The lake is at a very low level at the moment, quite the opposite to when we had problems. It is fairly easy to guage whether the level is "normal" or not by looking at the walls along the lakeside. The maximum level is fairly easy to see because of the colour of deposits on the stones. At the moment it is 80cm below the normal for this time of year. The maximum levels tend to be in June and July (July is very hot and humid) and would be another 40cm higher or about 1.2 metres above the current level. When we had our problem it was probably another 10cm higher and above the normal seasonal maximum.
Thanks. Time I got down there again I think!