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The nation’s 120,000 dams: Much more inspection, repair needed

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Last week, as Robert Plant of Led Zeppelin sang solo in the nearby Dodge Theatre, 750 million gallons of water from the 16-foot-deep Tempe Town Lake near Phoenix roared through a burst dam at up to 15,000 cubic feet per second. Fortunately, no one died; no significant property damage occurred.

Eight dam sections made of inflatable rubber constrained the lake, four at each end. The $4.4 million dam began receiving water from the Central Arizona Project in 1999. In 2002, one of the 40-foot-long, foot-thick rubber bladders (covered by a 10-year warranty from Bridgestone industrial Products) failed, requiring a repair. Tempe and Bridgestone officials have disagreed on how to prevent deflation and enlarging buffer zones around the dam. UPI reported that “[a] design flaw made it impossible to use sprinklers to keep the rubber cool and wet, which likely hastened its deterioration.” Also, said UPI:

Mayor Hugh Hallman told the Arizona Republic that work had been scheduled to start Wednesday on replacing the dam. He added the maintenance crew could have been killed if the collapse had occurred while the work was under way.

This dam was small and young. The average age of tens of thousands of dams tracked by a national database is 51 years old. Because state and federal budgets are fiscally challenged, dams in America are not inspected as often as law and common sense requires. That must change.

Dams have many often overlapping functions — flood control, water supply, irrigation, hydroelectric power, and recreation. They may also restrain materials other than water, such as tailings and mining slurries. Because they are static structures often in place for decades, we give little thought or budgetary attention to their potential for failure.

But, although failure is rare, such events represent extraordinary risk to life and property. On Saturday, the dam holding back 10-mile-long Lake Delhi in eastern Iowa failed, abetted by 15 inches of rain in 48 hours. Two years ago, repeated flooding had done an estimated $500,000 damage to this 83-year-old earthen dam. The latest flooding caused a breach about 125 feet wide and 40 feet deep, officials said. About 8,000 people were affected downstream with considerable property damage, officials said, but no deaths or injuries were reported.

This dam, like the majority of dams in the United States, was not owned by a government. A recreation association and a hydroelectric dam owned it. In 2008, the state of Iowa had 3,325 dams, of which 276 had high or significant damage potential. Iowa had the equivalent of 1.25 dam inspectors, operating with a budget of $20,000. But residents and businesses downstream of Lake Delhi could easily confirm whether the dam was listed as one with such damage potential.

The National Inventory of Dams, maintained by the U.S. Army Corps of Engineers, contains more than 85,000 dams. The inventory is limited to dams of high or significant hazard that would result in loss of life or significant property damage in the event of failure.

But not all the information about these NID dams can be viewed by the public. That’s because, presumably, of concerns that would-be terrorists might attack high-hazard dams. According to the Center for Public Integrity:

Upon recommendation of the security-conscious National Dam Safety Review Board in 2007, the Corps blocked public access to key fields such as the downstream hazard potential and the city nearest the dam. Moreover, the public can no longer download the entire database, a tool long favored by journalists interested in assessing dam safety in their communities. … Because of the Corps-imposed restrictions, however, there’s no way for the public to know which downstream areas were classified as high-hazard in, say, 2008 or 2009.

That makes it difficult to decide, for example, if buying or building a house, let alone a factory, downstream of a particular dam is a good idea.

The dams listed in the NID are at least 25 feet high or exceed 50 acre-feet of storage. Dams are regulated, but that burden falls mainly on the states. The Association of State Dam Safety Officials provides a state-by-state database of dam safety regulations.

But do states have sufficient inspectors for their dams? The dam safety group says no. According to the association:

Laws governing dam regulation are essential to reduce the threat of dam failures. Regulation of dams in the USA rests almost entirely with the States. States regulate about 86% of the approximately 83,000 dams inventoried nationally. While the majority of states have been working to improve their programs in the last 25 years, most are still struggling with minimum budgets and staff. A handful do not even have adequate programs in place to regulate the safety of dams in those states. [Ed. note: Different sources provide differing estimates of dams in the NID.]

State budgets for fiscal 2010 had a shortfall of nearly $200 billion, said the Wall Street Journal. So dam safety inspections, let alone repair, replacement, or rehabilitation, have a low priority.

In 2008, New York state, in which I live, had 5,624 state-regulated dams. Of these, 1,140 were listed as having high- or significant-hazard potential. The state had the equivalent of 13.35 dam inspectors, working with a budget of $1.6 million. (Check your state’s dam safety program here.)

But those 85,000 dams in the corps’ national inventory do not represent all of America’s dams. By definition, the Tempe Town Lake dam would not be on it. (An S&R request to the corps about the dam’s NID status remains unanswered.)

The privately owned Forge Pond Dam in Freetown, Mass., might not be, either. It is an 8-foot-high, 260-foot-long, 200-year-old earthen, stone, and concrete structure holding back 140 acre-feet of water.

This dam was owned by Andre Fournier of New Bedford, who, according to a state official, had not responded to numerous recommendations and orders issued by the Office of Dam safety dating back to 1999. Nor did he pay any of numerous fines levied on him. Fournier died in January 2009, leaving his dam a neglected orphan.

The dam partially breached in February, and state officials have decided to remove the dam. Its complete failure would have threatened two downstream dams as well.

Dam failures can have grave public consequences. Decades ago, on a rock-climbing trip west, I stood next to Teton Dam in Idaho with an engineer taking pictures of the dam. At at 11:57 a.m. the next day, June 5, 1976, the 305-foot-high, 3,100-foot-wide dam collapsed, allowing more than 80 billion gallons of stored water to race through the towns of Wilford, Sugar City, Salem, Hibbard and Rexburg. Officials attributed 11 deaths to the dam’s failure. The flood damaged more than 4,000 homes, killed more than 13,000 cattle, and tore up 32 miles of Union Pacific Railroad track. Damage totaled $2 billion.

The federal Bureau of Reclamation, which built the dam for $100 million, paid $200 million in damage claims. The bureau’s portfolio has “457 dams and dikes of which 362 have the potential to endanger people if a failure occurred. Fifty percent of these structures were built before 1950.” (The bureau’s role, especially under director Floyd E. Dominy, as the nation’s principal builder of big dams, the reasons for it, the benefits incurred, and the environmental costs exacted, is another subject for another time.)

Failures of small dams, like Forge Pond and Tempe Town Lake dams, have grave consequences as well. Not all dams are thought of as dams, for example. Consider coal slag heaps that might restrict the flow of water and create impounded lakes. In 1972, such a coal slag dam on Buffalo Creek in West Virginia breached, killing at least 92 people and injuring more than 1,100, destroying 1,500 homes and leaving 4,000 people homeless.

In December 2008, about 5.4 million cubic yards of wet coal ash spilled In Kingston, Tenn., when an earthen retaining wall breached, forcing the evacuation of 22 residents. Dams can fail, and they restrain more than water — in this case, a thick slurry. Soon after, the Environmental Protection Agency identified 44 such coal ash dams and storage ponds in 10 states that had high-hazard potential in the event of failure.

What about dams that do not meet the criteria for inclusion in the National Inventory of Dams?

The Department of Civil & Environmental Engineering at Stanford University operates the National Performance of Dams Program. It offers a chronology of major events in dam safety that led to the regulatory forces extant today. It has a database of American dams that includes dams not in the NID. A search for dams of all types between 3 and 24 feet high produced a list of more than 39,000 dams. Many, if not most, of these, presumably, are not in the NID.

That means the United States has at least about 120,000 dams that need to be inspected, regulated, and maintained.

More than half of America’s dams — 56 percent — are privately owned, according to the Federal Emergency Management Agency. The rest: local governments, about 20 percent; state and federal governments, a little less than 5 percent each; and public utilities, less than 3 percent. About 12 percent of dam ownership is undetermined.

Federal guidelines for dam safety were established in 1979. To grasp how disparate responsibility is for federal dams’ safety, consider this: FEMA coordinates the National Dam Safety Program with two partners, the National Dam Safety Review Board and the Interagency Committee on Dam Safety.

Interagency. Is there a more frightening word in the lexicon of the federal bureaucracy? In the case of dams, nine federal departments (with associated bureaus, departments, and divisions of this and that) are involved in safeguarding just 5 percent of America’s dams. (True: Many of these dams are significant in size, function, cost, and political and economic importance.)

In its annual infrastructure report card, the American Society of Civil Engineers notes the cost of repairing the nation’s dams:

In 2009, the Association of State Dam Safety Officials (ASDSO) estimated that the total cost to repair the nation’s dams totaled $50 billion and the needed investment to repair high hazard potential dams totaled $16 billion. These estimates have increased significantly since ASDSO’s 2003 report, when the needed investment for all dams was $36 billion and the needed investment for high hazard potential dams was $10.1 billion.

The 2009 report noted an additional investment of $12 billion over 10 years will be needed to eliminate the existing backlog of 4,095 deficient dams. That means the number of high hazard potential dams repaired must be increased by 270 dams per year above the number now being repaired, at an additional annual cost of $850 million a year. To address the additional 2,276 deficient—but not high hazard—dams, an additional $335 million per year is required, totaling $3.4 billion over the next 10 years. [emphasis added]

States do not have — and will not have in the near future — the money to fully inspect and repair deficit dams. According to the Center for Budget and Policy Priorities, 46 states face a total budget shortfall of $121 billion for fiscal 2011 and 39 states have projected gaps that total $102 billion for fiscal 2012.

Congress has done little. Parked since March 2009 in the Senate’s Committee on Environment and Public Works is S. 732, the Dam Rehabilitation and Repair Act of 2009. The House version, H.R.1770, is similarly parked in committee. An earlier version of the act, despite House passage, died in the 110th Congress.

Even if the act becomes law, it represents a pittance for dam safety. The act calls for spending up to $200 million over five years to address deficiencies in the nation’s publicly owned non-federal dams. That’s million, not billion.

Dams are extraordinary structures built to satisfy human needs. Many are indeed compellingly beautiful to view, such as Boulder Dam. (I refuse to call it Hoover Dam.) Many have played historically significant roles. In World War II Grand Coulee and Bonneville dams produced the electricity that smelted the aluminum that Boeing turned into tens of thousands of fighters and bombers.

But dams come with consequences — economic, cultural, environmental, and political. When dams fail, consequences become casualties — lives lost, property ruined.

Even through the nation is mired in a recession and two costly wars, inspection, repair, and replacement of deficient dams ought have a higher priority in Congress, statehouses, and federal agencies.

Reconsider the Tempe Town Lake dam that failed last week. No one was hurt; no property damaged. But if that dam had failed on Nov. 23, 2008, what would have been the fate of hundreds of competitors in the swim leg of the Arizona Ironman?

photo credits:

Burst dam at Tempe Town Lake:
Lake Delhi dam breach: Justin Hayworth, Des Moines Register
Forge Pond Dam: George Rizer, Boston Globe
Breach of Teton Dam: U.S. Bureau of Reclamation
Kingston, Tenn., coal ash spill: J. Miles Carey, Knoxville News Sentinel
Ironman Arizona competitors in Tempe Town Lake: Robert Body

xpost: Scholars and Rogues


Written by Dr. Denny Wilkins

July 25, 2010 at 12:44 pm

Posted in Uncategorized

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