Hydrological Modelling as a Support for Infrastructure Design and Maintenance

Abstract

One of the many concerns related to climate change is its impact on infrastructure, for example in the case of structures such as bridges or culverts which are more frequently exposed to conditions like significant differences in water table levels or floods. Varying weather conditions can also cause deterioration of properties of the materials which they are made of, which coupled with higher loads (water, wind or temperature variation, depending on the structure) decreases their durability and hinders their operation. Existing infrastructure facilities were designed with the use of historical data, and those design assumptions can be out of date at the moment, moreover their validity decreases with further climate changes. In order to support the design of new infrastructure facilities and the maintenance of already existing ones, climate change should be taken into account. One of the means that can be used to assess the impact of climate change on bridges and other river infrastructure is hydrological modelling. In this paper, the authors present a hydrological model of the flow in the Ślęza River, a 78.6 km long, left- bank tributary of the Odra River, as well as in its tributaries, with a particular focus on the points where bridges are located. The model was performed with QSWAT software, taking into account two scenarios of climate change: SSP2-4.5 and SSP5-8.5 (obtained with the use of NorESM2-LM model) and calibrated with the use of historical meteorological data. The results of the model include daily flows for years 2023-2050, which allows to compare characteristic (statistical) flows and observe trends; also a change in the dynamics of the river caused by thaws can also be observed. A greater number of extreme events can be seen in the results for the SSP2-4.5 scenario, the values of flood flows are also higher for this scenario, whereas the average flows are higher for the SSP5-8.5 scenario, which is due to higher rainfall in this scenario – although the threat of short-term extreme events is lower, but nevertheless, due to increased flows, scouring development can occur in this scenario, which when left uncontrolled can pose great risks to bridges. The obtained results would be helpful for engineers who plan the maintenance of infrastructure facilities, as this analysis would provide additional data in order to choose optimal solutions for the costs of exploitation and for the environment.