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:i: { November 20, 2003 Colorado water development proposals-myths vs. realities ~ BiQ Straw Proposal Mvth CDNR's Big Straw Study sponsors have assumed Colorado could and shourd pump back its currently wasted Colorado River Compact losses from near the Utah border. They claim west slope cities, farms; and envjronments need aU current wet year flood flows for benefjcia' consumptive and recreational needs4 They also assume Bjg Straw can pump Colorado River return flows at a constant day-fo-day, year-to-year flow rate, without Jarge new reservoirs at both ends of the pipeline. Realitv Colorado Rjver outflows at the Utah border vary from two to eight mHJion acre- feet durjng droughts and heavy snowmelt years. West slope consumptive and non- consumptive users need only a smaJl fraction of Colorado's normal ana above normal. outflows. Big Straw can not physjcaJly return Colorado's wasted outflow entitJements at a constant pumping rater without massive new flood and drought regulating reservoirs at both ends of the pipeline~ Without this additional storage, Big Straw's continuous pumping would dry up the Colorado River during droughts, and increase reservoir spilling and river fJooding throughout the region during wet cycles. CoforadoJs Big Straw Study is fatally flawed, because its major additional storage requirements were improperly omitted from the concept and cost estimates. Colorado's Gunnison and Colorado River Josses have actuaHy been increasing since the early 1960s~ because of the west srope's steady conversion from irrigated farming to tourism (see attached outflow trend charts for the CoJorado River Mainstream Basin and jts wetter untapped Gunnjson Basin Branch)4 CDNR's Big Straw Proposal is driven by its unauthorized, but defacto, "n'?t one drop from the Gunnison policy". South Metro Coniunctive Use Proposal Mvth Colorado's Conjunctive Use advocates assume that highly successful Arjzona- type conjunctive use techniques, that recharge unconsolidated gravel aquifers with settling ponds, can aJso be employed to recharge Denver Basin sandstone aquifers wjth deep wells and unused Two Forks water rights. Realitv Some small-scale Denver Basin recharge test wells have been marginaUy successful. However, large scale recharge operations into Denver Basin sandstone aquifers could greatly increase users costs and technical risks for the followlng reasons: 1) raw water treatment, injection, pumping! retreatment, maintenance, and well replacement costs would substantially increase over time; 2) unpredictable long-term chemical and biological reactions assocjated with treated surface water injections into sedimentary fo~matjons could create _ serious future public health problems; 3) the srow weir injection process required to recharge water-bearing sandstone would require substantiaJ new flood and drought storage, dedicated solely to recharging well fields; 4) extreme hydraulic pressure changes within sandstone formations from recharge injections can cause un"predictable bedrock fracturing, ground movementt and subsidence problems; and 5) use of excessive Two Forks water rights for South Metro recharge operations would further damage Colorado Mainstream and South Platte tributaries, "which have been excessively depleted by previous Metro Denver diversions. J