SWSI Environment and Recreation Needs and Priorities TRT Draft

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CWCB must determine the minimum amount of water required to preserve the natural environment to a reasonable degree. CWCB relies upon CD OW scientists to provide the biological information needed to make the statutory determinations. How the Program Works New Appropriation Process The process for appropriating a new instream flow or natural lake level begins with the CWCB's request for recommendations. Each February, staff hosts an Instream Flow Workshop where requests for streams and lakes to be protected are solicited. Any person, including any governmental entity, can submit recommendations. Recommendations must be submitted in writing and with specificity. All recommendations are compiled in the Instream Flow Work Plan and prioritized by staff based on resource value, data requirements and other criteria. Priority streams and lakes are added to the Candidate Stream List for immediate processing. Once field work is collected for the candidate streams and lakes, the data is analyzed and the instream flow amount is quantified using R2Cross or other standard methodologies. Colorado adapted the R2Cross methodology from a cross-section model used by Region 2 of the Forest Service; hence the name. The R2Cross model stages streamflow at a cross-section location using Manning's equation, and calculates key hydraulic parameters necessary for fish passage, egg incubation and food production. The R2Cross model is a cost-effective tool that provides consistent, reproducible results, and is easy to use. The model has been upheld by Colorado's Water Courts and is used by other agencies and states for quantifying instream flow needs. The model was also recently adopted by the Montana Water Trust for use in evaluating needs for project streams 3. Most instream flow water rights are based on the presence of a cold water fishery as an indicator of healthy natural environment. Numerous models have been developed to quantify the flow requirements for fish, and those models have been upheld in court challenges. However, Colorado's Instream Flow Program is not limited to protecting coldwater fisheries. The CWCB has appropriated and acquired water for non-fishery purposes. On Oageby Creek in southeastern Colorado, the CWCB's appropriation was based upon maintaining wetlands for waterfowl habitat. On the Arikaree River in northeastern Colorado and the Mexican Cut Ponds near Crested Butte, water was appropriated to protect unique species of frogs and salamanders. The CWCB has also appropriated water to protect unique hydrologic and geologic features (Hanging Lake) and acquired water to maintain critical habitat for endangered native, warm water fish (Yampa and Colorado River). The challenge in securing water for non- fishery purposes is identifying a scientifically reproducible and acceptable method for quantifying flow needs. Once flow needs are quantified, the statutes require that the CWCB determine whether water is available to meet those requirements. The intent of the water availability requirement is to ensure that water is legally and physically available to meet the modeled flow recommendations. To estimate hydrology, CWCB staff relies on existing gage records or standard methods or models for determining flow for ungaged basins in Colorado. Staff relies heavily on the resources and technical tools available through the V.S.O.S. and the Colorado Decision Support System. Recommendations that meet the statutory tests of 1) presence of a natural environment and 2) water available to preserve the natural environment are presented to the CWCB for appropriation. Colorado water rights are adjudicated by the Water Court on an annual basis; therefore, new instream flow or natural lake water rights are junior to existing decreed water rights. For that reason, new instream flow appropriations can not affect or impact existing uses on a given stream, so long as those senior rights are used for their decreed purposes. Water Acquisitions CWCB can acquire water released from storage reservoirs, direct diversions, interests in water owned in a ditch or reservoir, water pumped from wells, or other water, water rights or interests in water 3 Montana Water Trust web site, http://www.montanawatertrust.org/