In August 2022, the Oder River experienced an ecological disaster, resulting in the extinction of hundreds of aquatic organisms. Mass fish deaths also occurred during that time in the Gliwice Canal, located in southern Poland, which connects to the upper section of the Oder River. The aim of the article was to assess the impact of the waters from the Gliwice Canal on the water quality changes in the Oder River, as expressed by chloride, sulphate, nitrate, phosphate content, as well as its parameters such as conductivity, temperature, and pH. Statistical analyses were conducted based on our own research and a series of data collected by the Chief Inspectorate for Environmental Protection. Below the confluence of the Oder River with the waters of the canal, an increase in sulphates levels and a decrease in sodium content were observed. The other parameters remained unchanged. It was also noted that the magnitude of each parameter was significantly higher in the waters of the Gliwice Canal compared to the Oder River. The research conclusion is that there is no influence of the canals’ waters on the quality of the Oder River waters, both during the ecological disaster and afterwards. The presented research clearly indicates the need for separate analyses of flowing waters (with significantly higher salt and other pollutant dissolution capacity) and stagnant waters in water infrastructure (without water exchange).

The following databases contains information on land use with water in Poland: Corine Land Cover (CLC), the Urban Atlas (UA); Database of Topographic Objects (BDOT) the digital Map of Poland’s Hydrographic Division (MPHP); and the Register of Lands and Buildings (EGiB). All these data are referenced in scientific analyses and the Polish water management system, so the results of their processing should be the same (or at least similar); if not, output materials will be inconsistent and unreliable. In the Katowice sample, we checked the quality of this data using multi-criteria analyses, which is based on a grid of equal-area hexagons. Additionally, we applied the Normalized Difference Water Index to check real-time water presence. We detected discrepancies between all the data. The CLC does not reference any flowing water in Katowice. Most data overlapped between MPHP and BDOT, and both databases were similar to UA. However, a lot of uncertainty was also observed in the EGiB, which is considered to be the most accurate of the databases surveyed. In conclusion, we argue that water land cover data should be used with caution, and depending on the scales of analysis, that most actual data could be remote sensed data. We also include a diagram which can be useful in the data selection process.

This study examines historical water management practices as a means of addressing climate change, focusing on the Tyski Stream catchment in Upper Silesia, Poland, a region marked by extensive urbanization and industrial evolution. It investigates the effectiveness of historical hydrotechnical systems, such as bead-like ponds from the 15th to 18th centuries, in enhancing water retention, reducing flood risks, and supporting ecosystem services. In a critical period, over 54 years (1827–1881), the number of reservoirs decreased from 142 to 31 (the area of ponds decreased from 161 to 32 ha). Throughout the entire period, between 1748 and 2017, the surface area of the analyzed reservoirs decreased from 163 ha to 16.8 ha. This was related to progressive industrialization, urban sprawl, and changes in legal frameworks, such as land ownership laws, leading to ecosystem degradation, loss of biodiversity, and altered hydrological processes. The research emphasizes the potential of reviving historical water management systems on natural processes to mitigate the impacts of climate change. By analyzing historical cartographic resources, this study assesses the feasibility of reconstructing lake systems in areas with similar topographic and hydrological features. It also stresses the necessity of community engagement and securing widespread social and political support to ensure public acceptance and the success of renaturation initiatives. The findings indicate that restoring these systems can offer diverse benefits, including improved water management, enhanced biodiversity, and greater urban resilience, while addressing the socio-political complexities of implementing large-scale environmental restoration projects. The aim of this study is to utilize archival materials for engineering solutions to prevent flooding and enhance water retention.

In the current digital age, spatial management seems impossible without a set of data which maps the real situation on a computer screen. However, varying technologies (software, hardware) as well as methodologies (vectorisation, automatic classification, deep learning, etc.), together with the availability of input materials, result in a huge difference in the quality and timeliness of data collected infor example different countries. This statement also applies to hydrographic data, which undeniably affects water management efficiency. With increasing globalization, it seems necessary to standardize hydrographic data on a transnational level. The main aim of this article was to review the ways and techniques of collecting, updating and sharing hydrographic data by selected countries or organizations. In addition, the use of modern geo-information and remote sensing tools was reviewed, as well as work towards interoperability of inland surface water databases. As a result of the review, the authors identified a strong need to unify hydrographic data at both the national and continental levels, and in the future, globally (considering the dynamic change of data precision when changing the digital mapping scale). In addition,good practices were identified, and methods that can be used to create a universal spatial database of surface waters were identified.

In the digital age, spatial databases are the main source of information on the hydrographic network. However, the main challenge remains the need for frequent updates alongside the accurate presentation of current and potential coverage. Modern geo-information tools based on the processing of remotely sensed materials allow precise modeling of places where reservoirs historically occurred or are predisposed to form. The restoration of reservoirs is significant in the context of flood protection, the improvement of retention conditions, and the development of blue-green infrastructure. It is also much more economically viable than preparing sites for new construction. The missing element in the systematic use of the aforementioned materials and tools for these purposes is methodology. For this reason, in this article, based on images and a point cloud acquired during a photogrammetric aerial flight, five methods are tested, and the most effective method is identified, depending on the intended application.