions may be different under differing thermal conditions resulting, for example, in changes in disease virulence or cumulative effects of stressors. Finally, since substantial differences exist between laboratory and field studies, it is difficult to apply results of laboratory studies to fish responses in the field. It is important to note that these proposed mechanisms are speculative and, as the list of gaps indicates, substantial experimental work is required to establish their influences on fish in different stream systems. Workshop Summaiy Workshop participants recognized gaps in the available science. Additional knowledge about human influences on stream temperatures and, consequently, influences on cold-water fish populations, will improve our ability to prevent further degradation of stream habitat and will enhance efforts geared towards the recovery of depressed fish populations. Even with these gaps, there was enough agreement on factors that influence stream temperature to indicate information is available to start developing and implementing management practices that are designed to reduce stream warming. It was suggested that managers should consider riparian vegetation, channel morphology, and hydrology, and should account for site differences. Close