The Office of the State Engineer favors a proposal to construct a “New Mexico Unit” diverting the Gila River into four structures in side canyons with high hazard dams. The cost estimates range from $500 million to $1.1 billion. In stark contrast, $80 million total covers 11 proposed non-diversion agricultural and municipal conservation, water re-use and watershed restoration projects. Taxpayers lose from $400 to over $900 million with the New Mexico Unit option.
The non-diversion options can keep 12,000 or more acre feet per year in Southwest New Mexico. A summary from the Gila River Flow Needs Assessment report was presented at the Sept. 22 ISC meeting I attended. An analysis of the 47-year hydrograph of the Gila from river gauge records illustrated the effect of Consumptive Use and Forbearance Act regulations. The act sets rate of flow and volume requirements for diverting water.
The hydrograph showed annual divertible water ranging from 0-14,000 acre feet, with very few years where it would be equal or greater than the volume provided by conservation proposals.
As humans we are as much a part of the ecology as fish, birds, plants and other mammals. Disrupting the natural flow patterns of the Gila River will negatively impact all of the above.
Altered river flows will harm cottonwood establishment and growth and the spawning and feeding patterns of native fish. Non-native (many invasive) plants will increase, reducing habitat of threatened and endangered bird species.
The result will be an increase in insect pests of people, crops and livestock, a loss of shade along the riparian corridor and far less fishing and birding.
All species lose if a New Mexico Unit is pursued.