Soil Consolidation in Houston

What is the cause of the settling that is occuring
in the Houston area. I have heard that the downtown
area has settled over five feet in certain areas.
How would someone explain soil consolidation to a
city-council person with no engineering background?
Water has been removed from the ground so should not
the soil weigh less and not sink down?

 

[PECPESC]

This is called subsidence. Check any good soils book.

In Houston, it is caused by withdrawl of water and oil from the subsurface strata and the collapse of those strata.

Any city council person in Houston should understand the issue. Refer to the Brownwood Subdivision in Bay Town. The subdivision had to be abandonded in the early 80's because the houses were sinking into the bay.

 

[Bayou]

For information on subsidence,
USGS has published a report that
explains subsidence and gives
examples of occurence around the US.
One of the chapters is dedicated to
Houston and Baytown, TX.

USGS Circular 1182 can be downloaded at

http://water.usgs.gov/pubs/circ/circ1182/

Also you can check out:
Harris-Galveston Coastal Subsidence District

http://www.hgsubsidence.org/

or the tri-county area at

http://www.subsidence.org/

Subsidence is not do to soil consolidation.
It is due to water extraction. Every Houston
city-council member is quite aware
of subsidence. The east of Houston is no longer
extracting groundwater, however the west side
of town is still using groundwater. I think
by 2012 or so, all extraction is suppose to be
halted.

As far as Brownwood is concern, the subdivision
sank 9-10 feet due to extraction of water by the
refineries. When Hurricane Alicia came in 1983,
the bay just engulf the pennisula. FEMA ended up
condemning the whole subdivision.