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<br />capable of flood irrigation (Exhibit 37a), and the areas where the vegetation <br />suggests subirrigation are discontinous and limited to narrow bands along the <br />channel ways (Map 15a). Therefore, Bush Draw and Williams Draw are not alluvial <br />valley floors. <br />The four remaining areas meet the criteria for alluvial valley floors. The <br />floodplain of the Illinois River meets the water availability criteria for sub- <br />irrigation (p 785-27). The floodplain of the Canadian River is currently flood <br />irrigated (p 785-27), and is also subirrigated (p. 785-24). <br />Bolton Draw contains 55 acres of a flood irrigated pasture. The water used <br />for this irrigation is drived from the Michigan River (p. 785-aa). In addition, <br />95 acres of Bolton Draw alluvium contain vegetation suggesting subirrigation <br />(Map I5a). At one site, soil moisture data (Exhibit 38) collected during the <br />week of September 15, 1980, show the capillary fringe associated with the alluvial <br />water table to be within 1.5 feet of the surface. However, data are not available <br />for more than one site, or through the growing season. Therefore, based upon the <br />available data the entire 95 acres are assumed to be subirrigated. Analysis of the <br />regional flood irrigation practices (Exhibit 37a) indicates no capability for <br />additional flood irrigation using runoff from the watershed itself. <br />The applicant has identified 77 acres of alluvium along Sudduth Draw which <br />have vegetation suggestive of subirrigation. Soil moisture data (Exhibit 38) <br />collected during the week of September I3, I980, indicates subirrigation. At <br />the location sampled, the root zone ex*_ended approximately five feet into the <br />capillary fringe. No existing or historc flood irrigation has been identified <br />in Sudduth Draw (p. 7B5-16aa1. The analysis of regional flood irrigation practices <br />(Exhibit 38) does not indicate that the area is capable of flood irrigation. <br />Alluvial Valley Floors - Illinois River - Findings <br />1. The proposed surface coal mining operations would not interrupt, dis- <br />continue, or preclude farming on an alluvial valley floor. <br />The tipple is already in existence. Areas immediately adjacent to the <br />loadout include the marsh, a lumber mill, and the railroad. The bench itself, <br />although located within the floodplain, is in a marshy area that would probably <br />not have supported agricultural activities prior to bench constructions. <br />2. The proposed surface coal mining operations would not materially damage the <br />quantity and quality of water in surface and underground crater systems that supply <br />those alluvial valley floors or portions of alluvial valley floors. <br />Nearby areas within the Illinois River Alluvial G'a11ey Floor are used for <br />pasture and grazing lands, irrigated hay field, and as wildlife habitat (785-36). <br />Tipple operations would not diminish the supply of surface water to the Alluvial <br />Valley Floor. Monitoring of sediment pond effluent and the adjacent irrigation <br />ditch has not indicated any adverse change in water quality. <br />The tipple is located in a ground water discharge zone; surface flow is <br />diverted away from coal stockpiles; and structures and stockpiles are located above <br />the alluvium on a compacted man-made fill, therefore no effects are anticipated. <br />3. Surface coal mining and reclamation operations would be conducted to pre- <br />serve, throughout the mining and reclamation process, the essential hydrologic <br />functions of the alluvial valley floor. <br />-15- <br />