Part of the Provo River has been closed to fishing for the winter, but a draft report of the fishery released Monday proves the brown trout there aren't being ignored.

The optimum winter habitat for the fish exists when flows are between 100 and 200 cubic feet per second, the report concludes. "Significant" losses in brown trout habitat would occur if winter flows on the river were reduced from 100 to 60 cfs.The consistency of the river flow is as important to available spawning habitat for the resident brown trout as the total river flow, the report concludes.

The report was prepared by the Provo River Interagency Study Team and has been anxiously awaited by state and federal water officials and representatives of environmental and sportsmen's organizations. A coalition of water users and sportsmen struck an unusual one-time agreement Nov. 14 that resulted in a decreased flow in the river between Deer Creek Dam and the Olmstead Diversion six miles downstream.

The river is to stay at the 85 cfs level for the rest of the winter, and the segment of the river upstream from the Olmstead diversion to the dam has been closed to fishing until spring.

Flows in the Provo have been maintained in the winter at a minimum of 100 cfs to meet a National Environmental Policy Act provision imposed on the Central Utah Project. The Bureau of Reclamation cut flows to 85 cfs the day the agreement was struck to conserve scarce culinary supplies being stored in Deer Creek Reservoir.

But the agreement was signed without any scientific understanding of the effect lower-than-usual flows would have on the fishery - something that frustrated some signators to the agreement because of the knowledge a study was in progress.

Bill Geer, director of the Utah Division of Wildlife Resources, finished the draft of the study Friday, and copies were made public Monday.

The report compares two different flow levels - 100 cfs and 60 cfs, which means its results straddle the current 85 cfs level.

"There are some parts of the model someone might try to extrapolate from" to estimate what effect the 85 cfs level will have on the fishery, Geer said. But participants in the study will work through the winter to compare data in the study to actual conditions that exist through the time spring releases bring the flow in the river back to 100 cfs or more.

Geer said it will take 11/2 years of additional study for biologists to adequately determine the effect the 85 cfs winter flow will have on the fishery.

Comparing 100 cfs levels to a 60 cfs level, the report concludes that the quantity of important fish food organisms could be reduced at the lower flow level. "These data clearly indicate that significant losses in brown trout habitat would occur if winter fishery releases were reduced from 100 cfs to 60 cfs. Protection of full habitat value is the habitat protection policy for Class I fishing waters in the state of Utah."

Reducing the flow to 60 cfs would be unacceptable and inconsistent with the fishery-protection goals, the report states. "Continuation of winter fishery releases equal to or greater than 100 cfs is recommended by the interagency team when faced with the 60 cfs alternative."

The group that compiled the study recommends further study to identify additional "limiting factors," to compare analyses of fish habitat available at flows between 60 cfs to 200 cfs and beyond. The group also recommends other studies to compare operation of the reservoir with fishery management options.