The maintenance of bottom outlets is an essential activity for the safety of dams and artificial basins. When sediments and debris obstruct the discharge works, the ability to quickly empty the reservoir in case of necessity can be drastically reduced. In these scenarios, a dewatering (controlled emptying) intervention combined with sediment removal becomes crucial to restore the infrastructure's functionality.
This case study describes the intervention carried out at the Busa Dam in Vallarsa (Trento), where the cleaning of the bottom outlet was performed with a rapid and structured strategy.
Application Context
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Busa Dam, Vallarsa (TN)
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Artificial basin requiring restoration of discharge functionality
The Challenge: Outlet Obstructed by Meters of Sediment After a Flood
Following an autumn flood wave, the bottom outlet was covered by several meters of sedimented material. The operational consequence was critical: the water did not flow correctly, and the structure was less safe.
The objectives of the intervention were:
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to make the bottom outlet free and functional again;
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to create the conditions to empty the basin in case of emergencies or operational needs;
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to intervene quickly to prevent a worsening of overall stability.
The Aquageo Solution: Lowering the Level and Pumping with Submersible Electric Pumps
To allow the cleaning of the outlet with mechanical means under controlled conditions, the adopted strategy involved a lowering of the reservoir by about 10 meters. This choice allowed for greater accessibility and safety in the outlet area.
To achieve and maintain the level lowering, 4 TSURUMI high flow rate submersible electric pumps were used, selected to ensure:
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adequate pumping capacity for managing the reservoir level;
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operational continuity during all phases of the intervention;
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adherence to the timelines planned during the planning phase.
Result: Restoration of Outlet Functionality and Increased Basin Safety
Thanks to the combination of controlled level lowering and high flow rate pumping, the intervention allowed to:
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create operational conditions for sediment removal;
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restore the functionality of the bottom outlet;
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improve basin management in terms of prevention and emergency response.
The Benefits of the Intervention
A structured dam bottom outlet cleaning operation in this way allows for:
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greater infrastructure safety, reducing risks related to obstructions and lack of flow;
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restoration of the basin's emptying capacity in case of exceptional events;
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optimized intervention times, thanks to high flow rate submersible pumps;
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more controlled operations, with level lowering functional to mechanical access in the outlet area.
