Probable Maximum Precipitation in the U.S. Pacific Northwest in a Changing Climate

Abstract

The safety of large and aging water infrastructures is gaining attention in water management given the accelerated rate of change in landscape, climate, and society. In current engineering practice, such safety is ensured by the design of infrastructure for the Probable Maximum Precipitation (PMP). Recently, several numerical modeling approaches have been proposed to modernize the conventional and ad hoc PMP estimation approach. However, the underlying physics have not been fully investigated and thus differing PMP estimates are sometimes obtained without physics‐based interpretations. In this study, we present a hybrid approach that takes advantage of both traditional engineering practice and modern climate science to estimate PMP for current and future climate conditions. The traditional PMP approach is modified and applied to five statistically downscaled CMIP5 model outputs, producing an ensemble of PMP estimates in the Pacific Northwest (PNW) during the historical (1970–2016) and future (2050–2099) time periods. The hybrid approach produced consistent historical PMP estimates as the traditional estimates. PMP in the PNW will increase by 50% ± 30% of the current design PMP by 2099 under the RCP8.5 scenario. Most of the increase is caused by warming, which mainly affects moisture availability through increased sea surface temperature, with minor contributions from changes in storm efficiency in the future. Moist track change tends to reduce the future PMP. Compared with extreme precipitation, PMP exhibits higher internal variability. Thus, long‐time records of high‐quality data in both precipitation and related meteorological fields (temperature, wind fields) are required to reduce uncertainties in the ensemble PMP estimates.

Swiss Rainfall Mass Curves and their Influence on Extreme Flood Simulation

“…12 As Fig. 11 bur for the reservoir level evolution future climates in Europe (Rajczak and Schär 2017) and of PMP estimation under evolving climates (Chen et al 2017) also opens new perspectives for the analysis of RMCs under future climates.…”

“…For flood estimation, design rainfall volumes were obtained from so-called Probable Maximum Precipitation (PMP) maps (eg. Chen et al 2017) for Switzerland (Hertig et al 2005;Hertig and Fallot 2009) for durations of 4 h, 8 h, 12 h, 24 h and 35 h. These maps are valid only for spring to autumn (high air temperatures are necessary to sustain a PMP event) (Hertig and Fallot 2009). Following World Meteorological Organisation 2009, it can be assumed that such PMP maps represent the spatial distribution of a stationary event, which allows a separate analysis of the spatial and temporal variability of the event.…”

Climate‐Induced Changes in the Risk of Hydrological Failure of Major Dams in California

“…This study aims to examine possible changes in flood hazard under the projected climate change using 100-year flood concept for major dams over California. The hydrological driver of dam failure, in conjunction with the structural and mechanical failures, is attracting more attention as incidents such as Oroville Dam spillway failure impose large economic and social burden (e.g., Chen et al, 2017;Evans et al, 2000;Lane, 2008). Understanding the impacts of future hydrometeorological changes on the dams, hence, is one of the challenges yet to be addressed.…”

“…Understanding the impacts of future hydrometeorological changes on the dams, hence, is one of the challenges yet to be addressed. The hydrological driver of dam failure, in conjunction with the structural and mechanical failures, is attracting more attention as incidents such as Oroville Dam spillway failure impose large economic and social burden (e.g., Chen et al, 2017;Evans et al, 2000;Lane, 2008). The failure of a dam infrastructure can be attributed to a combination of factors (e.g., the age of dam, poor maintenance, flooding, land use land cover change, mechanical malfunctions; Evans et al, 2000).…”

An improved moisture and wind maximization method for probable maximum precipitation estimation and its application to a small catchment in China

“…Changes in weather conditions have led to extreme rainfall events that are occurring more frequently (Volosciuk et al, 2016;Chen et al, 2017b). The safety of major hydraulic projects is therefore becoming an important issue for both the security of people living in the surrounding areas and the stability of society (Wickramasuriya and Fernando, 2012), and the study of an appropriate design flood is urgent and significant.…”