Justification of the Contract. Intensive development within the catchment of Serafa River in the area of the City of Cracow and the Town of Wieliczka resulted in raised discharge of surface rainfall water to river-beds and streams (due to transformation of the existing green areas to sealed surfaces – roofs of houses, roads, yards, etc.). Furthermore, location of new development within flood plains provided new areas under flood risk. Flood hazard occurs especially in the area of the City of Cracow at chainage km 3+469 – 8+100 of the River Serafa, i.e. it covers areas of the Złocień Estate and of the Stary Bieżanów Estate. Due to development of Wielicka Strefa Ekonomiczna [Business Zone of Wieliczka], e.g. an industrial area with 2.5 K employees is located within a zone under flood risk. The following sections of the river-bed are under particular risk: area of Xxxxx Street, Zamłynie Street, Świeża Street, Korepty Street, and Półłanki Street at Stary Bieżanów; and area of Złocieniowa Street, Agatowa Street, Braci Czeczów Street, and Jasieńskiego Street on the northern side of the Cracow-Tarnów railway line. During the flood of 2010 those areas were flooded twice and inundated. Areas of Stary Bieżanów comprise detached houses, whereas in the area of Złocieniowa Street and Jasieńskiego Street there are blocks of flats at the Złocień Estate and industrial sites. Such an engineering and technical infrastructure provides high economic losses in case of flood damage caused by inundation of those areas by flood water of the River Sera- fa. Immediate works protecting the areas adjacent to the river-bed against the results of floods (e.g. sectional desilting of the river-bed, development of a dike raising the banks, protection of the river-bed) were undertaken after the flood of 2010. All those works improved flood protection in case of flood water with occurrence probability of over 10%. However, safe accommodation of 10% water requires additional protection works in some sections of the river-bed – flood embankments and channel regulation. Very dense development in the center of Bieżanów unfortunately disables development of flood em- bankments. Numerous studies – developed after the flood of 2010 – proved that at the cur- rent high progress of development only dry flood-storage reservoirs may provide an expected result, i.e. improvement of flood safety. An analysis of site conditions at the Malinówka Stream and at the River Serafa allowed for indicating feasible locations of reservoirs, optim...
