Marta Borowska-Stefańska

Abstract The work described here sought to assess land use in flood hazard areas within selected gminas (local authority areas) of Łódź voivodship. The analysis in fact encompassed 21 of the gminas, located in the catchment areas of the Warta, Pilica and Bzura and officially characterised by “high” or “very high” flood risks. A flood hazard zone is considered to coincide with the area reached by high waters 1% of the time. The term “use” is understood by S. Liszewski (1997, p. 61) as „…using something, benefiting from something in a rational way which brings as great an advantage as possible”. Consequently, almost every human activity is reflected in the land and ”…performs a clearly defi ned and diverse function” (1978, p. 17). River valleys are separate natural systems characterised by specific forms of geological structure, relief, water relations and climate, as well as fauna and flora. These are precisely those features of the environment that condition and shape forms of human activity. The type of valley development has a strong impact on valuable natural features as well as on flood protection issues. In areas with no urbanisation, the degree of conversion of natural areas relates directly to the system of land-use types. The highest degree of conversion is associated with areas of cultivation, while a more limited degree char-acterises grassland, and the lowest degree if all forest areas. The mosaic of land uses of differing intensities is associated with growing fragmentation of the river and valley environment. In turn, from the point of view of flood protection the greatest emphasis is placed on analysis of the level of investment in the areas in question, and on identifying places that face a more distinct hazard, the correct identification obviously being of key importance in ensuring proper protection (Słoneczka et al., 2008). A surge in built-up areas in flood-hazard zones tends to be associated with flooding of increased extent and frequency (Konrad, 2003). In the area under study, the highest degree of horizontal intensity of development is that characterising the three towns of Tomaszów Mazowiecki, Kutno and Łowicz. In the gmina of Tomaszów Mazowiecki approximately 14% of the flood-hazard area has been developed, mainly with technical and production facilities, with the major potential losses in the event of a flood being likely along the Rivers Czarna and Piasecznica. In Kutno, the index for horizontal intensity of development for flood-hazard areas reaches 7.5%, an example that illustrates how smaller rivers offer a greater sense of security. People are more willing to build in the valleys of such rivers, with tragic consequences, given the way that the floods occurring in smaller valleys are more dynamic and harder to safeguard against. In Łowicz, the horizontal intensity index for 1% water is found to be 4.5%. The valley bottom of the Bzura is very wide here, especially in the western and eastern parts of the gmina where buildings are present (the central section of the river within the town’s administrative boundaries has an embankment). Smaller rivers, especially the Czarna, Piasecznica and Ochnia, give users a sense of security, as does a location below the Sulejowski and Jeziorsko Reservoirs. All this is leading to an intensification of land development in this area, and to an increase in potential adverse consequences in the event of flooding.

Marta Borowska-Stefańska

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