Project structure and responsibilities
The Alpine Airborne Hydromapping (AAHM) research project essentially comprises the research areas of data collection, data processing/data management and data evaluation (see figure below). Each of these research areas is led by a scientific project partner, in some cases with the support of the industrial project partners.
The following section briefly introduces the academic project partners and outlines the planned outcomes of the three research areas.
Hydraulic Engineering Unit, University of Innsbruck (Link)
The Hydraulic Engineering Unit is the consortium leader and initiator of AAHM. The Hydraulic Engineering Unit is primarily responsible for Research Area 3, ‘Data Evaluation’. Prof. Dr Markus Aufleger is the head of this research area and is also responsible for the overall project.
Research Area 3, Data Evaluation, focuses on the application of laser data to hydrological and hydraulic engineering issues in Alpine river systems.
A key focus here is on the use of high-resolution digital terrain models in the numerical modelling of processes relating to hydraulics and sediment transport. The AAHM data are intended to enable a better understanding of dynamic processes such as sediment transport and the development of river structures in Alpine gravel-bed rivers, and to assess their potential hazards in the context of flood protection. Sediment transport caused by flood events can be quantified by conducting multiple aerial surveys of a given stretch.
Furthermore, the AAHM data are used to investigate ecological aspects of Alpine and pre-Alpine rivers and delta systems. The classification of river stretches into riverbed, vegetation and, where applicable, anthropogenic structures, together with the recorded flow depths and river geometries, also enables an assessment of river-related habitats.
Another aspect concerns the energy-related analysis of watercourses and reservoirs. Siltation in the vicinity of turbine intakes and water abstraction facilities leads to reduced efficiency in power stations. This can be identified using AAHM data, and countermeasures can be implemented where necessary. Sediment deposition in reservoirs leads to a loss of storage capacity. The integration of AAHM laser data with echo sounder data enables high-resolution surveying of the underwater geometry of reservoirs in alpine regions down to great depths.
Department of Geodesy and Geoinformation, Vienna University of Technology (Link)
The Photogrammetry Research Group (Institute of Geodesy and Geoinformation, Vienna University of Technology, TUW) is responsible for Research Area 2, ‘Data Processing and Data Management’. The principal investigators are Prof. Dr Norbert Pfeifer and Dr Gottfried Mandlburger.
The overarching aim of this research area is to develop data processing techniques and their application in the form of efficient methods and software tools. Furthermore, the aim is to carry out a comprehensive data analysis in order to understand and utilise the full potential of the collected data.
The analysis of topobathymetric AAHM data raises additional scientific questions compared with traditional topographic laser scanning: (i) The green laser signal is refracted and reflected at the air–water interface. The propagation speed of the laser pulse is lower in water than in the atmosphere. (ii) The complex scattering of the laser beam in water poses additional challenges for the reliable detection and characterisation of different laser echoes. (iii) Different types of water echoes (from the bottom of the water body, from volumetric backscattering and from the water surface) must be distinguished during the classification of the point cloud. (iv) Signal absorption within the water column must be taken into account during the radiometric calibration of the laser echoes, and (v) measurements in the two different media (water and air) raise additional issues regarding sensor alignment and the geometric calibration of the data.
The contributions from TUW therefore provide solutions to these issues, both from a theoretical perspective and through the provision of specific algorithms, best-practice processing routines and the implementation of software components.
AB Surveying and Geoinformation, University of Innsbruck (Link)
The Surveying and Geoinformation Research Group (Department of Basic Sciences in Engineering Sciences, University of Innsbruck) is responsible for the scientific management of Research Area 1, ‘Data Acquisition’. This encompasses both aerial surveys using the bathymetric, airborne LIDAR system and all terrestrial and SONAR measurements for subaquatic surface mapping.
In addition, the team led by Univ.Prof. Dr Klaus Hanke and Dr Thomas Weinold is responsible for terrestrial control measurements and the comprehensive evaluation of the LIDAR data analysed in Research Area 2; in selected test areas, the reliability and completeness of the data are also verified alongside surveying accuracy.