Konzeptentwicklung für Dotierwassersysteme an alpinen Bachfassungen

The Water Rights Reassignment Agreement (WRWV) for the hydro power plants Latschau (LAW), Rodund I (ROW I) and Rodund II (ROW II) in Montafon/Vorarlberg obliges the operator, illwerke vkw AG, to ensure a secure, permanent and metrologically documented supply of water to a total of seven stream intakes along the Partenen–Latschau headrace canal. The requirements are based on the WRWV's expert reports, which refer to the EU Water Framework Directive (EU-WFD) and the National Water Management Plan (NGP). The aim is to create ‘good ecological potential’ for the streams, defined as heavily modified water bodies, between the stream intakes and the river Ill through residual water discharges. In addition, the release of water into the stream is intended to improve the habitat of the river Ill and, through the increased flow rates, reduce the effects of hydropeaking and draw-down caused by flushing and discharges during power plant operation. The aim of this thesis is to develop technical concepts for the discharge, measurement, control and data recording of the water supply at the stream intakes along the Partenen-Latschau feeder tunnel, including an energy economic assessment, cost estimate and scheduling. This thesis provides a practical, scalable concept for mandatory and voluntary residual water discharge at alpine stream intakes under the given WRWV framework conditions. It combines hydraulic dimensioning of the discharge pipe, sensor-based measurement and automated control of the discharge volume to create harmonised concepts, reduces operational risks and maintenance costs through standardisation, and addresses the energy and cost effects with reliable energy industry figures. The implementation recommendations include consistent magnetic-inductive flow measurement, electrically operated plate valves, frost protection and enclosure concepts, telecontrol connection to the central control centre of illwerke vkw AG (ICC), documentation in accordance with official requirements and coordination of deadlines with other planned work on the headrace canal or the stream intakes in order to minimise production losses during the implementation period.