The project TeGeRam deals with the development of a measurement prototype for highly accurate spatial and temporal temperature determination in water bodies by means of fibre-optic monitoring systems using Raman spectroscopy. The prototype of a new type of fibre-optic temperature measurement system will be developed for both flowing and standing waters. Since the fibre-optic cable, used for the measurement, collects data over the entire length, the system promises great value compared to conventional measurement methods, which work with point measurements. The depth profiles over long distances in flowing waters as well as the water column in standing waters can thus be collected in a time-efficient and thus much more cost-effective way compared to previous methods. High-resolution temperature profiles can then be derived from the data and statements about the water quality of a water body. The cooperation project has been carried out jointly by the FiW e. V. and OSSCAD GmbH & Co. KG and started in August 2018 with a duration of 24 months. It is funded by the German Federal Ministry for Economic Affairs and Energy (BMWi) through the Central Innovation Programme for SMEs (ZIM). The project organisation is the German Federation of Industrial Research Associations (AiF).
Development of a mobile temperature monitoring system (mTMS) for flowing waters
A measuring technique has been developed for the use in flowing waters that can record the water temperature over a longer distance of the flowing water as well as over the entire width and depth of the water, if possible. For this purpose, a carrier system has been constructed that guides the measuring cable through the watercourse over a sufficient length. The measuring cable is attached to several so-called measuring fingers in order to be able to record measured values over the entire width and depth of a body of water. The measuring system must be adaptable modularly to the size of the water body and connected to a manned boat.
Development of a stationary temperature monitoring system (sTMS) for standing waters
Up to now, water quality monitoring has been carried out on reservoirs in NRW at three-year intervals. With the new system, data can be collected around the clock and sudden changes in the water body as well as trend developments can be detected in time. In this way, management can be adapted to the actual situation and security of supply can be guaranteed.
The stationary measuring system under development is installed at the extraction tower of the Wehebachtalsperre near Düren. Temperature readings are taken every minute over the entire depth and transmitted by remote data transmission. After installation, it has been possible to observe and document the autumn circulation typical of a standing water body as well as the winter stagnation.
Goal and outlook
The EU Water Framework Directive calls for the "good status" of our water bodies. Water temperature has a decisive influence on both the chemical-physical and biological status of water bodies. At the same time, the temperature-related pressures on water bodies are diverse. Discharges of cooling water from power plants or sewage treatment plants, for example, often lead to an increase in the water temperature in the water body. Although the influence of temperature on water quality is known, there is currently no continuous measurement in terms of time and space. The technical effort required for this exceeds the possibilities of those responsible for watercourse maintenance, or there is no available measuring technology on the market.
The prototype developed in TeGeRam aims to provide a way to address this problem.