CRWaterAvailabilityScope - Final Phase I Scope

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Water Availability Study of Colorado River and Tributaries ( Pursuant to SB 07 - 122 ) Phase I Scope of Work STUDY PURPOSE Over the last decade Colorado has seen rapidly increasing demands place d on our water supply by both traditional consumptive and more recent nonconsumptive (recreational and environmental) uses. By the year 2030 Colorado’s population is expected to grow to about 7.1 million people (current estimates are approximately 4.5 million people). This population growth coupled with concerns ov er both the recent severe drought and projections of greater climate variability raises significant concerns over the water supplies Colorado has available to meet the needs of our citizens and the environment. The water availability study is intended to help Colorado make wise resource m anagement decision s while acknowledging that the r e is a degree of uncertainty as Colorado m ove s into the future. The study is intended to answer what on the face seems an easy question: “ How much water from the Colorado River Basin System is availab le to meet Colorado’s current and future water needs? ” The answer to that question will take into consideration the following factors. Hydrology – varies in time, location and amount. Agreement on how to consider these fac tors in a water availability study will be important to gain greater understanding and acceptance of the study conclusion. As describe d later in this scope the initial study phase will focus on issues in a period of known hydrology , a period extended from known hydrology , and hydrology resulting from climate change . Water Availability - will include both legal and physical supply considerations Water Use – initial water use consideration (also referred to as demands) should include historical levels of u se from existing absolute water rights. Initial water use consideration will also include existing use of transmountain diversions. Phase II of the study will consider not only existing uses but also projected future uses of water . Water use can be measu red in terms of consumptive use, gross diversions or total deliveries. Categories of water use include beneficial uses recognized under Colorado water law and other “non - water right” considerations such as reservoir operations, by - pass flows, endangered s pecies flows. e tc . To fully answer the above question it will be important to examine the interplay between future consumptive and non - consumptive uses in the context of the Colorado River Compact. Colorado River Water Availability Study Scope 1 October 1 9 , 2007