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-15- THE MONITORING WELL FOR PIT 4 WILL HAVE A LOCATION APPROVED BY THE DIVISION, AND WILL BE INSTALLED WITHIN THE FIRST CONSTRUCTION SEASON FOLLOWING FINAL REGRADING. With the acceptance of the above stipulation, the application is in compliance with the requirements of this section. VII. Alluvial Valley Floors - Rules 2.06.8 and 4.24 Information from the reconnaissance level AVF study conducted by the applicant in 1980 is provided on pages V-14 and V-15 of the application. AVF Determination Information from the reconnaissance investigation (text, map and photos) submitted to the Division in September, 1980 has documented that a 20 acre body of alluvium exists along Grassy Creek approximately 1 1/2 miles downstream from the mining area. An insignificant portion of the alluvial body (approximately 2 acres) is a subirrigated Swale as evidenced by the lush grass and grasslike vegetation which contrasts with the surrounding sagebrush shrubland. The subirrigated area is too small to be developed as a hay meadow, or to be managed as a unit distinct from the surrounding rangeland. As such, the valley does not qualify as an AVF on the basis of subirrigation. The applicant has documented that, while the 20 acre alluvial body does meet the geomorphic criteria of an AVF, the valley is not flood irrigated. The applicant has not conducted a regional irrigation practices inventory as would be necessary to document whether alluvial bodies of similar size, elevation water availability, soil characteristics and channel characteristics are or are not typically irrigated within the upper Yampa River Basin region. Based on information available to the Division at this time, the Division concludes that the 20 acre body of alluvium extending downstream from the center of Section 16 to the county road (as mapped on the AVF Reconnaissance Map) is an alluvial valley floor. The determination is based on the apparent potential for flood irrigation. At present, the AVF is undeveloped rangeland and no impacts to the alluvial valley floor are anticipated to result from approval of the operation. The AVF will not be directly affected by mining disturbances, with the exception of the pre-existing access road. All coal extraction and associated surface disturbance will occur over 1 mile upstream from the AVF. Grassy Creek upstream from the 20 acre alluvial body continuing through the permit area is not an AVF because the upper portion of the valley is steep and narrow, and the limited extent of alluvium would not be useful for either flood irrigated or subirrigated agricultural activities.