Jun 11, 2014 12:16 PM by Dave Baker
There were a number of complaints yesterday about the flooding that took place on major roadways in Lafayette and Acadiana. It's not a new thing here, and it's not something that's going to go away. But before the blame game gets started, let's go over a few numbers.
The last two big rains have been fierce and record breaking. These weren't your everyday rains. Two weeks ago "officially" at the Lafayette Regional Airport we received 6.87 inches of rain. That was the third highest, one day May rainfall total in history. Yesterday's rainfall total was 3.69 inches. Both of these flood events had the bulk of the rain fall in less than six hours. Tuesday's rain came in just three.
I know there were other measurements and backyard rain gauges that had more. We had radar estimates that were as high as 12 inches two weeks ago, and up to 8 inches yesterday. To give some perspective, the May 28th event was HIGHER than the totals we received during Tropical Storm Allison back in 2001. More than the January 2013 flooding, and more than the March 2012 flooding.
I heard, "We have to move the water out more quickly". Sure, that would help. But let's face it. Lafayette is flat. Louisiana is flat. Water flows downhill. So, unless taxpayers are prepared to pay for something to move the water by force, it's staying. Believe it or not, Lafayette's drainage system is so efficient that it makes a river run backward!!! Two rains like that would seriously flood many cities. The majority of our roads were dry within hours.
More of us are connected to the drainage system. Lafayette is booming with development, not just homes, commercial business are concreting land that would normally absorb water. Most water from everyone's property is guided toward the street. The slope of your yard, the drainage system on your roof. You wouldn't believe how much water YOU are sending to the drainage system. How can we slow that flow so the main drainage for the city can keep up. A change in thinking, particularly landscaping may be the answer. KATC did a story about that back in 2012. Click here for that story.
The USGS has a great calculator on how much rainwater is removed from your roof, your yard, your community, city, and parish. Just put the numbers in and you will be amazed. You can calculate it by square feet, acres, and square miles. My roof spills almost 11,000 gallons of water with a five inch rain. That's enough to fill a 20 by 20 foot pool 4 feet deep. Filling it in three hours. Lafayette Parish is 270 square miles. An average five inch rain over Lafayette Parish is the equivalent to 23.5 billion gallons of water!! Check for yourself here.
They're were many calls for "dredging". The Vermilion, the coulees, everything. Sure, there's always room for maintenance, but it's doubtful digging deeper will solve all of the problems. That's just going to cause problems for someone else, and we should be nice to our neighbors. The number of waterways in Lafayette are mind-boggling. You probably don't even notice how many drainage areas you cross during your busy day.
Controlling tree and root growth and soil deposits from erosion need to be addressed and that's where maintenance comes in. But, our waterways are clogged with a tremendous amount of debris and garbage. Before you point fingers at the city and parish, remember just exactly how did all of that garbage get there in the first place?? Turn the finger around...it's us.
Heavy rain is a part of life in south Louisiana. It's not going away anytime soon.