The focus of this study is to assess how the direct construction costs of a hypothetical contour channel designed for the closure of a mine site could vary when exposed to different climate change scenarios.
The climatic characterization of the area is based on a specific climate change study developed using CMIP6 global circulation models under four SSP scenarios. Based on the probable maximum precipitation (PMP) obtained in that study, flood discharges are estimated using indirect hydrological methods. The channel is designed using classical open-channel hydraulics, assuming fixed geometric conditions (length, side slopes, gradient, and material). Costs are calculated using the unit prices from the La Coipa Mine Closure Plan approved by the local authority.
The results show that the increasing or decreasing trends observed in the PMP between the different scenarios and the historical period are preserved in the flood discharge, the channel dimensions, and the costs. However, the magnitudes of these variations are not equivalent in absolute terms: the percentage differences are progressively attenuated along the PMP–discharge–geometry–cost chain. In the case study, the differences between each climate change scenario and the historical period are small, and the percentage variability of direct costs falls within a narrow range, between –2% and +6%.
It is concluded that hydrological variations are not translated proportionally into costs, and that the most pessimistic scenario in terms of increased radiative forcing does not necessarily lead to a larger channel. These results reinforce the importance of having local climate change studies to support the design of safe, future-appropriate, and cost-efficient hydraulic closure works.
