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I I I I I I I I I I I I I I I I I I I l\,) 1\." ~ .....::i static to upward trend in much of the area. consequently there is little need for erosion control treatment. Treatment potential is limited over much of the area by real or effective precipitation limitations. Grazing deferment or rest may have some potential for improvement on some of the acreage. Cattle and sheep utilize the cisco pits unit for winter or spring grazing, and it is utilized by antelope. The extensive research of the 1950s and 1960s in the cisco pits area presents an important opportunity for follow-up research. Recommended research includes evaluation of the present condition of the area for hydrologic condition, sediment and salt yield rates, and especially for evaluating the efficacy of pits and furrows as sediment and salt yield control measures. A research proposal is included in Appendix III, cisco pits Research Proposal. PSIAC GEOMORPH~C UNITS: The following paragraphs are summaries of the PSIAC geomorphic units as delineated on Map I. Detailed field descriptions of the PSIAC geomorphic units are given in Appendix IV, PSIAC Sediment Yield Data, on the PSIAC field sheets. Detailed annual sediment and salt yield data are given in Appendix V, Annual Sediment and Salt Yield Data. Unit 1 - PINION-JUNIPER-SAGE TERRACE - This unit is an upland terrace developed in eolian and alluvial materials overlying Mancos Shale. Sage, pinion and juniper are the dominant vegetative types. The unit contains approximately 3548 acres. The annual Present and Future Without Project (FWOP) condition sediment yield rate is estimated at approximately 2.25 acre-feet per square mile or approximately 6.8 tons per acre (PSIAC sediment yield classification 2 - high). The annual Future with Project (FWP) rate is estimated at 0.45 acre-feet per square mile or approximately 1.3 tons per acre (PSIAC sediment yield classification 4 - moderate). Proposed project measures include chaining, seeding and livestock exclusion or very low intensity grazing. This will result in significant water spreading and lengthening of well developed, concentrated flow paths. Implementation of the proposed treatment will result in the annual control of 5204 acre-feet or 15,611 tons of sediment and the saving of 313 tons of salt. The salt yield rate for this unit is 2%. This unit is recommended for project-level land treatment planning. Unit 2 - MANCOS TERRACE - This unit is composed of severely eroded Mancos Shale. There is poor soil development, and raw shale is the dominant soil material. Large and small crystals of gypsum cover the eroding surface of this unit. The high gypsum content of the soil results in the surface appearing to have a sparkling or glittering aspect to it. This unit contains approximately 5658 acres. Low to moderate grazing is continuing to accelerate the erosion processes in this unit. The annual 10