Incident Report

2026-03-29Not underground but adjacent to cave entrance. Two manmade dams connected by pipes blocked with silt / cobbles. Request from landowner to clear blockage. Due to the lower dam being overgrown / inaccessible digging was attempted on upstream side. Diver entered water with small cylinders, depth never more than 1.5 meters. Long pry bar was inserted into the offending pipe to bash debris out. Bar jammed on one occasion but flow was being partially restored. Visibility very poor by now due to silting and the divers hand drifted too close to the inlet pipe, causing it to be sucked against it. Fortunately flow was still low so appendage could be removed. A hasty retreat was made in case the pipe cleared any more!! More of an obvious hazard for commercial divers in hydroelectric plants / water towers (anywhere with a head differential) but something to be aware of. The diver had two assistants at base but their capacity to provide immediate assistance would be limited. Be very cautious about operating in dams where it is possible to be trapped underwater by sudden suction. In this case it may have been wiser to attack from the downstream end (where a sudden onslaught of flow may be an issue instead!) or use bailing methods to dig dry. If diving must be attempted ensure there is plenty of spare air in case of entrapment. Surface cover seems appropriate, along with a means of communication / recovery from the surface (base-fed hauling line?).