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Replacements of historical return flow obligations associated with the City's use of its changed <br />shares are provided by the City's WWTP effluent, storage releases from Ralph Price Reservoir <br />and Union Reservoir, and summer credits from its lower ditches when the river is zeroed out <br />below the Oligarchy Ditch (generally starting in early- to mid-August) and the City is unable to <br />exchange the lower ditch credits upstream to its Pipelines or to Ralph Price Reservoir. <br />Consumptive Ilse <br />The consumptive use of all in-house potable uses is estimated at 5 percent of the in-house <br />diversion based on treatment at a centralized sewage facility. Lawn irrigation return flows <br />associated with outside uses of water diverted through the potable treatment plant have been <br />neither quantified nor adjudicated. <br />Water Supply <br />The combination of the original water rights, early transfers, later transfers, transmountain water, <br />and other ditch transfers have generally provided sufficient supplies for the City's water <br />demands. In-basin direct flow and storage water rights are currently used to supply about 60 <br />percent of the City's water demand, with the remaining supplies provided by transmountain <br />supplies. <br />The order of operations for the City of Longmont s water resources generally follow the pattern <br />enumerated below and described in more detail, following: <br />1) Direct flow rights <br />• Direct Flow Pipeline Water Rights <br />• Changed Water Rights at Alternate Points of Diversion or by Exchange <br />2) Transbasin Water (C-BT Project and Windy Gap Project) <br />3) Storage Releases <br />• Although not operated to-date, reusable supplies from the City's WWTP will either <br />be exchanged upstream or into the Oligarchy Ditch for storage in Union Reservoir to <br />provide additional carry-over storage and supplies for later use or exchange. <br />Winter <br />• Water supplies released from Ralph Price Reservoir to the North Pipeline are generally <br />sufficient to meet potable water demands during the winter (November to March). <br />• The City can also divert its approximately 77 percent ownership in the Pleasant Valley <br />Reservoir storage rights (including the number one storage priority in the St. Vrain River <br />basin) at its Pipelines or into Ralph Price Reservoir during the winter. <br />Summer <br />• The City's direct flow and changed water rights are generally sufficient to meet potable <br />water demands during the summer (April-October). <br />• The City's reservoirs divert water to storage under their storage water rights, to the extent <br />possible, during the spring runoff. <br />• Changed direct flow rights available in excess of the City's potable demands may be <br />exchanged up to Ralph Price Reservoir, diverted into Union Reservoir, or used for <br />replacement of return flow obligations, as necessary. <br />City of Longmont Operating Memorandum.doc Page 17 of 21 March 2, 2005 <br />