1986-06-13_GENERAL DOCUMENTS - C1981018

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-26- the potential for the development of flood irrigation agricultural activities along Red Wash of Scullion Gulch is minimal . Agricultural activities are absent within both the. Red Wash and Scullion Gulch drainages at the present time. No evidence of historical irrigation practices were observed in either basin within the 10 mile inventory area, aerial and ground surveys revealed no evidence of diversion and irrigation structures or remnant of agricultural fields. This lack of evidence of past or present irrigation activities provided the rationale for the permittees request for a negative AVF determination for Red Wash and Scullion Gulch. The original findings document prepared by the Division and OSM at the time of permit issuance indicated that the permittee' s description of 'the 10 mile irrigation reconnaisance inventory was insufficient to adequately demonstrate that irrigation is not feasible in Red Wash and Scullion Gulch. The reconnaisance inventory did not identify what drainage basins were included in the study. It was impossible to determine from the information presented if those basins inventoried were of similar size and water yield potential . It was unknown whether a basin the size of Red Wash (drainage area 122 square miles) occurs within the 10 mile inventory area. Scullion Gulch is generally one-tenth the size of Red Wash, and it is possible that the drainages inventoried were more along the size of Scullion Gulch. The permittee also had not identified the minimum physical and hydrologic characteristics necessary to establish successful irrigation in the region. This information is important to adequately demonstrate that irrigation would not be feasible in either Red Wash or Scullion Gulch. Typically, once the characteristics of current or historically successful irrigation are identified, it is then possible to contrast the watershed characteristics of the lands within and adjacent to the permit area with those of successfully irrigated areas. The study area should also not be limited to 10 miles; rather, the OSM June 11 , 1980 Alluvial Valley Floor Guidelines recommend a region containing those watersheds with "a few counties or an area a few tens of miles about a permit area". Typically, the size of the inventory area must be selected so that the minimum characteristics necessary to support irrigation can be established. During the initial permit review period, the Division and OSM consulted with local Soil Conservation Service personnel , reviewed the SCS publication "Important -Farmland Inventory of Colorado," and visited the site in order to obtain additional information regarding the feasibility of irrigation in Red Wash and Scullion Gulch. Review of the SCS publication confirmed that all irrigated lands of national and state importance within the project region are confined to the White River; no irrigation presently occurs along any tributary drainages. This fact was further confirmed for lands of local importance by SCS personnel (Mr. Alvin Jones, Range Conservationists, SCS Meeker Area Office). 1 . Red Wash At the time of issuance of the initial permanent regulatory program permit, the Division-and OSM made a "probable" positive AVF determination for Red • Wash, stating in the original Findings Document that "On the basis of available annual water yield, extensive drainage area, the presence of unconsolidated streamlaid deposits, probable subirrigation potential , and the professional judgement of Colorado MLRD representatives, the OSM identifies Red Wash and its associated alluvial deposits as a probable alluvial valley floor. "