Water Planning for Growing Southwestern Communities - Design with the Desert: Conservation and Sustainable Development - page 274

several other projects in development. 25 Arizona, California, and Nevada have engaged in
interstate water storage or banking arrangements that have been important to addressing
water supply needs across time and place.
Considerations of infrastructure to deliver water should include energy infrastructure.
It takes significant amounts of energy to deliver water. The CAP, which pumps diverted
Colorado River water uphill and as far as 336 miles, is the single largest consumer of
electricity in Arizona. 26 Similarly, the San Juan-Chama Project uses a series of channels
and tunnels to divert 110,000 ac ft annually, nearly 40 miles from the San Juan River Basin
southeast across the continental divide to the Rio Grande River Basin.* The approximately
5000 ac ft a year received by Santa Fe from this project must be lifted nearly 1500 ft to reach
municipal distribution systems. 28 Discussions of seawater or brackish water desalination
quickly involve questions about the availability, cost, and carbon emissions associated
with removing the salt from the water. Likewise, advanced treatment of wastewater for
reuse requires significant energy.
Finally, water research should be considered another form of water infrastructure. Research
and development are essential to understanding and evaluating alternatives in order to
make wise resource allocation decisions. The private and public sectors, with the involve-
ment of universities, will need to invest significantly in advancing our state of knowledge.
15.4 Regulatory Considerations
It is important to separate the matter of water to supply existing populations from that of
water availability for growing populations. Regulations, such as the Assured Water Supply
Program in Arizona, are designed to ensure that water supplies are legally, physically,
and continuously available to support growing populations for 100 years. In New Mexico,
similar planning regulations require a 40 year scope. Although, in the case of Arizona, these
Assured Water Supply requirements do not apply to all parts of the state, they do apply to
heavily populated Central Arizona, home to more than 80% of Arizona's population. These
regulations allow groundwater pumping to depths as low as 1000 ft below land surface, and
the groundwater replenishment requirements can be met in a very flexible manner, 29 but
the requirement for physically available water ensures that there is water to serve existing
populations. † Where water availability becomes a key concern is in identifying the water
supplies to support future populations, and even then the challenges are many years into
the future for some communities. Water planners must look to the long term because the
solutions to these challenges will likely take many years to gain approval and implement.
The limitations on water availability for communities may be legal and economic rather
than physical. Laws vary considerably across states. Legal water rights determine who has
more senior rights to surface water in the Southwest. Agricultural users were often the first
users and therefore hold the more senior rights. They may be willing partners in transac-
tions to provide water to cities and towns, yet the terms of the transactions could take years
to develop and take effect. 30 The law will determine who has the right to drill what kind of
wells, and the rights and regulations may vary with the type of water user. Exempt, also
* See U.S. Bureau of Reclamation homepage…. 27
† This statement assumes surface water supplies associated with the Assured Water Supply Requirements are
reliably available over the period of time either through surface water delivery or through recovery of stored
water.