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-16- Foidel Creek ~~ Map 6 (Twentymile Park Hydrology) of Permit No. 79-177 identifies several areas of unconsolidated streamlaid deposits along Foidel Creek. Some of these areas lie upstream of the proposed Foidel Creek Mine and would not be affected by the proposed mining operation. Therefore, no alluvial valley floor determination will be made for those areas that lie upstream of the USGS-WRD gaging station near Pinnacle Peak. Three other areas lie adjacent to or downstream from the proposed mining operation. The first lies in an area immediately adjacent to the proposed operation and the ~ic;c+;ng a~rface mining operations The second area occurs downstream in Sections 21, 22, and 28, and the third area is located at the confluence of Foidel Creek and tgiddle Creek. (The third area will be discussed in combination with Middle Creek and Trout Creek.) - -- The first area of unconsolidated streamlaid deposits alony Foidel Creek is found in Sections 28, 29, 31 and 32 (T5N, R86W). The applicant has not identified any historic or existing flood irrigation in this area of Foidel Creek. Flood irrigation was historically practiced in areas several miles upstream of this area, but was discontinued for reasons of poor water availability. The applicant has examined the flood irrigation practices in several adjacent watersheds and has found that the flood irrigation systems in these drainages are direct diversion systems, deriving water from perennial streams and other sources where flowing water is available for diversion during the growing season. The area under consideration would not be flood irriyable using this technique because Foidel Creek is an intermittant drainage. The applicant has included information concerning the possibility of subirrigation in this area in both the Eckman Park and Foidel Creek mine permit applications. USM provided a discussion of part of this information in its technical analysis for the Eckman Park Mine, and concluded that "although a conclusive decision can't be made at this time based on the preceding discussion, the evidence presented thus far suggests that subirrigation is not occurring on the South Fork of Foidel Creek and Foidel Creek valley bottom". Information provided in the Foidel Creek Mine permit revision application shows, on Figure 8, hydrologic conditions in the valley bottom as measured October, 1980. The water table is shown at a depth of 8 ft., the capillary fringe at 2 ft., and the rooting zone extending to a depth of 1.5 ft. The alluvial ground water level is reported to vary seasonally between 3 ft. and 10 ft. This suggests that the capillary fringe would extend up into the rooting zone during part of the growing season. The applicant reports (p. 33, Response to Adequacy Review Letter Dated December 14, 1982) that the only areas suspected of being subirrigated are directly adjacent to the channel. These areas are less than 10 acres in size. In addition, these areas contain sedges and reeds which are not agriculturally useful vegetation. Based on this information, subirrigation does not appear to be a significant function in this area.