Abstract
Cottonwood Creek is located in Powell County, Montana and flows through the town of Deer Lodge. The Natural Resource Conservation Service (NRCS), will be working with ranch owners along Cottonwood Creek on restoration and conservation projects in the spring of 2001. In September and October of 2000, six graduate students from the University of Montana completed a baseline assessment of the lower Cottonwood Creek watershed, including the tributary Reese Anderson Creek. The assessment is the start of a more comprehensive assessment to be completed in the summer of 2001. The purpose of this baseline assessment is to characterize the current condition of Cottonwood Creek.
The objectives of this study include:
1. To assess the current condition (“health”) of Cottonwood Creek’s riparian areas.
2. To provide baseline data needed to evaluate the benefits of conservation and restoration projects.
3. To gather information about the current and historical land-uses in the Cottonwood Creek Watershed.
4. To make recommendations on a landowner monitoring system.
Study Approach
The Fall 200 study synthesized existing data and conducted new field observations. Existing data includes maps, soil information, geology, climate, and historically and current land uses. The major component of the field research was the evaluation of the riparian corridor using University of Montana’s Riparian and Wetland Research Program’s (RWRP) Lotic Assessment Form. This method breaks up the riparian corridor into about ¼ mile to ¾ mile sections, called polygons, and evaluates each polygon’s vegetation, stream bank stability, and invasive species. Each polygon is then rated as “Properly Functioning”, “Functioning but at Risk”, or “Nonfunctioning”. Other field data collected included measurement of the stream cross section, photo documentation of the riparian area, and stream discharge.
Summary of results
The Fall 2000 assessment broke Cottonwood Creek into 11 polygons and Reese Anderson Creek into 4 polygons. The RWRP Lotic Health Assessment scored five polygons as Functioning but at Risk, and the remaining ten polygons, including all 4 on Reese Anderson Creek, were found to be Non-Functioning systems. A big factor in reduced functioning along Cottonwood Creek is over grazing which resulted in a streambank instability and lack of woody vegetation. This is most evident on Reese Anderson Creek and the downstream portion of Cottonwood Creek. Other concerns in the riparian corridor included dewatering, use of rip-rap and invasive species.
Comparing the cross sections measurements made in each polygon showed a widening trend downstream. A likely cause for this trend is the lack of woody vegetation along the stream bank downstream. Also, the limited discharged data collected suggested that the stream loses water as it flows downstream. This is likely because of the amount of diversions along the stream. However, further measurements need to be taken in the spring of 2001 to gain a better understanding of how much of a loss there is.
Start Date
14-4-2000 12:00 AM
End Date
14-4-2000 12:00 AM
Document Type
Poster
Cottonwood Creek Preliminary Assessment
Cottonwood Creek is located in Powell County, Montana and flows through the town of Deer Lodge. The Natural Resource Conservation Service (NRCS), will be working with ranch owners along Cottonwood Creek on restoration and conservation projects in the spring of 2001. In September and October of 2000, six graduate students from the University of Montana completed a baseline assessment of the lower Cottonwood Creek watershed, including the tributary Reese Anderson Creek. The assessment is the start of a more comprehensive assessment to be completed in the summer of 2001. The purpose of this baseline assessment is to characterize the current condition of Cottonwood Creek.
The objectives of this study include:
1. To assess the current condition (“health”) of Cottonwood Creek’s riparian areas.
2. To provide baseline data needed to evaluate the benefits of conservation and restoration projects.
3. To gather information about the current and historical land-uses in the Cottonwood Creek Watershed.
4. To make recommendations on a landowner monitoring system.
Study Approach
The Fall 200 study synthesized existing data and conducted new field observations. Existing data includes maps, soil information, geology, climate, and historically and current land uses. The major component of the field research was the evaluation of the riparian corridor using University of Montana’s Riparian and Wetland Research Program’s (RWRP) Lotic Assessment Form. This method breaks up the riparian corridor into about ¼ mile to ¾ mile sections, called polygons, and evaluates each polygon’s vegetation, stream bank stability, and invasive species. Each polygon is then rated as “Properly Functioning”, “Functioning but at Risk”, or “Nonfunctioning”. Other field data collected included measurement of the stream cross section, photo documentation of the riparian area, and stream discharge.
Summary of results
The Fall 2000 assessment broke Cottonwood Creek into 11 polygons and Reese Anderson Creek into 4 polygons. The RWRP Lotic Health Assessment scored five polygons as Functioning but at Risk, and the remaining ten polygons, including all 4 on Reese Anderson Creek, were found to be Non-Functioning systems. A big factor in reduced functioning along Cottonwood Creek is over grazing which resulted in a streambank instability and lack of woody vegetation. This is most evident on Reese Anderson Creek and the downstream portion of Cottonwood Creek. Other concerns in the riparian corridor included dewatering, use of rip-rap and invasive species.
Comparing the cross sections measurements made in each polygon showed a widening trend downstream. A likely cause for this trend is the lack of woody vegetation along the stream bank downstream. Also, the limited discharged data collected suggested that the stream loses water as it flows downstream. This is likely because of the amount of diversions along the stream. However, further measurements need to be taken in the spring of 2001 to gain a better understanding of how much of a loss there is.