Already a slightly queasy feeling to be standing seven meters below the level of the main river. On the chapped concrete floor in the shadow of the weir gate at the schweinfurt barrage. The water here is usually brown. The weir gate flussauarts should hold. It has been going on for over 50 years.
The water masses from below hold up a barrier that looks a bit like an oversized engineering construction kit: six panels of two steel plates each, mounted on A-shaped riders that are in turn anchored in the concrete floor.
The experts call the barrier an "inspection lock. The plates protrude into the drained space, they tower above the people by far, and behind the plates the main river stands four meters high. In a few places it seeps through, especially on the sides where the steel meets the concrete. But what goes in, two pumps immediately take out again.
Capable of handling 19 barrages
The schweinfurt waterways and shipping authority (WSA) is responsible for 19 barrages. "A barrage consists of a sluice, a weir, a hydroelectric power plant and a dam", it says on the homepage of the office. The locks are drained and inspected once a year, the weirs every six years. The principle is quickly explained: the main is blocked off above and below the weir, the water is pumped out, and the 30-meter-wide weir gate is dry and can be inspected and, if necessary, repaired or improved. The execution is a little more complex. "You couldn't build the plates with millimeter precision, then it wouldn't be possible to mount them", says helko frohner, deputy head of the WSA schweinfurt. The assembly is quite difficult as it is. The riders must be erected and anchored while the water is still in the river bed. This is only possible with a diver, who instructs the crane by radio, which hands him the riders, so to speak.