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IABG supports the Bavarian State Ministry of the Environment

Flooding means material damages to the citizen affected, sometimes even danger to life. This was demonstrated very impressively by the so-called 'Whitsun' floods in 1999 along the Danube in Bavaria and the massive floods along the Elbe in 2002.

The <link http: www.stmug.bayern.de external-link-new-window externen link in neuem>Bavarian State Ministry of the Environment has therefore made the designation of flood areas a focal task in its work. For the larger stretches of water in Bavaria, which have an overall length of about 9 000 kilometers, about 1/3 of the flood areas have already been established in law. For about half of the stretches of water, precise knowledge is currently not available regarding the possible floodwater dimensions of these areas.

The detailed surveying of the terrain by terrestrial survey methods was in the past very costly. With the compilation of digital terrain models of the water-valley areas and the recording of situation and usage data using aerial photography and using photogrammetric aerial photography evaluation, it is now possible to update the planning data with state-of-the-art methods in a considerably shorter period of time.

These tasks and the preparation of the data obtained for a Geographic Information System (GIS) have been taken over by IABG. Our work is thus the basis for the calculation of flooding limits. These are based on decisive flood water levels, which are normally established by means of hydrological data gathered over a period of years.

In the middle of April, IABG had more than 100 km of the course of the river Loisach overflown as part of the project. From a total of 780 aerial photographs, an area of over 20 000 hectares will be surveyed three-dimensionally. Besides the terrain elevation, also topographical objects (roads, houses, walls, bridges etc.) will be determined with a location and elevation error margin of less than 10 cm.

After IABG was commissioned in recent years with the overflying and photogrammetric surveying using aerial photographs of over 35 small and medium-sized rivers all over Bavaria, this year the company has been successful in acquiring with the survey of the Loisach its single biggest individual order to date from the Water Resources Board Weilheim. The project will last until June 2004.