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.
Philipp Stadler got his publication 'Real-time monitoring of beta-d-glucuronidase activity in sediment laden streams: A comparison of prototypes' recently published.
In his work he compares four automatic prototypes for the detection of enzymatic activity in the HOAL stream, which is used as a rapid surrogate for the culture-based microbiological pollution monitoring of water resources.
Today Ottavia Zoboli (Alumni of the DK programme on water resource systems) and Helene Trautvetter (Institute for Water Quality, Resources and Waste Management, TU Wien) installed a sediment sampler in the HOAL catchment. Within a project from the TU Wien and the Umweltbundesamt of Austria, a monitoring of priority substances in surface waters takes place with several of these installations.
The HOAL will be one of these representative catchments.
As predicted last weekend heavy rain fall occured in eastern Austria. Also the HOAL was affected by high precipitation rates.
In 30 hours around 60mm of rainfall occured and this led to a discharge rise at the catchment outlet from 1,5 l/s to over 40,0 l/s. Compared to the mean rates (820mm/year mean annual precipitation; 4,0 l/s mean annual runoff) this was a middle high event which we were happy to catch with our sensors and installations. Several water samples were taken automatically and are currently under analysis for chemical and physical parameters in the laboratory.
In the last days Rasmi and Xiaofei were operating electromagnetic induction (EMI) measurements at the HOAL with support of Geophysics students from TU Wien.
Two devices with a shallow and a deep range of the signal have been used. There were several profiles on the different managed crop fields in the HOAL measured and georeferenced. The goal is to further characterize the soil's spatial heterogenities in the electrical conductivity down to around 7m depth by using this contact-less probes.