*4.2. Simulations under Current and Future Rainfall Conditions*

Table 5 presents the hydrodynamic modelling process results for various return periods, which includes the Line 3 infrastructure points number where water accesses are identified, the maximum water depth in the 2D element surrounding water access points, and the maximum water depth projected in Metro stations' tunnels, for scenarios with climate change influence or without it. In the same way, it details the variation among every return period and the scenarios involving climate change impact, identifying such impact directly. Three things are evident from the changes among the results with the climate change influence and those not considering such influence. Firstly, rainfall intensities and water flow increment due to the climate change impact will impact Metro infrastructure, suggesting that the Metro system should develop adaptation measures against climate change effects. Secondly, the magnitude of the maximum water depth estimation varies between the differing return periods, with the climate change projections yielding a more significant water depth than estimated via non-influenced projections. Finally, the maximum water depth in Metro station tunnels increases between the different approaches; this is particularly evident when comparing T20 and T20 CC, which show a 54% increase estimation for the projected water depths.


**Table 5.** Outcome summary for hydrodynamic simulations performed under current and future rainfall conditions.

The results suggest that the magnitude of change is dependent upon the rainfall intensity for every outcome category. For example, the water depth changes appear most substantial for the T20 CC generated scenario, with the water depth estimates being shifted further than with the other approaches, without the climate change influence. However, the varying water depth associated with each return period is also highlighted, with the results differing between each return period.
