Determination of areas of local inundations based on DTM and HYDRO databases

Abstract

HYDRO databases are an important component of the Polish hydrographic maps made for several years. Special thematic data stored in spatial databases cover an area of nearly 60% of the country.
This paper aims to show new possibilities of using existing HYDRO databases integrated with Digital Terrain Models.
DTM is shown as the background for selected hydrographic data layers. For this purpose, the authors use an elevation data model developed with Airborne Laser Scanning data. These kinds of DTMs were developed for large part of the country, and the average error for most areas is less than 1 m. These results are kind of a three-dimensional view, which allows better understanding of hydrographic phenomena.
Using the GIS tools allowed to find runoff directions and to determine the places of water gathering. This will allow to designate areas of local flooding caused by heavy rain and also as a result of snow melt. This information could be a root for creation of relevant maps and place them in geoportals to help individual investors planning to purchase the land parcel or to use appropriate insulation in construction of houses. Delineation of flooding zones may also be useful for municipalities in areas not covered by the flood risk maps.
Targeting the places where water accumulates is also valuable information for the National Water Management Authority (KZGW) which can help to create periodic reservoirs (wetlands) and then use them in times of drought for the irrigation purposes.