CityGML urban model generation using national public datasets for flood damage simulations: A case study in Korea

Managing information at city level has become increasingly important owing to the introduction of smart cities and the increasing severity of disasters due to climate change. A data collection framework, model construction, and information management must be established to systematically manage information at the city level. This study developed an urban model generation method using detailed attributes within the City Geography Markup Language (CityGML), a standard data schema for 3D representation of cities based on different types of publicly available information within Korea. The generated model was used to develop a method for simulating flooding status, degree of flooding, and level of building damage after heavy rainfall, in Korea. Furthermore, we developed a method to estimate the loss of human life and property damage by combining the results of the flood analysis with the city model. The proposed methodology supports the creation of standard-based models for flood analysis and exhibits strong interoperability for application to different areas of analysis.

[Assessment of schistosomiasis transmission risk after flood damage in Wuhan City]

OBJECTIVE

To assess the schistosomiasis transmission risk after flood damage in Wuhan City.

METHODS

Schistosomiasis epidemic villages in Wuhan City were selected by using probability proportional to size sampling (PPS). The field investigations of Oncomelania hupensis snails, the activity of people and cattle on marshland, water infectivity of schistosome, reservoir host infection and wild feces contamination were conducted. I-III levels of risk environments were assessed and treated with appropriate measures.

RESULTS

A total of 90 schistosomiasis epidemic villages and 170 environments were monitored. Totally 9 811 snails were dissected but no Schistosoma japonicum infected snails were found. There were significant decreases in the density of snails and the survival rate of living snails after the flood (χ² = 102.517, t = 4.724, both P < 0.01). Totally 289 pieces of wild feces were captured, and no eggs of S. japonicum were detected. A total of 11 surveillance and forecast sites were detected on water systems, and 221 sentinel mice were placed. After breeding, 219 sentinel mice survived (99.10%), and no schistosome infection was detected. In addition, 1 720 mouse traps were placed in 3 survey sites, and 66 Apodemus agrarius were captured, and no schistosome-infected ones were found. All of the environments were assessed as Grade III. Meanwhile, 5 key schistosomiasis control areas were determined, and no emergency happened after the implementation of comprehensive control interventions.

CONCLUSIONS

The risk of schistosomiasis transmission remains low in Wuhan City after the flood, but the potential epidemic risk cannot be ignored.

Effects of spatial planning on future flood risks in urban environments

Urban development may increase the risk of future floods because of local changes in hydrological conditions and an increase in flood exposure that arises from an increasing population and expanding infrastructure within flood-prone zones. Existing urban land use change models generally consider the expansion process and do not consider the densification of existing urban areas. In this paper, we simulate 24 possible urbanization scenarios in Wallonia region (Belgium) until 2100. These scenarios are generated using an agent-based model that considers urban expansion and densification as well as development restrictions in flood-prone zones. The extents of inundation and water depths for each scenario are determined by the WOLF 2D hydraulic model for steady floods corresponding to return periods of 25, 50, and 100 years. Our results show that future flood damages and their spatial distributions vary remarkably from one urbanization scenario to another. A spatial planning policy oriented towards strict development control in flood-prone zones leads to a substantial mitigation of the increased flood damage. By contrast, a spatial planning policy exclusively oriented to infill development with no development restrictions in flood-prone zones would be the most detrimental in terms of exposure to flood risk. Our study enables the identification of the most sensitive locations for flood damage related to urban development, which can help in the design of more resilient spatial planning strategies and localize zones with high levels of flood risk for each scenario.

[Impact of schistosomiasis transmission by catastrophic flood damage and emergency response in China]

Flood damage is one of the ordinary natural calamities. The areas of middle and down of the Yangtze River and its south are the endemic area of schistosomiasis. As the flood damage, it causes property loss, and harm public and people health severely even. This paper aims at the status of catastrophic flood damage again in the Yangtze River basin, analyzes the impact of schistosomiasis transmission by it, and indicates that at present, the process of schistosomiasis control in China is marching from transmission control to transmission interruption and elimination, but the frequent flooding exacerbates Oncomelania hupensis snail breeding area and schistosomiasis source spreading, which may influence, in a certain extent, the realization of the goal of schistosomiasis control in China. We should timely assess and monitor the impact and risk of schistosomiasis transmission by flood damage, and give the early warning and adopt emergency handling measures in time. This paper also proposes the disaster prevention measures according to flood damage stages (the early, middle, later, and post-flood) and the occurrence and development of damage and endemic situation, so as to control the risk and damage of the disease transmission in a high limit, to consolidate the current achievements of schistosomiasis prevention and control and guarantee the realization of the goal of schistosomiasis interruption and elimination in China on the schedule.