Siphoning May Not Always Be Possible: Difference between revisions
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[[Category:Siphons]] | |||
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''' ''Message: Site constraints may eliminate [[siphons]] as a viable option'' ''' | |||
''Message: Site constraints may eliminate siphons as a viable option'' | |||
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The outlet works of this Montana dam was in disrepair. The outlet works consist of two cylinder gates. One cylinder gate had experienced failure of both operating/lift stems and had slammed shut earlier during operational discharges. It was damaged and no longer operable. The mandatory instream flow of 21 cubic feet per second in the downstream creek needed to be maintained during the dewatering, inspection, and repair of the outlet works gates. The elevation difference between the dam crest and the lowest reservoir level ruled out siphoning.</br> | The outlet works of this [[Montana]] dam was in disrepair. The outlet works consist of two cylinder gates. One cylinder gate had experienced failure of both operating/lift stems and had slammed shut earlier during operational discharges. It was damaged and no longer operable. The mandatory instream flow of 21 cubic feet per second in the downstream creek needed to be maintained during the [[dewatering]], inspection, and repair of the outlet works gates. The elevation difference between the dam crest and the lowest reservoir level ruled out siphoning.</br> | ||
Take Aways from the project: | Take Aways from the project: | ||
Site constraints would not allow a siphon to function and left the operator with pumping as their only option. Two different pump rental companies offered different pumping plans and related costs. Due to in‐stream flow requirements, the pumping plan was chosed that ensured continuous flow without requiring shut‐down to move suction lines due to fluctuating water levels. It was also the less expensive option. Six 8-inch submersible pumps, two diesel generators, HDPE piping, valves and fittings, and all mobilization, assembly, and demobilization cost $70,000 per week. | Site constraints would not allow a siphon to function and left the operator with pumping as their only option. Two different pump rental companies offered different pumping plans and related costs. Due to in‐stream flow requirements, the pumping plan was chosed that ensured continuous flow without requiring shut‐down to move suction lines due to fluctuating water levels. It was also the less expensive option. Six 8-inch submersible pumps, two diesel generators, HDPE piping, valves and fittings, and all mobilization, assembly, and demobilization cost $70,000 per week. | ||
From Guidelines for Use of Pumps and Siphons for Emergency Reservoir Drawdown, Morrison Maierle, Inc. 2012 | From Guidelines for Use of Pumps and Siphons for Emergency [[Reservoir Drawdown]], Morrison Maierle, Inc. 2012 | ||
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Latest revision as of 03:17, 2 December 2022
Message: Site constraints may eliminate siphons as a viable option
The outlet works of this Montana dam was in disrepair. The outlet works consist of two cylinder gates. One cylinder gate had experienced failure of both operating/lift stems and had slammed shut earlier during operational discharges. It was damaged and no longer operable. The mandatory instream flow of 21 cubic feet per second in the downstream creek needed to be maintained during the dewatering, inspection, and repair of the outlet works gates. The elevation difference between the dam crest and the lowest reservoir level ruled out siphoning.
Take Aways from the project:
Site constraints would not allow a siphon to function and left the operator with pumping as their only option. Two different pump rental companies offered different pumping plans and related costs. Due to in‐stream flow requirements, the pumping plan was chosed that ensured continuous flow without requiring shut‐down to move suction lines due to fluctuating water levels. It was also the less expensive option. Six 8-inch submersible pumps, two diesel generators, HDPE piping, valves and fittings, and all mobilization, assembly, and demobilization cost $70,000 per week.
From Guidelines for Use of Pumps and Siphons for Emergency Reservoir Drawdown, Morrison Maierle, Inc. 2012
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Reservoir elevation = 2,867 feet; Dam crest = 2,875 feet
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Discharge pipes running down dam embankment
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Submersible pumps and floatation
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Diesel Generators
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Pump discharge line
Note: The content on this page was originally created as part of DamOutletWorks.org (DOWL, 2018). It has subsequently been updated and reformatted as part of the Dam Safety Toolbox.
Revision ID: 4744
Revision Date: 12/02/2022