Technical problems of repair and renovation of flood-protection development in urbanized areas. Part I

A stream running through a settlement or town can create great hazard to the adjacent development areas; it is also, however, a natural decorative element. Because of time passing and lack of necessary maintenance of the structures, their rebuilding and modernization is often necessary. Here many problems arise. They include: lack of place for the required expansion of the river course and cross-sections, geological structure, requirements of the valid water and building law, architecture (especially in old-town development), and ecology. An approach to solve these problems is presented in the paper for a large stream of Wątok running through the old part of the Tarnów town. Because of the location of the stream, intensive urban development and the neighborhood of sacral buildings protected by law, it is the urban authorities' responsibility to ensure full safety to the neighboring land. This task was undertaken as early as in the mid-war years although the protection level was inadequate. The technical condition of the structures threatening to cause building catastrophe, and the aesthetics of solutions were additional arguments to undertake the project.To give the reader an illustration of the multiplicity and importance of technical problems of the designed development, the existing state ...

Technical problems of repair and renovation of flood-protection development in urbanized areas. Part II

The content of this paper is the continuation of the paper presented in the previous volume. The necessity of flood protection of urban areas was argued and the attention was paid to environmental and small architecture aspects. A typical solution that was discussed concerns the re-development and renovation of a stream of Wątok flowing through the old part of the Tarnów town with monumental sacral buildings. First regulation works were undertaken in the mid-war period. Time passing, water aggressiveness intensified with municipal wastes, and the lack of proper maintenance caused considerable damage to the existing structures. The extent of the damage threatened building catastrophe with all resulting consequences.Utilizing own resources and the acquired PHARE funds, the Tarnów authorities decided to undertake full-scale works on the stream reach under discussion. High requirements were posed concerning the environmental and aesthetics conditions with the simultaneous meeting the safety conditions of the neighboring terrain and the development itself. Because of varying character and technical state of the existing development, as well as different land conditions and the character of ...

Flood protection and preservation of natural values of rivers and their valleys

A modern approach to the problem of flood protection resulting from the necessity of integrating the three objectives of water management: conservation of water resources, meeting necessary water demands and protection against flood and other natural hazards is presented in the paper. In its flood-protection aspect, the approach forces fulfilling environmental criteria when protection measures are being selected and implemented. Also, the approach requires that the flood prevention which helps in restoration or conservation of natural condition of runoff from the catchment be treated on equal terms. This clearly has a positive effect on the correct linkage between flood protection and the natural values of rivers and their valleys. In this way, when solving a social-economic problem, which is flood hazard reduction, we preserve or protect against degradation the good ecological status of running water resources and therefore also the state of the related terrestrial and aquatic ecosystems. This creates favourable conditions for protection of natural values that are an integral part of these ecosystems. The assumptions and principles that water manager and hydro-engineer should follow when seek solutions to flood hazard reduction are the subject of the paper. However, the paper does not contain particular references neither to the ...

The construction and action of dry dams with the different characteristics and location

This paper aims at sharing feedback about dry dams. These structures are efficient to mitigate floods, while little disruption of the continuity of the main channel and its flows outside the flood periods. Five sets of dams are presented here. They were selected so as encompass the diversity of the structures and of the problems. The oldest structures are presented first. These are dams built in the beginning of the twentieth century in Poland and in the USA, which are still in operation today. Then, recent realisations in France are presented. Large dams in Gard catchment and small dams upstream the nearby town of Nîmes are described, with analyses of behaviour during intense floods. Finally, small dams in Seine-Maritime allow to address the issue of an efficiency diagnostic at catchment's scale, when both dams and stakes are spread out. This article gives key references for further information about structures design. ...

The study on dry dams efficiency during the flood events: the analysis of selected dry dams in France

The high precipitations, which appears now very frequently, are the main causes of damages in the infrastructure and the properties. Protection against flood should be still developed, but with the special attention on ecology and keep-ing the continuity of water and sediment flow throughout the river channel. Dry dam structure is efficient to mitigate floods, while little disruption of the continuity of the main channel and its flows outside the flood periods. In the paper we ana-lyse the efficiency of selected dry dams during the flood events. We have studied the dry dams located in southern France. In few cases the studies have shown, that dry dams had to be reconstructed in order to protect the area against the flood. ...