by Becky Denney, Missouri Chapter Conservation Chair
When the Taum Sauk Reservoir collapsed above Johnson’s Shut-Ins State Park on December 14, 2005, questions about the Park Superintendent and the condition of his three children were foremost on our minds. But as they recovered and we breathed thanks that no one else was in the park, we speculated on how it could have happened. Everyone became aware of dam safety in Missouri.We suddenly found out that the State of Missouri had no jurisdiction over federal projects in Missouri. The complete inspection responsibility belonged to the Federal Energy Regulatory Commission. The Taum Sauk Reservoir had passed an inspection in August of 2005.
Union Electric built the Taum Sauk Reservoir contending that it did not need a Federal permit to built it and to operate it. When it was dedicated in October, 1963 there had been no federal inspection of the construction. The U.S. Supreme Court decided in 1965 that it was under federal jurisdiction. Now we know that the earthen dam had rock “fill” material instead of bedrock, and the design and construction methods were substandard even for the 1960’s.Would federal oversight have meant that a spillway was included in the design? That might have prevented the total failure—particularly since overtopping was the force that precipitated the collapse.
As required, the Taum Sauk plant had an emergency plan. According to the time line established the morning that Taum Sauk ruptured, the plant supervisor didn’t follow the emergency plan until at least 30 minutes after the water hit the USGS station at Highway N. A USGS study released on December 14, 2006 estimated the velocity of the water: “At its peak, the water rushed down the side of the mountain at a rate of 289,000 cubic feet per second, roughly equal to the flow of the Missouri River at three to five feet over flood stage. High water marks along the water’s route down the mountain indicated that it reached depths of 50 feet or more. The subsequent flood of the East Fork of the Black River was approximately four times larger than a 100-year flood,” said report author Paul Rydlund.
“During a 100-year flood, water would flow through the river at 21,900 cubic feet per second,” Rydlund said. “At the peak flow of this release, it was coming through at 95,000 cubic feet per second.”
A simple check of the history of dam failures finds that there are many reasons for failure. According to Dr. J. David Rogers of the Department of Geological Engineering at the University of Missouri–Rolla, the early concrete dams were much more prone to fail than earthen ones. Dr. Rogers grew up in California and is famous, among others things, for his re-study of the St. Francis Dam failure of March 12, 1928. It was a failure which sent a wall of water 185 feet high down the San Francisquito Canyon to the Santa Clara River and then to the Pacific for a total distance of 58 miles.
The St. Francis Dam was considered the “Titanic of Civil Engineering.” The dam was designed and constructed between 1924 and 1926. It was at full reservoir level for only five days before it collapsed. The collapse in 1928 was one of the greatest disasters in California history with a loss of 420 lives and millions of dollars of damage. Rogers’ website claims it is the worst “American Civil Engineering failure of the 20th Century.”
Until the collapse of the St. Francis Dam, expert input on geology of the sites used for dams was not common. In fact, it was sited against a landslide. An investigation as of 1992 found a list of 254 American dams greater than 35 feet in height that were constructed against old landslides.
According to the interview conducted with Dr. J. David Rogers, a concrete gravity dam was supposed to be a conservative engineering structure, but in this case the stability calculations were eventually found to be off by a factor of 240 percent. Debate about uplift pressures developing beneath concrete dams came after the St. Francis dam failed and continued into the 1950’s. In fact, Hoover Dam which was completed in 1935 had major foundation grouting done in the mid 1950’s when excessive hydraulic uplift pressures were measured. Even when the Malpasset Dam failed in 1959 it took years for the uplift pressures to be understood.
The design for the Mulholland Dam (for the Hollywood Reservoir) which was another concrete dam built under William Mulholland was inspected by John L. Savage, the Chief Engineer for the Bureau of Reclamation. He informed the Los Angeles Department of Water and Power that the dam needed to be “retrofitted.” So the Hollywood Reservoir was drawn down and the work quietly done by 1933.
Another reservoir failure much later in California ended differently. But again it could not be emptied quickly. On December 14, 1963 abutment leakage suddenly appeared at Baldwin Hills Reservoir in California. By 12:30 p.m., after several hours of checking, an all-out attempt was made to drain the reservoir. By 3:30 p.m. the Baldwin Hills Reservoir breached with less than 20 percent of the reservoir drained.
The Laurel Run Dam failure resulted in a ten year legal battle over settlements with victim’s families. There were 39 victims with $5.3 million damages. But The Tribune-Democrat (Johnston, PA) had to unseal the records later to find that the failure of the dam during heavy storms was due to a history of poor maintenance and ignored warnings of the condition of the dam.
Early dam legislation in Missouri was passed in 1889 but was concerned with damages from construction and lake formation and was called the Dams, Mills and Electric Power Law.We had dam failures at Lawrenceton in 1968,Washington County in 1975, and Fredericktown in 1977. By 1979 the Missouri Legislature became aware that, according to the U.S. Army Corps of Engineers’ inspections of dams in our state, we led the nation in the total number of unsafe dams. The passage of HB 603 regulated dams over 35 feet high, but exempted dams used primarily for agriculture and dams regulated by state or federal agencies.
On January 22, 2006, after the Taum Sauk collapse, the Post-Dispatch ran titles like “Missouri leads the nation in unregulated ‘high-hazard’ dams.” The Southeast Missourian reported on January 31, 2006 that the Army Corps said we had 390 high-hazard dams— dams that can kill if they rupture.
The St. Louis Post-Dispatch pointed out that there are hundreds of dams in Missouri and Illinois that need repairs; that lack emergency plans; and that overworked inspectors can’t force owners to make repairs. More than half of the 641 dams in Missouri are either highhazard, significant hazard or not regulated. Governor Blunt ordered a review of dam safety rules by December 13, 2005. He supported the Department of Natural Resources (DNR) recommendations made public February 13, 2006 that were in line with the Federal Emergency Management Agency’s model dam safety law standards. Most dams that are at least 25 feet high or that hold 50 acre-feet of water would be inspected every five years. (An acre-foot is the volume it takes to cover an acre with one foot of water.) The recommendation increased the number of dams inspected by DNR from the 2005 figure of 600 to 5,000. Dams regulated by the Federal Power Act, agricultural dams, and dams constructed for conservation or irrigation would no longer be exempted. The state of Missouri now regulates only non-agricultural dams with a 35 foot or more height. The Post commented on December 15, 2005 that some agricultural dams are more than 50 feet tall. James Alexander, chief engineer for the Missouri dam safety office was quoted:
“A lot are in overpopulated areas,” Alexander said. “I doubt very seriously when people living downstream of these agricultural dams are going to notice the difference between agricultural water and water that would come out of a conventional dam.” The Post-Dispatch also reported that Martin McCann, director of the National Performance of Dams Program at Stanford University says that nationally there are ten to 20 dam failures a year but deaths are rare. He thought we needed to see dam failure in perspective. In The Southeast Missourian Brad Iarossi with the American Society of Civil Engineers said that the American dam system has gotten a “D” on its annual report card each year since they started rating them on dam safety in 1998.
Despite the rhetoric of Governor Blunt last year, SB 1236 was passed by the senate but not the House. This year there is a bill introduced in the house and also one in the senate. As they were introduced, neither one permitted most agricultural dams and both raised the definition of a dam to 50 feet which is worse that the bill we have now. A high-hazard dam was defined as loss of human life being probable or expected.
On February 27, 2006, House Bill 159 came out of committee radically changed. The regulations currently define dams as being 25 feet or more in height with a storage volume of at least 50 acre-feet of water. High Hazard dams are to be inspected at least every three years and significant hazard dams inspected at least every five years. Dams licensed under the Federal Power Act such as Taum Sauk are to be inspected yearly when before the state had no jurisdiction. Unfortunately, the agricultural dam exemption may still remain unless the state council on the advice of the chief engineer determines the dam to be a high or significant hazard dam or reservoir.
On January 22, 2007, the Army Corps of Engineers began to lower the water level of Lake Cumberland in Kentucky.Wolf Creek Dam was placed on a list of “structures” that have a high risk of failure after a post- Hurricane Katrina risk assessment of 400 Corps dams. An earthen dam with a concrete core, the Wolf Creek Dam is nearly a mile long and 240 feet high. It was started in 1938 and completed in the early 1950’s as part of a federal plan to control floods on the Ohio and Mississippi Rivers. Should the dam breach, the failure could result in a great disaster. A total of $3.5 billion in damages is estimated. Much of the sediment and debris from the December 14, 2005 Taum Sauk breach has been moved so it will not go down river into Clearwater Lake. But there is still sediment below the Lower Reservoir that needs to removed and stabilized. AmerenUE has decided to rebuild the Taum Sauk Reservoir.The Federal Energy Regulatory Commission (FERC) announced environmental scoping meetings scheduled for March 2007 for the rebuilding of Taum Sauk Plant 2277.
AmerenUE has yet to complete its plans to reestablish the Lower Reservoir. The East Fork of the Black River remains unusable for us and not even in a stable ecological state—yet AmerenUE is dependent on that very stream to fill the Lower Reservoir and then use the water for construction and operation. As dams are built they are indeed dependent on the natural materials available, the bedrock, and water that can easily and cheaply be obtained. Now let me tell you about the dam in the Black River watershed that is a greater danger to people and property than Taum Sauk Reservoir.When Clearwater Dam was completed in 1948 its main purpose was to prevent downstream flooding and damages. The Corps website says Clearwater Dam has prevented $217 million in flood damages.
Inspection reports from the Corps in late 1977 stated that the safety of the embankment at high upper pool was questionable. On October 15, 1987 an inspection report said that “Construction of the planned seepage control berm and right abutment grouting is necessary to ensure the continued structural safety of Clearwater Dam.”
In 2003 a sink hole was discovered which will take millions of dollars and five years to fix. On August 30, 2006 a large hole 30 feet beneath the base of the dam appeared causing engineers to believe that materials were moving from the dam. The core showed a mixture of clay silt, gravel, and water. Jason Lindsey reported that:
“Engineers say seepage has been occurring at Clearwater Dam since its completion in 1948, primarily because the bedrock is dolomite, a highly fractured rock subject to wear and erosion.”
The sinkhole found in 2003 was repaired, but a concrete curtain is to be built so a $17 million contract was awarded for Phase I work to be done from June 2006 to July 2007. In December 2006 during the drilling in the bedrock and grouting done to fill up the cavities or holes three pockets of sandy soil were detected within the dam. Based on information determined from core samples, engineers say they believe the dam’s core is intact.The Phase II contract to complete the cutoff wall, which has been described as a dam within a dam, should be awarded in mid 2007. A new (published in August 2006) study based on modern concepts of “state based soil mechanics” found that there was cracking in the core that had not been recognized in the design of the dam.
My early personal experience and dislike of dams stems from the fight against damming the Current River. The Corps of Engineers had plans to dam it but canoers from both St. Louis and Kansas City were up in arms. Leonard Hall wrote a marvelous book called Current River Running which we all loved. Politicians were taken on float trips with the result that in 1964 the Current and Jacks Fork were designated as a national scenic riverway. Two dams were stopped after construction had actually started. One was the Echo Park Dam which would have been near the junction of Yampa and Green Rivers in Colorado within Dinosaur National Monument. David Brower and the Sierra Club won that fight but compromised by allowing the Glen Canyon Dam to be enlarged. That was a bitter compromise to some.
The other dam that was stopped after construction started was the Meramec Dam. Dr. Rogers has an interesting presentation on his website about the Meramec Dam Basin plans and defeat. The first and largest dam planned was a zoned earthfill embankment for flood control and recreation. There were a total of 31 reservoirs planned for the Meramec Basin Project. Evidently there was a statement in the revised Environmental Impact Study (EIS) that the Indiana bats and the gray bats found in some of the more than 100 caves located in the project area would be extinct in 15–20 years anyway. But, thanks to everyone that helped win that fight, we still have those caves and we still have Indiana Brown bats and grey bats in Missouri caves.