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City of Longmont <br />2012Water Supply & Drought Management Plan <br />"Conserving our Water to Preserve our Quality of Life" <br />I. City of Longmont's Drought Supply Policy: <br /> The City of Longmont's raw water drought supply policy is outlined in the Raw <br />Water Master Plan. This plan describes the City's policy of using the 1-in-100 year drought <br />recurrence interval as the basis of planning for the City's raw water supply. This drought <br />interval is based upon a drought of approximately 7 years in length with a total Saint Vrain <br />Creek watershed deficit of 237,000 acre-feet. This plan also describes drought indicators and <br />potential forecasting methodologies to be used to predict drought and determine its severity <br />and impacts on the City's raw water supply. <br />The Saint Vrain Creek has historically experienced drought conditions and will <br />continue to do so in the future. The annual average measured flow in the Saint Vrain Creek <br />at the Lyons gaging station for the period 1896 to 1982 was 93,000 acre-feet. After the <br />addition of diversions from the creek above the Lyons gaging station, the estimated virgin <br />flow for this period is 124,000 acre-feet. A drought of seven years in length, with a total <br />deficit of 237,000 acre-feet, would result in a deficit of approximately 34,000 acre-feet per <br />year. <br /> During 2011, the Saint Vrain River Basin experienced above-average streamflow <br />conditions as a result of above- average snowpack and rainfall events. Consequently, Water <br />Board recommended and City Council concurred in May of 2011to remain at a Sustainable <br />Conservation Level Drought Response for 2011. Longmont continued to develop itsdiverse <br />water rights portfolio and was able, therefore, to finish the 2011 irrigation season (October <br />31, 2011) with above average local reservoir storage. Through continued long-term water <br />conservation efforts of the citizens of Longmont the Cityhas realized a slight decrease in <br />demands for water.This has resulted in Longmont having a slightly above average water <br />supply in storage for this time of year,with its select reservoir storage currently at 87% of <br />full. It is expected by July 1, 2012 that select reservoir storage will be approximately 97% <br />of full. During 2012 the Public Works & Natural Resourcesstaff will continue to implement <br />demand management strategies outlined in this plan. Water Resources staff will continue to <br />pursue opportunities to exchange additional water to supplement the existing water supply. <br />Data on Water Years 2010 and 2011: <br /> 2010 2011 <br />Total Water supply available: 25,236 acre-feet 23198 acre-feet <br />Total treated water demand: 17,081 acre-feet 17,108 acre-feet <br />2012 winter snow pack as of April 12, 2012: South Platte River Basin – 58% of normal <br /> Colorado River Basin – 33% of normal <br />PAGE 2 OF 9 <br />9 <br /> <br />