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I I I I I I I I I I I I I I I I I I I 2.3 TOTAL VATER SUPPLY AVAILABLE TO CITY Tasks 2 through 4 (Streamflow Analyses - Big Thompson River, Inflow Analyses - Colorado Big Thompson Project, and Inflow Analyses - Vindy Gap Project, respectively) determined the physical availability of water in the CBT and Vindy Gap projects as well as native streamflow derived from the Big Thompson watershed. In Task 6 (Total Vater Supply Analysis), it was necessary to determine what portion of the physical supply can be diverted for City use under Colorado Vater Law and the management policies of the NCVCD and HS-NCVCD. For the Big Thompson River direct-flow rights, this determination entails allocation of available water in accordance with water rights and the terms of the Transfer Decree (Vater Case Number 82-CV-202A). The availability of CBT water during any year will be partially dependent upon the annual "quota" set by the NCVCD. This "quota" is set each spring and it specifies the value in acre-feet of each share of CBT ownership for the coming year. Allocation of native river water (i.e., that water derived from runoff in the Big Thompson watershed) is based upon the water right and its priority of the individual users along the river. The Vater Commissioner for the Big Thompson River considers measured streamflow at rated locations along the river, return flows from irrigation diversions and the Loveland Vastewater Treatment Plant discharge, and tributary inflows in determining the distribution of water during times of shortage. A computer model was developed to simulate the allocation of water among the City and the 15 irrigation and ditch companies for any given monthly flow in the Big Thompson River. The model incorporated both hydrologic factors such as irrigation and tributary inflows, and management/legal factors such as priority rank, historic diversion patterns, and the terms of the Transfer Decree. The long-term synthetic streamflow record for the 2-5