ScholarWorks at University of Montana

The riparian forest community of Sleven’s Island at Fort Missoula, Montana is heavily disturbed due to exotic vegetation invasions, drastic alterations in the hydrological processes, and large amounts of debris deposited by the United States Army. In a joint venture with the Integrated Pest Management Program at the University of Montana (UM), the Montana Natural History Center (MNHC) has recently initiated efforts to restore the island. The MNHC is a non-profit organization affiliated with the UM Division of Biological Sciences and focuses on environmental education. They involve school children, University students, and community members in the restoration efforts through service learning projects. In doing so, their objective is to increase awareness of basic ecological concepts as well as present the importance of restoration projects. Currently, area school children assist with native plant cultivation and conduct field trips to the island. In addition, UM interns conduct vegetation surveys, remove exotic weeds, and lead the school groups. The overall goal of the project is to restore the structure, functional integrity, and resilience of a typical riparian system of West Central Montana. Eventually, Sleven’s Island will serve as an accurate example of an indigenous riparian ecosystem for educational and recreational purposes.

O’Brien Creek, near Missoula, Montana, has been altered by tree harvest, road building, grazing and dewatering. These actions led to loss of streamside vegetation, increased streambank erosion and scouring, and decreased native fish and wildlife recruitment. The Forest Service recently closed and recontoured roads in the upper watershed while the Montana Department of Fish, Wildlife and Parks regraded and revegetated the lower creek to return it to a more natural state. I monitored the efficacy of revegetation of the newly restructured streambanks within the first year and a half of planting. The survival rate of plantings after the first year was only 25%, due, most probably, to the small size of the plants, competition with exotic weeds, and the placement of the plants well above the mid-summer water table. I recommend larger plants, placed with their roots in the mid-summer water table, and an effort to control weeds near the plantings.

The restoration of O’Brien creek was done in patchwork fashion, with 2 agencies working on separate projects in different areas of the watershed without much coordination. Greater coordination and cooperation between agencies will likely result in more efficient and successful restoration efforts. However, the agencies are to be commended for their efforts which are already producing increases in fish populations in the creek.

The Chief of the Forest Service declared a moratorium on National Forest road construction until the impacts of existing roads is made acceptable. The Forest Service’s National Resource Agenda advocates the removal of several hundred miles of poorly constructed or maintained roads in the next 3-5 years (250+ miles on the Lolo National Forest alone). Yet, data on the effects of road removal is often viewed as inadequate. Current techniques for evaluating the effectiveness of road removal/recontouring are based on empirical studies and basic soil erosion properties extrapolated to forested environments.

The O’Brien Creek Watershed restoration project offers an opportunity to monitor the effects of road recontouring on sediment production and may be used to establish evaluation criteria for similar locations. This study compared sediment yield from existing Forest Service roads, newly recontoured roads, one-year revegetated-recontoured roads and natural/undisturbed sites. Two geologic formations with associated soil types were selected for sampling--Mount Shield’s formation, and Bonner formation. Two slope categories were sampled for each soil type: <45% slope and >45% slope. For all treatments, sediment runoff samples were collected using a rainfall simulator to generate rain, with five samplings over 2 days per site. Sample analysis determined percent infiltration, water and sediment yield, silt and clay content, and largest particle size removed. Hydrometer and sieve analyses determined particle size distribution. Soil bulk density and organic matter content were determined at each site. Statistical analyses are in progress. Some trends have been noted based on preliminary data.

Natural/undisturbed reference sites exhibited very little runoff or sediment yield; existing roads exhibited much more. When sampled soon after recontouring, recontoured roads generated more sediment and runoff than existing roads, but after one year, recontoured roads generated much less, and only a very little more than natural/undisturbed sites. Soil type seems to have more of an effect on sediment generation from recontoured roads, then did slope category; with the Bonner formation generating more sediment than the Mount Shield’s formation.

Road culverts often block fish migration, cutting fish off from critical habitat. In the past, stream crossings were designed based on economic, road grade and alignment considerations with resource values like fish migration and stream condition considered secondary. In the last ten years, knowledge of fish needs and swimming capabilities has increased, which has changed the focus of culvert design.

Culvert designers must consider not only efficient water passage, but also what water velocity and depth and culvert length and slope will accommodate the different swimming abilities of different fish species and age classes. In most instances, culverts should span the active channel with a natural or naturalized bottom, especially where stream gradients exceed 2-3%.

A variety of structures, such as bottomless box culverts, bottomless arches, pipe arches, and corrugated metal pipes, are available. Baffles can be used to slow velocities within the culvert and to provide resting opportunities for fish; however, they are generally viewed as a last option because they reduce flow capacity and commonly require heavy maintenance.

In June 1999, 10 Missoula high school students and their crew leaders surveyed roads in the Upper Lolo Creek and Dunham Creek areas. The students collected information on erosion associated with roads, on culverts which might be creating fish passage barriers and on road drainage problems. They photo-documented the most significant problems they encountered. The crews surveyed nearly 100 miles of roads; in the process, they acquired skills in navigation, map reading and Rosgen stream type classification. In addition, they learned about forest road design and construction, the dynamics of watersheds and fish habitat needs. The students’ work, totaling nearly $7000 in volunteer labor, was commissioned by a hydrologist with the Lolo National Forest. The LNF has already used the students’ data to help make determinations about road maintenance and obliteration needs. The students working on this Road Reconnaissance Project were members of the Wildlands Volunteer Corps. This summer project was sponsored by the U.S. Forest Service, the Flagship Program (a Missoula county, after-school program funded through a Dewitt-Wallace/Reader’s Digest grant) and Missoula County Public Schools. The Wildlands Volunteer Corps is a program of Northwest Connections, a non-profit organization devoted to conservation and education. The Road Reconnaissance Project will continue in the summer of 2000 with students from Big Sky High School and Sentinel High School in Missoula.