Electrical Power for Valdez and the Copper River Basin-1981

. Hydrology and Water Quality: The water quality of the AllisonCreek dra1nage 15 11ttle affected by conditions other than natural, andis considered typical of a small, glacial fed system.A recording thermograph was installed in Allison Creek at the weir inJune 1979 and the data will be collected for several more years. Therecordings indicate tnat high temperatures occur in August and lowtemperatures of 0 degrees Celsius first occur in early November (AppendixE, Table 1). Two additional tnermographs to record intergrave1temperatures of Allison Creek and the intertidal area are proposed forinstallation.A stream gage was installed in Allison Creek in March of 1981, and willcontinue to monitor stream flows until at least project completion.Calculated flows have been established for the drainage basin usingmeteoroloq;cal data from 1948 to 1977 (Appendix E, Table 2). The datainaicate unregulated flows and predict flows which would occur uponproject completion. Estimates were also calculated to predict averageinflows to Allison Creek below Allison Lake (Appendix E, Taule 3). Tneseestimates were derived only to predict flows whicn may occur in additionto the diverted flows. It should be noted that these flows are onlyestimates and may not precisely indicate actual flows.Water qua 1 ity ana lys i s for All i son Creek was performed for A lyeskaPipeline Service on several occasions between 22 February 1975 and11 April 1977. Water quality analysis of Allison Lake was performed bythe Alaska District on 7 May 1979 (Appendix E, Table 4).The proposed PRT action would not affect the aquatic environment.c. Esthetics: The scenic value in the Valdez area is stillconsidered high. The view from tne city of Valdez of the proposedhydroelectric project area is of steep mountainous terrain with thenatural values marred by the Alyeska Oil Terminal. Neither the lake northe creek can be seen from the city and the creek cannot be viewed by thegeneral public due to its location on restricted Alyeska property.The proposed site for the PRT is located south of the Lowe River in anarea changed by the construction of the Trans-Alaska pipeline. Theesthetic values have been changed in this area where the pipeline isunaerground, however the values are not considered poor.2. Biologicala. Vegetation: The transmission line corridor between Allison Creekand the Solomon Gulch substation is typified by dense coniferous forestof Sitka spruce ana mountain hemlock with an Llnderstory of alder andother shrubs. The area of the proposed powerhouse and lower reaches ofpenstock support tall thickets consisting primarily of alder with somesalmonberry, blueberry, ana devils club. Portions of the area have beendisturbed by the Alyeska terminal and pipeline construction. Tne steepEIS-4