Long-term land-use changes in Czechia as a flood risk influencing factor

Abstract

The floods that hit Czechia in the past decade posed a considerable threat to the life and property of the country‘s inhabitants and brought huge losses reaching dozens of billions of Czech crowns (Hladný 2003; Langhammer 2007). Vaňous factors were named in evaluation of the causes of these exceptional floods, besides others, changes in land-use. The aim of the article is to assess the nature of long-term changes in intensity, nature and spatial structure of land-use in Czechia with respect to their significance for the runoff process, and especially during the occurrence and progress of floods. The article makes use of LUCC UK Prague database (Bičík et al. 1996,2003), an extensive geodatabase designed to evaluate spatial land-use development of individual comparable territory units (CTUs - based on the cadastral units), for the years 1845, 1948, 1990 and 2000. The effect of changes in land-use on the progress and magnitude of floods has been studied by a number of foreign and Czech authors for various geographical conditions

The model studies cited are usually based on evaluation of selected flood events in a limited territory and simulations of land-use change effect, using recent data and methodical scenarios. However, none of the studies covers the whole country or the majority of its major river basins, and they do not describe long-term changes using real data. In order to perform assessment of long-term spatial-level changes in land use of the whole country, specific data and methodologies are needed. We applied long term development data of land-use (1845-1948-1990-2000) in four classes (arable land, grassland, built up areas, other areas) and one index (Change index shows share of changed land-use classes from the whole size of territorial unit). These data were summarized on third order of river basins. There was chosen as the most suitable base for land-use change analysis; this order delimits 121 Czech basins with the average size of 734 km2. Some charts show differentiation of changes in all observed classes of land-use and intensity of land-use changes. Results are discussed and compare with cited literature