There is no more identifiable symbol of the West’s water infrastructure than Hoover Dam. The 726-foot tall concrete arch gravity dam stands shock-white against Boulder Canyon’s red-rock walls, is made of 4.5 million cubic yards of cement, and has the capacity to hold back 26 million acre-feet of water in Lake Mead that glistens cloyingly blue against the desert sky.
We visited Hoover on the last morning of our trip and were privileged to get a presentation and “insider” tour of the facility by Bob Walsh, Ken Rice, Steven Hvinden, and Jim Byrne of the Bureau of Reclamation, which manages the dam. We had a chance to see the cavernous insides of the 2 gigawatt power plant and hear about the challenges of operating the Colorado River dams through nearly a decade of drought.
Hoover was completed in 1936 at the beginning of an era of dam-building by the Bureau of Reclamation. To this day, the West’s great dams, including Hoover, have provided more reliable water supply to irrigated agriculture and growing cities, hydroelectric power for industrial and urban development, and flood control on rivers that run quiet most of the year but in raging torrents during large storms and spring runoff. In the Southwestern U.S., the storage of Colorado River water – mostly in Lake Mead and Lake Powell – has enabled settlement and economic prosperity in a forbiddingly arid region. In 1922, the Colorado River Compact agreement between the basin states apportioned 15 million acre-feet of annual supply on the river and created the basis for future growth. Unfortunately, it also sowed the seeds of future conflicts on the river.
The story of the Hoover Dam in the 21st century is more embattled than triumphant, largely due to a seven-year drought that has stressed the ability of the Bureau’s infrastructure to deliver the water promised in the Colorado River Compact. At the time of our visit, Lake Mead was at 45 percent of capacity, and with below normal runoff forecast again in 2010, the lake is projected to drop another 20 feet by the end of the summer. That would put it dangerously close to the 1075-foot elevation level at which water delivery cutbacks to the lower basin states would be triggered. These cutbacks would likely cause interstate and international tensions, as Arizona, California, Nevada, and Mexico posture in case of further shortages. The decrease in water level also reduces Hoover’s power generation, which would be cut more dramatically if the lake falls below the 1050-foot watermark.
While Hoover Dam remains a critical linchpin in the Southwest’s water and power supply, it’s clear that grand 20th-century infrastructure alone will not be enough to solve the region’s water resource challenges in the 21st century, for a number of reasons.
First of all, it’s highly likely that the water “annuity” being withdrawn from the Colorado River system is greater than the long-term average water restored to the system in the form or rainfall and snowmelt. Between the 15 million acre-feet of water allocated to the basin states, the 1.5 million acre-feet promised to Mexico, and the 2 million acre-feet of evaporation in the basin every year, the total water withdrawn from the Colorado every year is 18.5 million acre-feet. However, the latest models show that the long-term average runoff in the Colorado basin every year is likely closer to 14 or 15 million acre-feet. In other words, the hydrological account is being overdrawn every year, and, sooner or later, there may be no water left to take.
To make the situation worse, most climate models predict that climate change will have a drying effect on the Southwest U.S., further reducing Colorado runoff and stressing the region’s water supply. The Bureau of Reclamation is quite aware of the potential climate impacts and shared preliminary results of climate studies they were conducting to try to anticipate what a warmer world might mean for the operations of their infrastructure.
Finally, as if the hydrological challenges weren’t enough, the Bureau is also combating the scourge of Quagga mussels, an invasive species that has colonized the Colorado River and threatens to clog up the pipes and equipment of Hoover Dam. Any requisite shutdown of the system could have further impacts on both water releases and power production.
At the end of the morning with our Bureau tours, our group came away astounded by the ambition of the early 20th-century engineers who constructed Hoover Dam and impressed by the modernization of the facility for current operations. It was a sight to behold. However, it was also clear to us that on the Colorado River, more 20th-century dam infrastructure could not solve the two most pressing water resource challenges of the 21st century – the overdraft of water resources and the conjunctive management of infrastructure and ecosystems.
Map Credit: Bureau of Reclamation
Tom Mercer is a recent graduate from Stanford's Graduate School of Business, where he also received an MS in Environment and Resources and focused on water resource management and residential energy efficiency. Before school, he worked as a marketing manager and editor in the media industry.