Summary:

In the 70-ties and 80-ties the river training was done in the Nida River. The river itself near Pińczów was shortened and the new channel was created. After the old channel near MOSiR recreational center was widened and deepened, the pińczowski reservoir was build in 1973 and then modernized in 80-ties. On east-southern in the place where in the past was a bridge in Nida River there is a district road running. At present the outflow culvert is localized there from which the water passes to the trapezoidal channel and then to the old channel. Finally the part of the water goes on the wetlands and the rest, below Pińczów, back to the Nida River. The length of the outflow channel is in total about 1.3 km, and the slope varies from 0.16 to 0.37 promiles. The water flows to the reservoir from the river by the side intake and stays there in average of 8 days. The projected retention period is about 5-6 days, and the time estimated on basis of current measurements of morphological, biological and water quality parameters should not exceed 2-3 days. Presently it is not possible because the outflow culvert was done without according to the engineering design and it's maximum discharge is about quoter of the designed one. This cause that the pińczowski reservoir exploitation cannot be well performed and many disadvantageous processes can be found in the inflow channel as well as in the reservoir itself. The silting processes and the afforestation cause the slow but contiguous degradation of the reservoir. As a solution the spillway with the pipeline is proposed to pass the overdischarge water directly to the Nida River. Additionally the deepening of the reservoir is proposed but with the care of the preservation of the mollusc's population.