Western U.S. Water Resources and Climate Change Adaptation
In the western United States, the rules of sharing water resources depend on the water rights of the owner of the property. Also, access to stored water is legally distinct from rights to natural water flows. The difference in rights arises from long standing patterns of seasonal use. Climate change and the warming of the waters in oceans and seas will create havoc in some localities. In western states where severe water shortages are expected, the rules of water use and consumption will depend on a number of variables including seniority rights, and dependence on reservoirs compared with natural water flows. There are also traditional seasonal rations of some water sources.
Western states that have the most senior water rights depend on it for agricultural irrigation. Irrigation is the number one consumer of water resources in these states, accounting for nearly 90% of water used. However, the value of preserving wildlife and recreational uses has only recently been understood as a part of the bigger picture and are now are categorized as priorities.
Western regions of the U.S. rely on its agricultural history but change is happening there quickly. Most of these states are the fastest growing in the U.S. – states such as the dry climates of Utah, Nevada and Arizona. People move there for the quality of life and emphasis on environmental concerns. But the reality is climate change will only be one factor affecting the regions’ water resources. There is already a sense of antagonism due to population growth, environmental impacts and the inevitable changes in the demand for water. The drought of the past several years has compounded he struggle.
In the West, climate change will be intertwined with a dwindling water supply. One solution involves buying or leasing water rights from more senior competitors. But this solution poses challenges all its own: the process can be extremely complicated and costly; water market trading relies on high-quality empirical records on realistic patterns of use but part of the problem is that some states do not keep those kinds of records; and protective measures must be taken for other regular users against negative effects of water rationing. A stream basin is formed with an intricate series of water pathways enabling water to enter. With each re-direction of water for allocation purposes, downstream users are affected. In reality, the logistics of moving large amounts of water may not be a feasible strategy.
Buying and selling of water resources will continue to be a practice that alters how water is used to support a growing population. Diverting water to dry up agricultural land is not a reasonable alternative for adaptation to climate changes. There are other arrangements available to reduce the contention that erupts over a resource so valuable: shorter-term water rental agreements, water banking arrangements and option contracts. In some urban areas water utilities are employing these strategies in planning for potential droughts. In southern California, The Metropolitan Water District of Southern California provides water supplies for urban water users. It has done so with agreements with agricultural water districts. The Metropolitan uses short-term water leases to insure against drought-related water shortfalls, and it has several longer-term option contracts. In 2004, Metropolitan and the PaIo Verde Irrigation District signed a 35 year agreement allowing Metropolitan the option not to irrigate up to 29% of the land in the district in a given year. In return, the landowners receive a payment to secure the option and yearly water rental payments in years in which the option is exercised. This arrangement can produce a water supply of up to 110,000 acre.
Many western cities are also implementing demand management to offer conservation incentives, using meters to monitor water usage and raising block rates to keep up with population growth. Generally, these plans can lead to decreasing per capita consumption; the down side is that this may not offer enough protection during severe droughts.
The collection of water in reservoirs has served to even out the ups and downs of seasonal variability. Water collection from snow-melt fed rivers offer water users some protection from short-term droughts. It will be important to modify the infrastructures to prepare for the earlier snow-melt that will inevitably come as a result of warming. Some reservoirs will help provide water in times of extreme shortages but warming will also hasten evaporation of surface water. Storing water in reservoirs cannot protect against the loss of snow melt resources that have always been relied upon for irrigation and human consumption. Building more reservoirs does not seem to be a long term fix.
Alternatives for adapting to climate change will be more successful if planning is coordinated for both short and long term planning. Federal and state agencies have contributed to watershed planning projects all across the western U.S. Planning involves the cooperation of citizens, farmers and large industrial water users backed up by the various levels of government. To date, efforts have been aimed at extreme local water shortages but there may be opportunities for long term strategies that arise from what is learned as smaller operations pop up. The culture of thinking outside the box is underway and innovations and improvements in water management will be critical as climate change becomes more obvious.
The many years of drought in the U.S. Southwest is prompting federal and state agencies to help the Lower Colorado Basin reassess the operation of the major federal dams in the Colorado River. The goal was to develop a management mechanism to coordinate storage in Lake Powell and Lake Mead to be used for periods of water shortage. The Secretary of the Interior suggested that conservation efforts be seen as “interim in duration.” This approach is expected to give time to figure out long term options for managing climate and water changes based on the experience and new knowledge gleaned from local projects.
