D-0010 The bottom is taken to be where the weight touches down

An artificial pond, closed off and built after the war, where there was long a rule of taking a boat out once a month to measure the depth with a weight and a rope. In a pond whose deepest point is about five meters, the logbook records months in which, at just one of the five fixed sounding points, the weight did not reach the bottom. Measured again on another day, it touches down at the usual depth. A later survey by instrument likewise returned, at that position alone, values far too large, which appeared and then did not. What survives are excerpts from the management office’s water-level and sounding logbook, copies of emails between the management office and a survey company over a sediment survey, and a few other items.