FLOOD RISK MANAGEMENT
http://www.telegraph.co.uk/news/picturegalleries/worldnews/8245847/Australian-floods-heavy-rains-continue-to-bring-misery.html?image=12The selected photos, below, show Australian flooding. Photos are from the web-link, above.
Please see the web-link, above, for more information.
FOR OUR DIOCESE...
For our Fairbanks northern Alaska diocesan facilities in flood zones, please recall basic flood risks and mitigation techniques.
RISKS...
Our floods are likely to have more slowly rising water levels, and are less likely for flash flooding. However, expect impact loads from ice chunks that often may be vehcile-sized and sometimes may be rail-road car size.
1. For buildings in flood zones, one great damage risk comes from stored materals in the crawl space below the building. The stored materials are likely (a) to get moved around by the flood waters, (b) piled up against the building foundation, and then(c) the flood pressures may become great enough to fail the building foundation. Literally, the building moves off of and away from its foundation. With open and unobstructed crawl spaces, the flood waters raise and fall more freely - with less sideways loading on the foundation. Historically, with no materials whatever below the building, the foundation damage is much less.
2. For people, one historically great risk is from inadequate health and sanitation after the flood(e.g., clean drinking water and appropriate sewage disposal). Clean fresh water is arguably the most important thing to protect.
MITIGATIONS...
1. Keep stored materials out from under buildings in our flood zones. Do NOT install skirting around crawl spaces for buildings in flood zones.
Figure 1, below, shows both what TO do and what NOT to do. Figures 2-4 show additional views of Austrailan flooding. Figure 4 shows flooding characteristics similar to what could occur in our diocese.
Figure 1. A Queensland resident watches the flood waters from his porch.
Note: for Fairbanks Diocese, DO keep the foundation system well open and uncluttered (like the left porch side of this home). Do NOT skirt-in area below the residence (right side of this photo). Do NOT store materials below buildings in a flood zone.
2. For health and sanitation, keep potable water as part of your emergency supplies - at least one gallon per person per day. Estimate 3 to 5 days minimum before relief efforts may get new fresh water to you. Renew your fresh water 'cache' at least annually.
