Disaster Management and Extreme Event Response Workshop EXERCISE 4: Analysis Integration: Hydrometeorological Disasters 1 – EXERCISE 4 – Integrating Analyses: Hydrometeorological Disasters Using hydrological and surface analyses of the DEMs, we eventually derive layers of areas with increased flood hazard and vulnerability related to soil loss. This basic understanding of the biophysical environment allows for a better understanding, not only of the current situation, but also of possible impacts under environmental change scenarios. In this exercise we will simulate a heavy rainfall event in the Republic of Panama. Required inputs: a) Weekly average of accumulated precipitation for the month of November b) Weekly accumulated precipitation during the week of November 25, 2008. c) Watersheds d) Rivers e) Flood susceptibility f) Soil loss vulnerability g) Municipal limits h) Road network i) Cities 1) Create a new project in ArcMap. Save as: C:\Taller_SERVIR\5_Desastre\Prec_pn.mxd 2) From the directory: C:\Taller_SERVIR\5_Desastre\ add the administrative boundaries and the two precipitation layers to the Project, and give them the same symbology: o Administrative boundaries: mes_admin_divisions_ccad_20080907.shp o Historic mean precipitation: prec_semana_promedio_nov_worldclim.img o Forecasted precipitation: prec_semana_20061120_gfs.img Precipitation: A normal week in November, according to Worldclim. o What is the spatial resolution of this information?
Using hydrological and surface analyses of the DEMs, we eventually derive layers of areas with increased flood hazard and vulnerability related to soil loss. This basic understanding of the biophysical environment allows for a better understanding, not only of the current situation, but also of possible impacts under environmental change scenarios. In this exercise we will simulate a heavy rainfall event in the Republic of Panama.
Required inputs: a) Weekly average of accumulated precipitation for the month of November b) Weekly accumulated precipitation during the week of November 25, 2008. c) Watersheds d) Rivers e) Flood susceptibility f) Soil loss vulnerability g) Municipal limits h) Road network i) Cities
1) Create a new project in ArcMap. Save as: C:\Taller_SERVIR\5_Desastre\Prec_pn.mxd
2) From the directory: C:\Taller_SERVIR\5_Desastre\ add the administrative boundaries and the two precipitation layers to the Project, and give them the same symbology: o Administrative boundaries: mes_admin_divisions_ccad_20080907.shp o Historic mean precipitation: prec_semana_promedio_nov_worldclim.img o Forecasted precipitation: prec_semana_20061120_gfs.img
Precipitation: A normal week in November, according to Worldclim.
o What is the spatial resolution of this information?
Predicted precipitation for the week of November 20, 2006, according to GFS
• What is the spatial resolution of this information?
3) The critical areas are probably already evident, but we want to know the anomaly between the
prediction and the baseline. Use Raster Calculator to see, calculate, and assign a color gradient to show the differences:
This is the result of the difference between the prediction and the baseline, but what spatial resolution does it have? Returning to Menu Options in Spatial Analyst, one may select the spatial resolution for the outputs of our calculations. In this case, the output will have the same resolution as the Worldclim layer or Minimum of Inputs. Though in real life it would not be correct to decrease the resolution of an input, we use this option for the moment to build a local prediction.
4) Add the hydrological layers: watersheds and regional rivers: o C:\Taller_SERVIR\5_Desastre\mes_watersheds_ccad.shp o C:\Taller_SERVIR\5_Desastre\rios_nacional_ccad.shp
5) Select the watersheds that are forecasted to receive much more water than normal, and export them as a new layer by right clicking the layer name, and selecting Data/Export.
• Focus on these watersheds of interest for the analysis of flood and mudslide prone areas. The
watersheds that flow into the Arco Seco are also selected because of the high accumulation in their high lands. Since there is a great distance between these high lands and the coast, the Caribbean watersheds probably call our attention more so.
6) Select by Location the rivers inside of these watersheds. Extract as a new layer and zoom in.
7) Save your work.
8) Add the flood susceptibility layer (vector) to the project. Look in: C:\Taller_SERVIR\4_Inund_Eros\
9) Again, use Select by Location to select areas susceptible to inland and coastal flood by their
proximity to rivers of interest. In other words, the rivers inside the watersheds of interest. Explore the selected areas.
• In which province or provinces and districts can the potentially affected area be found?
10) Add the cities and road network. Which populated place(s) may potentially be in danger? ______________________________________________
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11) The following graphic includes the road network. Note which roads cross rivers and their proximity
to areas susceptible to floods.
Floods aside, landslides must be prepared for as well. Landslides can be provoked by certain conditions related to slope, soil type, precipitation (and soil humidity), land cover and land use. Can areas with a high landslide potential be identified using the information currently available? What is missing? ______________________________________________________________________________________
