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Research about Montana

Source-linked reports with geographic coverage including Montana.

At least 415 records · Page 23Linked to original sources
USGS2004

Summary of studies supporting cumulative effects analysis of upper Yellowstone River channel modifications

During the last several decades, portions of the upper Yellowstone River have been modified for flood control and erosion prevention. The U.S. Army Corps of Engineers is responsible for administration of a permit program for evaluating construction activities affecting rivers, streams, and wetlands. The Corps regulates activities under the authority of Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act. Since assumption of jurisdiction in the mid-1970’s, the Corps has processed a total of 156 permit actions for the upper Yellowstone River. Over two-thirds of the permit actions occurred during or after two consecutive large floods during 1996 and 1997. In response to concern regarding the potential environmental and ecological consequences of channel modification, the Corps, in conjunction with State and local government agencies, initiated a series of scientific studies to better understand the effects of channel modification in the upper Yellowstone River (Figure 1). These included preparation of wetland and riparian inventory maps (Bon, 2001); hydraulic modeling and flood-plain delineation; watershed land-cover assessment (Pick and Potter, 2003); historic bottomland use analysis (Brelsford and others, 2003); analysis of channel modification effects on fish habitat (Bowen and others, 2003); comparison of juvenile salmonid use of modified and unmodified habitats (Zale and Rider, 2003); analysis of riparian vegetation and flood-plain turnover (Merigliano and Polzin, 2003); study of the relations between riparian habitat and bird communities (Hansen and others, 2003); analyses of geomorphology and historical channel changes (Dalby and Robinson, 2003); socioeconomic assessment (BBC Research and Consulting, 2002); and sediment transport investigations and modeling (Holnbeck, 2003). This report is a summary of results from the individual scientific studies as they bear on future programmatic cumulative effects analyses of channel modification of the upper Yellowstone River. We do not attempt a formal, cumulative impact assessment in the sense of evaluating alternatives or future scenarios. The first section presents major findings of the resource studies in terms of temporal comparisons, spatial comparisons, and causal relations. In this section, we present a series of conceptual models or flow diagrams of the major causal pathways of cumulative impacts from channel modification. These represent major pathways of potential impact based on knowledge from other rivers, concerns expressed about the upper Yellowstone, and results from the scientific studies. These diagrams serve to focus interpretation of study results as either supporting or not supporting the importance and magnitude of particular causal relations and to identify key linking variables appearing in multiple causal pathways. These key variables that connect channel modification actions to multiple, valued environmental attributes can serve as the foundation for both projecting and monitoring future responses of the system. A section on analytical realities outlines some of the limitations of projecting cumulative impacts from channel modification of the upper Yellowstone River on meaningful spatial and temporal scales and some of the difficulties of interpreting results from studies conducted shortly after two extreme floods and substantial increases in channel modification. A section on classification describes the two primary geomorphic classification systems of the upper Yellowstone River used in the various individual resource studies. Each of these systems has been valuable in supporting field sampling and expressing results concerning patterns of variation. Their integration or revision into a classification system to achieve some new purpose, such as a regulatory program or monitoring system, will depend on a crisp articulation of riverine management or regulatory objectives. A section on key variables identifies those that are central to the causal pathways connecting channel modification to impacts and provides a rationale for key variables as an alternative to other tools such as Proper Functioning Condition (Barrett and others, 1993), Index of Biotic Integrity (Karr, 1981), or the Synoptic Approach (Liebowitz and others, 1992). This section also explains relations among key variable to Hydrogeomorphic (HGM) assessment procedures (Hauer and Smith, 1998; Hauer and others, 2001) and outlines how these 2 variables might be monitored to track cumulative impacts. Examples of how selected key variables can be quantified using Geographic Information System data sets developed from the resource studies are presented for one reach. The largest portion of the document is an Appendix that summarizes each of the individual scientific studies in terms of scope and methods, findings, principal variables, and metrics used in the study or suggested by the study results, and important needs for further study.

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USGS2004

Integrated investigations of environmental effects of historical mining in the Basin and Boulder Mining Districts, Boulder River watershed, Jefferson County, Montana

The Boulder River watershed is one of many watersheds in the western United States where historical mining has left a legacy of acid mine drainage and elevated concentrations of potentially toxic trace elements. Abandoned mine lands commonly are located on or affect Federal land. Cleaning up these Federal lands will require substantial investment of resources. As part of a cooperative effort with Federal land-management agencies, the U.S. Geological Survey implemented an Abandoned Mine Lands Initiative in 1997. The goal of the initiative was to use the watershed approach to develop a strategy for gathering and communicating the scientific information needed to formulate effective and cost-efficient remediation of affected lands in a watershed. The watershed approach is based on the premise that contaminated sites that have the most profound effect on water and ecosystem quality within an entire watershed should be identified, characterized, and ranked for remediation. The watershed approach provides an effective means to evaluate the overall status of affected resources and helps to focus remediation at sites where the most benefit will be gained in the watershed. Such a large-scale approach can result in the collection of extensive information on the geology and geochemistry of rocks and sediment, the hydrology and water chemistry of streams and ground water, and the diversity and health of aquatic and terrestrial organisms. During the assessment of the Boulder River watershed, we inventoried historical mines, defined geological conditions, assessed fish habitat, collected and chemically analyzed hundreds of water and sediment samples, conducted toxicity tests, analyzed fish tissue and indicators of physiological malfunction, examined invertebrates and biofilm, and defined hydrological regimes. Land- and resource-management agencies are faced with evaluating risks associated with thousands of potentially harmful mine sites, and this level of effort is not always feasible for every affected watershed. The detailed work described in this report can help Federal land-management agencies decide which characterization efforts would be most useful in characterization of other affected watersheds.

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USGS2004

Precambrian basement geologic map of Montana– An interpretation of aeromagnetic anomalies

Newly compiled aeromagnetic anomaly data of Montana, in conjunction with the known geologic framework of basement rocks, have been combined to produce a new interpretive geologic basement map of Montana. Crystalline basement rocks compose the basement, but are exposed only in the cores of mountain ranges in southwestern Montana. Principal features deduced from the map are: (1) A prominent northeast-trending, 200-km-wide zone of spaced negative anomalies, which extends more than 700 km from southwestern Montana's Beaverhead Mountains to the Canadian border and reflects suturing of the Archean Mexican Hat Block against the Archean Wyoming Province along the Paleoproterozoic Trans-Montana Orogen (new name) at about 1.9-1.8 Ga; (2) North-northwest-trending magnetic lows in northeastern Montana, which reflect the 1.9-1.8 Ga Trans-Hudson Orogen and truncate the older Trans-Montana Zone; and (3) Subtle northwest- and west-trending negative anomalies in central and western Montana, which represent the northernmost segment of brittle-ductile transcurrent faults of the newly recognized Mesoproterozoic Trans-Rocky Mountain fault system. Structures developed in the Proterozoic provided zones of crustal weakness reactivated during younger Proterozoic and Phanerozoic igneous and tectonic activity. For example, the Trans-Montana Zone guided basement involved thrust faulting in southwestern Montana during the Sevier Orogeny. The Boulder Batholith and associated ore deposits and the linear belt of alkaline intrusions to the northeast were localized along a zone of weakness between the Missouri River suture and the Dillon shear zone of the Trans-Montana Orogen. The northwest-trending faults of Trans-Rocky Mountain system outline depocenters for sedimentary rocks in the Belt Basin. This fault system provided zones of weakness that guided Laramide uplifts during basement crustal shortening. Northwest-trending zones have been locally reactivated during Neogene basin-range extension.

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USGS2004

Methods for estimating flood frequency in Montana based on data through water year 1998

Annual peak discharges having recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years (T-year floods) were determined for 660 gaged sites in Montana and in adjacent areas of Idaho, Wyoming, and Canada, based on data through water year 1998. The updated flood-frequency information was subsequently used in regression analyses, either ordinary or generalized least squares, to develop equations relating T-year floods to various basin and climatic characteristics, equations relating T-year floods to active-channel width, and equations relating T-year floods to bankfull width. The equations can be used to estimate flood frequency at ungaged sites. Montana was divided into eight regions, within which flood characteristics were considered to be reasonably homogeneous, and the three sets of regression equations were developed for each region. A measure of the overall reliability of the regression equations is the average standard error of prediction. The average standard errors of prediction for the equations based on basin and climatic characteristics ranged from 37.4 percent to 134.1 percent. Average standard errors of prediction for the equations based on active-channel width ranged from 57.2 percent to 141.3 percent. Average standard errors of prediction for the equations based on bankfull width ranged from 63.1 percent to 155.5 percent. In most regions, the equations based on basin and climatic characteristics generally had smaller average standard errors of prediction than equations based on active-channel or bankfull width. An exception was the Southeast Plains Region, where all equations based on active-channel width had smaller average standard errors of prediction than equations based on basin and climatic characteristics or bankfull width. Methods for weighting estimates derived from the basin- and climatic-characteristic equations and the channel-width equations also were developed. The weights were based on the cross correlation of residuals from the different methods and the average standard errors of prediction. When all three methods were combined, the average standard errors of prediction ranged from 37.4 percent to 120.2 percent. Weighting of estimates reduced the standard errors of prediction for all T-year flood estimates in four regions, reduced the standard errors of prediction for some T-year flood estimates in two regions, and provided no reduction in average standard error of prediction in two regions. A computer program for solving the regression equations, weighting estimates, and determining reliability of individual estimates was developed and placed on the USGS Montana District World Wide Web page. A new regression method, termed Region of Influence regression, also was tested. Test results indicated that the Region of Influence method was not as reliable as the regional equations based on generalized least squares regression. Two additional methods for estimating flood frequency at ungaged sites located on the same streams as gaged sites also are described. The first method, based on a drainage-area-ratio adjustment, is intended for use on streams where the ungaged site of interest is located near a gaged site. The second method, based on interpolation between gaged sites, is intended for use on streams that have two or more streamflow-gaging stations.

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USGS2004

Yellowstone grizzly bear investigations: Annual report of the Interagency Grizzly Bear Study Team, 2003

The contents of this Annual Report summarize results of monitoring and research from the 2003 field season. The report also contains a summary of nuisance grizzly bear ( Ursus arctos horribilis ) management actions. The study team continues to work on issues associated with counts of unduplicated females with cubs-of-the-year (COY). These counts are used to establish a minimum population size, which is then used to establish mortality thresholds for the Recovery Plan (U.S. Fish and Wildlife Service [USFWS] 1993). A computer program that defines the rule set used by Knight et al. (1995) to differentiate unique family groups is currently under development. Once complete, we intend to use it to verify the accuracy of the rules using known bears and their telemetry locations in test runs. We hope to have this work complete by summer 2004. The grizzly bear recovery plan (USFWS 1993) established mortality quotas at 4% of the minimum population estimate derived from female with COY data and no more than 30% of the 4% (1.2%) could be female bears. Simulation modeling (Harris 1984) established sustainable mortality at around 6% of the population. We used the latest information on reproduction and survival to estimate population trajectory in the same simulation model originally used by Harris. A Wildlife Monograph has been drafted and submitted for consideration as a publication. We anticipate final word sometime during winter 2005. Our project addressing the potential application of stable isotopes and trace elements to quantify consumption rates of whitebark pine ( Pinus albicaulis ) and cutthroat trout ( Oncorhynchus clarki ) by grizzly bears was completed. Our manuscript on consumption rates of whitebark pine has been published (Canadian Journal of Zoology 81:763-770). A copy can be found on the Interagency Grizzly Bear Study Team (IGBST) website http://www.nrmsc.usgs.gov/research/igbst-home.htm. The manuscript on fish consumption is in final review and should be published in 2004. We began a new study in Grand Teton National Park evaluating habitat use both temporally and spatially between grizzly and black ( Ursus americanus ) bears. We will employ a new form of Global Positioning System (GPS) technology that incorporates a spread spectrum communication system. Spread spectrum allows for transfer of stored GPS locations from the collar to a remote receiving station. We tested 2 collars during the fall of 2003 and provide a summary of the results. We will attempt to deploy several of these collars during the 2004 field season. The annual reports of the IGBST summarize annual data collection. Because additional information can be obtained after publication, data summaries are subject to change. For that reason, data analyses and summaries presented in this report supersede all previously published data. The study area and sampling techniques are reported by Blanchard (1985), Mattson et al. (1991a), and Haroldson et al. (1998).

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USGS2004

Forecasting for natural avalanches during spring opening of Going-to-the-Sun Road, Glacier National Park, Montana, USA

The annual spring opening of the Going-to-the-Sun Road in Glacier National Park presents a unique avalanche forecasting challenge. The highway traverses dozens of avalanche paths mid-track in a 23-kilometer section that crosses the Continental Divide. Workers removing seasonal snow and avalanche debris are exposed to paths that can produce avalanches of destructive class 4. The starting zones for most slide paths are within proposed Wilderness, and explosive testing or control are not currently used. Spring weather along the Divide is highly variable; rain-on-snow events are common, storms can bring several feet of new snow as late as June, and temperature swings can be dramatic. Natural avalanches - dry and wet slab, dry and wet loose, and glide avalanches - present a wide range of hazards and forecasting issues. This paper summarizes the forecasting program instituted in 2002 for the annual snow removal operations. It focuses on tools and techniques for forecasting natural wet snow avalanches by incorporating two case studies, including a widespread climax wet slab cycle in 2003. We examine weather and snowpack conditions conducive to wet snow avalanches, indicators for instability, and suggest a conceptual model for wet snow stability in a northern intermountain snow climate.

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USGS2004

Natural avalanches and transportation: A case study from Glacier National Park, Montana, USA

In January 2004, two natural avalanches (destructive class 3) derailed a freight train in John F. Stevens Canyon, on the southern boundary of Glacier National Park. The railroad tracks were closed for 29 hours due to cleanup and lingering avalanche hazard, backing up 112km of trains and shutting down Amtrak’s passenger service. The incident marked the fourth time in three winters that natural avalanches have disrupted transportation in the canyon, which is also the route of U.S. Highway 2. It was the latest in a 94-year history of accidents that includes three fatalities and the destruction of a major highway bridge. Despite that history and the presence of over 40 avalanche paths in the 16km canyon, mitigation is limited to nine railroad snow sheds and occasional highway closures. This case study examines natural avalanche cycles of the past 28 winters using data from field observations, a Natural Resources Conservation Service (NRCS) SNOTEL station, and data collected since 2001 at a high-elevation weather station. The avalanches occurred when storms with sustained snowfall buried a persistent near-surface faceted layer and/or were followed by rain-on-snow or dramatic warming (as much as 21 o C in 30 minutes). Natural avalanche activity peaked when temperatures clustered near freezing (mean of -1.5 o C at 1800m elev.). Avalanches initiated through rapid loading, rain falling on new snow, and/ or temperature-related changes in the mechanical properties of slabs. Lastly, the case study describes how recent incidents have prompted a unique partnership of land management agencies, private corporations and non-profit organizations to develop an avalanche mitigation program for the transportation corridor.

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USGS2004

USA: Glacier National Park, Biosphere Reserve and GLORIA Site

The National Park Service of the United States has 388 designated protected areas and parks that include historic and cultural sites as well as ‘natural resource’ parks set aside for their unique and outstanding natural features. Early efforts to create parks were focused on areas of beauty or unusual features but later efforts increasingly aimed to protect biodiversity and intact ecosystems. Protected areas in the National Park Service are found in nearly all the fifty states from Florida to Alaska, with examples of preserved natural environments ranging from coral reefs to the icy summit of Mt. McKinley in Alaska, at 6,187 m. Many of the larger parks have been designated as Biosphere Reserves under the United Nations Educational, Scientific and Cultural Organization (UNESCO) Man and the Biosphere Programme. The area now managed as Glacier National Park was first set aside as a Forest Reserve in 1897 and then designated as a national park in 1910, six years before a national park service was created to oversee the growing number of parks that the US Congress was establishing. Waterton National Park was created by Canada immediately north of the US–Canada border during the same period. In 1932, a joint lobbying effort by private citizens and groups convinced both the United States and Canada to establish the world’s first trans-boundary park to explicitly underscore and symbolize the neighbourly relationship between these two countries. This became the world’s first ‘peace’ park and was named Waterton–Glacier International Peace Park. The combined park is managed collaboratively on many issues but each national park is separately funded and operates under different national statutes and laws. It was, however, jointly named a Biosphere Reserve in 1976 and a World Heritage Site in 1995. There have been recent efforts to significantly increase the size of Waterton National Park by adding publicly owned forests on the western side of the continental divide in British Columbia, Canada. For the purposes of this chapter, I will emphasize the US portion of the Waterton-Glacier International Peace Park and refer to it as the Glacier Mountain Biosphere Reserve (MBR).

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USGS2003

Comparing potential fuel treatment trade-off models

Understanding the trade-offs between short-term and long-term consequences of fire impacts on ecosystems is needed before a comprehensive fuels management program can be implemented nationally. We are evaluating 3 potential trade-off models at 8 locations in major U.S. fuel types. We present results of the initial testing of the 3 selected models/modelling approaches and a 4 th model on the Bitterroot National Forest (BNF) in western Montana. The selected models/modelling approaches were 1) the Fire Emissions Trade-off Model (FETM), 2) sequential use of the SIMPPLLE and MAGIS models, 3) the Vegetation Dynamics Development Tool (VDDT), and 4) the LANDscape Succession Model (LANDSUM). We simulated 3 fuel treatments over 50 years: 1) no action, 2) prescribed burning in ponderosa pine and Douglas-fir types at 2 different rates, and 3) timber harvesting that returns the stand to a reproduction stage. Simulation results for all models suggested that the acreage of Douglas-fir and ponderosa pine types would not be appreciably altered by the fuel treatments. Most models suggested the harvest treatment would reduce area burned by wildfire and smoke emissions; some models suggested the prescribed fire treatment would reduce wildfire acreage. All models suggested that the harvest treatment would reduce acreage of pole-size trees; some models suggested the fire treatment would increase acreage of sapling-size trees.

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USGS2003

Scale-dependent temporal variations in stream water geochemistry

A year-long study of four western Montana streams (two impacted by mining and two “pristine”) evaluated surface water geochemical dynamics on various time scales (monthly, daily, and bi-hourly). Monthly changes were dominated by snowmelt and precipitation dynamics. On the daily scale, post-rain surges in some solute and particulate concentra tions were similar to those of early spring runoff flushing characteristics on the monthly scale. On the bi-hourly scale, we observed diel (diurnal−nocturnal) cycling for pH, dissolved oxygen, water temperature, dissolved inorganic carbon, total suspended sediment, and some total recoverable metals at some or all sites. A comparison of the cumulative geochemical variability within each of the temporal groups reveals that for many water quality parameters there were large overlaps of concentration ranges among groups. We found that short-term (daily and bi-hourly) variations of some geochemical parameters covered large proportions of the variations found on a much longer term (monthly) time scale. These results show the importance of nesting short-term studies within long-term geochemical study designs to separate signals of environmental change from natural variability.

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USGS2003

Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss

We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi , and nonnative rainbow trout, O. mykiss , in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were determined to be nonhybridized in 1984. Patterns of spatial autocorrelation and linkage disequilibrium indicated that hybridization is spreading among sites and is advancing primarily via post-F 1 hybrids. Although hybridized populations were distributed widely throughout the study area, the genetic contribution from O. mykiss decreased with increasing upstream distance from the Flathead River mainstem, suggesting that O. mykiss introgression is spreading in an upstream direction. The spread of hybridization may be constrained more by demographic than by environmental factors, given that ( i ) hybridized populations generally encompassed the range of environmental variability in nonhybridized populations, and ( ii ) hybridization status was more strongly associated with neighborhood statistics than measured environmental gradients.

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USGS2003

Winter diel habitat use and movement by subadult bull trout in the upper Flathead River, Montana

We evaluated the diel habitat use and movement of subadult bull trout Salvelinus confluentus by use of radiotelemetry during winter in the upper Flathead River, Montana. Of the 13 monitored bull trout, 12 (92%) made at least one diel movement to other habitat locations during their respective day–night tracking surveys and moved an average of 73% of the time. The median distance moved from day to night locations by the mobile fish was 86 m (range, 27–594 m). Diel shifts in habitat use by nine of the tagged fish were related to light intensity; nocturnal emergence generally commenced immediately after the onset of night, and daytime concealment occurred at daybreak. When diel shifts in microhabitat use occurred, subadult bull trout moved from deep, midchannel areas during the day to shallow, low‐velocity areas along the channel margins without overhead cover at night. Resource managers who wish to protect the overwintering habitat features preferred by subadult bull trout in the upper Flathead River should use natural flow management strategies that maximize and stabilize channel margin habitats at night.

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USGS2003

Modeled climate-induced glacier change in Glacier National Park, 1850-2100

The glaciers in the Blackfoot–Jackson Glacier Basin of Glacier National Park, Montana, decreased in area from 21.6 square kilometers (km 2 ) in 1850 to 7.4 km 2 in 1979. Over this same period global temperatures increased by 0.45°C (± 0.15°C). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of glaciers and of the response of vegetation to climate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios, one based on carbon dioxide–induced global warming and the other on a linear temperature extrapolation. Under the former scenario, all glaciers in the basin will disappear by the year 2030, despite predicted increases in precipitation; under the latter, melting is slower. Using a second model, we analyzed vegetation responses to variations in soil moisture and increasing temperature in a complex alpine landscape and predicted where plant communities are likely to be located as conditions change.

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USGS2003

Annual survival and population estimates of Mountain Plovers in Southern Phillips County, Montana

Information about the demography of declining species is especially relevant to their conservation and future recovery. Knowledge of survival rates and population size can be used to assess long-term viability and population trends, both of which are of interest to conservation biologists. We used capture–recapture techniques to study the demography of Mountain Plovers ( Charadrius montanus Townsend) in southern Phillips County, Montana, USA, in 1995–2000. We used the robust design to estimate annual survival (φ), conditional capture ( p and r ) and recapture ( c ) probabilities, and the annual population size ( N ) in the presence of temporary emigration. The results support age-specific differences in annual survival that are a function of juvenile body mass and are correlated with the area occupied by prairie dogs. Body mass had a positive effect on juvenile survival; the slope coefficient for the additive effect of body mass on juvenile survival was 0.77 (95% ci = 0.25, 1.28) on a logit scale. A measure of plover habitat (the area occupied by prairie dogs) appeared to have no effect on survival; the slope coefficient for the additive effect of area occupied by prairie dogs on survival was –0.00004 (95% ci = –0.00003, –0.0001) on a logit scale. Estimated annual apparent survival rates were 0.46–0.49 for juveniles and 0.68 for adult plovers. Using these estimates, the life span of a Mountain Plover was 1.92 ± 0.17 years (mean ± 1 se ) from time of capture as a chick. Resighting rates positively influenced capture probabilities; the slope coefficient for the additive resighting effect was –0.49 (95% ci = –0.86, –0.11) on a logit scale. The size of this adult Mountain Plover population was estimated at 95–180 adults annually. Population size closely tracked annual changes in the area occupied by black-tailed prairie dogs, with both plovers and prairie dogs rapidly recovering from an outbreak of sylvatic plague in the mid-1990s. Given the low annual survival rates and low mean life expectancy of Mountain Plovers, we conclude that sustainable local populations are currently maintained by annual rates of productivity greater than those for other ground-nesting birds.

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USGS2003

A method for determining the onset year of intense browsing

McAuliffe studied the factors limiting seedling establishment of a common Sonoran Desert tree, Cercidium microphyllum, at three sites in bajada habitat in Arizona and Mexico. Distribution patterns of Cercidium seedlings in both habitats were random when seedlings emerged, however, seedling distribution in bajadas quickly became non-random and associated with other perennial plants. Seedlings closely associated with (rooted under) shrubby perennial vegetation survived because they had some protective cover and were not grazed by rabbits, however, future survival of these seedlings may be reduced due to competition with the protective plants. The authors concluded that herbivory was the main factor limiting the establishment of Cercidium microphyllum seedlings in the bajada habitats in the Sonoran desert.

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USGS2003

Water-quality, bed-sediment, and biological data, for streams in the upper Prickly Pear Creek watershed, Montana, 2001

The upper Prickly Pear Creek watershed encompasses the upstream 15 miles of Prickly Pear Creek, south of Helena, Montana (fig. 1). The headwaters of Prickly Pear Creek and its tributaries (Beavertown Creek, Clancy Creek, Dutchman Creek, Golconda Creek, Lump Gulch, Spring Creek, and Warm Springs Creek) are primarily in the Helena National Forest, whereas the central part of the watershed primarily is within either Bureau of Land Management (BLM) or privately owned property. Three mining districts are present in the upper Prickly Pear Creek watershed: Alhambra, Clancy, and Colorado. Numerous prospects, adits, tailings piles, mills, dredge piles, and mines (mostly inactive) are located throughout the watershed. These districts contain polymetallic (Ag, Au, Cu, Pb, Zn) vein deposits and precious-metal (Au-Ag) vein and disseminated deposits that were exploited beginning in the 1860’s. Placer Au deposits in the major streams were extensively mined in the late 1800’s and early 1900’s. As part of a cooperative effort with Federal land management agencies, the U.S. Geological Survey (USGS) is currently using an integrated approach to investigate two mining impacted watersheds in the western United States (the Animas River in Colorado and the Boulder River in Montana). These studies provide the USDA Forest Service and BLM scientific data for implementing informed land-management decisions regarding cleanup of abandoned mine lands within each watershed. A similar integrated-science approach will be used to characterize the upper Prickly Pear Creek watershed with respect to water and streambed sediment chemistry, aquatic biota, and geologic framework. This integrated database presents data that will be used to identify important pathways of metals movement and biological impacts, thereby guiding resource management decisions of land-managers in several publications that are in preparation. Watershed-level characterization in terms of water quality, streambed sediment chemistry, and fish health will facilitate determinations of whether removal of contaminated materials or other cleanup activities are necessary, planning of short- and long-term restoration efforts, and development of a monitoring plan to document cleanup effectiveness.

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