What is probably the largest-scale watershed and stream study ever undertaken in California will be launched by a Utah State University team this summer.

Chuck P. Hawkins, fisheries and wildlife department assistant professor, and graduate student Lynn Decker are collaborating on the watershed study in 13 national forests, to cost more than $400,000. A pilot study was done last year on four stream sites.Hawkins and Decker, a researcher with the Pacific Southwest Forestry and Range Experiment Station, will coordinate three crews of students collecting information on about 50 watersheds.

Three categories of sites will be studied: pristine, moderately used and heavily used watersheds.

The information gathered will be the focus of Decker's USU doctoral dissertation.

Students will begin work on Inyo National Forest, then move north as work is completed on each study site.

Decker said data will be collected on stream channel stability, fish habitat availability, fish abundance and aquatic invertebrate abundance. Surveys will be made of landslides, stream bank erosion and large woody debris.

Crews of four will move up the streams, with divers equipped with snorkeling gear in front. They will

quietly approach pools so the fish won't be disturbed, enter the water, count, identify and estimate size of the fish.

The other crew members will measure riparian vegetation and sample insect populations.

Although Western streams usually contain no more than a half dozen species of fish, the streams contain hundreds of invertebrate species, many of which serve as food for the fish, the researchers said.

"There are two aspects of ecological effects that we are concerned with," Hawkins said. One is change in the types or diversity of species. The other is changes in overall production capacity of the system.

While the pilot project was done with Forest Service research dollars, the extensive study represents a unique collaboration between the research and management branches of the U.S. Forest Service and a major university.

The researchers said the study is going to generate "some very good science, which will help us understand conceptually how watershed disturbance or management activities influence the general ecology of stream systems."

After the project is completed, they should be able to tell managers what management activities will produce either adverse or beneficial effects on stream systems.

With three crews, the researchers will be able to do 25 sites a season. After the two field seasons, additional time will be taken to analyze the information. Hawkins and Decker expect the project to be funded for two and a half to three years.