Monitoring of small and medium-sized water bodies using manned and unmanned surface vehicles - results of the RiverView®-project

In order to implement the EU Water Framework Directive (EU WFD) effectively, information on the state of and the changes within flowing waters is essential for planning processes in water management. Water monitoring is increasingly important as an integral part of water resources management, not least with respect to flood risk management. As the first project of its kind, the BMBF-funded joint RiverVieve (R)-project aims to establish a holistic approach to the targeted and systematic compilation of spatially referenced water data, under as well as above the water. Modern data collection techniques allow for spatially as well as temporally continuous capturing of high-resolution data. The extensive and comprehensive monitoring of the water body and its environment provides an objective representation of the present situation, as recommended by the EU WFD. By means of the built-in autopilot, water data measurements in different sections and at varying depths of the watercourse can readily be repeated, facilitating the monitoring of the development of a stretch of water. As one example, 360 degrees-panorama images are an efficient means of visualization on the one hand, and make measurements based on 3D-point clouds possible on the other hand. In addition, a multi-parameter probe transmits water quality data such as water temperature, pH-value and oxygen content. With the modular system developed in the research project, the comprehensive data on structure, quality and morphology of water bodies collected with the system as well as the images captured can be georeferenced with high accuracy, providing a representative set of high-resolution data for water-related planning and monitoring (e.g. at industrial and municipal discharge points and in ecologically restored areas). Expectations regarding the mapping sensor system outlined during the planning phase were met throughout the test runs on small and medium-sized rivers. The test runs were used to evaluate the hardware and software and provided the data for a web platform. Accurate spatial referencing of images and water quality data requires a positioning accuracy of 1 to 3 dm (position) and 1 dm (height), which is guaranteed with strong GNSS reception. In case of poor reception, in most cases the additional use of visual odometry ensures the required accuracy. Technological development is expected to advance in the future. Further applications, such as the integration of additional probes and use for other than water-related purposes, will soon be developed.