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-43- Determination The reconnaissance level investigation for determining whether an alluvial valley floor is present includes: 1) identification of streamlaid deposits 50 feet wide and greater than 10 acres in extent; and 2) the potential for flood or subirrigated agriculture. The applicant has identified several areas of unconsolidated streamlaid deposits that exceed 50 feet in width and 10 acres in size within approximately two miles of the mine plan boundary (Map 8 of the permit application). Areas identified include the Stonewall Valley (Middle Fork of the Purgatoire River), Apache Canyon, Ciruela Canyon, Parras Creek, the North Fork of the Purgatoire River and the Picketwire Valley (main stem of the Purgatoire River). The applicant identified quarternary alluvial deposits in Santistevan Canyon on the geology map (Map 6). The applicant did not indicate any areas of unconsolidated streamlaid deposits exceeding 50 feet in width and 10 acres in size within Santistevan Canyon. Fbwever, based on map 6 of the application and aerial photographs on file at the Division office, it is evident that unconsolidated streamlaid deposits meeting the above size requirement are present in Santistevan Canyon. The North Fork Purgatoire River and Parras Creek are located downstream from the proposed permit are a, and would not be affected by proposed operations. Santistevan Canyon is a downstream tributary of the Purgatoire River and would not be affected by the proposed Allen operations. Since the North Fork of the Purgatoire, Parras Creek and Santistevan Creek would not be affected by the proposed operations, these areas are not hydrologically adjacent to the proposed operation, and will not be considered for alluvial valley floor designation at this time. Alluvial valley floor designations will be considered for the Stonewall Valley, Picketwire Valley, Apache Canyon, and Ciruela Canyon. The Picketwire Valley Two types of unconsolidated streamlaid deposits; valley floor deposits and strath terrace deposits, have been identified along the main stem of the Purgatoire River (Plate 6 and Map 8 of the permit application). Valley floor deposits include the current floodplain and low-lying terraces up to 50 ft. above the river. These deposits contain alluvial ground water that is hydrologically connected to the river and supports hydrophytic vegetation. The applicant has also identified strath terraces with a thin alluvial veneer. The terraces are confined to the main stem of the Purgatoire. Strath terrace deposits are located 100 to 200 feet above the Purgatoire River. Field investigations, including backhoe pits and drill holes, provided no evidence of a saturated ground water zone in the deposits. These deposits are not in direct hydrologic contact with the river and do not support hydrophytic vegetation.