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Concept and Implementation of Solutions Improving Water Relations in the Area of the Flooded Opencast Lignite Mine Kazimierz Północ in the East Wielkopolska Region (Central-West Poland)
Over a period of 30 years, the surface water level in the north-west of Konin, in the east of the Wielkopolska region, decreased by almost 6 m, resulting in a reduction of the surface area of the majority of nearby lakes, the disappearance of smaller water bodies and wetlands, and the drying out of streams draining the area. The causes of the decrease in the surface and groundwater level in the region are complex. They include both natural and anthropogenic factors, among others broad-scale mining activity. Based on knowledge of the hydrostructural composition of the analysed region and the functioning drainage system of opencast lignite mines, a concept was developed of a change in water supply to the flooded opencast lignite mine, Kazimierz Północ. The task of redirecting waters from the drainage of a nearby opencast mine, Jóźwin IIB, was implemented in 2020. Current observations and forecasts suggest that, owing to the applied solutions, the analysed opencast mine will be flooded in 2023, and not, as previously assumed, at the end of 2021. As a result, groundwater levels in the vicinity of the opencast mine as well as in lakes and rivers within the range of impact of the related depression cone will be restored faster, particularly in the Lake Powidzkie catchment. The objective of the study is to present stages of flooding of the former opencast lignite mine Kazimierz Północ, identify factors determining the process, and describe solutions accelerating it, with a simultaneous environmental impact assessment of the undertaken activities.
Water Management Instructions as an Element of Improving the State of the Pakoski Reservoir (Central–Western Poland)
The management of reservoir dams in the context of observed climate changes and changing environmental conditions is becoming an increasingly significant challenge. Changes in the regimes of rivers feeding the reservoirs, sudden floods, long periods of drought, shallowing of reservoirs, water pollution, and algal blooms create unprecedented threats to the operation of these reservoirs. Among these challenges, the most crucial seems to be the proper management of available water resources, which condition the existence of the reservoir. The location of the reservoir has a significant impact on how water management is conducted. In the case of mountain and upland reservoirs created for flood protection of areas downstream, water management practices differ significantly from those for lowland reservoirs, which primarily serve to retain water for industrial and agricultural needs in the area, with an additional flood protection function. The aim of this study was to assess the factors determining the supply of lowland reservoirs using the example of the Pakoski Reservoir (Central–Western Poland) and to propose actions that would allow more efficient management of water resources in the catchment and reservoir, enabling the preservation of the current morphometric parameters in the face of climate change, adverse environmental phenomena, and increased anthropogenic pressure in the catchment area. This study focused on the Pakoski Reservoir, located in the southern part of the Kuyavian–Pomeranian Voivodeship. It was constructed fifty years ago as a result of damming water in the river systems of the Noteć and Mała Noteć Rivers. For decades, it served its functions, and its management posed no major issues. However, over the past decade, due to environmental changes and human activities in the catchment area, the reservoir has increasingly faced problems with filling.