Based on the data of meteorological, soil, and land use/land cover (LULC), the InVEST model was used to evaluate the water yield service in the middle and upper Ganjiang River region, which is an important ecological function area in the hilly region of South China. This study discusses the value of parameter Z, the impact of climate and LULC change on water yield service, and complements related studies in the monsoon hilly watershed in South China with obvious precipitation change, which is helpful to understand the ecosystem water service functions in this region. The results show that the water yield was closest to the statistical data of total water resources when the parameter Z value of 1.555. The overall distribution of water yield in the MU-GJR was high in the northeast (middle reaches) and low in the southwest (upper reaches), with minimum of 111.8–315.2 mm/a and maximum of 1679.1–2128.4 mm/a from 1980 to 2018. The northeast was a high importance region where high water yield values were clustered, and the southwest was a low importance region where low water yield values were clustered. Water yield was highest in living space and lowest in ecological space. The relationship between land development and water yield service should be coordinated. Climate change had a more significant impact on water yield service than land use change. The results of this study are consistent with the actual situation and help to investigate and identify important areas of water resources in the monsoonal humid zone.

Climate warming increases the intensity of extreme precipitation. Studying extreme precipitation patterns and changes is vital to reducing risk. This paper investigates thresholds, changes and timescales for extreme precipitation using sub-daily records from meteorological stations in the Ganjiang River basin. We use the gamma distribution and select the L-moment method to estimate the parameters α and β. Results show that (1) continuous precipitation events of 36 h contributed the most precipitation to the total but with lower frequency, which would be key events for flood monitoring; (2) the intensity and the occasional probability of extreme precipitation will increase in spring in the future in stations like Yifeng, Zhangshu and Ningdu, which will in turn increase the risk of storm floods; and (3) spatial distribution of extreme precipitation risk shows that the risk increases as elevation increases in the northern lowland and the Jitai Basin in the midstream region, while the risk in the southern mountainous region decreases as elevation increases. These findings will facilitate emergency preparedness, including risk management and disaster assistance, in the study areas.

This paper uses a comprehensive risk assessment method to investigate the population risk of debris flows in Southwest China. The methodology integrates models from hazard, vulnerability literature and some empirical equations. The main steps include debris-flow disaster-hazard zoning, estimation of the frequency of the disaster, factor identification of population vulnerability, and calculation of the fragility rate. The results demonstrate that the most hazardous regions in Southwest China are primarily observed in the mountains around the Sichuan Basin, the border area between Sichuan and Yunnan Provinces, the eastern and southern regions of Yunnan Province, and the eastern area of Guizhou Province. The extremely high vulnerability zones are characterized by a fragility rate of 3.89 persons per 10,000 people. The comprehensive risk gradually increases from the southeast of the study area to the central region, reaching its highest value (more than 100 persons/year) on the Jiangyou–Zhaotong–Baoshan Line and decreasing thereafter to its lowest in the northwestern region. Extremely large-scale disasters are the major factor of casualties. Appropriate risk management and mitigation solutions should be comprehensively determined based on the combination of debris-hazard levels and fragility rates in the hazardous regions.

The pattern of urban land use and the level of urbanization in China’s pre-modernization period are of great significance for land use and land cover change (LUCC) research. The purpose of this study is to construct a 1910s spatial dataset of provincial land urbanization in pre-modern China. Using historical topographic maps, this study quantitatively reconstructs the built-up area of various cities in Zhejiang Province in the 1910s. The research indicates that: (1) During the early period of the Republic of China, there were a total of 252 cities and towns in Zhejiang Province, including 75 cities at or above the county level, 21 acropolis, and 156 towns. The total built-up area was 140.590 km². (2) The county-level urbanization level had significant agglomeration characteristics. The overall urbanization rate of land was 0.135%. (3) Hot spots analysis showed that the Hang-Jia-Hu-Shao plain is hot spot. (4) The correlation coefficient between the city wall perimeter data recorded in the local chronicles and the measured city wall perimeter was 0.908. The research showed that the military topographic maps possessed a good application prospect for the reconstruction of urbanization levels. The research results provide direct evidence for urbanization and urban land use in China’s pre-modernization period.