Slope stabilisation and modernisation of road infrastructure at Gródek nad Dunajcem, Poland

The strategic location of provincial road No. 975 in Gródek nad Dunajcem, in the foothills directly on the shore of Lake Rożnowskie, determines its key importance for the region. The town is an important tourist destination and the road itself is a critical transport corridor, ensuring transport cohesion and connecting local economic activity zones with the national road network and the A4 motorway. The main challenge to be addressed by the project was the progressive geological destabilisation of the slopes on this key section. This area, located on unstable ground, is inherently prone to mass movements, and climate change exacerbates this problem, making it critical for public safety and transport continuity.  

Main risks include: 

• Extreme precipitation as a trigger: in 2010, as a result of the overlapping of violent storm rains with previous prolonged rains, there was a series of intense landslides in southern Poland, which destroyed or damaged nearly 1,600 residential and farm buildings and many roads. The first serious damage to provincial road No. 975 in Gródek nad Dunajcem occurred in the spring, destroying a half of the carriageway. Major gravitational movements in May, June and August led to further damage. According to the climate projections for Małopolska (Analysis of the current state of climate change in Małopolska), the frequency and intensity of such phenomena (especially torrential rainfall) will increase, which directly increases the risk. 
• Threat to critical infrastructure: rock-debris landslides in the area of Gródek nad Dunajcem descend to the shores of Lake Rożnowskie. The lack of slope protection (non-investment option) risked causing further damage and disruption to provincial road No 975, preventing access to the junctions and the A4 motorway. 
• Economic and social challenges: the road disruption would pose a real threat to the local economy (restriction of tourism and limited access to economic activity zones) and social safety (impeded access for emergency services and medical care). Landslides also threatened road users and potentially nearby buildings. 

The project was framed under Priority Axis 5 Environmental Protection and Measure 5.1 Adaptation to Climate Change of the Regional Operational Programme of the Małopolska Region 2014-2020 financed by the European Regional Development Fund (ERDF). The direct objective of the project, in line with objective of the Priority Axis 5, is strengthening the environmental safety of the region. This direction consists in striving to improve the state of the environment in order to preserve ecosystem services and promote sustainable development, while rationally using natural resources and minimizing adverse environmental impacts. The implementation of the project has a positive impact on the economic development and safety of residents and does not come at the expense of environmental degradation. The project is also in line with the provisions of the Development Strategy of the Małopolska Region for 2011-2020 (Area 6. Ecological, health and social safety). This strategy indicated the direction of the development policy aimed at improving the state of the environment and supporting the sustainable development of the region (Direction 6.1: ‘Improvement of ecological safety and utilization of ecology for the development of Małopolska’). The project specifically addresses Action 6.1.5 of this strategy: ‘Counteracting the occurrence of negative atmospheric and geodynamic phenomena as well as industrial accidents, and minimizing their consequences’, which explicitly indicated the need to identify landslides and areas at risk of mass movements and to ‘proper preservation and management of landslide areas and areas with landslide predispositions’. 

The main objective of the adaptation measure was to make key transport infrastructure more resilient to the impacts of climate change.  

Specific objectives: 

• Environmental objective: permanent protection and stabilisation of landslides on the key section of provincial road No. 975 to prevent further erosion, uncontrolled run-off of earth masses and environmental impacts on Lake Rożnowskie. 
• Social and economic objective: restoring full safety and continuity of communication on the provincial road. This objective directly contributes to minimising the risk to the life and health of road users and supports the territorial and economic cohesion of the region by providing reliable access to tourist resorts located around Lake Rożnowskie and local production zones of the municipality of Gródek nad Dunajcem, as well as connections to the A4 motorway. 

A comprehensive engineering and geotechnical intervention was implemented to ensure the permanent protection of slopes against displacement.

The following adaptation measures were implemented:

• Geotechnical stabilization: advanced techniques were applied by constructing a reinforced concrete grillage foundation placed on bored piles in order to permanently stabilise the earth masses. These actions were designed to take over the loads, preventing further gravitational movements caused by water seepage. The analysis of alternatives considered various methods of securing landslides, including nature-based solutions. However, due to the rock-debris nature and scale of the threat, it was concluded that nature-based methods alone would be insufficient. In the face of a critical threat to strategic road infrastructure, the only solution that could guarantee lasting safety and take over massive geological loads was an advanced engineering solution. The chosen option was therefore optimal and economically rational, as it prevented much higher costs related to the disaster and the disruption of the transport route.
• Reconstruction and modernisation: the road structure in the endangered sections was rebuilt and reinforced. In addition to securing the landslide, the scope of works carried out under the Project also included additional elements, such as the demolition of the old bridge replaced by a new one over the Szczecinówka stream. It was necessary for the proper functioning of the implemented project, as there was no other possibility to adapt the level of the newly designed road section (including securing the landslide) to the existing bridge structure.

Geotechnical solutions were designed to withstand the worst hydrological scenarios (increase in rainfall intensity) without losing functionality. It is a long-life passive infrastructure, requiring no continuous adjustment in response to climate change, but providing constant protection. Geotechnical stabilization of the slope is an inherently durable and rigid solution, adapted to the possible deterioration of climatic conditions. It also provides a safe foundation for possible future road infrastructure upgrades.

The most important result of the action is the permanent restoration of the full trafficability of provincial road No. 975 and maintaining the stability of slopes during the following seasons of heavy rainfall. Thanks to the investment, the main problem has been solved. A standard long-term maintenance of road infrastructure (drainage, road surface) is required. After the completion of the security and construction works, the landslide monitoring was also commissioned to a specialized geological company. The selection of the measurement method and duration has been agreed with the Polish Geological Institute – National Research Institute.

The project required the involvement of the public and private sectors. The Regional Roads Authority in Krakow led the application process for co-financing from European funds for these activities. The co-financing was granted under Measure 5.1 Adaptation to Climate Change from the Regional Operational Programme of the Malopolska Region for 2014-2020. The Board of the Małopolska Region and the Regional Roads Authority in Krakow were involved in the preparation, technical supervision and implementation of the project. The project was based on scientific data from the Polish Geological Institute – National Research Institute, the so-called landslide cards. A landslide card is an official, standardised document that records and describes in details an identified landslide, assigning it a unique number in the national SOPO database (System Osłony Przeciwosuwiskowej; Landslide Protection System). It contains key data on its location, size, type (e.g. rock-debris), causes and degree of activity, forming the basis for risk assessment and planning of security measures. The Polish Geological Institute – National Research Institute also provided expert opinion and verification of geological and engineering documentation of landslides. The private sector was involved in the execution of the works. Public consultations were also held for the residents of the region and users of provincial road No. 975; meetings were organised and information on traffic problems was provided.

The project was formally approved and financed under Measure 5.1 Adaptation to Climate Change of the Regional Operational Programme of the Małopolska Region for 2014-2020. At the same time, the project achieved many policy objectives, combining environmental protection (minimised erosion through slope stabilisation) with infrastructure development (road/bridge). 

Due to its strategic but also sensitive location, the project required numerous and complicated arrangements with many entities. It was crucial to obtain decisions on environmental conditions and water permits (due to the immediate vicinity and works on the shore of Lake Rożnowskie). Efficient coordination between the Regional Roads Authority in Krakow, the Polish Geological Institute – National Research Institute and the authorities issuing permits allowed to avoid delays in the preparatory stage and smooth implementation of the project. 

The use of scientific data from the Polish Geological Institute – National Research Institute and its involvement in reviewing the documentation ensured the highest level of expertise and reliability of the designed solutions. 

The damage to the road in 2010, documented threat of further landslides and the risk of communication exclusion strengthened public support for the project. The local community perceived the intervention as an urgent need to increase transport safety. 

A key success factor of the project was the high co-financing rate (85%) from the European Regional Development Fund (ERDF). Without this contribution, it would have been difficult to implement a costly and complex geotechnical investment, which did not generate any direct financial return. 

The main limiting factor identified for the project was the high cost of the investment, combined with the lack of a direct return. Such adaptation investments protecting infrastructure are very costly and difficult to finance only from national or regional budgets. 

A limiting factor was also carrying out construction and geotechnical works on active landslides, which increases the risks during their execution. 

The need to minimise the impact on the environment in the vicinity of Lake Rożnowskie during the implementation of the project, can also be considered a limiting factor. A rainwater sewage system was built to avoid environmental contamination. The system is equipped with sand traps and separators that purify rainwater from the road before it is released into the environment. In addition, after completion of the works, the construction sites were renaturalised by restoring the soil cover and sowing it with plant species characteristic for the region. 

The total cost of the project was PLN 19,031,872.33 (approximately EUR 4.47 million). European Union co-financing from the European Regional Development Fund (ERDF) covered 85% of eligible costs and amounted to PLN 16,026,409.28 (approximately EUR 3.77 million). Funding was retrieved from the Regional Operational Programme of Małopolska Region 2014-2020, Measure 5.1 Adaptation to Climate Change, Budget of Małopolska Region. 

Despite the need to carry out works additional to those originally planned, it was possible to maintain the implementation under the original financial plan. Ultimately, thanks to flexible management and the use of savings to cover unforeseen work, the initiative remained in line with the financial plan and did not require an increase in the originally allocated level of co-financing from the European Union. 

Maintenance costs relate mainly to the long-term maintenance of drainage and monitoring systems. These are regular expenses incurred by the Regional Roads Authority in Krakow, but they are significantly lower than the costs of a potential disaster, which is a key saving in the long term. 

The permanent securing of the road prevented the potential loss of valuable infrastructure. Moreover, the costs of crisis intervention, long-term management of detours and the costs of road restoration were avoided. 

Maintaining the full practicability of provincial road No. 975 (connecting to the national road No. 75 and the A4 motorway) strengthens the resilience of regional supply chains and enables continuous economic activity, including commuting residents to work and conducting tourism activities, which are crucial for the region. 

The investment prevents the transport exclusion of residents and businesses in the Gródek nad Dunajcem area. It provides a safe, stable and accessible road for residents of rural and sub-mountain areas, who are often highly dependent on road infrastructure in their daily lives and access to work and services (health care, education, government offices), and are also especially affected by traffic disruptions and access to public transport. Reliable and safe public transport is particularly important for vulnerable groups (senior citizens, children, people with lower incomes) and those who do not have alternative means of transport, as it ensures continuous access to essential services. 

The permanent stabilisation of landslides prevents further uncontrolled erosion and degradation of the slope. This in turn protects Lake Rożnowskie from physical pollution in the form of earth masses, preventing its silting up and water turbidity. On the other hand, the modernised road drainage system, equipped with sand traps and separators that capture and purify rainwater from the road, prevents traffic pollution (e.g. petroleum-derived, heavy metals) from flowing into Lake Rożnowskie, which additionally has a positive impact on the protection of water quality. 

The project started in August 2017 and ended in March 2022. 

The project implementation period was extended by law by 90 days in connection with the provisions of the Act of 3 April 2020 on special solutions supporting the implementation of operational programmes in connection with the COVID-19 outbreak in 2020 (Journal of Laws 2020, item 694). 

The stabilisation of landslides on provincial road No. 975 is a hard-type engineering investment aimed at long-term resilience to climate hazards (extreme rainfall). The expected lifespan of the geotechnical and structural solutions (palisades, new bridge) is at least 50 years. This is a permanent and continuous task. The durability of the infrastructure will be ensured by regular maintenance, mainly focused on maintaining drainage systems and geodetic/geotechnical monitoring after extreme phenomena, in order to quickly detect possible damage.

Rafał Darocha 
Head of the European Funds Team 
Regional Roads Authority in Krakow 
r.darocha@zdw.krakow.pl 
sekretariat@zdw.krakow.pl

Wódka, M, 2022, Conditions of landslides development during the last decade in the Rożnów Dam-Lake region (Southern Poland) based on Airborne Laser Scanning (ALS) data analysis.

Pawluszek-Filipiak, K., Borkowski A. & Motagh, M., 2021, Multi-temporal landslide investigation by spaceborne SAR inferometers: The case study of the Polish Carpthians. 

Wódka, M., 2020, Assessment of the activity of selected landslides in the area of ​​Lake Rożnowskie in the light of field studies and differential terrain model analyses (in Polish).