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Study Plan, Rito Seco 2 Sediment Damage: The SCS economist and geologist wilt work together In determining this damage. Field surveys, in accordance with the Economic Guide, will be conducted to determine the magnitude and extent of sediment and erosion damage. Flood Damage: Inventories of flood damage to cropland will be obtained from Interviews with farm owners and operators by the economist, and through hydrologic studies. Canal company officials will be asked to furnish information on flood damages to the canal and resulting delays in time of irrigation water deliveries. Interviews of local residents will be utilized to obtain informa- tion on flood damage in the urban area. Valley cross-sections will be surveyed to enable the hydrologist to prepare flood flow lines • that will show area flooded by the largest flood of record. Because the urban area contains a large number of houses and commercial - estabiishments, a sample will be drawn from the flooded area. Upon development of information on the area and depth of floodinci by floods of various sizes, the economist can coordinate this 'nforma- tion into a depth-damage curve for the area. B. Benefit Evaluation Damages and benefits will be calculated in accordance with the economic guide. Current normalized prices will be used 'for agri- cultural products and current prices for values other than agricul- tural products. Localized cost-return data will be used. Flood flows will be derived by the hydrologists. ENGINEERING Engineering design data will be acquired from field reconnaissance surveys to obtain information for structure sites, along with informa- tion obtained from the use of U.S. Geological Survey maps. Structural quantities along with present estimated cost will be used in developing the engineering cost. Fifteen percent will be added to this cost for contingencies to obtain estimated construction cost. _ngineer- ing services and project administration will be 14 and 17 percent, respectively, of the construction cost. Average annual cost will in- clude the cost of operation and maintenance. HYDROLOGY Drainage area determinations necessary for making hydrologic e~•aluations will be based on 7-1/2" USGS topographic maps. Precipitation data will be taken from NOAA Atlas 2, 1973 for Colorado. Soils groups and cover conditions will be taken from the files of the Soil Conservation Service office in San Luis, Colorado, and a field reconnaissance of th~~ watershed. Future condition of the watershed will be determined with the .assistance of local planning groups.