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In summary, the narrow terrace widths in combination with a sinuous, incised channel, would not <br />provide sufficient widths of land for farming of any significance in the upland areas of Grassy and Sage <br />Creeks. Flood irrigation could not be economically conducted in a majority of the upland areas <br />because of channel erosion and high maintenance concerns. Only one hay field in the upper portions <br />of Sage Creek was found to be flood irrigated, which substantiates the above conclusions. The lower <br />portions of each drainage are quite different from the upland valleys and significant areas with good <br />alluvial widths (true alluvium, not mixed deposits) were mapped. The principal factor controlling <br />farming in these reaches is water availability. This will be discussed in more detail in the following <br />sections concerning water availability. <br />Irrigation. Aland use and irrigation map (Exhibit 16-3, Land Use, Flood I«igated, and Subirrigated <br />Areas Along Dry Creek, Sage Creek, and Grassy Creek) was constructed to depict the extent of <br />subirrigation, existing land use, and extent of flood irrigation in alluvial areas along upper Grassy and <br />Sage Creek within the boundaries of the study area previously described. The extent of subirrigation <br />was determined on the basis of the vegetation growing on the valley fill and alluvial deposits. In <br />general, the Subirrigated areas were defined as those that were currently supporting wetland <br />vegetation or vegetation that was strikingly different from the surrounding uplands. Areas of existing <br />flood irrigation were evaluated using existing aerial photographs, field checking, and water rights <br />information (see Water Rights section of this Tabl provided to Peabody by Tipton and Kalmbach, Inc. <br />Irrigation potential was evaluated on the basis of the relative size of the valley floor, topographic <br />considerations, and the availability of water. The cost of implementing an irrigation program was also <br />an important consideration. <br />The upper portions of Grassy Creek and Sage Creek occur in narrow mountain valleys. These portions <br />are Subirrigated where the stream channels are not deeply incised. Also, the activity of beavers keeps <br />the soils and valley fill deposits saturated. There are two hay fields in the upper portion of Sage Creek <br />(Sections 30 and 19 in T5N1. One of the fields has the potential for being flood irrigated. In order to <br />create the field, it was necessary to relocate the stream channel. The channelized portion of the <br />stream runs alongside the road and has the potential for being used as an irrigation ditch. The other <br />field occurs at the base of a side tributary to Sage Creek. This field is Subirrigated but not flood <br />irrigated. A third hay field is located approximately 1.5 miles downstream (Section 181. It occurs on <br />valley fill material and was created in much the same way as the upstream fields. The stream was <br />relocated along the western side of the valley so that the field occupies the central portion of the <br />valley bottom. The field is Subirrigated land occasionally flood irrigated) and is used to produce grass <br />hay. <br /> <br />16-3-3 Revised 2/99 <br />