Enhanced dam safety and resilience through revised probable maximum precipitation as insights from hydroelectric scheme in Malaysia

Unforeseen shifts in climate patterns have significantly impacted the stability of hydraulic structures, emphasizing the need for precise and adaptive design criteria to ensure their resilience. The Probable Maximum Flood (PMF) is a critical parameter in the design and safety assessment of high-risk hydraulic structures, such as large dams and spillways, and is heavily influenced by the Probable Maximum Precipitation (PMP). However, traditional PMP estimation methods often overlook the impacts of future climate dynamics, leading to potential underestimations or overestimations that can compromise structural safety or economic feasibility. This study addresses this critical research gap by reassessing PMP and PMF values for the Cameron Highlands–Batang Padang Hydroelectric Scheme (CH-BPHES), which includes the Sultan Abu Bakar (SAB), Jor, Mahang, and Ulu Jelai dams, under future climate scenarios. The study develops historical PMP maps for the period 2010–2020 and integrates these findings into hydrological modeling using HEC-HMS to simulate PMF values. Novel insights reveal that, except for Jor Dam, the highest flood levels remain below designated dam crest levels. However, the simulations highlight that maximum spillway discharge capacities at SAB, Jor, and Mahang dams have exceeded their original design specifications, underscoring the need for immediate intervention. The study integrating evolving rainfall variability into PMP/PMF estimations, thereby bridging a critical gap in the design and management of hydraulic structures. To address these challenges, the study proposes a suite of mitigation measures, including the development of an Integrated Community-Based Disaster Management (ICBDM) system, enhancement of dam monitoring practices, advanced hydro-met monitoring, and flood forecasting capabilities. These findings provide actionable recommendations to strengthen the resilience and safety of the hydroelectric scheme against both existing and emerging risks, setting a precedent for similar assessments globally.