Journal of Świętokrzyskie Mountains Region
Series B – Natural Sciences
2009, No 30, 99-110
ECOLOGICAL CONDITIONS OF SMALL RETENTION IN THE UPPER VALLEY OF THE BOBRZA RIVER
Key words: river catchments, small retention, depression, water reservoirs
The paper presents very simple and useful methods of water researches in small catchments for define ecological conditions of small retention. For several dozens of years some unfavourable processes, like: drying out of lands, decreases of ground water levels and high variations in river flows have taken place in the upper catchments of the Bobrza river (Burchard 1978, Prażak 1991). Significant changes in a surface water level caused a larger exploitation of underground waters in the Zagnańsk intake water. When in 1974 Kielce started water uptake from the underground Triassic reservoir, a successive process of drying out of the Bobrza river and its tributaries took place in the area of the water intake. In order to improve a water balance in the mentioned area some actions have been
undertaken within a project “Small retention of the Swietokrzyskie Province” carried out by the Swietokrzyski Office of Meliorations and Water Appliances (1999). The program aims at increasing a time and way of water circulation in river catchments by storing the water in water reservoirs. It will bring changes from a fast surface outflow to a slow ground outflow (Dziewoński 1973, Mioduszewski 1997). The positive project results can bring many changes in natural and social environments of the upper valley of the Bobrza river. By the other side dirty water in reservoirs can be danger for water organism. It would be a cause of eutrophication of natural water, increased temperature of surface water and silting reservoirs.