Development of high-resolution 72 h precipitation and hillslope flood maps over a tropical transboundary region by physically based numerical atmospheric–hydrologic modeling

Abstract

Long-term, high spatial and temporal resolution atmospheric and hydrologic data are crucial for water resource management. However, reliable high-quality precipitation and hydrologic data are not available in various regions around the world. This is, in particular, the case in transboundary regions, which have no formal data sharing agreement among countries. This study introduces an approach to construct long-term high-resolution extreme 72 h precipitation and hillslope flood maps over a tropical transboundary region by the coupled physical hydroclimate WEHY-WRF model. For the case study, Da and Thao River watersheds (D-TRW), within Vietnam and China, were selected. The WEHY-WRF model was set up over the target region based on ERA-20C reanalysis data and was calibrated based on existing ground observation data. After successfully configuring, WEHY-WRF is able to produce hourly atmospheric and hydrologic conditions at fine resolution over the target watersheds during 1900–2010. From the modeled 72 h precipitation and flood events, it can be seen that the main precipitation mechanism of DRW and TRW are both the summer monsoon and tropical cyclone. In addition, it can be concluded that heavy precipitation may not be the only reason to create an extreme flood event. The effects of topography, soil, and land use/cover also need to be considered in such nonlinear atmospheric and hydrologic processes. Last but not least, the long-term high-resolution extreme 72 h precipitation and hillslope flood maps over a tropical transboundary region, D-TRW, were constructed based on 111 largest annual historical events during 1900–2010.

A numerical coupled atmospheric–hydrologic modeling system for probable maximum flood estimation with application to California's southern Sierra Nevada foothills watersheds

“…Traditionally, the PMF is the flood associated with the probable maximum precipitation (PMP), and this perception has been popular in the estimation of design floods in many early applications (Franchini et al, 1996; Jothityangkoon & Sivapalan, 2003; Svensson & Rakhecha, 1998; Viessman et al, 1977). However, the practice of designing and evaluating flood‐related infrastructure based on the corresponding PMP has become a controversial topic due to many uncertainties in PMP prediction (Chen et al, 2016; Salas et al, 2014; Trinh et al, 2020). Some uncertainty results from the lack of a standard approach in estimating the PMP.…”

Hydrologic modeling by means of a hybrid downscaling approach: an application to the Sai Gon–Dong Nai Rivers Basin

“…This method relies heavily on observations that may not be available and does not account for the ongoing change in the world's hydroclimate conditions (Milly et al 2007). Recently, there have also been attempts to simulate streamflow data by means of hydrological models with input provided from estimated atmospheric data; Kavvas et al (2013) and Trinh et al (2020) developed and applied a physically based, distributed hydroclimate model to reconstruct and project flow data using global reanalysis climate data (Chen et al 2011;Kure et al 2013;Trinh et al 2017;Gorguner et al 2019). The global reanalysis climate data are generally too coarse for direct application to regional studies, such as water allocation and flow forecasting at the watershed scale; therefore, an application of downscaling techniques is required.…”