June 24, 2010

The Hoover Dam: 20th Century Infrastructure, 21st Century Challenges


Earlier this spring
, a group of students from the Stanford Graduate School of Business took a trip through California and Nevada. Their mission: to investigate water. The trip began in Sacramento with a tour of the Delta, following the flow of water south. The group visited agricultural communities in the San Joaquin Valley, then continued down to Los Angeles and Orange County, to learn more about urban water use and corporate water management—finally examining Nevada's water use through the lens of Las Vegas.

Along the way, the group met with policymakers, corporate executives, nonprofit leaders, water managers, and farmers. Students investigated ecosystem protection, water economics and markets, wastewater treatment and recycling, water infrastructure, the water-energy nexus, water quality issues, corporate water footprinting, and climate change, to name but a few.

Here is the fourth installment of what they found:

There is no more identifiable a symbol of the west’s water infrastructure than the Hoover Dam. Made of 4.5 million cubic yards of cement, with the capacity to hold back 26 million acre-feet of water from Lake Mead, the 726-foot tall concrete dam stands in stark contrast against the backdrop of Boulder Canyon’s red-rock walls.

We visited the Hoover Dam on the last morning of our trip, and were privileged to get an insider's tour by the team that oversees it. We had a chance to see the cavernous insides of the two-gigawatt power plant and hear about the challenges of operating the dams through nearly a decade of drought.

The Hoover Dam was completed in 1936, during an era of dam-building, led by the Bureau of Reclamation. To this day, the west’s great dams, including Hoover, have provided a 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. While 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, 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 it is 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 for this year, the lake is projected to drop another 20 feet by the end of the summer. That would put it dangerously close to the 1,075-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 the Hoover’s power generation, which would be dramatically impacted if the lake were to fall below the 1,050-foot watermark.

While the 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.

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 and anticipate what a warmer world might mean for the operations of their infrastructure.

At the end of the our, our group came away not only astounded by the ambition of the early 20th-century engineers who constructed the Hoover Dam but 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.

Tom Mercer is a recent graduate from Stanford's Graduate School of Business, where he received an MBA and MS in Environment and Resources and focused on water resource management and residential energy efficiency.

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