The area west of Houston was never a "sponge". In its natural state, it would absorb 4-5" of rainfall before it became saturated. But land developers did not destroy the prairie - farmers did. They graded the land and put in drainage channels. Much of the area was rice farms, which held a lot of water, but these have been slowly converted to row corps and/or ranch lands over the years. There is little native prairie remaining, even in the undeveloped areas. Besides paving, agriculture is one of the worse things you can do to soil as it pertains to its permeability. Today, the soils can only handle 3-4" of rainfall IF they are dry at the beginning of the event.
Houston was built in an area that naturally floods. There are areas that we should have never built. Starting with the agriculture and then the massive development, we have compounded it. Yes, new concrete limits the ability of the land to absorb runoff, but new development must put this incremental increase into detention ponds. So the net impact should be null. We have had flooding over the years. You can pull up annual peak flowrate data at USGS gages online, and the trend in flowrates is not rising.
What has happened is that we have had some crazy rainfalls in the past few years. Add to that that we went about 15 years without a major flood, and that leaves us feeling like it has got much worse in the past few years. But there have been major floods in 1979, 1983, 1989 (twice), 1993, 1994, 1998 (twice), and 2001. The rainfall in 1929 and 1935 were way less than Harvey, and severely flooded downtown and closed the ship channel for a year.
Why Flood Waters Occur More Than Ever
in Houston and the Environment
Posted
The area west of Houston was never a "sponge". In its natural state, it would absorb 4-5" of rainfall before it became saturated. But land developers did not destroy the prairie - farmers did. They graded the land and put in drainage channels. Much of the area was rice farms, which held a lot of water, but these have been slowly converted to row corps and/or ranch lands over the years. There is little native prairie remaining, even in the undeveloped areas. Besides paving, agriculture is one of the worse things you can do to soil as it pertains to its permeability. Today, the soils can only handle 3-4" of rainfall IF they are dry at the beginning of the event.
Houston was built in an area that naturally floods. There are areas that we should have never built. Starting with the agriculture and then the massive development, we have compounded it. Yes, new concrete limits the ability of the land to absorb runoff, but new development must put this incremental increase into detention ponds. So the net impact should be null. We have had flooding over the years. You can pull up annual peak flowrate data at USGS gages online, and the trend in flowrates is not rising.
What has happened is that we have had some crazy rainfalls in the past few years. Add to that that we went about 15 years without a major flood, and that leaves us feeling like it has got much worse in the past few years. But there have been major floods in 1979, 1983, 1989 (twice), 1993, 1994, 1998 (twice), and 2001. The rainfall in 1929 and 1935 were way less than Harvey, and severely flooded downtown and closed the ship channel for a year.