ScholarWorks at University of Montana

Gold Creek, a tributary of the Clark Fork River in western Montana, has regularly exceeded the Environmental Protection Agency's total phosphorous (TP) water quality criterion of 0.050 mg/ 1 since monitoring began in 1988 and often exceeds 0.100 mg/l during late summer and fall. Gold Creek drains forested uplands tU1d lower elevations of irrigated fields and pastures. Cattle manure, fertilized hay fields, sediment erosion, and septic tanks are possible anthropogenic sources of P. Geologic P sources include the Permian Phosphoria Formation and volcanics that are mixed with Cretaceous and Tertiary sediments.

The intent of this study was to determine if the high P levels in Gold Creek have an anthropogenic source. Samples were collected twice a monthly from April to October 1990, from Gold Creek's mainstem, tributaries, and springs, and analyzed for soluble reactive phosphorus (SRP), TP, and N. Discharge, pH, and conductivity were measured and fall base flow samples were analyzed for Si and F, two elements expected to correlate positively were SRP of geologic origin. Groundwater samples were collected from ten domestic wells. Bank sediments suspected of releasing SRP when eroded by cattle 3Jld irrigation diversions were collected for SRP extraction.

The results indicate that much of the SRP is from all unidentified geologic source. Gold Creek appears to be receiving groundwater (rich in SRP and other dissolved solids) that is surfacing where the mountain mass meets ti1e valley fill material. Groundwater samples and springs above the influence of human activity were high in SRP (0.034-0.524 mg/l). SRP correlated positively Si, F, and conductivity, but did not correlate with N. SRP levels in the stream increased as discharge decreased and the SRP/TP ratio in the mouth of Gold Creek during summer low flows was 0.8 to 1.0. The sediment in two tributaries fed by P-rich springs had extractable SRP, and irrigation practices and erosion by cattle appear to influence SRP loads in these creeks. SRP in the Clark Fork River significantly increased below Gold Creek although the increase averaged only 0.00 Img/ 1. Hence, geologic P sources contribute to) the nuisance algae problem in the upper Clark Fork River.

The Pacific Northwest Rivers Study was initiated in 1984 by a measure in the Northwest Power Planning Council's Fish and Wildlife Program. Funded by the Bonneville Power Administration, the study was designed to identify, assess, and rate the significance of river-related natural resources values in Montana, Idaho, Washington, and Oregon and to produce a consistent and verifiable database. The Montana Rivers Information System (MRIS), the Montana portion of the Pacific Northwest Rivers Study, included the assessment of resident fisheries, wildlife, recreational, natural, and cultural features along 4,000 reaches of Montana's rivers and streams. In addition to detailed descriptive and location information, each data base contains quantitative data on key features of each resource area such as species abundance, fishing press life, presence of species of special concern (fish and wildlife), boating suitability, scenic quality (recreation), scarcity, and scientific or educational use (natural/geologic features).

The databases are managed in dBase III+ software; however, the programming can be compiled to run on any computer with MS/Dos operating system. Reports are available in hard copy, floppy disks, or through modems. The Natural Resources Information System (NRIS) in the Montana State library is the data manager for the MRIS. Direct all requests to NRIS: (406) 445-5356 (address listed above). In addition to data reports, NRIS can also provide criteria and other documents produced for MRIS.

The MRIS is an ongoing federal and state interagency project. During the next phase (1990-1991) portions of the rivers system will be converted from tile state's water code system to the Environmental Protection Agency (EPA) River Reach Number System. The EPA reach system, a geographically continuous system with reaches linked to one another, will be available in a Geographic Information System by 1991 with coverages compiled at the 1:100,000 map scale. Other planned updates will include connecting the system to other agency bases such as those of the Heritage Program, Montana Riparian Association, federal land management agencies, and for adding new data for land ownership, special management areas, consumptive and non-consumptive wildlife recreation, and river recreation.

The benthos of Lake Creek, Lincoln County, Montana were sampled in 1984-85 to determine the effects of a 2.5 years old tailings impoundment located adjacent to the stream. Sampling results were compared spatially in the 1984-85 data set, and temporally with a baseline data set collected three years prior to installation of the impoundment. Lack of replication in the baseline sampling design precluded the use of two-way ANOVA for analysis of temporal changes. Therefore temporal comparisons were made on the basis of changes downstream of the impoundment relative to changes upstream, as measured over time. Spatial comparisons upstream and downstream were made by one-way ANOVA.

Determination of the effects of the tailings impoundment was confounded by a tailings spill that directly contaminated the downstream stations. The spill was assumed to have had a much larger biological effect that did the tailings impoundment itself. Simuliidae and Rhithrogena spp. increased in abundance after the spill, the former as an opportunist, the latter was a coincidental benefactor since it was in the adult stage during the spill.

The before and after data sets were collected with different sampling gear and had unequal replicate samples within plots. The gradient effect of Bull Lake on Lake Creek was also a concern. These concerns were minimized by utilizing a methodology that analyzed the change in the relationship between control and impact areas over time.

Of 16 taxa analyzed, 10 decreased, two increased, and four showed no significant change in abundance in the impact area relative to the control from 1977-78 to 1984-85. Spatial comparisons above and below the impoundment in 1984-85 showed eight taxa significantly more abundant in the upstream area, five with comparable abundances, and three with greater abundances downstream.

A number of resource investigations were initiated in 1988 in the Blackfoot River drainage to address public perceptions of a declining fishery. Investigations included

• Monitoring of ambient water quality during summer low flow now and spring runoff conditions
• Chronic toxicity surveys using the cladoceran Ceriodaphnia
• A benthic macroinvertebrate survey
• Analyses of sediment and biota for heavy metal contamination
• Fishery surveys

Although some studies are ongoing, information to date suggests that the fishery has been impaired by a number of causes and sources. In the headwaters area, heavy metals from historic mining have created acutely toxic conditions. Aquatic life criteria for cadmium, copper, lead, and zinc are frequently exceeded. Cadmium has accumulated in fish tissue in concentrations, which likely impair reproduction and survival. Sediment analyses indicate that contamination has penetrated approximately 25 km downstream since the Mike Horse line tailings impoundment failure in 1975.

The fishery in the middle river (from approximately Poorman Creek to the Clearwater River) is generally poor. Heavy metals il1 sediment are near backgrow1d concentrations. However, cadmium and zinc contamination of the biota is still detectable. Water quality is generally good, although increasing nutrient and sediment concentrations during runoff indicate greater nonpoint source impacts. Benthic macroinvertebrate communities suggest possible organic enrichment and/ or siltation effects. Siltation, a lack of spawning tributaries, and other environmental factors interact to depress fish populations in most of this reach.

In the lower river, fishing pressure appears to be limiting the larger size fish in all otherwise good fishery. Water quality analyses and benthic macroinvertebrate indices indicate that water quality is good to excellent.

The various studies indicate that the fishery is moderately to severely depressed in much of the Blackfoot River. Heavy metals, siltation, degraded tributary streams, and over harvesting may be the most significant limiting factors. Drought conditions during the last few years have exacerbated these detrimental influences.

University of Montana Nuisance algal accumulations occur in the upper Clark Fork River because of near optimal growing conditions, including high nutrient levels. Bioavailable nitrogen and phosphorus are often high enough to saturate growth and standing crop. Anthropogenic activities are thought to contribute significantly to these high nutrient levels. Point and nonpoint nutrient sources are beginning to be identified quantified and evaluated.

This study sought to estimate the contributions of eroding streambank and fluvially deposited mine waste (slicken) sediments to the upper rivers bioavailable phosphorus (HAP) levels. Soil samples were collected from eroding streambank and slicken surfaces, homogenized and sieved. Samples of the < 2mm size fraction were suspended for 8 hours in filtered river water at a concentration approaching the upper river's maximum total suspended sediment concentration (500 mg/l). The resulting extract was filtered and analyzed for soluble reactive P (SRP), a good indicator of HAP. The contribution of these sediment sources to the rivers BAP levels was estimated by multiplying the average amount of SRP extracted per gram of sediment by the total suspended sediment (TSS) levels in the river. Some of the factors that influence phosphorus extractability were examined, including concentration of TSS extracted, pH of extractant and particle size and soil textural class of the extracted sediment. Over the ranges tested here, none of these factors had any apparent effect on the amount of SRP extracted from these sediments.

Both sediment types were composed primarily of silts and find sands with little clay content (10-12%) and an average of 5- 7% organic matter content. Slightly alkaline (pH= 8) eroding streambank soils released amounts of SRP similar to the acidic slicken sediments (pH= 4). The SRP contribution from these sources (2-4 ug SRP per gram of sediment) to the total SRP in the river was an insignificant part of the rivers high SRP levels. Total soluble phosphorus extracted was analyzed for some extracts and found to be similar to the amount of SRP extracted.

Missoula lies in the heart of western Montana, recently coined "The last best place." An abandoned railroad right of way in a riverfront, which bisects Missoula's downtown is the setting for development of a recreational corridor. Missoula is experiencing revitalization of its downtown thanks to the creation of a "reinvestment tax" which skimmed revenues generated by new developments in the downtown (Urban Renewal District) after a "base tax year" was established in 1980. The tax was designed to foster revitalization over a ten year period and then the agency which administers reinvestment in the renewal district is expected to sunset. With only one-year remaining and much money set aside the City Council needs to decide on priorities for the Urban Renewal District.

The riverfront in the middle of this urban area of 75,000 people, hosts beavers, blue herons, mergansers, wood ducks, and rainbow and brown trout. On a hillside, visible from the downtown, a team of biologists is considering transplanting a herd of bighorn sheep. The community has a sensitivity toward enhancing wildlife viewing opportunities, yet some people still respond. "Do those wilderness people want more wilderness right here in the middle of town?" This constituency is asking that the riverfront be a "people place." After many public workshops some compromise has been reached for riverfront development. Now some questions remain.

Will the Urban Renewal Agency make substantial investment in a riverfront park system or is the money better spent on more traditional renewal projects such as building demolition, parking structures and facade improvements? Will a community which prides itself on providing a quality of life for its residents, but divided about whether to encourage more in-migration or promotion of tourism, give the high sign to the Riverfront Park System? These are the issues Missoula will be wrestling with in the coming year. The "Downtown Riverfront Plan for Missoula" addresses these issues and provides strategies for future development. The Plan will be published in January of 1989, followed by public review and presumably adoption by Missoula City Council.

In the mid and late 1980' s, attached algae levels in the Clark Fork of the Columbia River varied from unnoticeable to extreme nuisance levels. Thi.5 study addressed the question: are P and N levels low enough long enough to limit algal growth and standing crop in this river? If so, river reaches with nuisance levels may improve if nutrient levels are lowered, and high quality reache.5 may worsen if nutrient levels are allowed to increase. Because the Clark Fork often exhibits N and P levels thought to saturate algal growth, there was doubt that nutrient management would affect algal levels. Through the use of artificial stream fertilization experiments, this study showed that the standing crop of these attached algal communities saturate at much higher nutrient levels than does growth. At most river sites from Sept.1987 to 1989, dissolved P and N were almost always below levels that saturate algal standing crop. The ratio of dissolved N:P in the water suggested that N limitation, P limitation or a balance between the two existed for significant periods of time at almost all sites. Hence management of both N and P may reduce nuisance levels (when other factors are not limiting) and are important to protecting high quality areas.

Note: This presentation was both an oral presentation as well as a poster.