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City of Longmont Water Conservation Planning Grant Application Section 1 - Background Information Water Supply Sources Raw water rights are received by the City of Longmont (the City) from the St. Vrain Creek watershed, which includes the North St. Vrain Creek, South St. Vrain Creek, St. Vrain Creek and Left Hand Creek, a tributary to St. Vrain Creek. Headwaters of the North St. Vrain Creek are in Rocky Mountain National Park and Ralph Price Reservoir is used foJ' storage. Headwaters of South St. Vrain Creek are near the Indian Peaks Wilderness Area. In 2005, 42 percent of Longmont's water supply was from North St. Vrain Creek (2005 Water Qualih) Report). The north and south forks combine to form the St. Vrain {3:reek near the town of Lyons downstream of Ralph Price Reservoir. Water from St. Vrain Creek can be diverted to Burch Lake and stored. In 2005,6 percent of Longmont's water supply was from St. Vrain Creek (2005 Water Quality Report). The City also has ownership in the Colorado-Big Thompson (CBT) and Windy Gap trans- mountain diversions operated by the Northern Colorado Water Conservancy District (NCWCD). Water from the Colorado River headwaters and the Fraser River are stored in several reservoirs west of the continental divide. CBT water is conveyed through the Alva B. Adams Tunnel to the east slope, and then through severallakes are reservoirs to Carter Lak'e. From Carter Lake the City receives CBT water through the St. Vrain Supply Canal. In 200:), 52 percent of Longmont's water supply was from CBT water (2005 Water Qualih) Report). The City has four treatment plants and is currently in the process of decommissioning two of its older treatment plants, the North and South Treatment Plants. The two remaining water treatment plants in operation will be the Wade Gaddis plant and the newly constructed Nelson-Flanders Water Treatment Plant (WTP). The Nelson-Flanders WTP was completed in 2006 and has a current capacity of 30 million gallons per day (mgd). The plant has been built to be expandable to 80 mgd to accommodate the City's anticipated water demands at build out. Water Demand and Population Growth A sllmmary of water use by customer classification is presented in Table 1 for 2002 to 2011. Water use data for 2002 through 2005 is based on actual readings. Water use data for 2006 through 2011 was estimated based on historic water use trends for each customer claEsification. Population projections for 2007 through 2011 were based on values in the City's Raw Water Master Plan Update (January 2004).