Saturday, May 14, 2011

Tracking progress and depth of flooding

The Army Corps of Engineers will begin gradually opening the Morganza Spillway today. Where will the water go? When will it reach Terrebonne Parish? How deep is the water ultimately expected to get?

To answer these questions, or at least share their best guesses, the Corps of Engineers released updated versions yesterday of two types of maps: a Travel Time map and an Innundation map.

The Travel Time map provides the approximate time the water will take to initially travel from the Morganza Spillway to all of the parishes in the water's path. According to a map released by the Corps, the waters from the spillway will be visible in Terrebonne Parish between 144 and 192 hours after the spillway is opened. The Times-Picayune has published a simplified version of the flooding time map (above), in which the estimated number of hours the water will take to be visible at each stage are marked in square white boxes.

A revised inundation map, Scenario 1a, was also released yesterday by the Corps. This map reflects the new plans to open the Morganza spillway no more than 25%, less than half of the original planned release. Click here to see a large, very readable version of the Scenario 1a flooding estimated by the corps. The excerpt below shows that Terrebonne Parish is still expected to see flood depths of 0-5 feet, but there are many ridges of higher land, including the highly populated areas around Houma, that may see very little to no flooding at all.

- Jen Hamilton and Ross Mays, TPL Reference Staff

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