Electrical Power for Valdez and the Copper River Basin-1981

Should a major earthquake occur, this site could be severely damagedor destroyed by seismic sea waves.DISCUSSIONWith fossil fuel prices continuing on an upward spiral, increasingattention is being given to alternative energy sources. In Alaska,with steep slopes and abundant streams, hydropower is a logicalchoice. Sites with large hydropower potential close to populationcenters are limited, but potential small hydropower sites are numerous.Alaska also has abundant fish resources, which frequently inhabitthe same drainage systems suitable for hydropower development.Unfortunately, these two resources may not be completely compatible.Allison Creek, cumulatively with the other short coastal streams ofPrince William Sound, provides an important contribution to theoverall salmon production of the area. Both the commercial andsport fisheries play an important role in the economy of Valdez. Inaddition, maintenance of natural and wild stocks of salmon in~llison Creek can be viewed as an aesthetic value which cannot bemeasured in monetary terms.The most significant impacts upon fish and wildlife resources whichwould occur from construction of the Allison Lake project are thepotential changes in the flow and temperature regimes of the creek.All other potential impacts are considered less significant. Ananalysis of existing data and subsequent impacts indicate thatappropriate structural and non-structural features to mitigate majoradverse impacts could be incorporated into project design includingeither of the proposed powerhouse sites which would make the proposalacceptable environmentally. However, baseline data gaps presentlyexist which preclude a complete assessment of potential impacts.Execution of appropriate studies before or during the advancedengineering and design stage of planning will enable a thoroughevaluation of potential impacts to fish and wildlife and refinement/development of necessary mitigation features. In addition to thesestudies, a cooperative study jointly scoped by the FWS and CE, andconducted through project construction and operation, would enablerefinement of mitigation recommendations; assessment of the accuracyand effectiveness of those recommendations; and provide a comprehensivedata base useful in the future planning of similar projects.Available data suggests that peaking or excess flow should bedischarged directly to port Valdez year round and that regulatedflows be discharged through the tailrace to Allison Creek. Apre-project instream flow analysis of Allison Creek is needed toderive accurate and specific optimum flow recommendations for fishmaintenance. The regulated flows would vary according to life stagerequirements of fish and natural streambed flow. For example, fromapproximately mid-July to early September adult salmon are presentin the creek and a constant flow optimum for spawning should occurin Allison Creek. Peaking or excess flow would continue d:i.rectly toPort Valdez and this discharge should occur subtidally to at least-10 feet mean lower low water from June through September to eliminateattracting adults.