Middle Fork Research Articles

Landscape Heterogeneity and Disturbance Interactions in a Subalpine Watershed in Northern Colorado, USA

Three major disturbances affect subalpine forests in the Rocky Mountains: blowdown, insect outbreaks, and fire. These disturbances may influence one another temporally and spatially, creating a mosaic of disturbance patches. In 1997, a severe windstorm blew down trees on over 10,000 ha of subalpine forest in northern Colorado. Did previous disturbances influence the spatial pattern of blowdown in a representative part of the blowdown in the Middle Fork Elk River watershed? Dendrochronological evidence and a geographic information system were used to reconstruct the disturbance history, and the relationship between disturbance history (i.e., patch age) and the 1997 blowdown was examined. The fire regime varies temporally and spatially, with an area-weighted mean fire interval/fire rotation of 108 to 195 years. Stand-replacing fires appear to have had the most impact on the fire regime, but evidence of non-stand-replacing fires was also found. South-facing, lower-elevation slopes were the settings most likely to burn. Low-severity spruce-beetle disturbance was found in the mid-1700s and mid- to late 1800s, possibly related to regional outbreaks. Sheep-grazing and fire suppression may have influenced tree-regeneration and fire-frequency patterns. Each disturbance event occurred with varying severity across the landscape, influenced, in part, by the patterns of severity of previous disturbances. Patch age contributed to the pattern of the 1997 blowdown, but the relationship is complicated. The vegetation mosaic influenced spatial patterns of blowdown, resulting in new complexity and maintaining landscape heterogeneity.

Population Structure of an Endemic Species of Yellowcheek Darter, Etheostoma moorei (Raney and Suttkus), of the Upper Little Red River, Arkansas

Abstract The yellowcheek darter, Etheostoma moorei (Raney and Suttkus), is an endemic species of the upper Little Red River, Arkansas. Population estimates over the past two decades have identified an 80% reduction in numbers. Seventeen presumptive loci and six meristic characters were analyzed for 85 individuals to determine the relatedness of populations from three headwater streams. Genetic distances, based on allozyme analysis ranged from 0.000 to 0.213, with each stream population partitioning into distinct subpopulations. Turkey Fork individuals had high genetic distance values from Middle and South Fork individuals. None of the six meristic features studied demonstrated significant differences between stream sites. These findings and previous ecological and life history studies all suggest that the Turkey Fork and Middle/South Fork populations be treated as unique management units.

Three-dimensional mapping of geomorphic controls on flood-plain hydrology and connectivity from aerial photos

The Nyack flood plain of the Middle Fork Flathead River, MT, USA is a 9-km anastomosed alluvial montane flood plain. Upstream from the flood plain, the river is unregulated and the catchment virtually pristine. A patchy mosaic of vegetation and channels exists on the flood-plain surface. The surface and subsurface geomorphic structures of the flood plain facilitate high hydrologic connectivity (water flux between the channel and flood plain) marked by complex seasonal patterns of flood-plain inundation, extensive penetration of channel water laterally into the alluvial aquifer, and springbrooks formed by ground water erupting onto the flood-plain surface. After delineating and classifying flood-plain “elements” (vegetation patches and channel reaches) on the flood plain, we analyzed field-based elevation survey data to identify expected relationships among flood-plain element type, surface scour frequency, and flood-plain elevation. Data analyses show that scour frequency was inversely proportional to the elevation of the flood plain above river stage, except when localized geomorphic controls such as natural levees prevent normal high flows from inundating and scouring relatively low flood-plain elements. Further, while different flood-plain element types occupy distinct elevation zones on the flood plain, the elevation of each zone above the river channel varies with localized channel entrenchment. We found that topographic variation among flood-plain elements is greater than the variation within elements, suggesting that coarse-scale flood-plain topography can be characterized by delineating flood-plain elements. Field data document strong associations between specific classes of flood-plain elements and preferential ground-water flow paths in the upper alluvial aquifer. Combined with preexisting ground penetrating RADAR (GPR) surveys, these data intimate a sinuous lattice of preferential ground-water flow paths (buried abandoned streambeds) in the upper alluvial aquifer at approximately the same elevation as the main channel's streambed. Using aerial photo interpretation and the identified relationships among element-types, elevation, and preferential ground-water flow paths, we developed a quantitative, three-dimensional characterization of surface and subsurface geomorphology across the entire flood plain to support a heuristic modeling effort investigating the influence of flood-plain geomorphology on spatio-temporal patterns of surface and ground-water flow and exchange under dynamic hydrologic regimes.

Assessing landslide potential using GIS, soil wetness modeling and topographic attributes, Payette River, Idaho

This study utilizes GIS modeling to determine if the location of 559 landslides in the 875 km 2 catchment of the Middle Fork of the Payette River, Idaho can be predicted based on topographic attributes and a wetness index generated by the DYNWET model. Slope and elevation were significantly related to landslide occurrence at this landscape scale. Aspect was also retained as a variable for further analysis because, despite a non-significant chi-square relation to landslide occurrence, graphical analysis suggested a relation between aspect and mass wasting. Chi-square analysis indicated that plan and profile curvature, flow path length, upslope contributing area, and the DYNWET-based moisture index were not significantly related to landsliding. A Bayesian probability model based on combinations of elevation, slope, aspect, and wetness indicates that elevation exhibits the closest relation to landsliding, followed by slope; but that neither aspect nor wetness index values help in prediction. The Bayesian probability model using elevation and slope generates a map of relative landslide risk that can be used to direct activities away from mass wasting prone areas. The association between elevation and landslides is perplexing but is perhaps due to the location of logging road at specific elevations (roads could not be included in the input data for analysis because they have not been adequately mapped). The lack of explanation provided by the DYNWET wetness index was also surprising and may be due to the 30-m digital elevation model (DEM) and the soils data having resolutions too coarse to adequately portray local variations key to mass wasting. We believe the inadequacy of data to drive the models is typical of the majority of catchment scale setting. For now, the ability of researchers to effectively model landscape scale landsliding is more limited by the type, resolution, and quality of available data than by the quality of the landslide models.

Late Pleistocene, post-Vashon, alpine glaciation of the Nooksack drainage, North Cascades, Washington

During the maximum late Wisconsin glaciation ca. 15 000 14C yr B.P., the Cordilleran Ice Sheet overwhelmed the Nooksack drainage of the northwestern Cascades, leaving only peaks higher than 2000 m above the ice surface. Ice-sheet flow over the Nooksack drainage and the adjacent Puget Lowland was essentially north-south. Rapid deglaciation between 14 500 and 12 500 14C yr B.P. resulted in dropping of the ice-sheet surface below ridge crests in the Nooksack drainage, and glacial activity thereafter became topographically controlled. Long valley glaciers in the upper Nooksack Valley were no longer connected to the Cordilleran Ice Sheet, and the source area changed from the main ice sheet to Mount Baker, Mount Shuksan, and the Twin Sisters Range. At that time, the margin of the remnants of the Cordilleran Ice Sheet was 30 km to the northwest, separated from the Nooksack Valley glaciers by several ridges 1200 m higher than the surface of the ice sheet. Moraines were built in all three forks of the Nooksack drainage, 25–45 km downvalley from their sources. The Middle Fork glacier stagnated 12 300 14C yr B.P. and deposited ice-contact drift that was later overridden when ice readvanced over ice-contact drift and deposited a prominent, 2-km-long, lateral moraine. Logs in a lateral moraine in the upper Middle Fork were dated at 10 680 ± 70 and 10 500 ± 70 14C yr B.P. The North Fork glacier, which originated at a large cirque on Mount Shuksan and was fed by glaciers from Mount Baker, extended to Kendall, where two moraines were deposited. Outwash from the younger moraine in the North Fork valley overlies glaciomarine drift, dated as 11 910 ± 80 14C yr B.P., and contains charcoal layers dated at 10 603 ± 69 and 10 788 ± 77 14C yr B.P. The South Fork glacier at its maximum was joined by ice from the Middle Fork and extended downvalley to Lake Whatcom and to Cranberry Lake. It retreated from its terminal position slightly before ca. 12 700 14C yr B.P.

Habitat Use by Three Species of Snakes at the Middle Fork Fish and Wildlife Area, Illinois

We used radiotelemetry to determine habitat use by 11 black rat snakes (Elaphe obsoleta obsoleta), five fox snakes (Elaphe vulpina vulpina) and four blue racers (Coluber constrictor foxii) at the Middle Fork Fish and Wildlife Area in east-central Illinois in 1997 and 1998. Black rat snakes selected forested habitats, whereas fox snakes and blue racers selected old fields and prairie restorations. No consistent association with forest- field edges was noted for any species. Fox snakes and blue racers were primarily terrestrial, whereas black rat snakes used all categories of vertical space but were primarily arboreal. Snakes were tracked to three hibernation sites, including an abandoned railroad trestle and two abandoned trash and construction-material dumps. These data provide the first comparative, quantitative descriptions of habitat use for these species in sympatry, and one of the few descriptions of hibemacula in a region dominated by row-crop agriculture. Due to their secretive behavior, snakes are difficult to study in the field and many impor- tant features of their ecology and natural history are not well known (Seigel et al., 1987; Seigel and Collins, 1993). Snakes also are frequently considered vermin and often indiscriminately killed by humans (Dodd, 1987; Greene, 1997). Because many species of snakes are declining in numbers (Dodd, 1987; Greene, 1997), it is im- portant to identify and protect critical habitats and landscape features relevant to their conser- vation. In temperate regions, sites used as hi- bemacula may be particularly important to the persistence of populations of many species of snakes (e.g., Prior and Weatherhead, 1996; Bur- brink et al., 1998). However, little information exists about habitat selection and sites used as hiberacula by snakes in agricultural regions of the midwestern United States.

POTENTIAL CLIMATE CHANGE IMPACTS ON MOUNTAIN WATERSHEDS IN THE PACIFIC NORTHWEST1

ABSTRACT: Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present‐day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. The RCM results indicate an average warming of about 2.5°C, and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds, the American River and Middle Fork Flathead, in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate, there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore, under the specific climate change scenario, the impacts are largely driven by the warming trend rather than the precipitation trend, which is small.

Microsatellite diversity in sympatric reproductive ecotypes of Pacific steelhead (Oncorhynchus mykiss) from the Middle Fork Eel River, California

Abstract– Genetic differentiation between two reproductive ecotypes of anadromous steelhead found in the Middle Fork Eel River in northern California was tested using 16 microsatellite loci. Twelve of these loci showed significant differences in allelic frequency between the two Middle Fork Eel River steelhead populations (Fisher's exact P <0.05). Fisher's combined test for independence also supported significant genetic separation between the two reproductive ecotype (P < 0.001). Analysis of molecular variance indicated that only 1% of the overall microsatellite allelic variation contributed to differences between summer‐ and winter‐run steelhead in the Middle Fork Eel River. Variation found among individuals within the two runs equaled 18.2%. Analyses showed less genetic distance between the two populations of steelhead in the Middle Fork Eel River than in comparisons made with geographically proximate coastal winter‐run fish. Divergence time based on genetic distance for the two within‐basin reproductive ecotypes was estimated to be 16,000–28,000 years ago.

MULTISCALE THERMAL REFUGIA AND STREAM HABITAT ASSOCIATIONS OF CHINOOK SALMON IN NORTHEASTERN OREGON

We quantified distribution and behavior of adult spring chinook salmon (Oncorhynchus tshawytscha) related to patterns of stream temperature and physical habitat at channel-unit, reach-, and section-level spatial scales in a wilderness stream and a disturbed stream in the John Day River basin in northeastern Oregon. We investigated the effectiveness of thermal remote sensing for analyzing spatial patterns of stream temperature and assessed habitat selection by spring chinook salmon, evaluating whether thermal refugia might be responsible for the persistence of these stocks in rivers where water temperatures frequently exceed their upper tolerance levels (25°C) during spawning migration. By presenting stream temperature and the ecology of chinook salmon in a historical context, we could evaluate how changes in riverine habitat and thermal spatial structure, which can be caused by land-use practices, may influence distributional patterns of chinook salmon. Thermal remote sensing provided spatially continuous maps of stream temperature for reaches used by chinook salmon in the upper subbasins of the Middle Fork and North Fork John Day River. Electivity analysis and logistic regression were used to test for associations between the longitudinal distribution of salmon and cool-water areas and stream habitat characteristics. Chinook salmon were distributed nonuniformly in reaches throughout each stream. Salmon distribution and cool water temperature patterns were most strongly related at reach-level spatial scales in the warm stream, the Middle Fork (maximum likelihood ratio: P < 0.01), and most weakly related in the cold stream, the North Fork (P > 0.30). Pools were preferred by adult chinook salmon in both subbasins (Bonferroni confidence interval: P ≤ 0.05); however, riffles were used proportionately more frequently in the North Fork than in the Middle Fork. Our observations of thermal refugia and their use by chinook salmon at multiple spatial scales reveal that, although heterogeneity in the longitudinal stream temperature profile may be viewed as an ecological warning sign, thermal patchiness in streams also should be recognized for its biological potential to provide habitat for species existing at the margin of their environmental tolerances.

Individual-based model of sympatric populations of brown and rainbow trout for instream flow assessment: model description and calibration

This paper describes an individual-based model of sympatric populations of brown and rainbow trout in a stream habitat. The model provides a tool for projecting flow and temperature effects on trout populations by linking the hydraulic component of the instream flow incremental methodology/physical habitat simulation system (IFIM/PHABSIM) to an individual-based population model. PHABSIM simulates the spatial distribution of depth and velocity at different flows, and indirectly, the availability of spawning habitat, cover and feeding station. The individual-based model simulates reproduction, growth and mortality of individual trout as a function of flow and temperature. Population dynamics arise from the survival and reproduction of individual trout. The spatially explicit nature of the model permits evaluation of behavioral responses used by fish to changes in physical habitat. The model has been calibrated to a stream segment in the North Fork Middle Fork Tule River, California. Selected parameters were adjusted to calibrate the model for length and abundance (including production of a new year class) at the end of 1-year simulations for each of 9 years. Predicted and observed lengths were in good agreement, although neither varied appreciably among years. Predicted and observed abundances were not in as good agreement, and differed considerably for some years. These differences reflect a combination of uncertainties in the field data and uncertainties in the model structure and parameter values. Fifty-year simulations indicated that model projections of length and abundance were stationary, although abundance values fluctuated considerably. Seven advantages for using simulation models of this type are emphasized. How to most effectively interpret results from such simulation models as part of instream flow environmental assessments remains a challenge. Variability and uncertainty in both field data and replicate model simulations are realities that have implications for scientists, resource managers, and regulators in projecting growth and abundance responses of fish populations to alternative flow or temperature regimes.

Development of a video-based coal slurry ash analyzer

Automatic control of fine-coal cleaning circuits has traditionally been limited by a lack of adequate sensors. Although several nuclear-based analyzers are available, none have seen widespread acceptance. In this investigation, image analysis is used for the on-line determination of ash contents in fine-coal slurries. The ash content of a flotation tailings stream is correlated to the mean gray level of the slurry. Based on a 90% prediction interval, an analysis of sensor performance indicates an accuracy of 73 ± 4% ash over a range of from 65% to 90% ash. While the results are comparable, the video-based system costs only a fraction of what a nuclear-based analyzer costs. The sensor is now installed at the Middle Fork preparation plant, which is owned by Pittston Coal Co.

Herpetofauna of Glacier National Park

The current distribution of amphibians and reptiles in Glacier National Park, Montana was documented from museum records and field surveys conducted in 1990 to 1992. Eight species were recorded at 141 sites at elevations from 1000 m to 2300 m. Rana luteiventris was the most common amphibian, occurring parkwide to elevations of 1800 m. Ambystoma macrodacEylum occurred in woodlands and wet meadows west of the Continental Divide at elevations between 1050 and 1500 m. This salamander was uncommon on the east side of the park with most sightings recorded in the lower Waterton Valley; none were found in the upper Missouri River drainage. Buto boreas was widely distributed to elevations up to 2250 m, but was not abundant at most locations. Ascaphus truei was found in small, cold, high gradient streams throughout the Middle Fork drainage, but occurred intermittently in the North Fork and upper Missouri ltiver drainages. A single population of A. truei was located in the South Saskatchewan River drainage. The range of Hyla regilla was restricted. Most sightings were made near the community of West Glacier, Montana, or at breeding ponds along the Middle Fork, Flathead River, a few km upstream. Chrysemys picta occurred mostly in the lower Lake McDonald valley at elevations between 1000 and 1120 m. A few turtles were seen in the North Fork drainage south of Polebridge, Montana. Thamnophis elegans was more abundant than the similarly distributed T. sirtalis. The widespread introduction of sport fish in park waters may have reduced amphibian populations in some drainages, notably in some of the high elevation valleys east of the Continental Divide. This content downloaded from 207.46.13.52 on Sat, 22 Oct 2016 04:48:40 UTC All use subject to http://about.jstor.org/terms 18 NORTHWESTERN NATURALIST 78(1) an, and terrestrial habitats. Intensive area searches were employed instead of more rigorous sampling methods (i.e., time-constrained searches, trapping, etc.) to ensure maximum coverage within the budget constraints and time available for the survey. Searches were conducted along major stream courses and their principal tributaries from the valley terminus to tree line. Some sites were revisited during successive years, however, most were searched only once. Sighting data were sorted by drainage within the 4 watersheds in the park (Appendix). Site locations were resolved to the nearest 50 m by UTM coordinates determined from standard 7.5', 1:24,000 USGS quad maps. UTM and elevation data were processed via a Unix-based Sun SPARC IPX Geographic Information System (GIS) running GRASS, Version 4.1. Survey data were used to generate range maps for each species. Adjustments were made during GIS processing of location data to minimize errors in the generation of species range maps arising from habitat variability across similar elevations, and to accommodate special circumstances such as disjunct or geographically restricted species distributions. To deal with variable weather influences, exposures, and radically different microhabitats at the same elevation within a watershed, range maps generated by the GIS excluded the highest 5% of recorded elevations for most species. This adjustment was not made for painted turtles, Chrysemys picta, or Pacific treefrogs, Hyla regilla, because both species occupy restricted geographic and altitudinal ranges in the park. The range map for tailed frogs, Ascaphus truei, includes only streams with documented sightings, because this species occupies a highly disjunct range in Glacier National Park. Frogs and toads were collected with a telescoping capture net fitted with a 25 cm diameter bag of 5 mm mesh size. A small handheld dip net was used for capturing tadpoles and salamander larvae. Captured specimens were identified in the field (Stebbins 1985) and in some cases measured and released. Garter snakes were hand-captured for positive identification and released. Field data included location, weather, water temperatures, habitat types, proximity of fish, and developmental stage of specimens. Field work was limited to daylight hours from late May through September 1990 to 1992. Night searches were not made due to the presence of dangerous predators in the study area; occasional night observations were made opportunistically in the vicinity of back country cabins and field camps. Field investigations were supplemented by examination of specimens and collection records from the Glacier Park Museum. Thirteen other museums issued collection permits for herpetofaunal studies in Glacier National Park also provided data. Because the present survey was undertaken to assess current conditions, museum data were not incorporated into the GIS range maps. However, past sighting and collection records are discussed in the accompanying species accounts.

Timing and significance of Late-glacial and Holocene cirque glaciation in the Sierra Nevada, California

Mapping and radiocarbon dates of cirque moraines in the Sierra Nevada demonstrate that the last significant pre-Little Ice Age glacier advance in the range, the Recess Peak, resulted from snowline lowering roughly twice that of the Matthes (Little Ice Age) advance, and that the Recess Peak advance is late Pleistocene in age. We mapped Recess Peak and Matthes deposits in 64 cirques along a profile of the main Sierran crest that spans the north-south limits of ‘Neoglacial’ deposits in the range. Equilibrium-line altitudes for the reconstructed Recess Peak glaciers vary greatly but coherently with those of the Matthes advance. The variability of both sets of deposits reflects strong topographic influences on snow accumulation and ablation patterns in their deep cirques. Tephrochronology and radiocarbon dates from lake-sediment cores provide limits on the timing of the two advances. Previous work documenting the absence of a young, regionally extensive tephra on Matthes moraines in the central Sierra demonstrates that they formed after ∼700 14C years BP (∼650 cal. years BP). The age of the Recess Peak advance has been less certain; we therefore collected and dated sediment cores from lakes dammed behind terminal moraines correlating to the Recess Peak advance in four widely separated drainages along the Sierran crest (north to south): South Fork American River, Lee Vining Creek, Middle Fork San Joaquin River, and Bishop Creek. Twenty-three high-precision AMS radiocarbon dates on gyttja, peat, and macrofossils from the cores are internally consistent and demonstrate that the Recess Peak advance, previously thought to be of late Holocene age (∼2500 years BP), ended before 11,190±70 14C years BP (∼13,100±85 cal. years BP). Recess Peak is therefore late Pleistocene in age and probably predates the North Atlantic Younger Dryas climatic reversal. The absence of any glacial deposits on the bedrock between the Recess Peak and Matthes deposits indicates that: (1) any advance related to the Younger Dryas event in central California was smaller than the Matthes advance; (2) the Matthes advance was the most extensive, and possibly the only, Neoglacial event in the range; and (3) climate in the Sierra between ∼13,000 cal. years BP and 650 cal. years BP was apparently too warm and/or dry to support glaciers larger than those of the Little Ice Age. Other mapping indicates that the Recess Peak is the first significant glacier advance after retreat of Tioga (local late-Wisconsin maximum) glaciers. These results suggest a regionally variable climate in western North America during the Younger Dryas event, because glaciers appear to have expanded in the Canadian Rockies at that time. The new Recess Peak age limits, combined with other dated lake cores, indicate that the Sierra was essentially deglaciated by 14,000–15,000 cal. years BP (∼12,000–13,000 14C years BP), substantially earlier than previously estimated. This finding indicates that current production rates of some in situ cosmogenic nuclides, calibrated on an assumed deglaciation of the range at 11,000 cal. years BP (∼10,000 14C years BP), may be systematically too high by as much as 20%.

ECONOMIC IMPACTS OF GUIDED WHITEWATER RAFTING: A STUDY OF FIVE RIVERS1

ABSTRACT: This paper presents estimates of the statewide economic impacts of guided whitewater rafting on five rivers in six states: the Nantahala (North Carolina), Gauley (West Virginia), Kennebec (Maine), Middle Fork of the Salmon (Idaho), and Chattooga (Georgia‐South Carolina). Except for the Chattooga and Middle Fork, rafting is dependent on upstream dam releases. Guide fees range from about $15 per trip on the Nantahala to over $1,000 on the Middle Fork. Economic impacts per nonresident 1000 visitors increase along with length of the rafting trip and remoteness of the river. Total industrial output per 1000 nonresident visitors ranged from $95,000 on the Nantahala to over $2.5 million on the Middle Fork. However, because of differences in annual visitation levels, total impacts were greatest at the Nantahala, at over $14 million in 1993. Multipliers for all economic measures were relatively consistent over the rivers. Employment multipliers (Type III) ranged from 1.67 to 1.90, income multipliers from 2.0 to 2.4, and industrial output multipliers from 2.1 to 2.5.

CHANGES IN CHANNEL MORPHOLOGY ASSOCIATED WITH PLACER MINING

Channel morphology along the Middle Fork of the South Platte River near Fairplay, Colorado has changed from 1859 to the present in association with placer gold mining. Based on the premise that mining destabilized channel-bed and bank sediments, we hypothesize that there will be a relation between mining and channel morphologic and sedimentologic characteristics. To quantify differences in channel morphology between mined and unmined reaches, four primary channel characteristics (shape, bed material, migration, and sinuosity) were examined. A discriminant function analysis showed no statistical difference in channel shape between mined and unmined reaches. Bed material in reaches where mining occurred in the channel can be distinguished from unmined reaches on the basis of mean grain-size, sorting, and skewness. Mean grain-size and sorting increase and the skewness of the distribution is nearly symmetrical in mined areas. Statistical differences in planimetric form also were observed. The channel has been...

Never Turn Back: The Life of Whitewater Pioneer Walt Blackadar by Ron Watters

300 WesternAmerican Literature at a particular point “left their pastoral and entered a genesis, a time of creation that in their case included a fall into history,”and she elaborates on the nature of the bomb’s ability to obliterate cultural notions of containment and separation. The second half of the book explores the landscape and history of Yosemite National Park. Threaded through Solnit’s history of the area—accounts of explorers, soldiers, Native Americans, settlers—is her personal experience of the landscape and literary digressions on philosophical and cultural views of wilderness. Particularly valu­ able because ofcontinuing debate on the nature ofNature is her account and discussion of Native Americans for whom the Park is home and workplace as well as ancestral land. For some readers, the personal accounting and the eclectic spirit of the book may detractfrom the arguments ofthe book; for many thesewill be sources ofpleasure. Solnit succeeds in her intention to describe a West omitted from popular historical accounts, from painting, literature, official accountings of its Parks and landmarks, and she suc­ ceeds in describing personal relationships—historical and contemporary—to the land­ scapes. ZITAINGHAM Southwestern Oregon Community College Never Turn Back: TheLifeofWhitewaterPioneer WaltBlackadar. ByRon Watters. (Pocatello: The Great Rift Press, 1994. 295 pages, $14.95.) Walt Blackadar did not invent big-water kayaking, but he certainly popularized it, though many purists resented his brash ways. Watters, director of the Idaho State University Outdoor Program, knows the area and the arena ofBlackadar’sworld though he came into the eraalittle late. Nonetheless, Watters does an excellentjob ofrecreating all three ashe captures the essence ofBlackadar: the three-decade era (1949 to 1978), the area (Idaho), and the arena (big-water kayaking). Walt, as everyone called him, began kayaking in his mid-40’s, and though he barely lived through his mid-50’s,his briefpaddling career took him to the pinnacle ofthe sport that he so powerfully influenced. What he lacked in technique and finesse, he achieved through dynamic physical power, bravado, and ego. Blackadar, a surgeon from the East, moved west to begin his medical practice in Salmon, Idaho, in the fall of 1949. There he fell in love with the outdoors and began steeping himself in such activities as hunting, fishing, and whitewater boating on the Salmon River and its Middle Fork. Watters’ biography captures all this and more: the metamorphosis of Idaho’s conservation movement in the 1970s, the development of Blackadar’s medical practice, and the evolution of whitewater paddling in the go-for-the-gusto mode. Blackader became a legend in his own time through his pioneering river trips by kayak on big water and small rivers: the Colorado River in Grand Canyon, the Alsek and Susitna in Alaska, and a series of small, tight Idaho rivers at high water. Perhaps the most poignant episode in the book is the account of Julie Wilson’s death on the West Fork of the Bruneau in 1974, a trip which Walt led. Watters writes sensitively about her entrapment and drowning, the search for her body and her subse­ quent memorial service and burial, all ofwhich haunted Walt for the rest of his life. His own paddling days ended a few years later when he drowned on the South Fork of the Reviews 301 Payette River in Idaho the spring of 1978. The rapid in which he died is now called Blackadar Drop, a Class III+ run. The biography has minor grammatical and usage errors, but carves for the reader a clear three-dimensional picture of the man. VERNE HUSER AlbuquerqueAcademy KillingCuster:TheBattleoftheLittleBighornand theFateofthePlainsIndians. ByjamesWelch, with Paul Stekler. (New York: Norton, 1994. 320 pages, $25.00.) James Welch’s first published foray into nonfiction resulted from work he did writing ascriptfor documentaryfilmmaker PaulSteklerand continues atheme central to all of his writing to date: that Native Americans “are not noble red men. Nor savages. These are Native Americans. Human Beings.”To his credit he largely accomplishes this task even-handedly, writing with empathy for individuals from every side (including Indians who helped the whites against their own people), while focusing on the much analyzed yet still magnetic Custer myth. From the Indian art of the attractive dustjacket...

Thermally Stratified Pools and Their Use by Steelhead in Northern California Streams

Thermal stratification occurred in pools of three rivers in northern California when inflow of cold water was sufficiently great or currents were sufficiently weak to prevent thorough mixing of water of contrasting temperatures. Surface water temperatures in such pools were commonly 3–9°C higher than those at the bottom. Cold water entered pools from tributaries, intergravel flow through river bars, and streamside subsurface sources. In Redwood and Rancheria Creeks, cold water was protected where gravel bars encroached into pools that were scoured along bedrock banks, creating isolated backwaters. Sixty-five percent of the juvenile steelhead Oncorhynchus mykiss found in the Rancheria Creek study reaches moved into adjacent stratified pools during periods of high ambient stream temperatures (23–28°C). Fish showed a decline in forage behavior and increased agonistic activity just before movement into stratified pools. In the Middle Fork Eel River, pools deeper than 3 m stratified when surface flow decreased to less than 1 m3/s. Summer-run steelhead adults were found in deep stratified pools on the Middle Fork Eel River throughout summer when midday ambient stream temperatures ranged from 26 to 29°C and coldwater pockets averaged 3.5°C cooler. Thermally stratified pools provided refuge habitat for significant numbers of young-of-the-year, yearling, and adult steelhead in marginal river habitats where stream temperatures reach upper incipient lethal levels.

A distributed hydrology‐vegetation model for complex terrain

A distributed hydrology‐vegetation model is described that includes canopy interception, evaporation, transpiration, and snow accumulation and melt, as well as runoff generation via the saturation excess mechanisms. Digital elevation data are used to model topographic controls on incoming solar radiation, air temperature, precipitation, and downslope water movement. Canopy evapotranspiration is represented via a two‐layer Penman‐Monteith formulation that incorporates local net solar radiation, surface meteorology, soil characteristics and moisture status, and species‐dependent leaf area index and stomatal resistance. Snow accumulation and ablation are modeled using an energy balance approach that includes the effects of local topography and vegetation cover. Saturated subsurface flow is modeled using a quasi three‐dimensional routing scheme. The model was applied at a 180‐m scale to the Middle Fork Flathead River basin in northwestern Montana. This 2900‐km2, snowmelt‐dominated watershed ranges in elevation from 900 to over 3000 m. The model was calibrated using 2 years of recorded precipitation and streamflow. The model was verified against 2 additional years of runoff and against advanced very high resolution radiometer based spatial snow cover data at the 1‐km2 scale. Simulated discharge showed acceptable agreement with observations. The simulated areal patterns of snow cover were in general agreement with the remote sensing observations, but were lagged slightly in time.

Tectonic implications of radiolarian cherts from the Placerville Belt, Sierra Nevada Foothills, California: Nevadan-age continental growth by accretion of multiple terranes

We have recognized several age groups of radiolarians in cherts in a belt of rock in the Sierra Foothills between the Melones-Gillis Hill fault and the Bear Mountains-Wolf Creek-Big Bend faults. They are Late Permian, Late Triassic, Early Jurassic, Middle Jurassic, and late Middle Jurassic in age. The biostratigraphic control provided by recognition of these groups, combined with study of lithologic assemblages related to them, has enabled us to divide this belt in the area between the Cosumnes River and the Middle Fork of the American River into five terranes; Mother Lode, French Creek, Mount Ararat, Cool Quarry, and American River. The slate and volcanic breccia of the Mother Lode Terrane (Mariposa and Logtown Ridge Formations) are depositionally linked to unmetamorphosed Late Permian basalt, chert, and gabbro which we propose represents basement of the stratigraphie sequence. In addition, the late Middle Jurassic Colfax Formation is depositionally linked to the early Middle Jurassic olistostrome (Clipper Gap Formation) in the American River Terrane. Recognition of separate terranes and the stratigraphy within them indicate that terrane amalgamation (probably during accretion to North America) is constrained to be younger than Callovian, and that the Nevadan orogeny was the result of accretion of multiple terranes to the continental margin during the period of 163-143 Ma.

Column Flotation at the Middle Fork Preparation Facility

Abstract A laboratory and pilot-scale test program was carried out to assess the merits of installing column flotation cells at the Middle Fork coal preparation facility. The test data showed that column cell technology was superior to single- and multi-stage conventional flotation circuits in terms of fine coal recovery and product grade. In light of these promising results, a full-scale column flotation circuit was designed, installed and commissioned at the Middle pork plant. The circuit utilizes five 3-m diameter Microcel™ flotation columns to process approximately 100 tph of minus 150 μm raw coal. The column retrofit reduced the ash content of the plant's flotation circuit by nearly 7 percentage points and increased the combustible recovery by approximately 27 percent. This article provides a summary of the test results and discusses the scale-up procedures used to design the commercial columns.