Wednesday, May 11, 2011

Finding Your Flood Risk: How High is Your Property?

As the Mississippi River continues to rise, the Corps of Engineers is predicting that much of Terrebonne Parish could be flooded. The flooding will be worse if the Morganza Spillway is opened, but there is likely to be flooding even if it stays closed. Officials are urging everyone to prepare for rising waters. One of the most important things to find out is the elevation of your home, apartment, or business. Flood waters are predicted to reach up to five feet above sea level across the parish. Anyone who lives or owns property below five feet is being encouraged to prepare for rising water.

How do you find your elevation? The easiest way to do so is to go to the Wind Speed and Elevation Map webpage maintained by the LSU AgCenter. When you click on this page, you will see a map of Louisiana, showing different wind speed predictions for hurricanes. Since wind speed not applicable in this situation, you can click the Basic Wind Speed button on the left side of the page to "Off". The map will now show a basic, zoomable road map of the state. Buttons above the map let you switch to a satellite, or "aerial" view, or a hybrid road/aerial view.

While you can simply click on the approximate location of your property, a more accurate method is to enter your address into the search box at the top of your page. Enter the street, city, state, and zip code; each separated by a comma. If the page recognizes your address, the elevation at that point will appear on the left side of the page. The lower the elevation of your property, the more critical it is to prepare for flooding.

You may also encounter other flood maps online. FEMA produces detailed flood maps used to map flood risks for particular locations. The older style of flood maps, called a Flood Insurance Rate Map, or FIRM, were originally print maps, although they can often be found online as zoomable, scanned images. The newer style of FEMA flood map is called a Digital Flood Insurance Rate Map, or DFIRM. FIRM's and DFIRM's are excellent for finding detailed flood risk information, but understanding them requires a good deal of background information. The LSU AgCenter has an excellent interactive flood mapping website, but people using it should be sure they understand how to read FIRM and DFIRM maps. The site links to important special instructions for using these maps when flood waters are rising. Also, this site seems to work in Internet Explorer, but not Firefox. LSU AgCenter's blog also has instructions for using both of its mapping services.

If you have any difficulty finding the elevation for your property, call or visit our reference desk at the Main Library. Our friendly reference staff can be reached at (985) 876-5861, option 2.

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