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Regional Water |
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The Galveston-Houston area draws its water supplies
from underground limestone and clay formations. Unlike many other
Texas limestone aquifers, such as those in the San Antonio and
Austin area, our underground supplies cannot recharge quickly.
When water is pumped out, all the earth above is slowly compressed.
When subsurface ground is lowered, a process known
as subsidence, it changes the way that rainwater at the surface
collects and flows. At the surface, where higher ground naturally
sheds water to lower ground and then into natural water channels,
the newly lowering ground now collects water and forms new paths
that water takes in response to gravity.
Problems with Continued Underground Water Use
In a coastal area of relatively flat land running
to the seashore, subsidence forms large areas that are more prone
to flooding and holding water. This problem afflicts our area.
This natural phenomenon has been occurring over
time since early settlers sank the first water wells. As all users
sharing the same resources pump more water to the surface, areas
within the aquifer begin to sink, some more rapidly and deeper
than others.
On top of this natural process, more and more development
for houses, industries and businesses encourages more paving for
sidewalks, roads and parking lots. As this surface is covered
and no longer available to absorb water to layers below, rainwater
runoff increases in velocity and force toward natural channels.
With a less absorbent surface, natural channels fill quickly overflow
conditions - and flooding occurs.
Finally, the problem becomes circular, as supplying
additional water for an increasing population grows with the number
of people and industries that require water.
Mandatory Conversion Plan
Early pioneers to the Galveston-Houston area had
abundant well opportunities and no natural reservoirs. They busied
themselves draining coastal plains for agriculture.
Studies of water use and subsidence have been underway
since the early 1940's. One potential solution to the growing problem
is to create man-made, surface reservoirs. This solution
has been extensively practiced in North Texas. In fact, there are
only a few natural lakes in the entire state - most were created
as surface water reservoirs.
By the 1960's subsidence in the Houston ship channel
area could not be ignored. Later, it was discovered that neighborhoods
in far northwest Harris County, far from the coastline, were also
subsiding.
In 1999, the State of Texas and the Harris-Galveston
Coastal Subsidence District acted with legislation and rules that
required a migration by 2010 from ground water well sources to
surface water. This requirement drove the formation of the North
Harris County Regional Water Authority. HCMUD18 is a member of
this authority.
The plan recommended reservoirs, rivers and streams
as new water sources. In our area the City of Houston has authority
over Lake Houston, the San Jacinto River and Lake Livingston, the
3 current sources of surface water.
To help accomplish the changeover, new water
authorities were formed to aggregate water utility districts to better
work with the City of Houston toward achieving surface water goals.
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