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Project For=laticn I Project Formulation l.AND TREA.1MEN'I' MEASURES of the programs of the AgriOlItural Stabilbation and Conservation Ser~ vice, the Fa1'1llers HOllIe Administration and the Great Plains Conservation Program will assure additional funds for the planned land treatment program. Land treatment measures were selected and included in the project to provide necessary conservation, develqment, improvement, and prevent enviromJeJ1tal pollution of the lands under private ownership and state leased lands in the watershed. It is planned that the rate of application and teclmical assistance will be ~celerated on the COlorado portion during the five-year project penod. Measures to be applied on the irrigated land were selected to iJrtprove irrigation efficiencies, yields of crops, wildlife habitat and to reduce runoff and erosion. Increased net returns should result to the land owners and opera tors . No additional land will go into agricultural production as a result of the project works of improvement. SfRlJCIlJRALMEA.'iJRES ProjectPr02ram Measures to be applied on rangelands and woodlands above the floodwater retarding struc:tures are those which tend to improve soil and vegetative cover condition and will result in a reduction of nmoff erosion and sediment and also ~rove food and cover for livestock ~ wildlife. /obch of the plant cover on the watershed rangeland can be improved to conditions approaching or equalling the potential of the range sites by lTlell1lS of proper gradng lI5e and gradng systems which provide for periodic rests during the critical spring and early Sl.llllller plant gr~ stages. A project program of five floodwater retarding and one grade stabilizing struc:tures will achieve the project requirement for providing protection frem floodwater, sediment and erosion damages to flood plain agriOlltural crops and property. Grade Stabilization Structure B-7 is a necessary structure located in an active headcut below an irrigated meadow. Sediment fron this headcut has been II prcblelrt with downstream irrigation diversions causing excessive costs for canal main- tenance and crop losses from diversion of silt-boon water. This stl'"..lC- tore will enhance enviro~tal values above the doomstream Structure B-2. About 30,740 acres of the upper part of the watershed are forest or brush-covered rangeland. Wlth this are widely scattered small stands of poor site ponclerosa pine. The Wy(llling State Forester, after field cx:ll1\ination, recOlmlended no incre35e in the rate of a.pplication of forestry land treatt1ent measures in Wyw.ir.g. He also detemir.ed t.l:l.:l.t the Wyoming fire protection facilities were presently adequate for pro- ject.purposes. Therefore, no forestry programs for the Wyeming portion are lncluded. Immediately below Structures B.S, B-6 and B-4 a 37 year level of pro- tection is achieved and Structure B-2 provides a SO year level of pro- tection. Structure 8-3 together with the irrigation canals llJld the existing capacity in the Boxelder Creek charmel provides the town of Wellington and the adjacent farmland a 100 year level of protection. The level of protection decreases as the distance below the structures increases. At Ilighway 14, east of Fort Collins, the 100-year frequency storm flow, present condition, will be decreased to the equivalent of a 4-year frequency stonn flow with the project structures installed. An average of greater than a 10.year level of protection is achieved for most of the watershed. See Project Map for structure locations. To achieve the project objectives ten reservoir sites were studied in various canbinations, together with a possible charmel improvement flrogr~m. Alternative Structural Measures Studied In Colorado, emphasis will be placed on continued improvement of the forest and brush covered lands and protection from fire loss and e~ces' sivc.grazlng pressure. Activity will aim toward maintaining and 1m- ptovmg vegetative cover to reduce nmoff and sedim.entation. The major works of improvement will be for fire control intensification on all the ColoraGo lands (14S,032 acres) through the Wellington Fire Protection District. The land owners and operators have the capability to continue applica- tion of needed land treatment measures at the planned and the acceler- ated rate. Soil Conservation Distril;:t sponsors have w-ritten assurance fran the COlorado and the Wyaning State Boards of Land Ccmnissioners that needed land treatment measures will be applied and maintained on state lands through the efforts and funds of the lessees. Continuation B-1, B-2R, B-3 vs B-2 A three-structure alternative to Structure B-2 was studied. The canbi- nation of sites B-1 in Section 8, T. 10 N., R. 69 w., site 8-8 in .Section 3D, T. 11 N., R. 69 w., both on Hoxelder Creek, and B-2R in Section 13, -17. -18-