Uncertainties of Precipitable Water Calculations for PMP Estimates in Current and Future Climates

Abstract

Probable maximum precipitation (PMP) is the design criterion for many hydraulic and hydrologic structures. Despite its significance in water resource engineering, estimation of PMP values carries uncertainties. On the other hand, recent research suggests that PMP values are subject to change as a consequence of climate change. To study these issues, PMP estimates from three precipitable water calculation methods were first compared to evaluate sensitivity of PMP values to the selected estimation methods. All required data for PMP estimates were obtained from climate models’ outputs to ensure consistency in comparing results. Seven climate simulations of the 1961–1990 horizon were used to produce PMP values for three watersheds in the south, center, and north of the Province of Québec (Canada). To analyze the future climate influence on PMP, climate projections of the 2041–2070 horizon were used. Results show that a general increase in PMP in a future climate for the three watersheds studied is ubiquitous in all methods employed, reinforcing the conclusion that PMP will be rising in the future in these regions.