Michał Wierzbicki Department of Hydraulic Engineering Agricultural University of Poznań

Transcription

1 Michał Wierzbicki Department of Hydraulic Engineering Agricultural University of Poznań The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir

2 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir Topics of the presentation: -Characteristic of the Jeziorsko reservoir, -Characteristic of the Warta river, -Water managment in the reservoir, -BOD 5 changes, -Total nitrogen changes, -Total phosphorus changes, -Conclusions.

3 The Warta river and the Jeziorsko reservoir characteristic

4 The Warta river and the Jeziorsko reservoir characteristic Total capacity: 203 milion m 3 Surface area: 4230 hectares Section of the Warta river: 19,5 km The construction of the reservoir began in 1975 The water managment started in 1992 The whole project was completed in 1996

5 The Warta river and the Jeziorsko reservoir characteristic The highest maximum flow: 425,0 m 3 /s The average maximum flow: 174,7 m 3 /s The average flow: 49,8 m 3 /s The average minimum flow: 19,7 m 3 /s The lowest minimum flow 10,5 m 3 /s

6 The Warta river and the Jeziorsko reservoir characteristic Inflow, outflow and water levels changes in ,00 1 st -31 st January minimum water level 122,00 Water flow [m 3 /s] 200,00 150,00 100,00 1 st February 15 th April filing the reservoir 16 th April 20 th June maximum water level 21 st June 30 th November empting the reservoir 121,00 120,00 119,00 118,00 Water levels [m over Kr.] 50,00 1 st 31 st December minimum water level 117,00 0,00 116, Date Inflow Outflow Waterlevels

7 Water quality measuring points Outflow The reservoir Inflow

8 Water quality BOD 5 changes in 1998 BOD 5 in BOD5 [m go 2/l] , 1 BOD 5 maximum = 23,0 mgo 2 /l/l Date InflowBOD5 OutflowBOD5 ReservoirBOD5

9 Water quality total nitrogen changes in 1998 Total nitrogen in 1998 Tota l nitroge n [m gn/l] TotNitrogen maximum = 10,82 mgn/l/l Date InflowTotNitrogen OutFlowTotNitrogen ReservoirTotNitrogen

10 Water quality total phosphorus changes in 1998 Total phosphorus in 1998 Total phosphorus [mgp/l] Date InflowTotPhosphorus OutflowTotPhosphorus ReservoirTotPhosphorus

11 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir Conclusions: 1. The main source of nitrogen and phosphorus for the reservoir is the Warta river: - 88,9 90,1% of nitrogen, - 78,3-86,3% of phosphorus, 2. Quantity of nitrogen carried out with the waters of the Warta river ranged from 49,5 77,7% and 42,5 51,7% of phosphorus of the total quantity brought into the reservoir,

12 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir 3. There are processes in the reservoir causing nitrites slight increase at the same time nitrites at the inflow and outflow tend to decrease their concentration. 4. Phosphates distinctly accumulate in the reservoir there is a tendency to decrease the concentration of phosphorus compounds (the decrease of its contents in detergents). 5. An essential feature is varability in time of brought and accumulated loads of biogens and also periods of domination of their outflow over inflow it is not only connected with changing concentration of biogens in water but first of all with the quantity of water masses carried by the river.

13 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir 6. Relatively long time of water retention in the reservoir, small average depth, intense inflow of biogens affects the intensity of biological processes algal bloom and in summer months blooming of blue-green algae. 7. The contents of organic substances defined by oxygen demand and contents of suspended matters were increased in the periods of phytoplancton bloom (hot summer 1992,1995) and in the period of flood (1997). 8. On the ground of water quality observation in terms of sanitation (coli titer) a positive influence of the reservoir on microbiological water quality in the Warta river can be observed.

14 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir 9. The overbottom and surface layer in the reservoir irrespective of seson of the year showed almost the same temperature which indicates that water in the reservoir was intermixed and without stratification, 10. Because of its attractive location, the reservoir is a place of intense but not arranged touristic activity, which causes dangeres of pollution increase coming from the touristic premises with unarranged sewage managment.

15 The changes of water quality in Jeziorsko reservoir and Warta river against the background of hydrology characteristic and water managment in the reservoir Inflow, outflow and water levels changes in ,00 122,00 200,00 121,00 Water flow [m 3 /s] 150,00 100,00 120,00 119,00 118,00 Water levels [m over Kr.] 50,00 117,00 0,00 116, Date Inflow Outflow Waterlevels