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<br />SUMMARY (Continued) <br /> <br />acres of riparian vegetation would be temporarily disturbed by construc- <br />tion of the Diamond Fork Pipeline. Potential for flooding would be <br />reduced because flows in the streams would be controlled. Flood control <br />has been included in the design of Monks Hollow Reservoir. <br /> <br />Under projected init ial operating condit ions, both Fifth Water and <br />Monks Hollow Reservoirs may start to weakly stratify in May and June. <br />However, with larger flows during July and August, both reservoirs are <br />expected to mix continuously during the remainder of the summer period. <br />Under maximum operating conditions, neither reservoir is expected to <br />stratify. Therefore, project operations under either situation should <br />result in similar water quality conditions in both reservoirs as well as <br />in lower Diamond Fork. Even though neither reservoir is expected to <br />stratify significantly, the top several feet of water would probably <br />become several degrees warmer than the rest of the reservoir on a daily <br />basis during the warmest part of the summer. These combined conditions <br />may result in abundant algae growth in both reservoirs, part icularly in <br />more isolated or calmer bay areas. Under project operation, nutrient <br />levels in Diamond Fork should not be significantly higher than at pre- <br />sent. The sediment load in Diamond Fork would be reduced significantly <br />from present conditions. The increased late summer and autumn flows from <br />the project would improve water quality in the lower reaches of the <br />Spanish Fork River by diluting the flows, which presently consist mostly <br />of seepage and irrigation return flows. <br /> <br />Approximately 47 miles of fishery habitat in Diamond Fork, the <br />Spanish Fork River, and Fifth Water and Sixth Water Creeks would be <br />affected by the project as a result of altering existing streamflow <br />patterns. The recommended plan would result in considerable enhancement <br />of stream fisheries, mainly because the Diamond Fork Pipeline from Monks <br />Hollow to the Spanish Fork River would remove excess flows from Diamond <br />Fork, thereby reducing water velocities, scouring, and bank erosion. <br />Trout standing crop, habitat, and angler use would increase over existing <br />conditions, especially in the lower reach of Diamond Fork. This increase <br />would more than compensate for the loss of habitat upstream because of <br />inundation by Monks Hollow Reservoir and the dewatering of Sixth Water <br />Creek, which is the only stream that would be adversely affected by <br />implementation of the plan. Reduction in trout habitat would occur <br />because the irrigation flows from Strawberry Reservoir that now flow <br />through Sixth Water Creek would be diverted through Syar Tunnel into <br />Fifth Water Reservoir. Sixth Water Creek would revert to natural flows, <br />which would be much less than the high flows it now carries. These <br />lowered flows would not provide the existing level of trout habitat. <br /> <br />Project reservoirs under initial operating conditions are expected <br />to have fish production potential. Under maximum operating conditions, <br />however, the fisheries would be severely limited or nonexistent because <br />of extreme water level fluctuations. <br /> <br />The recommended plan would cause the greatest impact to wildlife of <br />all project alternatives and thus would require the greatest amount of <br />mitigation to compensate for losses. With the recommended plan, the <br /> <br />S-7 <br />