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• <br />• <br />7. Associated Issues <br />Each of the groundwater alternatives that has not been deferred was <br />evaluated according to the associated issues evaluation criteria <br />previously reviewed by the Water Management Committee. The five <br />categories of associated issues are physical, legal and institutional, <br />social, economic and environmental. Tabular scoring according to <br />each criterion is presented in Tables 8.G.80 through 8.G.85 for <br />scenarios both with diversion losses and without diversion losses. A <br />description of the numeric score applied to each sub - criteria in <br />provided below. The following discussion initially presents an <br />evaluation of each alternative assuming that water is protected from <br />downstream diversions. Differences in the scoring evaluation under <br />the scenario with diversion losses are discussed at the close of each <br />criteria category. For more detail on the numeric score applied to each <br />sub - criteria refer to Chapter 6. <br />Groundwater Recharge /Return Flow Projects <br />Physical <br />Each of the alternatives for groundwater recharge /return flow projects <br />is scalable, however, there are limitations on the amount of flow <br />available for diversion, canal capacities, and available recharge sites. <br />This alternative is sustainable over time. Although the life span of <br />recharge projects can easily be extended beyond 10 to 13 years, wells, <br />pumping equipment and associated facilities would need to be <br />replaced on a periodic basis (every 10 to 20 years). Recharge projects <br />are technically implementable at the scale proposed and have been <br />instituted to a large degree in the Lower South Platte River Basin. <br />Protecting water from diversions in Colorado, however, is currently <br />not possible due to the inability to bypass existing sand dam diversion <br />structures. Significant costs would be incurred if these structures were <br />to be modified and/or replaced to allow additional water to be <br />protected downstream. The time to yield realization is dependent on <br />the length of time required for recharged water to return to the river. If <br />implemented at an SDF factor ranging from 60 to 300 days, the time to <br />yield realization would be within one year from the start of the project. <br />The alternative yield is not very easily measured. Calculations of <br />recharge using the SDF method are engineering estimates with some <br />uncertainty depending on site specific conditions. Observation wells <br />8 -G -81 <br />