Watershed Restoration Assessment for Lost Creek
-- a tributary of the Upper Clark Fork River
PowerPoint presentation on this paper
by John Lhotak, presented at American Water Resources Assn. meeting, Oct 2000 in West Yellow Stone, MT
James A. Harris and Vicki Watson,
Environmental Studies, University of Montana, Missoula, MT 59812
Lost Creek, a
tributary to the Upper Clark Fork of the Columbia, is listed on Montana’s
303(d) list as impaired for a number of beneficial uses, including aquatic life
support, drinking water supply, and cold water fishery. Lost Creek is undergoing
major riparian restoration and grazing management changes which will be the
basis of a Total Maximum Daily Load (TMDL) for nutrients and sediment for the
lower 17 stream miles. Therefore the objectives of
this project include the following:
assess current conditions in
Lost Creek including kinds and degrees of impairment;
baseline data to evaluate benefits of restoration work;
evaluate Lost Creek as a
nutrient source to the nutrient-impaired Clark Fork River;
evaluate nutrient sources along
make recommendations for TMDL
development for Lost Creek, and how it should relate to the Clark Fork VNRP
(which calls for a 20% reduction in nonpoint sources of nutrients).
Water samples were collected from May through August 1999 at sites along the
creek which bracketed suspected sources. Samples
were analyzed for nutrients (nitrate/nitrite, total Kjeldahl nitrogen, soluble
reactive phosphorus, and total phosphorus) using an EPA-approved protocol.
Riparian health assessments were performed on the lower 20 miles of Lost Creek
using the University of Montana’s Riparian and Wetland Research Program’s
Lotic Inventory Form. Riparian inventories are used to identify and prioritize
problem areas and provide detailed baseline information for gauging the success
of restoration projects on Lost Creek.
Lost Creek does not provide good habitat for attached algae growth, but in some areas aquatic plants may be a problem. Hence, the main reason for reducing nutrients in Lost Creek is to reduce the load to the Clark Fork. Phosphorus levels in Lost Creek were below those considered to be a problem for streams according to the Clark Fork VNRP. Total nitrogen (particularly nitrate/nitrite) levels are high enough to be a concern. Nitrate/nitrite levels increase in the area near Dutchman reservoir. Although wetland disturbance by cattle grazing is a likely source of nutrients in this area, it appears likely that irrigation water from the land application of Anaconda’s municipal wastewater is leaching into groundwater from nearby hay fields and from storage ponds in the Dutchman Creek drainage. Riparian inventories found 30% of riparian areas were not performing their functions while the other 70% were at risk to become nonfunctional.
In terms of TMDL development for Lost Creek, the conservation practices being undertaken by landowners with state and federal funding will likely improve habitat and reduce nutrient loads. Success should be judged by periodic reevaluation of riparian condition and nutrient loads. Lost Creek does provide a significant TN load to the Clark Fork, and this is probably best addressed by riparian wetland restoration and land application of Anaconda wastewater over a larger area at an appropriate agronomic rate. Additional recommendations for monitoring and TMDL development are detailed in the full report.
This work was supported by the Montana University System Water Center with funds from the USGS Section 104 Program. Our grateful thanks to Montana Dept of Fish, Wildlife and Parks, the US NRCS and landowners in the Lost Creek Basin for their efforts to restore Lost Creek.