FLOOD11185 - Laserfiche WebLink

Home Browse Search

be used to add additional sources to the 7,700 acre-feet alternative to produce a yield equivalent to that produced by the 20,600 acre-feet of storage absent any significant contraindications. It was also discussed that action alternatives would include infrastructure requirements for the users, for using the additional storage. Additional infrastructure in reservoir lands would also require easements. (2) Optimization. The PDT welcomes Vertical Team counsel on simplifying the analysis of alternatives past the point it is reasonably demonstrated that the optimized level of reallocation as currently identified at the maximum of 20,600 acre-feet, if that is the case. The antecedent flood study shows no impacts of alternatives on flood control ability of the reservoir, i.e., gains and losses of flow in S. Platte due to reallocation are "a wash". In other words, the 20,600 acre-feet proposed for reallocation currently provide no flood damage reduction benefit from the flood control purpose they are presently dedicated to. The Reallocation Study did not utilize the antecedent flood study to calculate the maximum reallocation that could occur within the reservoir. However, it was stated that above 20,600 acre- feet the dam would need to be raised, the spillway modified, or something of that nature done to accommodate the increased storage. Rick McLoud described the thought process that had gone into picking the different levels of storage. Basically the higher level was the maximum storage that could be attained without a significant loss of recreation facilities. Likewise, the lower level was identified as being below a point where cost increased disproportionately to the addition of storage capacity. It appeared that there was agreement that framing the selection of alternatives for analysis in this manner would suffice so long as it was described thoroughly in the report. It also appears that it will not be difficult to document the highest and best use of the water being M&I water supply. (3) Yield as a basis for alternatives comparison. There was much discussion of dependable, firm, or average yields, each as a basis to compare alternative sources of stored water, rather than storage space. It was pointed out that if 20,600 acre- feet could be realized only 1J4 of the time, the dependable yield could not be 7,000 acre-feet. It was explained that dependable or firm yield may be insufficient to be very meaningful, and it was granted that if the State had a different way of evaluating yield, that could be used. For example, Mark Wagge of Denver Water board mentioned that they use the 3-4 year "planning drought" of 1950's - worst drought of record, to estimate firm yield (not average yield). It is required that we are comparing "apples to apples" when comparing costs and benefits of alternatives. Comparing on the basis of storage is not reasonable, as 5