ScholarWorks at University of Montana

This paper summarizes a basin-wide trends analysis of water quality data collected in the Clark Fork-Pend Oreille watershed from 1984-2004. The subject data were collected by the Montana Department of Environmental Quality (formerly MDHES) from 1984-1996 and by the Tri-State Water Quality Council from 1998 to the present. This study describes how nutrients, heavy metals and attached algae levels vary in time and space in the Clark Fork-Pend Oreille watershed. Nutrient constituents include total phosphorus, total nitrogen, soluble reactive phosphorus, and total soluble inorganic nitrogen. Heavy metal constituents include total recoverable fractions of copper and zinc. Attached algae biomass is reported as ash-free dry weight and chlorophyll a sampled from natural substrates.

Water quality was sampled at 32 stations along the Clark Fork River and tributary streams in Montana and Idaho, and at two stations on the Pend Oreille River in Washington. Seven Clark Fork River stations were sampled for algae.

Observed water quality is compared to standards and targets to determine the percent of samples meeting standards and targets. In addition, time trends are evaluated to determine whether or not water quality is changing significantly. Analysis results are used to gauge the effectiveness of management activities throughout the watershed, and to provide recommendations for future sampling efforts. A similar analysis is planned for 2008.

This work was funded by the Tri-State Water Quality Council.

Water quality models are being used to predict nutrient concentrations in the Clark Fork and Bitterroot Rivers. The modeling will support the activities of the Montana Department of Environmental Quality and the Tri-State Water Quality Council including Total Maximum Daily Load (TMDL) studies and the Clark Fork River Voluntary Nutrient Reduction Program (VNRP). The TMDL studies and the VNRP are meant to reduce nutrient pollution from point and nonpoint sources to these rivers. The models were built using public domain programs for rivers and watersheds.

A stream and river model, the Enhanced Stream Water Quality Model (QUAL2E), is being used to model the Clark Fork and Bitterroot Rivers. QUAL2E is a one-dimensional river model capable of steady flow simulations of multiple water quality parameters. Input flows to the QUAL2E model include point sources, tributaries, groundwater, and non-point sources. The results of the current modeling efforts led to improved interpretation of water quality data, recommendations for the monitoring program, and the identification of key tributaries and nonpoint sources impacting water quality in the rivers.

The Soil and Water Assessment Tool (SWAT) model is being used to estimate watershed nutrient loading to the Bitterroot River. SWAT is a watershed-scale hydrologic and water-quality model developed to predict the effects of alternative land use management operations on water, sediment, and chemical yields. The model includes Geographic Information Systems (GIS) data for land use and soil data for the watershed sub-basins. The modeling will be used to quantify loads from point source dischargers and non-point sources. The model will be applied to evaluate various land use and other management scenarios.

The German Gulch Watershed Restoration Project will benefit the Silver Bow Creek watershed, complement Superfund remedy and restoration, and enhance recreational opportunities for local residents. Midway between Butte and Anaconda, German Gulch Creek is a major tributary of Silver Bow Creek that was heavily placer mined about 100 years ago. Restoring and protecting natural resources in German Gulch is a key element in maximizing aquatic habitat and recreational opportunities in the Upper Clark Fork River Basin.

This restoration project has four objectives:

1. Insure connectivity between German Gulch Creek and Silver Bow Creek;
2. Restore and protect habitat for native Westslope cutthroat trout;
3. Improve public access to lower German Gulch; and
4. Enhance water quality and quantity to German Gulch Creek and Silver Bow Creek.

German Gulch Creek is the most popular recreational fishery in the Silver Bow Creek watershed, and its restoration will directly benefit Silver Bow Creek through the recruitment of native trout—a seed stock to repopulate the remediated and restored stream. Furthermore, the proximity of German Gulch to Butte, Anaconda, and the Greenway insures that the public will benefit from this restoration effort.

The restoration and protection of Westslope cutthroat trout in German Gulch Creek is an integral part of George Grant Trout Unlimited’s vision for the Silver Bow Creek watershed. Native populations of Westslope cutthroat trout persist in the headwaters of many streams feeding Silver Bow Creek. Because of historical pollution in Silver Bow Creek, it was never colonized by exotic species such as rainbow and brown trout. Thus, the remediation and restoration of Silver Bow Creek by Montana’s Natural Resource Damage Program brings a major opportunity to restore the upper Silver Bow Creek watershed for native trout. Along with this opportunity come serious challenges, including high levels of nutrient pollution from Butte’s sewage treatment plant, metals pollution from mine tailings in the Butte Priority Soils superfund operable unit, agricultural dewatering of tributary streams that severs connectivity with Silver Bow Creek, and the presence of exotic brook trout in most tributary streams. Though these challenges make the restoration of a native fishery in Silver Bow Creek a long term goal, we argue that authentic restoration requires what the philosopher Albert Borgmann calls focal realism and patient vigor.