Layers are organized for display at one or more of three "eye altitude" map scale ranges in Google Earth: status maps at high altitudes, regional overviews of flood hazards at medium altitudes, and detailed flood hazard maps at low altitudes.
Click on the hyperlinked folder name of the application to see the altitudes at which data in the layers are displayed. You must have the Google Earth viewer software installed on your computer. Other important areas are the navigation controls for Google Earth area d and the eye altitude "Eye alt" readout area e. Figure 1. What is the NFHL? What does the "Big red X" on the map display imply?
How do I turn off the Quick Start Instructions? How do I use other information to "fly to" a location? Why is the "Eye alt" eye altitude readout area D in Figure 1 not visible? Turn on the status bar. Go to the menu bar File, Edit, View, etc.
The map display has a confusing set of overlays that I do not remember turning on. How do I limit the overlays to those that I want to see? Google Earth allows other location information e. Inspect the status of all the layers in the "Places" panel. See area C in Figure 1.
Why might the flood map and Google Earth imagery not register? Why is the KMZ responding slowly? Once the infrastructure is at full capacity, we will look into revising the KMZs to reduce the default lag time. Should the KMZs be used for making flood determinations? For official NFIP purposes base maps must have a horizontal radial accuracy Accuracy better than or equal to 38 feet This paper presents an approach to explore the im- ring damage, as this appears to be the most uncertain factor pacts of sea-level rise and socio-economic developments on in the risk assessment.
The model has been used to assess the effects of several pines , and Brisbane, Australia These participatory developed adaptation strategies to reduce flood floods vividly illustrate that coastal mega-cities have increas- risk, expressed in expected annual damage EAD. Adapta- ing vulnerability to storm-surge flooding Nicholls et al. By the middle of this century, the majority sea-level scenarios and land-use scenarios.
Such strategies until , taking into account depreciation rates socio-economic trends further amplify the possible conse- of 2. The net areas. Using a discount rate nam is a typical example of a vulnerable coastal city, which is frequently hit by floods. Lasage et al. However, while recent Different types of flood adaptation strategies are available research has focused on vulnerable coastal cities in Europe to reduce flood risk.
These consist of strategies to reduce the and the US, relatively little is known about the flood risk of probability of flooding, for example dikes and levees Merz coastal cities in Asia, including HCMC Huq et al. In a global assessment by Hanson et al. This requires input assuming different scenarios of changes in land use and cli- from different disciplines, varying from coupled hydrody- mate.
To achieve this assessment, we combined a participa- namic flood modelling e. Winsemius et al. In this assessment we only include direct impacts of der to calculate the cost and expected benefits of different floods on urban land uses.
Indirect effects, and societal and strategies over a given period of time e. Hallegate, This method is ap- There are many studies that quantify flood hazard and ex- plied to District 4 in HCMC, one of the most exposed parts of pected changes in the hazard due to sea-level rise Nicholls the city.
Section 2 describes the method and data, including and Cazenave, Other studies use flood risk assess- the case study area. Sections 3, 4, and 5 present, respectively, ment models, focusing both on the flood hazard, and on the results, discussion and conclusions.
Some of these studies use catastrophe risk models 2 Method and data to calculate risk reduction for different flood adaptation mea- Figure 1 is an overview of the methodology of this pa- sures on local to regional scales e. Veerbeek and Zevenber- per. We used a flood damage model to calculate flood risk gen, ; Bouwer et al. The damage model used syn- basin scale e. Future sce- flood adaptation measures in terms of costs and benefits e. The effectiveness risk reduction of depth—damage relations of the studied area.
We applied of HCMC to flooding by coupling data on urban development a participatory approach to develop several key parts of the with projected maps of sea-level rise scenarios. Their conclu- method, such as novel stage—damage curves and adaptation sion is that socio-economic development and urban expan- strategies, both tailored to HCMC. This conclu- 2. However, they only assessed the reduced exposure of as- Fig. Hence, existing studies have not assessed western part and the East Sea on the eastern side Vo, World Bank, The city consists of 24 curves are not available for South East Asian cities.
As the administrative districts subdivided into wards and com- EAD for flooding has not yet been established, it was also munes and five townships , which vary in size, population not possible to assess the cost-effectiveness of different flood density and land use World Bank, ; ADB, Overview of methods applied in this paper filled shapes indicate use of participatory developed information, ovals are external scenarios, diamonds are models, squared boxes are maps, polygons are adaptation strategies, and rounded squared boxes are evaluation criteria.
Ho Chi Minh City is a fast-growing city. The mean an- buildings, intermingled with small shops often as part of the nual GDP growth was 7. By , the city is expected to grow Inundation depths used in this research are modelled with the further to at least 10 million people MPI, , and eco- Mike 11 hydraulic software package. The HCMC region is an economic hub for the sediment transport in different types of water bodies DHI, whole of Vietnam and generates one-third of the national Impacts and effects of floods can be visualized using GDP Eckert et al.
The resulting flood inundation maps can be and this hazard is expected to increase in the future as a re- used as input for flood damage assessment studies. They also identify District 4 as one FIM, a and current river discharge. We focus on District 4 because 2. The district covers an Aerts, This requires two inputs: a land-use map for area of 3 km2 and is a typical example of the densely popu- determining exposed assets, and an inundation map. These lated urban centre of HCMC. The main land use is residential inputs are combined using the stage—damage curves, which www.
Map of the study area in Ho Chi Minh City. Ward et al. A dam- with a sufficient spread low and high probabilities are suf- age curve provides the expected damage for a given inun- ficient to estimate the EAD. Stage—damage functions for HCMC ble 1 , and are derived from an existing land-use map for were not available prior to this research. The survey was carried out fined on the basis of the presence of two types of residen- in 17 districts of HCMC which were exposed to flooding in tial buildings in sectors in District 4.
To assess the change in The majority of these districts are located in the older EAD due to socio-economic developments, we have used the part of the city. A few are located at newly developed residen- land-use map , developed by the government of HCMC tial areas. In analysis of the survey data, this has been taken as part of the socio-economic Master Plan DPA, The experienced flooding depth varies be- , since projections of land use in are not available.
After , land use remains the following topics: general information of households; past the same until One represents the baseline situation, and the assets; suggestions as to which actions the HCMC govern- other represents the situation in Using different combi- ment, flood control programme, and communities respec- nations of land-use and sea-level scenarios makes it possible tively should undertake to reduce flood risk; and the potential damage caused by higher inundation levels.
The households Nat. Stage—damage curves as used in this study, including the stage-damage curves for dry- and wet-proofing. Table 1. LU class Max. This recent flood en- olated the data, assuming a slope that is half of the slope abled the interviewed households to better recollect the im- between the reported damages of 60 cm and cm, in line pacts and damage.
A household selection was made, using with the flattening off found in many residential damage an inundation map of the flood of , and with additional curves see e. We distinguished two information on the specifications of each ward from the local types of houses: up to two floors e.
The questionnaire was pre-tested on floor , and houses with more than two floors, representing, households before the survey was executed. The stage—damage curve for furniture was devel- old for poor families according to the HCMC government; oped in a similar way.
Out of the house- For other land-use classes, we have estimated the maxi- hold interviews, had information on flood depth, damage mum damage values, using the ratio of maximum damage to the house, damage to the furniture, value of the property, to the residential land use to that of other land uses, as used size of the ground floor, number of floors, and expected dam- by FIM a.
The maximum damage values, expressed in age if the flood depth were to increase by 20, 40, and cm. The maximum flood ble 1. Examples of the spatial distribution of damage caused depth reported by the respondents was cm. For damage www. In this way, the government mobilizes public support, whilst maintaining 2.
An interactive approach was applied using a Touch to develop flood-adaptation strategies. The local cul- Table Arciniegas et al. For instance at the of the workshops represented the visions of the participants, first sessions of the workshop cycle, we only asked feedback which should assure acceptability. At a later stage, after trust was built, the partic- ity by S2 wet-, and S3 dry-proofing buildings; S4 ele- ipants were willing to take a wider perspective and suggest vating roads and buildings, aiming to reduce flood exposure; what potentially could be changed, also on topics that were and S5 a combination of several measures referred to as not directly the responsibilities of their organization.
Vietnamese circumstances, starting with bringing together These strategies were drafted by the experts using inputs of factual information, like maps, and policies and plans, which the stakeholders during the workshops and the results of the does not include giving opinions. Most participants were hes- household survey. The draft strategies were presented to the itant to give their opinion at the beginning, as it might be stakeholders in a subsequent workshop, and where necessary different to what their boss thought Huntjens et al.
We referred to workshops as Charettes, because this concept was not known yet in Vietnam. Hence, there were no expec- 2. As a result, the Charettes were an open style of meet- two metres above average water level, or 3.
This dike height is used by the tively participate. We also used the first workshops to train Vietnamese government FIM, a.
This ring dike pro- people in the understanding and use of scenarios. The waterways of the dis- once it has been approved. The concept that the future might trict, which are in contact with the main water bodies, can develop in different directions, which are equally likely to be closed by sluices and floodgates. We assume there will be happen, was a big challenge.
After several workshops, the no damage when flood levels are below 3. If water participants had become involved in the process and more levels are higher, the levee will be overtopped and we assume comfortable in making suggestions to adjust plans, even if the water level in the district will reach the same level as in these had already been approved. From that moment onward, the main water bodies. The first set of workshops 2. Other workshops then focused on climate and socio- Wet-proofing reduces the damage to the house and furniture, economic change, how to assess impacts of climate change, but water can still enter the house.
Measures include, for ex- the different types of adaptive measures available, and other ample, putting expensive appliances at a higher elevation in issues and characteristics of importance for the evaluation of the house, and having the power sockets higher above the an adaptation strategy by the Vietnamese government. The ground. For each workshop additional experts universi- Moel et al. However, this district is regularly flooded, ties, NGOs, etc.
It should be noted that the role and, hence the inhabitants have already taken several mea- of NGOs in Vietnam is smaller than in many other countries. On the basis of discussions with local experts during the 2. As wet-proofing involves moving as- decades, and most buildings will be replaced by new ones sets to higher floors or raising them to a certain elevation, we VCAPS, This process provides the opportunity to assume that the measure is no longer effective when the in- raise the ground level on which the buildings are built.
Re- undation depth is more than 3 m. At this point, the second cently built commercial and residential buildings are already floor will also be flooded. In order to assess the damage-reducing effect of tres, and rises to the normal damage curve in the following elevating new buildings, we included three elevation levels metre.
The NFF program is used to estimate peak discharges for unregulated streams. Values discharges derived by the program often serve as input for other applications such as hydraulic computer models that are used to technically support end-products map revisions of the NFIP. The following additional sites also are accessible to designated FEMA staff and agency representatives through this page; however, a FEMA-provided password is necessary.
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