Lake Walen

Lake Walen is a long, narrow basin between the Churfirsten and the Glarus Alps. Its shape matters: inflows enter a deep store and many shores drop steeply. A shower beside the lake therefore has a different effect from widespread rain across the upper Linth catchment.

The Escher Canal carries the Linth from Glarus into the lake, while the Seez drains the Sargans valley. The Linth Canal starts at the western end and leads towards the Obersee. The Linth works thus use the lake as natural retention, smoothing flood peaks and trapping much of the sediment.

Its annual rhythm is alpine. Water is held as snow in winter before meltwater and spring rain increase supply. Summer storms can swell tributaries quickly, while the lake level responds more smoothly. With no regulating weir, Lake Walen follows its natural water balance more directly than many large Swiss lakes.

Use a station on the open lake for the lake level. Discharge readings on the Filibach, Seez or Linth instead show cubic metres per second at a specific river section. They help explain causes and delays but do not replace elevation above sea level. Read the level curve, timestamp and inflow curves together.

The surface can warm markedly in summer while deep water remains cold. Wind mixes and shifts the upper layer, so a shore reading is not a temperature map of the whole lake. The current value helps swimmers, but location, depth and time of day matter too.