Airborne laser scanning technology has become widely used and has made it possible to measure the height of a wide range of ground surfaces. In this study, we conducted a basic analysis of the relationship between snow depth and vegetation/topographic features using airborne laser scanning in the northernmost island of Japan, Hokkaido. The vegetation was differentiated between forest areas and non-forest areas, and topographic features such as elevation, overground-openness, slope angle, and slope aspect were selected for analysis. As a result, trends in spatial variability of snow depth differed significantly between forest and non-forest areas, clearly confirming the influence of vegetation. Spatial variability was relatively smaller inside the forest than outside the forest. In terms of topographic features, a clear relationship with overground-openness and slope aspect (non-forest only) was found. We also confirmed that our findings are generally consistent in quantitative terms with those of previous studies, showing that the spatial heterogeneity of snow depth is smaller in forest areas and greater in non-forest areas.

The primary cause of conflicts over water allocation is growing demand and limited supply, which has become an increasingly serious issue in many watersheds. To alleviate water disputes, effective management strategies can be employed, particularly in the context of intensifying agricultural production and unpredictable changes in weather. In this study, two models, SWAT and WEAP, and the modified surface water supply index (MSWSI) were utilized to evaluate water allocation in the Srepok River Watershed (SRW), considering the prioritization of demand and various irrigation methods, during both wet and dry years. The crop irrigation was chosen to be the main focus in relation to the unmet water demand (UWD). The results indicated that coffee was the primary cause of UWD in the middle of the watershed during the second half of the dry season, and annual crops (AC) were the secondary cause. This research further elucidated that while prioritizing demand had an insignificant impact, transitioning from hose irrigation to sprinkler irrigation could be remarkably effective in mitigating the issues of UWD in coffee crops during both wet and dry years.

Climate change will contribute to sea level rise (SLR), impacting coastal land use, groundwater salinity, and coastal flooding. Previous studies have analyzed the direct impact of SLR on flooding by considering coastal subsidence and the enhancement of high tide events; however, it also impacts river hydrodynamics, further worsening fluvial flooding. Here, we analyzed how SLR could enhance fluvial flooding via backwater effects and impact coastal megacities under various climate and SLR scenarios using a global hydrodynamic model. We found that the future mean inundation area for these cities is projected to increase by up to 11.2 ± 9.0% under the warmest scenario. Similarly, the projected increase in mean flood exposure is by up to 11.1 ± 9.1% at the end of the century. Cities with high increases in flood exposure are located less than 100 km from the coast, while some cities located far inland could be impacted. Climate tipping scenarios show an even greater impact. More than three-fourths of examined cities were affected due to the backwater effect of SLR in the warmest scenario, with a minimum of 141% larger inundated area compared to simple coastal subsidence, suggesting consideration of SLR’s effect on fluvial flooding is indispensable for future flood risk assessment.