Urban flooding has long been a critical issue, particularly in rapidly urbanizing regions of developing countries, where land use changes—especially the conversion of rice paddies into urban areas—have significantly increased flood risks. This study investigated the impact of urbanization on flood risk taking Chiang Mai, Thailand, as a case study. Based on historical flood data, the study identified and analyzed frequent flood–prone areas in Chiang Mai during the period from 1990 to 2018. By integrating the Rainfall–Runoff–Inundation (RRI) model simulation results and the remote sensing data, the research quantified dynamics in flood risk, exposure, and vulnerability across these frequent flood–prone areas. The findings demonstrated that the conversion of high–exposure paddy fields into urban areas markedly elevated area flood risks, primarily due to the reduction in water retention capacity and the inheritance of the high–exposure characteristics of paddy fields. This study highlighted the importance of integrating sustainable urban planning and land management strategies in rapidly urbanizing regions. Furthermore, this study examined the feasibility of adopting flood characteristics quantification in frequent flood–prone areas as a systematic approach to analyze the dynamic interplay between flood risks and urbanization in developing countries.

This paper interprets the results from field monitoring which was carried out during vacuum-PVD improvement in a site located near an actively moving slope. Interestingly, the monitoring results showed, among other things, mitigation in the outward lateral movements during and after the preloading process indicating relative stability in the slope and the efficiency of vacuum to mitigate lateral movements during the preloading period. Analyses were made on other field parameters such as pore pressure and settlement, as well as back-calculation of flow parameters to be considered during vacuum preloading design, such as permeability ratio (k_h/k_s) and horizontal consolidation coefficient (C_h) due to vacuum-PVD, were carried out. Post improvement, appropriate geotechnical properties were obtained from laboratory tests of clay specimens from borehole samples and undrained shear strengths were measured from unconfined compression and field vane shear test. The obtained properties indicated improvement in soft soil properties with a reduction in water content and an increase in maximum past pressure, OCR and undrained shear strengths. The prediction made for final shear strength using past literature, where applied additional incremental stress was reduced with depth, matched well with the shear strengths recorded from field testing.

The basic controls leading to slope failure driven by rainfall are still not well quantified. Therefore, the uncertainty input parameters are considered, such as soil properties and spatial variation of soil thickness, and different spatial resolutions of a grid cell. Those parameters are well-known essential factors controlling shallow landslides. In this paper, the physically-based model is used to evaluate the effect of spatial variation of soil thickness, the spatial distribution of rainfall, and spatial resolution at the Uchi and Gofukuya rivers basin, Marumori town on Typhoon Hagibis event. The model prediction accuracy is evaluated by ROC curve for different scenarios selected by soil thickness model, distribution rainfall, and spatial resolution. As a result of the model, the soil thickness is an important parameter and related to the slip failure plane. In addition, the distribution of rainfall, rainfall intensity and slope gradient affect landslides by increased driving force that causes different landslide characteristics in Uchi and Gofukuya river basins.