CASE STUDY REPORT #~6" FRENCH ... - State of California

More documents

Recommendations

Info

to have altered the physical habitat. Post-project instream flow releases have been maintained well above the minimum instream flow reservoir. Beginning in 1961, the Department of Fish and Game began field investigations to assess instream flow needs at French Meadows. During June, July and August, temperatures were measured. Eight years of hydrologic instream flow data were compiled and tabulated for mean and minimum monthly flows in cfs. To assess relationships between flow and fisheries habitat, one reach of stream was studied using nine transects spaced about i0 feet apart at four flows (3, 9, 17 and 28 cfs). Water depths and habitat characteristics were recorded along each transect and transferred to sketch maps. Wetted areas and habitats relating to food, cover and spawning areas were noted. From these results and their general knowledge about the stream, the Department of Fish and Game recommended a fishery maintenance flow of 20 cfs or the natural flow which- ever is less. The agreed to releases for fish are thought to be a compromise that slightly improved the late summer flows over historical conditions. Although no evidence was found, it is speculated that fish and wildlife habitat below French Meadows Reservoir may have improved because of the project, if one considers stability and diversity as improvement. Late summer flows have been improved over the h~storical condition and although the stream channel is not fully wetted, conditions for fish, cover and C--0641 30 C-064130
food are improved. Flows during the spring spawning period are less than what the Department of Fish and Game judged adequate for rainbow trout, but are more than adequate for the fall spawning of brown trout. The available data and information indicate that DFG requests for in-stream flow were generally based on their judgment relating mostly to historical low summer flow, the availability of water from the project as determined by the water agency and the habitat possibilities for trout. Although stream transect studies were done, the results mostly intensified DFG judgments about habitat possibilities and lent some credence to their requests in negotiations with the water company. Angling surveys made by DFG personne! between 1965 and 1970 downstream from French Meadows indicate that the river supports a fair to good fishery for small rainbow trout up to 9 inches long and brown trout up to 12 inches with abun- dance progressively increasing downstream. Exposure of iron ochre deposition within the first half mile of stream below the dam has inhibited fish production in this area. This situation was unforeseen in evaluation of the instream flow needs below French Meadows Dam. C--0641 31 147 C-064131
Page 1 and 2: CASE STUDY REPORT #~6" FRENCH MEADO
Page 3 and 4: II.. P.re-Prqject Conditions During
Page 5 and 6: data (1951-1960) were compiled and
Page 7 and 8: Figure 3 RESULTS OF STREAM TRANSECT
Page 9 and 10: Source: McCreary-Koretsky Engineers
Page 11: three rainbow trout fry and one 9.6

CASE STUDY REPORT #~6" FRENCH ... - State of California

Create successful ePaper yourself

Delete template?

Save as template?