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<br />Forecasts are made at the following gaging stations: <br /> <br />Alamosa Creek above Terrace Reservoir <br />Conejos River near Mogote <br />Culebra Creek at San Luis <br />Rio Grande at 30 Mile Bridge (48.3 km Bridge) <br />Rio Grande near Del Norte <br />South Fork of Rio Grande at South Fork <br /> <br />Forecast accuracy on these streams is relatively good. Average errors <br />range from 9% to a high of 16% except for the Culebra. The Culebra <br />presents some problems in forecasting due to its relatively small flows <br />and I imited snow catchment area. <br /> <br />It is hoped that forecast accuracy will be greatly improved on the <br />Culebra and somewhat improved on all the other basins with the addi- <br />tional data from SNOTEL. <br /> <br />A pilot project was initiated in 1975 to evaluate total snow cover in <br />the Rio Grande Basin utilizing LANDSAT photo imagery. LANDSAT are the <br />letters used to Identify NASA's satellite used to photograph all the <br />land masses of the world. There are two LANDSAT's and they photograph <br />every section of the world every 9 days. A 5-year study was developed <br />with NASA to ascertain if snow cover could be used as another variable <br />In the forecast formula. Several other possibilities exist for use of <br />the data from the satell ite pictures: monitoring crops, sprinkler <br />systems, range lands, and uncultivated lands. <br /> <br />Since a large amount of data will become available once the SNOTEL sites <br />are activated, modeling becomes a real possibility. <br /> <br />This would util ize the total water balance equation for the basin and <br />provide input and output data on a daily basis. <br /> <br />Forecasting of any stream in the basin could be updated daily if desired. <br />This would also provide a good deal of insight into the potential flooding <br />or drought on any given year. Modeling of the Conejos Basin is utilizing <br />the computer terminal at the SCS state office and the facil ities at the <br />Fort ColI ins Computer Center. <br /> <br />This model became operational in 1977. <br /> <br />A number of agencies cooperate in the snow survey program in the Rio <br />Grande Drainage including the U. S. Forest Service, Colorado State <br />Engineer, U. S. Geological Survey, Trinchera Irrigation Company, Santa <br />Maria Reservoir Company, San Luis Irrigation Company and National <br />Weather Service. <br /> <br />At the present time snow survey installations are adequate. If addi- <br />tional data for forecasting are needed, appropriate changes to the <br />system will be made. <br /> <br />r,- f ~ <br />:.....'.... .1. <br /> <br />E-5 <br />