Laserfiche WebLink
• It has been determined that Hay Gulch meets the criteria for an AVF based on the <br />following findings: (1) The valley contains unconsolidated stream-laid deposits; (2) <br />The valley contains sufficient water to support agricultural activities as evidenced by <br />(a) the historical use of flood irrigation in the azea, and (b) the demonstrated capability <br />of the area to be flood imgated, and (3) the valley has demonstrated subirrigation. <br />Hay Gulch does not contain a stream channel probably because the original channel <br />was plowed over and smoothed out to facilitate hay production and grazing. Surface <br />water flow in the gulch is diverted into the Hay Gulch Imgation Ditch which pazallels <br />La Plata County road 120 <br />The Hay Gulch Irrigation Ditch is used for flood imgation in the vicinity of the King <br />Coal and King II Mines. The naturally occurring water table of the AVF fluctuates <br />from just above the ground surface to a few feet below the surface. This ground water <br />supply is sufficient to provide subirrigation on the AVF. The land use on the AVF is <br />primarily pastureland with occasional hay production. The essential hydrologic <br />functions that supply water to the AVF aze flood irrigation and subirrigation as <br />described above. Absent information to the contrary, the AVF is considered <br />significant to individual farming units in the area. <br />Degraded water from the King Coal and King II Mines could infiltrate Hay Gulch <br />• alluvium either from the mines' ponds or haul roads. The infiltrating volumes would <br />be so small compared to the volume of natural flow in the alluvium that the natural <br />flow would readily dilute and attenuate the infiltration. The Division concludes that <br />the mines have been designed to minimize impacts to the AVF. <br />Sufficient information has been supplied by the operator in regazd to Pine Gulch, and <br />confirmed in the field by the Division, to make the determination that Pine Gulch does <br />not contain an alluvial valley floor (AVF) in the proposed permit azea. While there aze <br />limited alluvial deposits in Pine Gulch, they aze not currently flood irrigated for <br />agricultural purposes and have not been cultivated historically. Due to the limited <br />surface water availability in Pine Gulch and ephemeral deposits, there would appeaz to <br />be no potential for future surface irrigation along Pine Gulch within the proposed <br />permit area. Additionally, there is not sufficient alluvial ground water to enhance the <br />productivity of agriculturally useful vegetation along Pine Gulch within the permit <br />area. <br />The operator has indicated that the area of confluence of Pine Gulch with Hay Gulch <br />which lies several miles beyond the permit area is an alluvial valley floor where <br />agricultural practices are being conducted. This agricultural activity depends primarily <br />on irrigation water diverted to the area from the La Plata River and does not depend on <br />surface or ground water associated with Pine Gulch. While subimgation may also be a <br />factor in the productivity ofthis area, it is the opinion ofthe Soil Conservation Service <br />• that this subimgation would most likely be related to the Hay Gulch water table <br />25 <br />