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Section 6 Water Needs Assessment The "Conserve" component is centered on keeping currently "healthy" - both in terms of quality and quantity - rivers healthy. This could include the following strategies: ^ Acquisitions of interests in water to improve an existing environment via Senate Bill 02-156 authority ^ New CWCB instream flow appropriations ^ Interruptible water supply agreements ^ Leases and other methods Segments for consideration under the "Conserve" component could include Gold Medal fisheries, wild trout reaches, three-factor (R2 Cross method), intact instream flow reaches, Great Outdoors Colorado Legacy reaches, TNC designated reaches, reaches in wilderness and national parks, and other known high-quality stream segments. The gap between supply and demand might then be measured through ecologically sustainable water management, or other method(s) that fully protect flows, noting that in some cases there may be no gap. The "Protect" component suggested by the interest groups includes keeping threatened but currently healthy reaches whole, or as close to whole as possible. In addition to the strategies indicated above for the "Conserve" segments, strategies could include integration of permit conditions (federal, state, or local) and agreements such as that contemplated under the ongoing UPCO process. Relevant segments could include any reach that might be affected by future water management actions (e.g., the Identified Projects and Processes or other future actions). The "gap" associated with protecting those identified reaches would then be the difference between current conditions and the minimum (or higher) flow necessary to maintain a functioning, healthy ecosystem. The "Restore" component suggested by the interest group representatives revolves around restoration of dry, low-flow, or low-quality segments. Project reoperations and ditch lining are two possible strategies that could be employed, in addition to those listed for "Conserve" and "Protect." Possible candidate segments could include truncated instream flow reaches; two-factor instream flow reaches; reaches with endangered, threatened, or sensitive species; Dry Legacy reaches; or others from the Colorado Water Trust maps. Truncated instream flow reaches are those that do not connect habitat, such as r~ portions between tributaries and mainstems, through which fish may not be able to move within a region. Two- factor instream flow reaches are those on which CWCB has used two of the normal three factors in determining minimum flows using the R2 Cross method, often resulting in lower flow criteria and often the result of a lack of water availability on the subject reach. The gap in the "Restore" segments could be considered to be the difference between current conditions and flow goals estimated from this approach, ecologically sustainable water management conditions, or other considerations. It was noted that the "CPR" approach may differ for environmental versus recreational flow needs. This approach could be integrated into the Identified Projects and Processes, Options for Alternatives, or as new stand-alone options, as each moves from concept toward implementation. 6.1.3.2 Concepts for Estimating Environmental Flow Needs Environmental and recreational interest groups suggested that in characterizing environmental water needs, a two-step approach could be implemented: ^ Identify and locate critical water-dependent species and natural systems ^ Assess the environmental demands (or ecological flow needs) of those systems Key sources for information for water-dependent species and systems might include: ^ CDOW ^ Colorado Natural Heritage Program (CNHP) ^ Colorado Water Trust ^ TNC Ecoregional Plans ^ Colorado River Endangered Fish Recovery Programs It was also suggested that a model could be developed to determine environmental or instream needs of these communities by identifying integral components of the flow regime such as: ^ Base flows ^ Normal high flows ^ Drought and flood conditions ^ Interannual variability 6-6 S:\REPORIIWORD PROCESSING\REPORllS6 11-8-04.DOC