Subsidence in the District

February 11, 2020 5:58 am

Subsidence, the sinking of the ground due to the removal of water, minerals and petroleum, has been affecting the Houston area since the early 1900’s. It has affected Newport. We have already been required to build a surface water treatment plant to comply with regulations of the Harris Galveston Subsidence District. (HGSD), and we will have to expand that plant by 2025 to stay in compliance.

Subsidence was first documented at the Goose Creek Oilfield in Baytown. The building of the Houston Ship Canal, the growth of the oil industry and subsequent population growth caused additional subsidence. This was caused by the additional pumping of ground water from the aquifers. The ground was sinking at a rate over 1 inch per year. Studies began in the 1940’s. It wasn’t until Hurricane Carla in 1961 that the population became aware of the property damage being done by subsidence. In 1973, the HGSD was formed by the Texas State Legislation. HGSD regulates the withdrawal of groundwater and is empowered to levy significant penalties to well permit holders that do not comply. The regional plan was to switch from ground water to surface water to slow or stop subsidence. Reservoirs were utilized, including Lake Livingston on the Trinity River, and surface water treatment plants were built in Harris and Galveston counties. After several years, the well permit holders in areas 1 and 2 as defined by the HGSD were using 20% of the original amount of groundwater. The subsidence stopped. (Part of Newport MUD is in area 2) Houston and surrounding areas continued to grow. Between 1977 and 1997 the aquifers below us saw a reduction of 100 ft in elevation. Because of this, addition conservation measures were required. Newport MUD pumps water from the area designated as Area 3. We must comply with this mandate.

What Newport MUD has to do is reduce the pumping of our Area 3 ground water from the current 70% of our permitted amount to 40% by 2025. Fortunately, Newport MUD is one of the few MUDs with its own Surface Water Treatment Plant. (SWTP) We have a contract to purchase water from the San Jacinto River Authority (SJRA) However, to meet the needs of the community, we must expand our SWTP to compensate for the loss of ground water. With the foresight of the engineers and legislature, the Trinity River will supply water into Lake Houston so water will be available to meet our needs.

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