Two recent op-ed pieces have proposed that the solution to future water challenges involve interbasin transfer of water from the Mississippi River basin (Sunday Journal, Sept. 18, 2022) to New Mexico or, far more ambitiously, pump water from the mouth of the Atchafalaya River in Louisiana across the continental divide to the Colorado River (Sunday Journal, Jan. 1, 2023).
The practical and political complexities of these concepts are stunning. Let’s consider them a bit more thoroughly.
Probably the most feasible option for bringing water from the Mississippi River basin would be to transfer water from Lake Sakakawea, a huge lake on the Missouri River in North Dakota, to the middle Rio Grande.
The distance from Lake Sakakawea to the middle Rio Grande is approximately 1,000 miles. More importantly, it’s located at an elevation of 1,800 feet above sea level which greatly reduces pumping requirements.
A recent study done by the New Mexico Bureau of Geology and Mineral Resources suggests that water supply in the middle Rio Grande will decrease by about 30% over the next 50 years. That deficiency is approximately 300,000 acre-feet per year. (An acre-foot of water is 326,000 gallons, enough to provide water to three households for one year).
Transferring 300,000 acre-feet of water from the Missouri River during six months of high flow each year, requires a flow of 830 cubic feet per second, similar to today’s flow in the Rio Grande at Albuquerque. This is far too much water for a pipe – it requires a canal 25 feet wide and eight feet deep. To pump this water, 650,000 horsepower or 500 megawatts of power will be needed. This is roughly half the power generated by a single unit at a nuclear power plant.
The proposal to pump 100,000 gal/sec (10 million acre-feet per year) from the Atchafalaya River is simply incredible. The canal would be 1,400 miles long, 200 feet wide, 20 feet deep, and would require roughly 11 megawatts of power.
These numbers help put the practical aspects of interbasin water projects in perspective. Moving huge volumes of water through pipelines as is done for oil and natural gas is simply not feasible. However, I submit the technical difficulties are trivial compared to the political challenges.
Transporting water from North Dakota to New Mexico would involve a canal that passes through or near seven states; North Dakota, Montana, South Dakota, Wyoming, Colorado, Kansas, and Oklahoma. Bringing water from Louisiana to the Colorado River will require passing through or near Louisiana, Texas, Oklahoma, New Mexico, Arizona, and Utah. Each of these states face serious water shortages. It is inconceivable to imagine that each of them won’t demand a proportionate share of water passing over or near their lands.
We must recognize that multistate interbasin transfers quickly become impractical when factoring in the water demands for all participants.
The volumes of water in the Missouri River, Atchafalaya River and other North American rivers are large, but they are nowhere near sufficient to meet the demands of the arid West. We simply need to learn to live with what we’ve got, accept the fact that future shortages are inevitable, and then manage this most precious resource wisely and equitably.
Bruce Thomson, Ph.D., P.E., is a research professor in the Department of Civil, Construction and Environmental Engineering and in the Water Resources Program at the University of New Mexico.