Importance of Blue–Green Infrastructure in the Spatial Development of Post-Industrial and Post-Mining Areas: The Case of Piekary Śląskie, Poland

Abstract

Post-industrial and post-mining areas are an important element of cities historically associated with industrial activity. The transformation of degraded areas is a challenge for spatial policy, which is characterized by a substantial impact on the cultural heritage of mining and industry. The case of Piekary Śląskie shows the consequences of deindustrialization, which leads to the degradation of urban space and requires innovative revitalization strategies considering the principles of sustainable development and the concept of blue–green infrastructure. Archived topographic maps and current interactive maps of the study city were used in a spatial data analysis. The aim was to determine the directions of the spatial development of post-industrial and post-mining areas using the example of a medium-sized city located in the core of the Katowice conurbation, while considering the role of blue–green infrastructure in the revitalization process. Integrating blue–green infrastructure into the city’s planning documents may serve as a model for other urban areas, highlighting the synergy benefits between urban development and environmental protection. Such solutions support the development of a green economy to improve residents’ living conditions and increase the city’s competitiveness in the region. The specific examples of the revitalization of the areas in the Andaluzja and Julian mines and the reclamation of the brickyard in the area of Kozłowa Góra in Piekary Śląskie show that a multifunctional approach to revitalization contributes to the harmonious development of urban spaces.

1. Introduction

Piekary Śląskie is characterized by a rich tradition associated with hard coal mining and metallurgy. The city is located within the Katowice conurbation [1], a complex settlement system shaped by the dynamic development of traditional industrial sectors [2]. A key turning point in developing this urban structure was the economic transformation initiated in 1989 [3]. This process entailed a radical shift in the primary objectives and fundamental economic conditions of the enterprises operating within the state. For Poland’s industrial sector, it meant a gradual departure from mining and the closure of coal mines, including those in Piekary Śląskie.

For a large segment of the city’s residents and the broader region, mining and metallurgical activities were not only sources of employment but also integral elements of cultural heritage. Mining and industrial enterprises played a foundational role in the economic development of traditional Silesian families. This is particularly evident in the presence of workers’ housing estates, which formed the basis of the settlement network in the cities of the Katowice conurbation. Piekary Śląskie played a crucial role in these processes, hosting several coal mines, including Andaluzja, Julian, and Bobrek-Piekary [2].

With the progressing socio-economic transformation, challenges typical for such areas, such as unemployment and urban shrinkage [4,5], became more pronounced. A significant factor contributing to the deepening crisis was the lack of social acceptance for restructuring the mining sector. The closure of industrial and mining enterprises led to urban decay and further environmental degradation. The presence of post-industrial and post-mining remnants became a major challenge for the city’s spatial economy. A significant portion of these areas within the Katowice conurbation remains undeveloped. Given their size and strategic location, they represent a crucial resource for the future development of individual cities.

An analysis of the strategic and planning documents for Piekary Śląskie allows for an assessment of the extent to which local authorities perceive post-industrial sites as key elements in urban development. Additionally, it provides insight into the strategies and development directions adopted for these areas and evaluates their alignment with the principles of sustainable development.

This study aims to identify spatial planning strategies for the post-industrial and post-mining areas in a medium-sized city within the Katowice conurbation, focusing on the role of blue–green infrastructure in sustainable urban development. The functional transformation of these areas is a key challenge in urban spatial policy. Special attention should be given to the cities in regions with a strong industrial heritage, such as the Katowice conurbation. Medium-sized cities struggle with the consequences of deindustrialization, which directly contributes to urban space degradation. In this context, the concept of blue–green infrastructure is gaining importance as a revitalization tool aimed at improving residents’ quality of life [6,7,8,9,10,11].

Existing studies on the revitalization of post-industrial and post-mining areas often focus on the role of large or small urban centers, overlooking the significance and specificity of medium-sized cities. The literature lacks comprehensive and exhaustive analyses directly addressing the integration of blue–green infrastructure into the planning process for such areas. This study aims to bridge this gap by providing new data and proposals for redeveloping the post-industrial and post-mining areas in a medium-sized city, considering ecological aspects and the principles of sustainable development [12,13,14]. Despite significant achievements, blue–green infrastructure is still insufficiently researched in Polish conditions, so it is not used appropriately to counteract climate change’s effects and adapt Polish cities [15]. It is worth emphasizing that medium and small cities face particular challenges because they have less autonomy in adapting to climate change. Cities of this size often lack the expertise, human resources, and budget for significant investments [16]. An analysis of the medium-sized city of Piekary Śląskie was conducted to assess its potential for implementing BGI elements in transforming and revitalizing post-industrial and post-mining areas. Appropriate provisions were developed in the city’s planning documents that allow for the spatial development of post-mining areas according to the principles of sustainable development and can show the future functions of these areas. The study results can serve as an example for other cities struggling with the problem of developing post-industrial and post-mining areas, showing what benefits can result from the introduction of blue–green infrastructure.

An attempt is made to answer the question of which spatial planning strategies for the post-industrial and post-mining areas in highly urbanized regions best support the concept of sustainable development, with particular emphasis on blue–green infrastructure.

2. Research Review

2.1. The Concept of Blue–Green Infrastructure in Urban Development Planning

The concept of blue–green infrastructure in relation to urban development planning should include the following:

• Competition between cities for new investments is crucial from the perspective of local and regional policy;
• The redevelopment of post-industrial areas according to the concept of sustainable development;
• Blue–green infrastructure as an element of sustainable urban development.

Blue–green infrastructure is a system of solutions supporting the natural environment by improving stormwater management and urban quality of life. Such solutions include bioretention swales, ponds, rain gardens, green roofs and facades, and permeable surfaces. Implementing blue–green infrastructure in cities can mitigate the effects of climate change, such as urban heat islands, floods, and droughts. Key elements of this concept include improving stormwater retention, increasing biodiversity, and enhancing residents’ quality of life [15,17].

In 2013, the European Commission published “Green Infrastructure—Enhancing Europe’s Natural Capital”. The report states: “In Europe, we consequently continue to degrade our natural capital, jeopardizing our long-term sustainability and undermining our resilience to environmental shocks” (p. 2) [18]. The document also defines and outlines the importance of blue–green infrastructure. These solutions have been proven to generate economic, social, and environmental benefits through nature-based strategies that align with the principles of sustainable development. Nature becomes an asset to human communities and should be a key consideration in investment planning. From an economic perspective, blue–green infrastructure should be supported and strengthened to maintain biodiversity and ecological balance. Blue–green infrastructure (BGI) offers multi-faceted benefits such as managing stormwater, purifying water, mitigating heat effects, and providing a habitat for species. A broader perspective of the benefits of implementing BGI in cities is presented in

Table 1. Analysis of benefits of blue-green infrastructure elements.

Green Infrastructure Element	Applicable Areas	Ecological Benefits	Community Benefits
Urban parks and gardens	Large urban spaces—city centers, commercial outskirts	Reduction of the urban heat island effect, improved air quality, protection of plant and animal species, and soil conservation	Improved urban landscape aesthetics, creation of recreational and relaxation spaces, educational functions, and fostering human–nature connections in urban environments
Pocket parks	Small urban spaces between buildings	Improved air quality and preservation of soil and groundwater properties	Enhancement of urban aesthetics, promotion of urban greenery within local communities, and fostering social integration through collective environmental stewardship
Flower meadows	Open urban spaces such as flower beds, wastelands, and fallow land	Biodiversity conservation by providing shelter for pollinators, increased plant pollination, and rainwater retention	Enhanced urban landscape aesthetics and attractiveness
Green roofs	Public buildings, residential buildings, and transport infrastructure (e.g., bus stop shelters)	Reduction of the urban heat island effect, thermal insulation, and rainwater retention	Improved urban aesthetics and attractiveness, creation of recreational spaces, educational functions, and engagement of local communities in green roof initiatives
Water-recreational spaces	Post-extraction pits from natural resource exploitation	Increased biodiversity, water filtration and retention, local climate regulation, and ecosystem balance maintenance	Expanded tourism and recreational opportunities, flood protection, and improved urban landscape aesthetics

Source: own elaboration based on Strumiłło [19].

.

In Poland, projects are being implemented to implement the principles of blue–green infrastructure in urban areas. One example is a project in Leśna municipality (Lower Silesian Voivodeship), which includes a comprehensive system of solutions such as rain gardens, green roofs, and retention basins [20]. A flagship example of blue–green infrastructure implementation in northern Poland is Gdańsk’s Stormwater Retention System. This initiative includes rain gardens along the coastal belt to reduce surface runoff and retention reservoirs on the Strzyża River and Potok Oliwski, which store rainwater and help mitigate flood risks [21]. Another example is the revitalization of Park na Zdrowiu in Łódź, where infiltration basins have been installed to improve the city’s water balance, and retention ponds serve ecological and recreational purposes [22].

2.2. The Importance of Blue–Green Infrastructure in Revitalizing Post-Industrial (Post-Mining) Areas

Post-industrial areas (brownfields) play a significant role in the urban development of cities that historically relied on mining, metallurgy, and heavy industry [4,6,9,10]. These areas often remain undeveloped and are not covered by local spatial development plans, yet they possess high investment potential. However, investments in these areas must align with the principles of sustainable development [7]. Strategic planning should avoid short-term trends leading to increased maintenance costs for poorly designed projects.

Taking the opportunity to implement blue–green infrastructure concepts is essential to redevelopment efforts. These initiatives can positively impact the development of a green economy while enabling the preservation of green spaces in new urban projects. Moreover, maintaining regional and local identities by protecting the cultural heritage associated with mining and industrial cities is a key consideration [23,24,25].

The revitalization of post-industrial areas brings significant economic, social, and environmental benefits, which are critical to a sustainable development strategy and the implementation of blue–green infrastructure [1]. The transformation of brownfield sites contributes to improved air quality, increased ecological biodiversity, and a reduced urban heat island effect. The introduction of vegetation in previously industrially exploited areas naturally purifies the soil and water while creating new habitats for flora and fauna. Revitalization efforts also enhance the perceived attractiveness of post-industrial areas from the perspective of local communities, which is crucial for urban development and can positively influence potential investors [26]. It is beneficial to involve the local community in investment planning and the revitalization of post-industrial areas, which significantly increases social acceptance of new projects and the transformations of these areas [1,9,13,14]. According to Lamond and Everett [27], BGI cannot only be a government undertaking (national, regional, or local) because sustainability requires the local community’s involvement in new management practices in post-industrial areas. During the preparation of BGI projects, consultations with residents, investors, and experts are recommended. In characterizing the forms of public consultation, we can distinguish between obligatory and optional forms [28]. Obligatory forms are comments in paper or electronic form. Optional forms are oral comments, meetings, debates, workshops, study walks, surveys, interviews, and representative groups. The number and variety of public involvement mechanisms are growing [29]. BGI can potentially empower communities through participation in the design of new social and recreational spaces in cities [30].

2.3. Practical Recommendations for Implementing Blue–Green Infrastructure in Post-Industrial (Post-Mining) Cities

Theoretical postulates for implementing BGI cover different aspects, such as spatial planning, integration with existing infrastructure, and ecological, social, and economic benefits. In order to effectively implement BGI, urban policies should formally designate BGI as a central element of spatial planning [31]. As L. Loures [32] states, the redevelopment processes of brownfields must consider planning, real estate transactions, and land use aspects. The implementation of BGI in urban design and planning offers a range of ecosystem services, which can be divided into provisioning services (food, fresh water, and fuelwood), regulating services (climate regulation, water regulation, and carbon sequestration), cultural services (recreational, spiritual, and aesthetic), and supporting services (soil formation and nutrient cycling) [33].

Among the postulates concerning increasing the effectiveness of implementing blue–green infrastructure (BGI) in cities, we can mention the following [31]:

-Integrating BGI with spatial planning policies and making local legal regulations in this area flexible (including reducing legal barriers);

-Flexibility of administrative procedures, adapting them to the current state of knowledge and solutions related to BGI, along with strengthening interdisciplinary cooperation and raising awareness of designers and decision-makers;

-Taking into account non-economic values in the analysis of the profitability of infrastructure investments (intangible benefits, ecosystem services);

-Shaping social support for BGI projects (raising social awareness and education in this area);

-Using appropriate technological and geospatial tools to implement projects.

A blue–green infrastructure management plan should include the following: 1. an inventory of and an assessment of BGI resources, an assessment of the current policy regarding the development of BGI, and an assessment of the principles and method (including in organizational terms) of managing BGI resources and the flow of information between stakeholders; 2. a determination of the directions of action and an assessment of the principles of financing projects related to the development, modernization, revalorization, or protection of BGI resources; 3. an identification of problems/barriers resulting from the lack of and/or inadequate data, which translate into an insufficient consideration of BGI issues in the city’s development policy; 4. a determination of the necessary actions, the institutions responsible for their implementation and the sources of financing, as well as the possibilities of conducting a cost–benefit analysis and establishing a basis for monitoring and evaluating the implementation of the BGI management plan [34].

3. Materials and Methods

3.1. Research Area

Piekary Śląskie is a city with county rights in southern Poland within the Silesian Voivodeship. Covering an area of approximately 40 km² and having a population of 51,707 (Surface Area and Population by Territorial Division in 2024 [35], Local Data Bank, Central Statistical Office in Poland [36]), the city is part of the urban complex known as the Katowice conurbation (Figure 1). The Katowice conurbation developed during the 19th and 20th centuries as one of Europe’s largest mining and industrial regions. Key transformations in the Katowice agglomeration after 1989 included the growth of the service sector, socio-economic restructuring and modernization, and the closure of a significant portion of traditional industries, such as mining, metallurgy, and textiles [37].

According to the official physiographic classification, Piekary Śląskie is located within the Silesian-Kraków Upland sub-province, specifically in the Silesian Upland macroregion. The city’s southern part belongs to the Katowice Upland mesoregion, while the northern part is part of the Tarnowskie Góry Ridge mesoregion [39].

The oldest geological formations in Piekary Śląskie include Carboniferous rocks, which are widely exposed on the surface. These geological layers contain sequences of shales and sandstones interbedded with coal seams [40]. Hard coal was historically extracted in the Andaluzja, Julian, and Piekary Mining Plant coal mines [1,41,42,43]. In this region, hard coal was commonly referred to as “the black gold of Silesia”. However, due to ongoing economic changes, its significance has greatly diminished. Despite the decline in mining operations and the closure of coal mines, this resource remains an essential part of the city’s residents’ cultural identity and Piekary Śląskie itself. Outcrops of Carboniferous formations in Piekary Śląskie can be found in several locations: Florów Beds—in the area of Pope John Paul II Street, Poręba Beds—in the Wieczorek Estate, and Poręba Beds—west and south of Bytomska Street [44].

3.2. Data Collection and Processing Stages

The first stage of the research concerned the inventory of post-industrial and post-mining areas in Piekary Śląskie. The work environment was the QGIS (Quantum Geographic Information System) program, version 3.10 A Coruña. This advanced open-source GIS (Geographic Information System) software enables comprehensive visualization and the management of spatial data. Due to its multi-platform functionality and layer-based approach, it is widely applied in environmental sciences, urban planning, spatial analyses, and natural resource management. The primary data source for the inventory process consisted of archival topographic maps from 1962 to 2002. These maps were obtained from the online resources of the Chief Office of Geodesy and Cartography (GUGiK), which provides spatial data through the Web Map Service (WMS) [45]. The WMS is an international standard for distributing raster geospatial data over the Internet (Figure 2).

The topographic maps for urban areas in Poland are characterized by high precision and detail, enabling an accurate analysis on both regional and local scales—such as in the case of the mid-sized Polish city, Piekary Śląskie. These features contribute to the precise representation of terrain morphology, road and railway networks, hydrography, administrative boundaries, and the borders of the post-industrial and post-mining areas.

The GIS Support plugin in QGIS was used for the inventory process (Figure 2). This tool expands GIS functionalities for Polish users, enabling the following:

• Searches for cadastral parcels;
• The downloading of WMS and WMTS layers;
• The retrieval of archival maps from the Mapster database;
• Access to the Digital Elevation Model (API NMT GUGiK) [46,47,48].

Resources available in WMS standards were selected due to the extensive digital library of topographic maps from various years in Poland’s territory. The maps are already georeferenced and placed according to the Polish coordinate system ETRS89/Poland CS92—Authority ID EPSG:2180—the PUWG 1992, used in Polish geodesy.

At this stage, a key process was vectorization, which involved transforming raster data (topographic maps in the WMS standard) into vector data representing spatial objects using points, lines, and polygons. This study used manual digitization to achieve the most accurate result. The vectorized data were also analyzed based on the literature regarding the post-industrial and post-mining areas in Piekary Śląskie. This led to the creation of a database that served as a foundation for further research. An attribute table was created for the collected vector data. The collected vector data were cross-referenced with the Silesian database on post-mining areas. The OPI-TPP 2.0 system, an open-access spatial information platform, was utilized to analyze the post-industrial and post-mining areas in the Silesian Voivodeship [49]. This system was developed as a new e-service, offering a database that evaluates such sites’ economic, social, and environmental potential. This study facilitated a comparative spatial analysis by leveraging interactive maps, enhancing data accessibility and usability [50].

The second stage of the research involved reviewing planning documents and city reports, including the following:

• The Study of Conditions and Directions for Spatial Development of Piekary Śląskie [1],
• Local Spatial Development Plans [51],
• The 2022 Report on the State of Piekary Śląskie [52],
• The Development Strategy of the Upper Silesian-Zagłębie Metropolis for 2022–2027, with a Perspective until 2035 [53].
• The analysis of planning documents was part of the qualitative research. The records concerning the directions of urban policy in the context of implementing blue–green infrastructure in the city were checked.
• Compiling quantitative and qualitative data in the third research stage allowed for the ultimate creation of the attribute table in the QGIS program with layers of the post-industrial and post-mining areas for Piekary Śląskie. A total of eleven post-industrial and post-mining areas were inventoried. The data in the attribute table include area names, inclusion in the Local Development Plan, directions in the Study of Conditions and Directions of Spatial Development, and current land use. The preparation and description of the attributes concerning current land use were made possible by field research and a map analysis using the OSM (OpenStreetMap) service.

4. Results

4.1. Historical Outline—Industry and Mining in Piekary Śląskie

4.1.1. Ore Mining

Ore mining in Piekary Śląskie developed as early as the 16th Century, establishing numerous exploitation shafts across the city. These shafts were excavated to extract zinc, lead, and brown iron ore. The latter was mined in the area of the present-day Liberation Mound (Kopiec Wyzwolenia) near Wyzwolenia Street, as well as in the Pod Lipami housing estate to the west of Kasztanowa Street [6,40,41]. Extraction was conducted through open-pit mining for shallow deposits and underground mining for deeper ones. The larger exploitation fields were located in the Kocie Górki area, where remnants of mining activities can still be observed in numerous land depressions and water-filled trenches. Additional brown iron ore shafts were near Podmiejska Street and the Szarlejka River [54,55].

Iron ore was also extracted in the neighboring areas of Bytom, Tarnowskie Góry, and Piekary Śląskie, where it was often smelted on-site. The forges processing the extracted iron ore were typically situated near rivers. The Brzozowice Forge, which processed iron ore in Piekary Śląskie, was established in the early 18th Century and was owned by the princely Donnersmarck family. It ceased operations by the late 18th Century due to a shortage of wood for fuel. Other significant forges in the vicinity included Brynicka Forge in the village of Żyglin, Przełajka Forge in Przełajka, Niezdara Forge, Bizja Forge (north of Świerklaniec), and a forge in Tąpkowice near the Brynica River [56].

4.1.2. Andaluzja Hard Coal Mine

Between 4 June and 21 July 1903, mining fields were merged in the Brzozowice-Kamień area. This consolidation combined four mining fields: Andalusien, Rest Phoenix, Rest Oppurg, and Kronprinzess, creating a total mining area of 9.6 km². In 1908, the construction of a hard coal mine named Andaluzja commenced, initiated by the company Schlesische A.G. für Bergbau und Zinkhüttenbetrieb, which acquired the mining rights from the landowner, Guido Henckel von Donnersmarck. In the same year, work began on deepening the first shaft, now known as the Żeromski Shaft. In 1910, the construction of a second shaft, Sienkiewicz, was also initiated [1,2,57].

Coal extraction in the Andaluzja mine commenced in 1912, marking a significant milestone in the development of the mining facility. Production steadily increased over the following years, with coal output reaching 14,594 tons in 1912, 391,137 tons in 1922, and 495,505 tons in 1938 [1,6,41]. During World War II, a special committee at the Andaluzja mine took steps to prevent its destruction with occupying forces. Their efforts were successful, allowing mining operations to resume shortly after the liberation.

Following the war, from 1945 onwards, the mine faced the challenge of preparing for an intensified exploitation of coal seams. These deposits were located far from the center of the Andalusia mine in protective pillars and safety pillars. The primary extraction method in these areas was the application of hydraulics backfill, which was used to fill post-mining voids [2,9].

From 1954 to 1970, the mine was dominated by backfill exploitation. In the 1970s, however, caving exploitation was resumed. Intensive mechanization contributed to increased harrowing coal. This is evidenced by the record-high productivity achieved in 1973, with an average daily extraction rate of 3312 kg per worker. In the 1980s, annual coal output fluctuated around 4 million tons, but by the 1990s, it had declined to approximately 1.5 million tons. The closure of the Andaluzja mine was initiated in the late 1990s, culminating in 2014 with the demolition of the Reymont, Sienkiewicz, and Żeromski shaft towers [58].

4.1.3. Julian Hard Coal Mine

Following World War II, plans emerged to establish a new hard coal mine in the eastern part of the former Radzionków mine area. Initially, the project envisioned the construction of a ventilation shaft for the Radzionków mine. However, in 1948, a decision was made to develop a new mining facility. The Julian mine was officially commissioned on 4 December 1954 [59]. Coal production in selected years was as follows: in 1955—433,084 tons; in 1970—2,026,950 tons; in 1980—3,031,303 tons; and in 1998—1,686,700 tons [33].

During the 1960s and 1970s, the Julian Mine experienced a steady increase in coal output, reaching its highest daily extraction rate in 1976, with 9654 tons per worker per day. In the 1980s, production levels began to decline, followed by a reduction in workforce numbers throughout the 1990s. In 1999, part of the Julian mine and its associated mining area were merged to form the Piekary Hard Coal Mine [2,60,61].

Mining activities significantly transformed both the landscape and urban space of Piekary Śląskie. Intensive natural resource extraction led to industrial waste deposits, known as heaps. The long-standing mining tradition contributed to environmental degradation and city spatial structure alterations. Notable consequences included depressions, sinkholes, and surface fissures, primarily resulting from shallow zinc, lead, and iron ore mining. The southern and southwestern parts of the city were particularly affected by land subsidence [52,55,62]. Intensive industrial and mining activities also caused significant environmental degradation. Zinc, lead, and iron ore extraction left a lasting impact on sediment deposits and surface waters, leading to contamination and elevated concentrations of heavy metals such as zinc and lead. Additionally, the deformation of watercourse channels was observed [63].

4.1.4. Brickworks in Kozłowa Góra

Even in the 20th Century, in the northern part of the city in Kozłowa Góra, a clayey layer of weathered Carboniferous was exploited, which residents used for brick production. The remains of former brickworks serve as evidence of this activity. In 1933, the site started industrial-scale production, manufacturing approximately 22,000–23,000 bricks daily. Production was halted shortly after the outbreak of World War II but resumed in 1941 under German occupation, primarily to supply construction materials for the Julian mine shafts in Piekary Śląskie. Following the war, brickworks were nationalized. In 1952, they became part of the Bytom Building Ceramics Plant, including facilities in Miasteczko Śląskie and Miedary [64].

According to historical records, the bricks produced in Kozłowa Góra were used to construct the Wieczorek Housing Estate and contributed to the post-war reconstruction of Warsaw. Today, a small water reservoir, a remnant of the former brickworks, remains a significant feature of the landscape in this part of Piekary Śląskie, serving recreational and leisure functions.

4.2. Development of Post-Industrial and Post-Mining Areas in Piekary Śląskie

Piekary Śląskie contains extensive post-industrial and post-mining areas, including abandoned industrial and mining sites and metallurgical waste heaps [Figure 3].

Most of these areas have been designated for land reclamation and revitalization to reintegrate them into the urban fabric and assign new functions within the city’s spatial structure (

Table 2. Spatial development of post-industrial and post-mining areas in Piekary Śląskie.

No.	Area Name	Inclusion in the Local Development Plan	Directions in the Study of Conditions and Directions of Spatial Development	Current Land Use
1.	Andaluzja Hard Coal Mine	No	• Areas designated for production and service development • Infrastructure development directions: an area designated for the installation of renewable energy facilities with a capacity exceeding 500 kW, including a protective zone	• Green areas • Wasteland
2.	Andaluzja Hard Coal Mine—Dołki Shaft	Yes	• Areas designated for production and service development • Areas designated for service development (public and commercial) • Infrastructure development directions: an area designated for the installation of renewable energy facilities with a capacity exceeding 500 kW, including a protective zone	• Green areas • Wasteland • Service buildings
3.	Siemianowice Hard Coal Mine—Rozalia Shaft	Yes	• Low green areas • Single- and multi-family residential areas	• Green areas • Wasteland • Remnants of the Rozalia Shaft
4.	Orzeł Biały Mining and Metallurgical Plant	Yes	• Areas designated for production and service development	• Orzeł Biały S.A.—Waste Recycling Plant
5.	Aluminum Transmission Areas—Brzeziny Śląskie	Yes	• Areas designated for production and service development • Areas designated for the installation of renewable energy facilities with a capacity exceeding 100 kW, including a protective zone	• Wasteland • Spoil heaps • Post-mining areas • Green areas
6.	Aluminum Transmission Areas—Brzeziny Śląskie Spoil Heap	Yes	• Areas designated for production and service development • Areas designated for the installation of renewable energy facilities with a capacity exceeding 100 kW, including a protective zone	• Wasteland • Spoil heaps • Post-mining areas • Green areas
7.	Powstańców Śląskich Hard Coal Mine—Shaft VI	Yes	• Areas designated for production and service development • Low green areas • Boundaries of documented mineral deposits under mining ownership • Public-purpose investment (local): boundaries of areas of particular natural value	• Green areas • Wasteland
8.	Brick Factory near Grzybowa Street—Kozłowa Góra	Yes	• Areas designated for production and service development	• Service development areas
9.	Former Brick Factory—Now “Staw Cegielnia” (Brickworks Pond)	Yes	• Water areas	• Water area (Staw Cegielnia)—a reservoir formed by the flooding of the former brickworks
10.	Bobrek-Piekary Hard Coal Mine	Yes	• Areas designated for central urban functions as a newly developed city center • Boundaries of post-industrial areas designated for revitalization	• Post-industrial area • Wasteland designated for revitalization
11.	Food Processing Plant	Yes	• Areas designated for service development (public and commercial services)	• Service buildings (confectionery shop, travel agency) • Green areas

Source: own elaboration based on planning documents [1,51,52].

).

One example of post-industrial land reclamation in Piekary Śląskie is the redevelopment of the former brickworks site in Kozłowa Góra. Excavations from raw material extraction for brick production were transformed into a water reservoir. The reclamation of the Kozłowa Góra brickworks followed the “water direction” approach, which involves adapting post-mining excavations into water bodies [1,51,65].

With this approach, water bodies can be designated for various recreational fishing activities and as fire protection and retention reservoirs. Given the complex natural conditions, this approach is less frequently utilized in reclamation processes than afforestation or agricultural reclamation [66,67]. The Cegielnia Pond and Sachta Pond are water reservoirs formed in excavation sites in Kozłowa Góra. They serve recreational, leisure, and fishing functions [Figure 4].

Coal mining has been deeply embedded in the identity and consciousness of the residents of Piekary Śląskie. Mining facilities shaped residential settlements and concentrated the social lives of the inhabitants around them. However, with socio-economic transformations, post-mining areas have remained within the urban space [2,10,68].

The Study of Conditions and Directions of Spatial Development states that the former Andaluzja Coal Mine area has been designated for biological reclamation [1]. This area is located in the Brzozowice-Kamień district, near Partyzantów and Brzechwy Streets [Figure 4]. The land suffered severe degradation due to coal mining activities. Reclamation aims to restore biologically active areas in the place of degraded post-mining sites [69]. Currently, these areas consist of green spaces and wastelands. The designated direction for technical infrastructure development in this area includes installing renewable energy facilities with a capacity exceeding 500 kW, accompanied by protective zones. Selecting an appropriate location is crucial in the investment planning process for renewable energy sources (RESs). In Poland, spatial planning is governed by a document known as the local spatial development plan [51]. Depending on its provisions, local plans may allow various types of RES investments, restrict them to specific forms (e.g., only photovoltaic power plants), prohibit such investments, or remain silent [70].

For the former Andaluzja coal mine, the local spatial development plan precisely defines the investment opportunities for this area. In addition to biological reclamation, the municipal authorities aim to designate investment areas for renewable energy sources [Figure 5].

The Julian Coal Mine was located in the central part of Piekary Śląskie, near the border with Będzin County. The long-maintained post-mining buildings negatively affected the visual attractiveness of the city’s center. The mine ceased extraction in 2020, and in 2022, parts of its infrastructure were demolished. The municipal authorities swiftly addressed the issue of vacant industrial spaces following coal exploitation in the city’s core [1,71].

An analysis of the Study of Conditions and Directions of Spatial Development regarding the post-mining areas of the Julian coal mine indicates that this area plays a crucial role in urban planning. It has been designated for revitalization (in the study, it falls under the category of boundaries of post-industrial areas intended for revitalization). The site is intended to serve central functions, thereby it will be shaped as a new part of the city’s core [1].

Urban centers are distinct zones within any city. They concentrate on compact buildings and multifunctional structures, serving as hubs for daily life and social interactions. They undergo both modernization and aesthetic transformations. The primary objectives of a city center include representation and maintaining a strong position within a competitive urban environment [72,73]. Piekary Śląskie consists of several distinct structural units that could function autonomously, such as Kozłowa Góra, Brzozowice-Kamień, or Brzeziny Śląskie. Unlike other cities, its central area is not compact. Instead, it extends along Bytomska and Cardinal Wyszyński Streets. The core of the city center is characterized by dense development and an anthropogenic environment. Thus, the redevelopment of the Julian coal mine area is strategically important to the city [Figure 6]. The municipality aims to fully utilize this site’s potential, mainly derived from its prime location [1].

From a spatial planning perspective, this area is designated for revitalization. Considering the settlement network of Piekary Śląskie and the location of new investments, this site is key to shaping central functions. Many researchers describe post-mining and post-industrial areas in city centers as spaces that negatively impact their surroundings by disrupting spatial order [74,75,76]. This case demonstrates strategic spatial planning by local authorities, aiming to enhance and repurpose the areas degraded by coal mining. Integrating new investments within city boundaries is expected to elevate the city’s status and improve its competitiveness within the metropolitan region [1].

4.3. Possibilities of Using Blue–Green Infrastructure for Post-Industrial Areas

The post-industrial areas in Piekary Śląskie, due to their diversity and strategic location, offer extensive opportunities for implementing blue–green infrastructure (BGI). Reclamation and revitalization processes in these sites restore degraded areas to functional use and address environmental, social, and economic needs per sustainable development principles [77,78,79].

One example of effective BGI implementation is the transformation of a former brickyard site in Kozłowa Góra. The excavation pits have been converted through water-based reclamation into a water reservoir called Cegielnia Pond. Today, it serves recreational and leisure purposes while functioning as a fishing ground. Similar water bodies, such as Sachta Pond, contribute to stormwater retention, which is crucial given the increasing frequency of extreme weather events due to climate change [1,51,52,53].

The former Andaluzja and Julian coal mine sites also hold potential for BGI implementation. The Andaluzja site in the Brzozowice-Kamień district has been designated for biological reclamation. Additionally, it is planned as a site for renewable energy installations, such as photovoltaic systems. These initiatives support regional energy transition while fostering biologically active spaces that benefit local ecosystems [70,80].

The area of the former Julian coal mine, located in the central part of the city, has been included in a revitalization plan aimed at creating central urban functions. Incorporating this site into the urban fabric by constructing a new city center and transport infrastructure, including a high-speed railway station, opens up opportunities for integrating blue–green infrastructure solutions. Examples include green roofs, living walls, and public spaces that combine natural elements with urban functions [1,52].

The spoil heaps and transmission areas in the Brzeziny Śląskie district, as remnants of industrial activity, serve as exemplary locations for implementing blue–green infrastructure. The planned reclamation of these sites envisions their transformation into green recreational spaces and the establishment of renewable energy installations. Such interventions can enhance environmental quality and increase these areas’ attractiveness for residents and investors [70,80,81].

Blue–green infrastructure offers solutions to mitigate the impacts of climate change, such as floods, droughts, and the intensification of the urban heat island effect. Water management solutions can be implemented on post-industrial sites in Piekary Śląskie, including rain gardens, bioretention swales, and water retention systems. Incorporating such elements into the urban landscape will enable more effective stormwater management, enhance biodiversity, and improve the local microclimate [82,83,84].

The post-industrial areas in Piekary Śląskie are closely linked to the region’s industrial heritage. Implementing blue–green infrastructure solutions can simultaneously preserve and highlight the historical features of these sites. Examples include historic workers’ housing estates and former mining facilities, which, after revitalization, could serve educational, tourism, and recreational functions while aligning with the principles of blue–green infrastructure [1,51,77,78].

In conclusion, integrating blue–green infrastructure in the post-industrial areas of Piekary Śląskie represents an effective strategy for sustainable development. By combining environmental protection measures with social and economic needs, the city can successfully transform degraded areas into spaces that support climate change adaptation, enhance residents’ quality of life, and preserve the region’s unique industrial heritage.

5. Discussion

This article directly addresses the revitalization of post-industrial and post-mining areas, particularly emphasizing blue–green infrastructure and sustainable development. It is noted that urban investments in the context of brownfield revitalization demonstrate significant potential for the implementation of blue–green infrastructure [66,69,80,81]. As indicated by other authors, this enhances the quality of urban spaces and has crucial ecological implications, such as improving residents’ living conditions, increasing biodiversity, and introducing new ecological, social, and economic functions. This discourse aligns with current spatial planning trends [81,82,83]. Studies by other researchers highlight the importance of integrating post-industrial and post-mining areas into the urban fabric as a key component of sustainable urban development [71,75]. These considerations encompass ecological aspects and the creation of infrastructure supporting the development of renewable energy sources [85,86].

An analysis of the post-industrial and post-mining areas in Piekary Śląskie indicates their substantial potential for implementing blue–green infrastructure. The city’s strategic planning facilitates the transformation of degraded areas into spaces that align with the principles of sustainable development, while adopting new economic, social, and, most importantly, ecological functions. One example of well-planned revitalization is the redevelopment of the former brickyard site in the Kozłowa Góra district in the northern part of the city. As part of the reclamation process, an artificial water reservoir, Cegielnia, was created within former industrial excavation sites, now serving recreational functions. The development of this area adheres to the principles of blue–green infrastructure and sustainable development, providing the local community with a new recreational space while maintaining ecological balance [1,51].

We also concur with the broader discourse on managing post-industrial areas in line with sustainable development principles. This perspective presents a comprehensive approach to the revitalization process, in which post-industrial spaces are not merely seen as a challenge in spatial planning but as valuable assets whose potential can be harnessed through blue–green infrastructure solutions. The case studies from Piekary Śląskie illustrate how brownfield sites can be reintegrated into the urban fabric while adhering to sustainability principles in the economic, social, and ecological dimensions [87,88].

From the investment planning perspective, particular attention was given to the extensive post-mining area of the former Andaluzja coal mine. These brownfield sites in the Brzozowice-Kamień district retain significant elements of the region’s cultural heritage that are associated with coal mining. The proposed project envisions the ecological reclamation of these areas alongside the development of technical infrastructure for renewable energy sources, with the potential for installations exceeding 500 kW in capacity. This approach facilitates the ecological restoration of biologically degraded sites and contributes to the region’s energy transition. A similar initiative is planned for the brownfield sites in the Brzeziny Śląskie district, where the development strategy includes the construction of renewable energy installations and the reclamation of post-mining spoil heaps into green spaces, incorporating elements of blue–green infrastructure [1,51,52].

In the central part of the city lies the site of the former Julian coal mine. During the planning of new spatial transformations, this area was designated for revitalization, focusing on central urban functions and serving as an exemplary case of brownfield integration into the existing urban fabric [1,89]. The proposed transformations include constructing a new city center and a high-speed railway station connecting Katowice with the Pyrzowice Airport. The development of this new urban core presents an opportunity to integrate blue–green infrastructure concepts, including the implementation of green roofs, pocket parks, and water-based recreational spaces [80,81]. From a biodiversity perspective, including a wildflower meadow in the new city center would be a valuable investment, enhancing both ecological function and the visual appeal of the urban space. In long-term urban planning, this investment should align with sustainable development strategies to ensure that the city conforms to the principles of green city development and ecological transformation. This space is emerging as a key urban element with the potential to enhance the city’s attractiveness for residents and future investors. Consequently, this area currently represents the most significant potential for developing blue–green infrastructure within the city [80,81,82,83].

Considering the flagship investment projects aimed at brownfield reclamation, it can be concluded that their strategic objectives incorporate blue–green infrastructure elements and the principles of sustainable development. In their urban planning initiatives, municipal authorities consider the needs of the local community and investors while simultaneously promoting environmental protection measures and the preservation of cultural heritage [1,51,52].

The rich industrial heritage can be used as a tourist attraction, as widely presented in the book entitled Mining Heritage and Tourism: A Global Synthesis [90]. A new type of tourism related to industrial heritage has developed, among others, creating tourist attractions related to mines. Transforming post-mining areas into areas for other purposes is a key challenge for post-industrial and post-mining cities. Post-industrial areas can be a driving force for urban redevelopment [32].

Piekary Śląskie is an example of a city where it is possible to apply many solutions in BGI implementation. Comparing Piekary Śląskie with the implementations used in former industrial centers internationally, many challenges faced by the studied city were noticed. There is no standard recipe for revitalizing former industrial centers because each case is considered locally, as J. Sattler [91] stated when analyzing Detroit and the Ruhr area. However, the IBA Emscher Park project implemented by the government of the state of North Rhine-Westphalia can be a model of a good strategy for revitalizing post-industrial areas. Investments created as part of revitalization processes in the cities of the Ruhr area show that it is possible to successfully combine facilities and areas with entirely different functions. Examples include a mine (Zollverein mine in Essen) as a cultural center or a steelwork site (Ironworks in Diusburg) as a sports and recreation park. Some industrial plants in the Ruhr area have been transformed into modern technology centers, e.g., the Rheineelbe Science Park in Gelsenkirchen, built on the land around the Thyssen mine and foundry. The rest have been reclaimed and transformed into modern centers of culture, recreation, and tourism, which have created four routes presenting the main achievements of the IBA Emscher Park: industrial, natural, artistic, and architectural [92]. The IBA Emscher Park aimed to develop innovative strategies for abandoned industrial areas and to provide different functions (compensatory for the balance of nature, political–pedagogical functions, ecological functions, aesthetic functions, and others) in post-industrial urban landscapes [93]. The Ruhr area is an international model that serves as an example of transforming industrial landscapes into attractive park complexes and ecological recreational areas. The Ruhr area is now a “green metropolis” [94].

Based on the conducted analysis, it can be stated that revitalization investments in post-industrial and post-mining areas in medium-sized cities are oriented toward new functions and the creation of spaces according to sustainable development principles. This context supports the implementation of blue–green infrastructure, which contributes to the aesthetic enhancement of urban fabrics and improves residents’ quality of life. These efforts directly impact the long-term development of green cities and the ecological quality of the Katowice conurbation. From a regional competitiveness perspective, new urban spaces incorporating blue–green infrastructure must attract potential investors. This, in turn, will enhance the city’s appeal at both local and regional levels.

6. Conclusions

This article delineates the spatial development directions for post-industrial and post-mining areas in a medium-sized city within the core of the Katowice conurbation. A key focus was placed on the role of blue–green infrastructure in fostering sustainable urban development in a region strongly shaped by the legacy of industry and mining. The revitalization and transformation of such areas constitute crucial aspects of spatial policy, directly influencing the competitiveness of medium-sized cities within the region.

Applying blue–green infrastructure concepts in the spatial planning and redevelopment of brownfield sites mitigates adverse environmental impacts, fosters the growth of a green economy, and enhances urban resilience to climate change. Implementing this strategy in Piekary Śląskie could serve as a model for other cities in Poland and Europe by demonstrating how integrating environmental protection with urban development can yield both socio-economic and ecological benefits.

Piekary Śląskie faces direct consequences of deindustrialization, which has significantly contributed to urban degradation and the necessity of revitalizing post-industrial and post-mining sites. Brownfield areas within the city exhibit substantial potential for implementing blue–green infrastructure solutions. By incorporating the principles of blue–green infrastructure and sustainable development into investment planning, the city enhances its environmental quality, making these areas more attractive to investors and residents. Monitoring the transformation of post-industrial and post-mining areas contributes to minimizing environmental degradation while supporting the development of a green economy. Examples such as the redevelopment of the former Andaluzja and Julian coal mines and the reclamation of the Kozłowa Góra brickyard illustrate that a multifunctional approach to revitalization can facilitate the harmonious development of urban spaces.

From the perspective of the local community, preserving the cultural heritage of post-industrial areas remains paramount. This includes elements such as workers’ housing estates and the existing infrastructures of former coal mines. Such an approach fosters greater public engagement in revitalization projects, ultimately strengthening local identity. Moreover, cross-sectoral collaboration in this process should be ensured to accommodate diverse social needs while maintaining economic benefits. Integrating these elements enables the implementation of projects that hold high environmental value (through the application of blue–green infrastructure and adherence to sustainability principles), social value (through the preservation of cultural heritage), and economic value.

The development of new central urban functions—such as those planned for the former Julian coal mine site—demonstrates the considerable potential for incorporating blue–green infrastructure into emerging urban spaces. A city center structured by the green city concept will have a significantly enhanced visual appeal, benefiting residents and prospective investors. Equally important for local authorities are brownfield areas that offer opportunities to combine green infrastructure with expanding renewable energy systems. The reclamation and transformation of these sites into green spaces and their designation for renewable energy production illustrate the possibility of reconciling environmental conservation with sustainable energy generation while simultaneously repurposing degraded urban land.

The ongoing and planned brownfield revitalization projects in Piekary Śląskie provide evidence that integrating blue–green infrastructure constitutes an effective strategy for transforming degraded areas. This approach supports climate adaptation, enhances residents’ quality of life, and safeguards local natural resources.

To sum up, the authors showed a medium-sized post-industrial city’s potential in implementing blue–green infrastructure. The research proved the importance of BGI in the spatial development of post-industrial and post-mining areas. However, there is a constant need to monitor whether the transformation of post-industrial areas follows sustainable development principles.