TESTING The Colorado River Basin is a vital source of water, ecosystem services, hydropower, recreation, and other amenities for the seven basin states (Colorado, Wyoming, Utah, New Mexico, Arizona, Nevada, and California), at least 22 federally recognized tribes, and the Republic of Mexico (Figure 1.1). The Colorado River system is managed and operated in accordance with the Law of the River, which consists of compacts, treaties, federal laws, regulations, contracts, and court decisions and decrees. There is an increasing imbalance between supply and demand in the basin. Water use, including consumptive use, within the basin has steadily increased over time and, when combined with deliveries to Mexico, is now approaching the average historical water supply (Figure 1.2). The average conditions, over time and across the basin, suggest a (barely) sufficient supply and, by smoothing out the variability, mask existing and prospective shortages.
Describing the spatial and temporal variability of the Colorado River Basin’s hydroclimate, and recent trends in hydroclimate, can help frame expectations of future basin hydrology even before consulting the tools explicitly designed for forecasting and projection. It also provides context for the different datasets and modeling platforms that are considered in Chapter 2. Current Understanding of Colorado River Basin Climate and Hydrology 44 much greater detail in later chapters. Understanding the physical mechanisms that drive basin climate and hydrology, and their links with the global climate system, can also help identify and understand issues with the output of both hydrology models (Chapter 6) and global climate models (Chapter 11).
http://coloradoriversciencebeta.org/index.php?title=Science&action=edit Planning and operations models support decision making by providing computer-based representations of water supply systems that allow analysis of a variety of hydrologic, operational, administrative, and infrastructure scenarios. They are designed to represent systems with networks of inflows, uses, and storage that serve multiple objectives, and they are built to generate or accept large databases of streamflow data. These models track the movement and storage of water through river reaches, reservoirs, canals, and other infrastructure, and account for withdrawals and gains and losses. They usually simulate operations and the administrative rules that govern water allocation. World-wide, a number of generalized modeling tools have been used to simulate large scale river basin systems. There are differences and similarities among the tools in core solver type and the kinds of processes simulated, but most of them are flexible as to time step, spatial extent, resolution, and operations. They have advantages and limitations that make them more or less suitable for particular analyses. For more information about generalized, river basin system modeling tools, and some in-depth comparisons, see Wurbs (1994; 2012); Stratus Consulting (2005); Zagona (2010); US Army Corps of Engineers (2012); Johnson (2014); California Dept.