It is widely agreed that a growing population and economy, combined with current drought conditions and increasing understanding of long-term climate variability, create an urgent need to develop new water supplies in the US. This is especially true in Texas and California, two states where I focus much of my attention. One type of project that always seems to be misunderstood and maligned, however, is interbasin water transfers.
The term “water transfer” may refer to either the movement of water from one river system or groundwater basin to another or the reallocation of water rights from one owner to another, often involving a change in the point of diversion and place and purpose of use. While the two concepts are different, some projects do involve both. An example would be the successful transfer of up to 277,700 acre-feet of Colorado River water per year from the Imperial Irrigation District to the San Diego County Water Authority in Southern California. (I am partial to that transfer because I worked on negotiating and implementing it.)
Despite the promise of increased water supplies in the destination area, there is often a strong emotional reaction against water transfers. They are sometimes labelled as “water grabs” or attributed with causing significant environmental impacts. I believe, however, that at a conceptual level water transfers should be seen in a different light, as they are highly beneficial for furthering sustainable development.
It is widely known that relatively dense urban development is more efficient in using water resources than other types of development. For example, apartment housing tends to use less water than suburban single-family homes, due largely to the difference in landscape irrigation. Large cities tend to use less water than smaller cities or suburbs on a per capita basis.
At the same time, urban areas concentrate the use of water resources in a relatively small area. It is virtually impossible for a city to consume only natural resources that were derived from within city limits, whether those resources be minerals, timber, energy, food or water. Cities import many supplies for their residents to process, manufacture and consume.
While cities almost always require the importation of water resources from surrounding areas, they also tend to be more efficient users of water than the rural or suburban areas that were the original sources. Instead of being seen as a negative, this fact should be judged as a positive, since it leads to greater efficiency and economic productivity from the use of scarce water resources. A transfer of water from outside to inside an urban area, if designed properly, has the potential to lower environmental costs when compared to use of the same water in the source area. The emotional reaction we see against water transfers is, in some respects, contrary to sustainable water policies.
This macro view does not, of course, obviate the need to implement proposed water transfers in a manner that will avoid certain impacts to the environment and third parties. It does mean that the focus of everyone involved should be on refining the details of a water transfer rather than simply saying “no” to every proposal.