Hydraulic Numerical Simulations of La Sabana River Floodplain, Mexico, as a Tool for a Flood Terrain Response Analysis

The floodplain of La Sabana River, Guerrero State, Mexico, was subject to disastrous floods due to the passage of extreme weather phenomena. This is a situation facing many ungauged rivers in Mexico, as well as in other developing countries, where increased urbanization and a lack of monitoring systems make many inhabited areas more vulnerable to flooding. The purpose of this work is to provide a tool for determining the flood terrain response to flooding based on a hydraulic study. This methodology combines a hydrological analysis of the river basin with the floodplain hydraulic study for the precise identification of overflow points and the resulting flood levels. Results show that, for an ungauged river, hydraulic analysis is an essential tool for determining the main potential flood points and establishing whether the river has the capacity to contain floods. Specifically, it is shown that La Sabana River is predisposed to overflow long before the river reaches its maximum flow, even in correspondence with more frequent flood scenarios. This study shows a further application that a hydraulic model can have to improve flood risk preparedness for ungauged rivers of regions where other types of monitoring tools cannot be used.

Disaster Preparedness and Resilience at Household Level in Yangon, Myanmar

Resilience has become important in disaster preparedness and response. Unfortunately, little is known about resilience at the household level. This study presents the results of a survey into individual and household level preparedness to disaster events in Yangon, Myanmar, which is prone to natural disasters such as tropical cyclones, flooding, and earthquakes. The study aimed to understand societal resilience and to provide information that could be used to develop a holistic framework. In four different Yangon townships, 440 households were interviewed. The results of the survey indicate how risk preparedness could be improved by specific measures related to the following five factors: 1) increasing the general public’s knowledge of first-aid and its role in preparedness; 2) improving mobile phone infrastructure so that it can be used for communication during disasters, along with building up a redundant communication structure; 3) better use and organisation of volunteer potential; 4) more specific involvement of religious and public buildings for disaster response; and 5) developing specific measures for improving preparedness in urban areas, where the population often has reduced capacities for coping with food supply insufficiencies due to the high and immediate availability of food, shops and goods in regular times. The findings of this survey have led to specific recommendations for Yangon. The identified measures represent a first step in developing a more general framework. Future research could investigate the transferability of these measures to other areas and thus their suitability as a basis for a framework.

Worry about Climate Change and Urban Flooding Risk Preparedness in Southern Italy: A Survey in the Simeto River Valley (Sicily, Italy)

Intensive urbanization and related increase of impervious surfaces, causes negative impacts on the hydrological cycle, amplifying the risk of urban floods. These impacts can get even worse due to potential climate change impacts. The urban areas of the Simeto River Valley (SRV), the largest river valley in Sicily (Italy), have been repeatedly hit by intense rainfall events in the last decades that lead to urban flooding, causing several damages and, in some instances, threats to population. In this paper, we present the results of a 10-question survey on climate change and risk perception in 11 municipalities of the SRV carried out within the activities of the LIFE project SimetoRES, which allowed to collect 1143 feedbacks from the residents. The survey investigated: (a) the level of worry about climate change in relation to extreme storms, (b) elements of urban flooding risk preparedness: the direct experience of the residents during heavy rain events, their trust in a civil protection regional alert system, and their knowledge of the correct behavior in case of flood, and (c) the willingness of citizens to implement sustainable drainage actions for climate change adaptation in their own municipality and real estates. The results show that more than 52% of citizens has inadequate knowledge of the correct behavior during flooding events and only 30% of them feel responsible for mitigation of flooding risk. There is a modest willingness by the population to support the construction of sustainable urban drainage infrastructures. A statistical cross-analysis of the answers to the different questions, based on contingency matrices and conditional frequencies, has shown that a greater worry about climate change has no significant impact either on the behavior of people in dangerous situations occurring during flooding events or on the willingness to support financially sustainable solutions. These results suggest that to build a higher worry about climate change and related urban flooding risk is not sufficient to have better preparedness, and that more direct educative actions are necessary in the area.

Volcanic risk communication challenges in the global south: the case of Goma, Eastern Democratic Republic of Congo

<p>The city of Goma is located in the eastern region of the Democratic Republic of Congo. With around one million inhabitants, it is built on lava flows, 15 km south of the active Nyiragongo volcano. Historically, the town was affected twice by eruptions, in 1977 and 2002 and severe destructions were reported. At that time, no volcanic risk preparedness and management tools had been implemented, and communication during and after the eruption was not consistent enough to avoid panic and human casualties. Without an appropriate and accurate risk communication, people may adopt a behavior which can put them at risk, by increasing their vulnerability. Nineteen years after the last disaster, risk management still have to develop an effective risk preparedness strategy and integrate risk awareness raising tools. The aim of this ongoing doctoral research is the assessment of risk culture, building upon a risk perception assessment and identification of risk reduction measures to be enhanced.</p><p>A survey of 2224 adults among the general population of Goma was conducted in eight representative neighborhoods in order to assess the risk perception, the experience of the risk communication as well as the risk preparedness of inhabitants. We here present a first analysis of the results regarding the risk communication challenges. Goma is a dynamic town with a young population (80% are under 45 years old), living in relatively poor and large family (51% of households have 4-7 members and 31% 8-11 members; 57% of household have an income between 0-250$), with rather low education (47% is secondary level and 34% graduated). Language is one of the volcanic risk communication challenges in Goma: apart from French as the official language, Swahili as local, and English imposed by the large humanitarian sector, there are many dialects. Moreover, most communication tools are informal (social networks, friends and relatives…) and inhabitants mostly look for information on religion (22%), health (15%) and politics (12%), but not so much about risk reduction. Local radio (24%), television (14,5%) and social networks (13%) are the most preferred information channels. The city of Goma is also very dynamic: with a high migration rate, the population is growing and renewing itself regularly, to the point that risk communication must take into account the newcomers in order to be efficient. Additionally, our survey shows that experience of disasters and trust in decision-makers also provide a basis for effective risk communication.</p><p>By presenting, as examples, the communication chain during the 2002 Nyiragongo eruption, as well as a more recent example of miscommunication due to the publication, in the general public press, of a scientific article with significant uncertainties in eruption forecast modelling (leading to misinterpretation by non-expert readers), we will demonstrate that the cascading reactions may have consequences putting risk decision-makers and scientists in a difficult position, by provoking a feeling of mistrust and doubt among the population. Based on the Goma case study, we will show that risk communication in the global south is a major risk management challenge with complex issues.</p>