Heavy rain fall event

Last night a heavy thunderstrom crossed the HOAL catchment. In around 15min 40mm of rainfall occured, the highest measured intensity of the rainfall was 3,5mm/min for a duration of 10min. The highest measured discharge at the catchment outlet was >800 l/s and the installed H-flume (designed for 700l/s) there was slightly overtopped. This was also verified by the occurence of the water level mark at the installations around and by leaves and branches which stayed left on equipment or the cabin at the outlet.

In the already harvested barley fields in the HOAL erosion was mainly prevented by the still remaining plant residuals after the harvest (stalks). Soil management didn't take place yet. But you could directly see where overland flow occurred and that non-rooted plant remains where flushed away.

Also again the development of overland flow in tractor tracks could be directly visible again. On the pictures you see Peter Strauß (Ikt Petzenkirchen) checking the water level mark, Lukas Nemeth (IWAG, TU Wien) at maintenance works and Alexander Eder (erosion studies, DK waterresource systems) making documentations about the overland flow and erosion processes.
stream water level


overland flow

overland flow 2

plant remains

tractor tracks

water level mark

water level mark 2

leaves branches