Laserfiche WebLink
years of the study period were examined more closely. Calibration targets were chosen to <br />generally simulate conditions within 5 to 10 percent of observed conditions. <br />The steps used in the calibration process were as follows: <br />Diversions: <br />1 Compare simulated diversions to historical diversions to identify shortages <br />2 Determine reason for any shortage <br />3 If required, adjust proration factors, return flow pattern/location, operational rights <br />4 Regenerate baseflow and rerun simulation <br />Reservoirs: <br />1 Compare simulate EOM contents to historical EOM contents to identify differences <br />2 Determine reason for any EOM content differences <br />3 If required, adjust proration factors, operational rights <br />4 Regenerate baseflow and rerun simulation <br />Streamflows: <br />1 Compare simulated stream gage flows to simulated flows <br />2 Repeat diversion and reservoir steps until simulated gage flows approximate historical <br />Results - Baseflows <br />Final average annual baseflows for the Phase lc surface water model are summarized in Table 2 <br />along with historic data and their difference. Note that the difference column can be interpreted <br />to be an estimate of all historic depletions that have occurred upstream of each gage. Average <br />monthly baseflows at seven key points along the Rio Grande and four key points along the <br />Conejos River are shown graphically in the Figures 1 and 2, respectively. It is interesting to note <br />that the river system between the Rio Grande gages at Del Norte (USGS 08220000) and Monte <br />Vista (USGS 08221500) looses approximately 25,000 of per year. This is generally consistent <br />with observations of the District 20 Water Commissioners. During peak runoff months and <br />throughout much of the irrigation season, baseflows, as expected, generally increase in the <br />downstream direction as the River gains from additional tributary inflow and return flow. <br />River losses consistent with District 22 Water Commissioners are also evident in the baseflows <br />calculated for the Conejos River and along its tributary the Rio San Antonio. Model results <br />suggest that the Conejos River system losses nearly 60,000 of between the Magote gage (USGS <br />08246500) and the LaSauces gage (08249000), inclusive of gains from the Rio San Antonio. <br />Numerous seepage studies conducted along the Conejos River by the Division 3 Engineer have <br />confirmed significant losses in this reach. <br />A component of the reporting during operation of the surface water model in baseflow mode is to <br />report on calculated negative flow values if they occur. Calculated negative flows can occur at a <br />gage in the baseflow model run if simulated return flows are greater than historical flow <br />observations adjusted for historical upstream diversions. In this event, StateMod resets the <br />calculated negative value to zero flow, and proceeds with the run. However, the warning of <br />negative flows can suggest the need for adjusting such things as return locations, return timing <br />patterns, and/or irrigation efficiencies. Calculated negative flows may also suggest less accurate <br />stream flow gage data. <br />C:Acdss\Task8-8.doc Phase lc Model September 27, 2000 -Page 7 of 17 <br />