Wires

The soil on the discharge side of the weir was removed down to the bedrock. Loose material in the bedrock surface was carefully washed out, after which a 20 cm high concrete bed was cast. The hardened concrete was treated with silicate solution to bind free calcium as calcium silicate. Water resistant plywood sheets were attached to the concrete bed with steel bolts and the joint between concrete and plywood was sealed with silicon. The free space between the untouched soil of the watershed and the plywood was filled with gravel and small stones washed free from sand and finer material. A plastic tube (Æ 50 mm) was installed within the concrete and an automatic flow meter (Aquamatic) was connected to the tube and installed in a small cabin constructed on the discharge side of the weir. The tubes are placed together with heating cables to keep them unfrozen if needed. L-shape steel plates were laid on the gravel at the height of the eluvial layer and pushed some centimeters into the soil in order to collect the surface runoff.