Project Status
Phase I—Auxiliary Gated Spillway
Contract for excavation of the auxiliary gated spillway was completed in Sept. 2000.
Phase II--Auxiliary Gated Spillway
The spillway structure was completed in June of 2005.
The Moonshine Beach boat launch ramp and parking area were completed in December of 2005.
Phase III-- New Moonshine Beach Recreation Area
Contract for construction of the relocated recreation area was completed in October 2003.

December 2005--Work on the new Spillway was completed in June.  Work is finishing on the Moonshine Beach boat launch ramp and parking area, and is expected to be completed soon.

Dam Safety Project Nears Completion
LITTLE ROCK, Ark., April 12, 2004 – The new auxiliary spillway and the bridge over the spillway are complete and the last phase of construction, upstream channel excavation, is nearing completion. The 500 ft long auxiliary spillway has eight tainter gates is similar in appearance to the original spillway that has ten tainter gates. Granite Construction Company of Watsonville, Calif., constructed the new spillway, bridge and upstream channel under a $44.2 million contract.

This work followed an initial phase of excavation and earthen embankment construction by Kiewit Western Co. of Omaha, Neb., that was completed in September 2000. Mack Inc. of Topeka, Kansas relocated the Moonshine Beach swimming area to make room for the new spillway. Most of the new park has been completed, with the exception of the boat launch ramp and parking area.

The auxiliary spillway is the most cost-effective way to keep Table Rock Dam safe during a catastrophic flood. The new spillway will only be used during extreme flood emergencies.


Table Rock Dam was constructed between October 1954 and August 1958. It consisted of 4,821 feet of earthen embankment with a 1,602 ft long concrete section. The concrete section is designed to withstand the erosive forces of water released from the spillway gates at the top of the dam. The designers based the size of the spillway on the worst flood Mother Nature might reasonably create based on weather data.

Under the dam safety program, in the 1990’s, the spillway capacity was evaluated using improved weather data, and more modern technology and safety requirements. Engineers determined that the lake would rise ten feet higher during the worst-case flood than previously calculated. An event of this magnitude would overtop the earthen embankment and destroy Table Rock Dam with catastrophic losses in downstream areas including Branson. To prevent the potential loss of life and property damages, the Dam Safety Project was constructed. After considering several options and gathering considerable public input, the auxiliary spillway was determined to be the best solution.

Project History
April 1999 – December 2000: initial phase of excavation and earthen embankment construction.
July 2000 – July 2004: constructed auxiliary spillway, bridge, and excavated upstream channel.
November 2001- October 2003: constructed new Moonshine Beach recreation area.

Photos
Table Rock Auxiliary Spillway Photo Album - A brief photographic history of the project from May 2001 – April 2004.

PowerPoint Slide Shows
Click on one of these titles to learn more about the Table Rock Auxiliary Spillway.
Why is the spillway needed? (project history)
Phases and explanation of construction work (project phases)

Frequently Asked Questions
Q1. Does the construction effect the level of Table Rock Lake?
A1. No, construction of the auxiliary spillway does not effect the lake level. In general, lake levels fall due to the withdrawal of water for water supply, the generation of hydroelectric power and vaporation. Lake levels rise due to runoff from rainfall. In the Table Rock Lake basin, rainfall has been well below normal since July 1999 while water supply usage and the generation of hydroelectric power has been normal. That is the sole reason why the lake level is so low, lack of rainfall. Should conditions worsen and the lake continues to recede, a Drought Contingency Plan will guide us in water management decisions. If you have more questions about lake levels, visit our River and Lake Levels page. If you have specific questions about Table Rock's Level, e-mail our reservoir control office or our Table Rock Lake office.

Q2. What does the auxiliary spillway do?
A2. It provides additional capacity for the release of floodwaters during extremely large and rare catastrophic flood events.

Q3. Has a probable maximum flood event ever occurred at Table Rock Lake?
A3. Not since records have been kept. This type of flood would be an extremely rare event. The top of the flood control pool for the dam is 931, and the maximum pool ever recorded at Table Rock Lake is 932.5 on May 10, 1961.

Q4. How much does the spillway cost?
A4. The combined cost of the three construction contracts for the auxiliary spillway is about $58.2 million.

Q5. Have you assessed the environmental effects?
A5. The Corps district conducted an Environmental Assessment in 1997 and determined that the project would cause no significant adverse effects to the environment. As a result, a more detailed Environmental Impact Statement was not prepared.

Q6. What affect will there be on Table Rock Lake?
A6. There would be no change in the way Table Rock Lake is operated from day to day. The new spillway would only be used during extreme emergencies when lake levels exceed elevation 937 feet. By that time, the existing spillway gates would be fully open and much flooding would have already occurred.