Rawa – a river of the Anthropocene

The Rawa is a right-bank tributary of the Brynica River, which in turn is a right-bank tributary of the Przemsza River, which flows directly into the Vistula. The catchment area of the Rawa River is located within the cities of the Upper Silesia-Zagłębi Metropolitan Area: Ruda Śląska, Świętochłowice, Chorzów and Katowice, as well as small fragments within Siemianowice Śląskie, Bytom and Mysłowice (about 82 percent within Katowice and Chorzów). Its area is 86.98 square ^kilometers, and the length of the Rawa is 19.2 kilometers.

The Rawa, by virtue of its history and current situation, may be an example of a river subject to strong anthropopression over the past 200 years. Its catchment area has been influenced by coal mining, iron, zinc and lead metallurgy and the chemical industry, as well as the associated urbanization – more than 60 percent of its area is built-up land (Figure 1).

Although there has been a reduction in industrial development in the catchment area since the 1990s due to political and economic transition, the physiognomy of the river has not changed. After many years of intensive exploitation of the area, negative effects remained in the form of environmental degradation, i.e. the accumulation of post-mining and industrial waste, the pollution of soils and watercourses, and the destruction of biological life in them (Absalon et al., 2012; Absalon et al., 2025).

Changes in water conditions in the catchment consist of modifications to the hydrographic network, lowering of the groundwater table, the formation of floodplains in subsidence basins (caused by underground coal mining). The course of the Rawa River and many of its tributaries has been straightened and shortened, and their channels are mostly stone or concrete-lined.

The Rawa is a receiver of municipal and industrial wastewater. Despite the fact that no coal mines no longer operate in the area of Katowice, through which it flows, saline mine water still enters the river.

Currently, the flow of the Rawa River is more than twice as low as it was in the 1980s, and during dry periods, the river mainly carries treated urban wastewater with mine water and probably a small proportion of groundwater. The total amount of wastewater discharged into the river currently remains at about 70,000^m3 per day, while in the 1980s it was 230-257,000^m3 per day (Absalon et al., 2024).

Another manifestation of the river’s strong transformation is its outflow regime. Already studies conducted in the 1960s indicated that the influence of anthropogenic factors on the flow of the Rawa River was significant – the outflow coefficient, i.e. the ratio of flow to precipitation, fluctuated between 0.60 and 0.92 in 1946-1953 (Les-Rogoz, 1962). The human impact on the waters of the Rawa River continued to grow until the 1980s, when the runoff coefficient exceeded 2.5, meaning that runoff was more than two-and-a-half times the value of precipitation in the basin (Absalon et al., 2025). Until 1991, a water gauge station in Szopienice (a district of Katowice) operated on the Rawa River. In 1981, a record value of the average annual unit outflow was recorded there, which reached 51.7 dm ^{3 s-1 km-2} – under natural conditions, such values are reached by rivers and mountain streams.

The quality of the Rawa’s water in the past depended mainly on industrial development in the catchment area, and the increase in sewage has deteriorated the river enough to lead to the almost complete disappearance of biological life in it. The Rawa became a sewage collector, with natural waters making up a small part of the flow (Czaja, 1999). In recent years, the composition of the Rawa’s waters has been marked by the impact of increasing urbanization, with industry’s contribution limited to the discharge of water from now-defunct coal mines.

The 2021-2024 study confirms the impact of mine waters on the river’s water quality, as manifested by high chloride and sulfate content (Absalon et al., 2024). This affects the high values of specific electrolytic conductivity of the waters. However, these parameters are still significantly lower than those recorded in the second half of the 20th century. (Czaja, 1999). Thus, although the river’s flow is currently dominated by municipal wastewater, mine waters – despite their smaller share – are responsible for the Rawa’s high salinity and its poor ecological potential (Absalon et al., 2025).

In 2021-2024, detailed chemical tests of the waters were also carried out, which revealed the presence of micropollutants from the group of so-calledemerging contaminants (emerging contaminants), mainly pharmaceuticals and personal care products (e.g., antibiotics, hormones, non-steroidal anti-inflammatory drugs, antidepressants, cosmetic ingredients and detergents). The highest concentrations of detected micropollutants were recorded at a point below the discharge from the Klimzowiec wastewater treatment plant – sucralose and oxypurinol, which are difficult to remove from wastewater, were found there. These and other constituents detected in the Rawa River and its tributaries suggest the involvement of domestic sewage in the raw waters (Slósarczyk, Witkowski, 2024).

Any positives? The reduced influx of industrial wastewater has contributed to lower concentrations of heavy metals compared to archival data. In the past, heavy metals led to the disappearance of biological life in the Rawa River (Kowalczyk et al., 2022). Currently, other hazardous compounds are affecting water quality.

Due to the high variability of flow and the high dynamics of water quality parameters in the Rawa River, an automatic continuous monitoring station was installed on the campus of the University of Silesia in Katowice in December 2024 to measure selected water parameters (Photo 1).

From the position of the web browser, we have direct access to the current measurement results and their history (Figure 2 and Figure 3). We can also download the measurement history of any range in a csv file.

Preliminary analysis of monitoring data from the first half of 2025 indicates a high dependence of water quality on wastewater discharges, rainwater and saline mine water. Among other things, rapid diurnal changes in water temperature and electrolytic conductivity were observed. During the analyzed period, changes in this parameter ranged from 320 to 15181 mS ^cm-1. In Figure 3, we can also observe a rapid change in water conductivity from a value of almost 1100 mS ^cm-1 recorded on January 12, 2026 at 5:00 am to almost 6000 mS ^cm-1 after only 2 hours. Large changes in a short period of time were also observed in the dissolved oxygen content of the water and its turbidity. The significant dynamics of the physical and chemical parameters of the water indicate the reasons for the poor quality and poor ecological potential of the Rawa River. Only a small number of organisms are able to function under such extreme conditions (Absalon et al., 2025).

What does the Rawa’s future look like in the post-industrial era? It’s time to redefine the function of the river, knit together with the cities through which it flows. Obtaining a river that is clean, with biological life, safe during extreme weather events and people-friendly is difficult to meet, but not impossible. Five entities – the City of Katowice, the Upper Silesian and Zagłębie Metropolis, the University of Silesia, the Silesian University of Technology and the University of Economics in Katowice – are pursuing the concept of a Green Learning Zone in the center of Katowice, and one of its goals is to integrate the campuses of the universities located downtown around the Rawa River. Researching the river is one means of bringing this goal closer to fruition and changing the face of the river in the city center.

Damian Absalon – Ph.D. Professor at the University of Silesia – hydrologist, geographer, deals with m. in. issues of the impact of anthropopressure on runoff and water quality and modern methods of monitoring rivers and lakes; author of more than 250 publications; deputy director of the Silesian Water Center at the University of Silesia; member of the State Water Management Council; expert of the Water Management Committee of the National Chamber of Commerce.

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In the article, I used:

Absalon D., Czaja S., Jankowski A.T., 2012, Geographic environment, in: Katowice. Environment, history, culture, language and society , t. 1, edited by A. Barciak, E. Chojecka, S. Fertacz, Museum of the History of Katowice, Katowice, pp. 43-78.

Absalon D., Matysik M., Ślósarczyk K., Boroń P., Woznica A., Kowalczyk A., 2025, Impact of industry and urbanization on surface water – 200 years of changes in the Rawa River catchment, [in:] Sadzikowska L., Kowalczyk A. (eds.): Rawa – the river that connects, 2025, Katowice, University of Silesia in Katowice, 221 p., ISBN 978-83-226-4646-5.

Absalon D., Ślósarczyk K., Matysik M., Sadzikowska L., Krodkiewska M., Kowalczyk A., 2024, Changes in Hydrological Conditions in the Rawa River Catchment. Preliminary Natural and Cultural Considerations , in: Silesia Superior. Narratives on Upper Silesia – The Multitude of Perspectives , TRANSitions series, vol. 14.1, eds. R. Dampc-Jarosz, A. Kowalczyk, L. Sadzikowska, Vandenhoeck & Ruprecht unipress, Göttingen, pp. 213-248.

Czaja S., 1999, Changes in water relations under conditions of strong anthropopression (on the example of the Katowice conurbation), University of Silesia Publishing House, Katowice.

Kowalczyk A., Sadzikowska L., Tomczok M., Tomczok P., 2022, Anthropocene Rawa. Aquaphilology of an industrial river, “Teksty Drugie”, No. 4, pp. 32-51, https://doi.org/10.18318/td.2022.4.3

Les-Rogoz A., 1962, Hydrographic characteristics of the Upper Silesian Industrial District, “Bulletin No. 64. Polish Academy of Sciences – Committee for the Upper Silesian Industrial District,” pp. 129.

Psiuk J., ed., 2006, Monograph of the Rawa River, Publishing House of the District Water Supply and Sewerage Company, Katowice.

Kloskowicz M., 2025, Rawa – an invisible river, University Gazette of the University of Silesia, no. 1 (131), https://gazeta.us.edu.pl/node/437573.

Ślósarczyk K., Witkowski A.J., 2024,Screening of pharmaceuticals and personal care products in the water environment of a region diversified in land use and urban development (Silesian Province, southern Poland), Journal of Hydrology, no. 635, s. 131-191.