Dam Security Measures Flawed; Public Kept in Dark Over Risk

Dam Security Measures Flawed; Public Kept in Dark Over Risk

by David Orr/LIVING RIVERS Friday, Oct. 12, 2001 at 2:45 PM
david@livingrivers.net 435-259-1063 PO Box 466, Moab UT 84532

Dam Security Measures Flawed; Public Kept in Dark Over Risk Colorado River dams, including Hoover and Glen Canyon are at risk of catastrophic release, either from terrorist attack or from major flooding. Government officials are resisting releasing maps of areas subject to inundation in such an event.

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L I V I N G R I V E R S

POB 466 * Moab, UT 84532
435-259-1063/fax 259-7612

POB 1589 * Scottsdale, AZ 85252
480-990-7839/fax 990-2662

www.livingrivers.net


FOR IMMEDIATE RELEASE
THURSDAY, OCTOBER 11, 2001

CONTACT: Owen Lammers, Executive Director; David Orr, Director of Field Programs, 435-259-1063


Dam Security Measures Flawed
Public Kept in Dark Over Risk


In the wake of the tragic airline hijacking attacks of September 11, 2001, emergency security measures have been put in place at major dams in the Colorado River system. But the newly evolving security plans of the federal government are flawed, and reflect a continuing unwillingness to seriously address dam safety issues, as before the attacks.

LIVING RIVERS has learned that the new measures instituted by the Bureau of Reclamation (BuRec) are weakest at two of the system's most vulnerable structures, Glen Canyon and Flaming Gorge Dams. The failure of either could set the stage for a series of catastrophic events with massive human and economic impacts from Utah to Mexico.

While federal resources are currently focused on protecting 726-foot Hoover Dam near Las Vegas from possible terrorist attack, comparatively little is being done at Glen Canyon Dam upstream on the Colorado River, and at Flaming Gorge Dam upstream on the Green River. These two dams represent the second and third largest dams, respectively, in the Colorado River basin, after Hoover.

Dam failure, whether caused by terrorist attack or by floodwaters, would cause not only catastrophic damage to the reservoir and immediate downstream areas, but also a possible "domino effect" that could result in major impacts on the water supply systems of more than 25 million people in the lower basin, and lead to economic disruptions in Nevada, Arizona, California, and northwestern Mexico.


Focus on Hoover Ignores Real Risks

While around-the-clock patrols at Hoover prevent boaters from approaching the dam within a mile upstream and a half-mile downstream, no such controls are in place at either Glen Canyon or Flaming Gorge. Boats may freely approach Glen Canyon Dam from the downstream side, and only a small-diameter cable 150 yards from the dam impedes boater access from the reservoir. Boats have free access to both the visitor center and dam area at Flaming Gorge.

Trucks and trailers are prohibited from crossing Hoover Dam, and passenger vehicles are subject to search by state highway patrol officers at checkpoints on either side of the dam. Yet truck traffic still flows freely over the crest of Flaming Gorge Dam and across the Glen Canyon Dam Bridge, as before September 11. No security checkpoints have been erected at either site.

Oddly, despite the extraordinary security attention Hoover is receiving, it is by far the best-constructed component of the Colorado River plumbing system. Built into massive granite canyon walls and designed with enough mass for gravity to hold its reservoir--the nation's largest--in check, a major attack is unlikely to cause structural failure. The real problems are further upriver.

Near Page, Arizona stands 710-foot Glen Canyon Dam, tucked into porous, weak, Navajo sandstone that constantly leaks water around the dam. Large pieces of sandstone adjacent to the dam routinely break away. BuRec must install increasingly longer rock bolts in an ongoing attempt to protect the dam's powerplant from falling rock, and to ensure stability of the dam's abutment. This past summer workers could be seen patching the dam's face where massive slabs of concrete had fallen off.

[EDITORS: Contact LIVING RIVERS for recent photos of patching operations.]

In 1983, high water flows caused the dam's sandstone spillway tunnels to crumble in places, posing a threat to the integrity of the abutment. The dam's greatest vulnerability is in a high-water event.

Any compromise of the crumbling sandstone abutments would allow two years' annual flow of the Colorado River to blast its way around the dam, scouring the Grand Canyon before surging across Lake Mead on its way to Hoover Dam. In the best-case scenario, this water would flow over the top of Hoover, creating a downstream flood similar to that were Hoover to fail by itself. At worst, failure of Glen Canyon would compromise Hoover Dam, multiplying the flow by a factor of two, and sending four years' annual flow of the Colorado River heading toward Mexico all at once.

"Glen Canyon Dam is an accident waiting to happen," said Owen Lammers of LIVING RIVERS. "Not only should security be stepped-up, but serious plans must be put in place for the dam's controlled decommissioning, as the dam very likely could fail on its own."

A failure at Flaming Gorge Dam, with a full pool of 3.7 million acre-feet, would threaten Glen Canyon Dam downstream if Glen Canyon's reservoir were incapable of accommodating the inflow. This is often the case during peak flow periods in the spring and early summer. As at Glen Canyon, security at Flaming Gorge is comparatively weak.

Regardless of the scenario, the most significant damage would occur below Hoover Dam. Despite their smaller size, Davis, Parker and Imperial Dams constitute critically important elements of the Colorado River plumbing system. These dams are not constructed to absorb massive inflows, and would be severely damaged by a catastrophic flood event. The Central Arizona Project Canal, California Aqueduct, and All-American Canal — the region's major water delivery systems — would also be jeopardized. Municipal water supplies for cities from Las Vegas to San Diego could be wiped out.

The riverside communities of Laughlin, Nevada, Needles and Blythe, California, and Bullhead City, Lake Havasu City, and Yuma, Arizona are all at risk in the event of a major lower basin flood. The reservations of the Fort Mojave, Colorado River Indian Tribes, Chemehuevi, Cocopah, and Quechan nations lie along the lower river and are all at great risk of flooding, as are numerous Mexican farming communities in the Colorado River delta region. Three interstate highways and numerous oil and gas pipelines cross the river below Laughlin.

The federal government is supposed to make available dam failure inundation maps to inform the public of these potential threats. However, BuRec recently told LIVING RIVERS that access to these maps is restricted under new security measures. LIVING RIVERS has filed a Freedom of Information Act request, which had not yet been honored at presstime.

"We certainly don't want to aid any terrorist in mapping out potential targets, but these safety concerns exist regardless of the threat of terrorism," said Lammers. "It's time for the Bureau to get serious about addressing dam safety, starting with ensuring the public is fully aware of the risks its projects pose."


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LIVING RIVERS builds coalitions for river protection and restoration throughout the American Southwest and Northwest Mexico.


Internet Info Resources:

Living Rivers: www.livingrivers.net
Bureau of Reclamation: www.usbr.gov
Hoover Dam: www.hooverdam.usbr.gov
Glen Canyon Dam Facts: www.uc.usbr.gov/information/gcdfacts.html
Flaming Gorge Dam Facts: www.uc.usbr.gov/information/fg_factsheet.html
USGS: Grand Canyon Floods: walrus.wr.usgs.gov/grandcan/floodflows.html
1997 Flaming Gorge Emergency: www.uc.usbr.gov/pao/gorge/fgorge.html
Davis Dam Facts: www.lc.usbr.gov/~pao/davis.html
Parker Dam Facts: www.lc.usbr.gov/~pao/parker.html
Central Arizona Project: www.cap-az.com
Las Vegas Valley Water District: www.lvvwd.com
Metropolitan Water District: www.mwd.dst.ca.us/mwdh2o/index02.html