C150150 Feasibility Study - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I Reservoir were assumed to have operated during the entire period. Consumptive use and return flow factors from LA WMA's current Arkansas River Use Rules replacement plan were used. LA WMA' s commitments to its various cooperators including Colorado Beefwere fully recognized. The replacement water available under LA WMA' s direct flow water rights is operated separately from the replacement water available under its various Article II Storage Accounts, which is consistent with the way LA WMA' s replacement plans have operated since the Arkansas River Use Rules were adopted in 1996. This representation in the operating plan required the calculation of inflows to conservation storage for years prior to 1979 before. the 1980 Operating Plan for John Martin Reservoir was approved creating the Article II Storage Account System. The operation study also required distribution of the calculated conservation storage to LA WMA's Article II Storage Accounts using the percentages in the 1980 Operating Plan for John Martin Reservoir. Generally, water was held in LA WMA' s Article II Storage Accounts when LA WMA' s direct flow water rights were adequate to meet LA WMA' s replacement requirements and released from the Article IT Storage Accounts when needed for additional replacement. Evaporation was charged against the water stored in the accounts and LA WMA's Article II Account water was spilled when the reservoir spilled historically. LA WMA allocates water to its stockholders in the winter and/or spring of the year. A full, or 100% allocation, is 1.00 acre-foot of consumptive use replacement water for each share. A 50% allocation is 0.50 acre-foot of consumptive use replacement water for each share per share and so on. Once the annual allocation is made, the allowable annual pumping is calculated for the wells that serve each farm from the number of shares on the farm, the presumptive depletion factor for the well or wells on the farm, and the appropriate "usability" factors. The operation study represented in Tables 1 and 3 assumed that conservative criteria would be used by LA WMA to set the annual allocations to insure that sufficient replacement water would be available to cover pumping depletions in dry years and the years following. This conservative allocation process that LA WMA intends to follow in future years would involve an initial allocation in December and possible additional allocations later in the winter or spring when more replacement water has become available and it is clear that LA WMA' s water supply will be sufficient to justify the additional allocation. The conservative allocation process is also intended to result in an accumulation of a substantial "cushion" of LA WMA replacement water in storage in John Martin Reservoir to cover LA WMA' s replacement requirements through a series of dry years. Table 4 summarizes the results of these operation studies. Without the Keesee water rights, LA WMA's replacement supplies would be adequate for less than full allocations of replacement water to LA WMA members in 19 of 56 years. With one-half of the Keesee water rights, LA WMA' s replacement water supplies would be significantly improved, especially in dry-years, and would justify full allocations of replacement water to LA WMA members in 4 additional years. Furthermore, with the addition of one-half of the Keesee water rights, the allocations in the years of less than a full allocation of replacement water increased by as much as 30% in some years and by 11.2% overall. On average, this translates into 7,143 acre-feet of additional pumping in these years by LA WMA shareholders. 9