Sluice gates are metal or wooden structures used to hold back or permit the flow of water passed a particular point in a water channel. These gates can be used as coastal defence structures: reducing water loss from agricultural land during dry periods, displacing water from floodplains following heavy rainfall, or preventing flooding during high tides. Due to the high level of influence these gates can have on a water channel, and its surrounding floodplains, these structures are continuously monitored and maintained.
At a site in Somerset a sluice gate was found to be leaking during a period of light rainfall. In order to maintain upstream water levels a stoplog was installed to halt the flow of water through the gate. As the rains started up again the stoplog had to be removed. Due to the inherent risks associated with working on sluice gates, namely differential pressures either side of the structure, an experienced dive team headed up by an ADC Diving Supervisor is required. It was for this reason that Commercial & Specialised Diving were called in to conduct the works.
CSD carried out a site specific risk assessment of the structure before the dive operation took place. Having assessed the risks and made arrangements for diver access and egress, we carried out a survey of the stoplog in situ before carrying air lifting to remove silt and debris either side of the instalment. A further removal attempt was made but it was agreed that a greater load would be required to carry out the lift. CSD liaised with the client regarding the installation of some new lifting brackets which meant that when the time came to repeat the lift, we were well equipped to attach the unfamiliar brackets. With the new brackets in place and the diver clear, the stoplog was successfully lifted from the estuary bed allowing the sluice gate to return to full operation.
