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<br />DATA COLLECTION AND PROCESSING <br /> <br />2. Data Collection and Processing <br /> <br />RTi collected a large amount of data to support the project activities. All investigations were limited to <br />October 2003 to June 2008, the period for which SNODAS data are available. Table 2-1 presents a <br />summary of the collected data. <br /> <br />Table 2-1. Summary of Collected Data <br /> <br />Data Source(s) Data Type Data Description <br />NSlDC SNODAS data products SWE <br />NOHRSC Blowing snow sublimation <br /> Surface sublimation/condensation <br />CDSS Streamflow Observed daily flow volumes <br />NRCS Natural flow Monthly natural flow volumes for RIODELCO <br />NRCS Water supply forecast Seasonal forecasted (April-September) runoff volumes <br />NRCS SNOTEL SWE <br /> Soil moisture <br /> Temperature <br />FAA/NWS METAR Climate Wind speed <br /> Humidity <br />PRISM Climate Monthly precipitation grids <br /> <br />RTi obtained a complete historical record of daily SNODAS products from the National Snow and lee <br />Data Center ftp site (NSlDC 2008). Real-time data products for WY 2008 were received directly from <br />NOHRSC. RTi processed the SWE grids from SNODAS to obtain daily average SWE depths and <br />volumes for each index basin. The blowing snow sublimation and surface sublimation/condensation data <br />products were processed to ascertain the significance of these losses in the project area. <br /> <br />To quantify the discrepancies between the seasonal observed flow volumes and the water supply <br />forecasts, RTi collected observed flow volumes, natural flow volumes, and historical seasonal water <br />supply forecast volumes. RTi downloaded daily observed flow volumes from the Colorado Decision <br />Support System (CDSS) for the six key index gages (CODWR 2008). Monthly natural flow volumes for <br />RIODELCO for WY 1958-2005 were provided by the NRCS. RTi collected the historical water supply <br />forecasts from the basin outlook reports developed by the NRCS and the National Weather Service <br />(NRCS 2008). <br /> <br />RTi collected SWE, soil moisture, and temperature data at selected SNOTEL gages. SWE data were <br />collected for 22 gages around the project area, including the six gages utilized in the NRCS water supply <br />forecast equations (i.e., Lily Pond, Middle Creek, Molas Lake, Upper Rio Grande, Upper San Juan, Wolf <br />Creek Summit). The SNOTEL SWE data were used to compare against SNODAS SWE estimates and to <br />better understand the water supply forecasts developed by NRCS. Soil moisture data were collected at <br />the six SNOTEL stations in the project area that have soil moisture sensors installed (i.e., Lily Pond, Red <br />River Pass #2, Slumgullion, Upper Rio Grande, Upper San Juan, Wolf Creek Summit). RTi used the soil <br />moisture data to assess relative soil moisture conditions for recent years. Temperature data were collected <br />at five SNOTEL stations near the RIODELCO basin (i.e., Beartown, Middle Creek, Slumgullion, Upper <br />Rio Grande, Wolf Creek Summit) for estimating potential evapotranspiration (PET) rates. <br /> <br />Climate data for WY 2004-2008 were used in the water supply investigation. RTi processed monthly <br />precipitation grids from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) to <br />obtain monthly precipitation values for each key index basin (PRISM Group 2008). PRISM data are <br />generally considered a reliable source for precipitation in mountainous regions with strong orographic <br /> <br />2 <br /> <br />~Riverside Technology, inc. <br />