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<br /> <br /> <br />J. Herron & F. Banta -2- June 3, 1982 <br />3) The applicant should identify the source of water for the spring located <br />in the NW'2 of Section 2, T115, R98W. <br />4) The report identifies four diversion structures for adjudicated water <br />rights derived from Rapid Creek. The applicant should identify the amount of <br />water diverted at each location, and the area to which the water is diverted. <br />In addition, the applicant should identify which areas, if any, are irrigated <br />by water derived from the Colorado River. <br />5) On the map of unconsolidated streamlaid deposits, the applicant should <br />identify those areas in which the vegetation suggests subirrigation. The infor- <br />mation concerning subirrigation included in the report is insufficient to identify <br />the possible extent of subirrigation of unconsolidated streamlaid deposits in or <br />adjacent to the permit area. Data on the Coal Seam Well provide no indication <br />of the nature of alluvial ground water. Two vegetation point samples, one of <br />which is located outside the area studied in detail, are insufficient to show <br />the extent of subirrigated vegetation. <br />6) The applicant has supplied no information on the capability for flood <br />irrigation. However, the numerous existing and historic areas of flood irrigation <br />would suggest that most or all of the unconsolidated streamlaid deposits are <br />flood irrigable. <br />Based upon the information provided, it appears that alluvial valley floors exist <br />along both Rapid Creek and the Colorado River. The extent of these alluvial <br />valley floors has not been fully determined by the information provided. <br />It is debatable whether terrace Cis an alluvial valley floor, but given its use <br />for flood irrigated agriculture, I recommend that the Division determine it to <br />be an AVF. More precise AVF determinations could be made if the applicant <br />supplies the above information. <br />The application contains no information concerning the agricultural significance <br />of areas of existing agriculture (Terraces B, part of C, and D). The Division <br />can proceed to make the AVF determinations without this information by assuming <br />all areas of existing agriculture are agriculturally significant. <br />Since no mining activities would be Iocated in or adjacent to the potential <br />alluvial valley floors, it would be relatively easy to determine that the proposed <br />operations would not interrupt, discontinue, or preclude farming on the alluvial <br />valley floors. <br />A determination that the proposed mining operations would not cause material damage <br />to surface and ground waters that supply the AVF would be more difficult. Although <br />the permit application identifies Cottonwood Creek and Rapid Creek as intermittent <br />streams, your conversations with the USGS indicate that flow is artificially <br />maintained by release from upstream reservoirs. (The details of this system <br />are not described in the permit application.) This flow is apparently diverted <br />for flood irrigation on potential alluvial valley floors along Rapid Creek. The <br />applicant should provide a technical assessment of the probable hydrologic conse- <br />quences of mining upon this flow. The applicant should show that the proposed <br />operations would not cause material damage to the surface and ground waters which <br />supply the potential Rapid Creek and Colorado River alluvial valley floors. <br />