SWSI_Demand_Methodology_11-26-03

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CONI Methodologies for Estimating and Projecting Urban (Municipal & Industrial) and Agricultural Demands and Environmental and Recreational Flow Requirements November 2003 Approach for Projecting Environmental and Recreational Flows The CWCB has an existing program for appropriating, acquiring, and protecting instream flow water rights and natural lake levels. This stream and lake protection program is designed to "preserve and improve the natural environment. . ." The CWCB appropriates minimum stream flows or natural surface water levels or volumes for natural lakes to preserve the natural environment. The CWCB typically uses the "R2 Cross method" for determining minimum stream flow requirements for in-stream flows. The CWCB is also authorized "to acquire, by grant, purchase, donation, bequest, devise, lease, exchange, or other contractual agreement, from or with any person, including any governmental entity, such water, water rights or interests in water in such amount as the Board determines is appropriate for stream flows or natural surface water levels or volumes for natural lakes to preserve or improve the natural environment to a reasonable degree." The CWCB protects these instream flow water rights both legally, by obtaining terms and conditions in water rights decrees filed by other water users, and by physically monitoring stream flows and assisting the State and Division Engineers is administering the prior appropriation system so that the CWCB's instream flow water rights are not injured. For the purposes of preparing a future baseline estimate of environmental in-stream flow water rights, the current decreed CWCB instream flows will be assumed to remain in place. In 2001, the General Assembly formally recognized a new type of water right, through the passage of Senate Bill 216 - recreational in-channel diversions (RICDs). Prior to the effective date of Senate Bill 216, six entities have obtained water rights for RICDs. Now, after the passage of Senate Bill 01-216, there is a new avenue available to obtain water rights for RICDs. Environmental and recreational flow needs have not historically been considered in water resources planning as standard water demands such as municipal, industrial and agricultural uses. Municipal, industrial and agricultural uses have widely accepted standard methods for projecting future water demands. During the first round of SWSI public and roundtable technical meetings, and during the public comment process, comments were received proposing different methodologies for estimating future environmental and recreational flows. Based on these comments it is apparent that differences of opinion exist regarding existing and proposed methodologies to determine environmental and recreational flow needs. The CWCB utilizes the R2 Cross Method, which provides an objective approach to determining environmental flow needs. In addition, the CWCB has adopted an objective method regarding RICD flows, which the CWCB will apply to future RICD applications. Requests and comments on future needs and methodologies for additional environmental and recreational demands will be catalogued, listed, and forwarded to the appropriate contacts in the Stream and Lake Protection section. 12 S:\TASK 8 & 9 SUPPLY AND DEMAND\SWSI DEMAND METHODOLOGY 11-26-03.DOC