This state-mandated shift from groundwater to surface water is an attempt to offset subsidence—which is the lowering of land elevation by withdrawing too much groundwater and can lead to flooding—in the Greater Houston area, said Mike Turco, Harris-Galveston Subsidence District general manager. The transition from groundwater to surface water is also necessary to keep pace with the water needs of the Greater Houston area’s growing population, he said.
The HGSD is the state entity that regulates the groundwater usage of the water authorities in the region. Turco said the subsidence district tasked entities in north Harris County with ensuring that by 2035, surface water will supply 80 percent of the water used in north Harris County, with groundwater comprising the remaining 20 percent.
Today, most entities in north Harris County pump 70 percent of their water from the ground and 30 percent of their water from the surface. Before reaching the 2035 goal, entities must transition to pumping 60 percent of their water from the surface and 40 percent from the ground by 2025.
“[Subsidence] is definitely something you want to solve because any subsidence that occurs is subsidence that will be there forever,” Turco said.
One of the major projects that will increase the amount of surface water available to residents is the Luce Bayou Interbasin Transfer Project, which is being completed by the Coastal Water Authority. This project will transport water from the Trinity River in Liberty County to Lake Houston—which serves as a major source of surface water for the Greater Houston area, CWA Executive Director Don Ripley said.
The estimated $380 million project involves building a pump station on the Trinity River, along with pipelines and channels to transport the water to Lake Houston. Construction on the project started in 2016 and is scheduled to finish in 2020, Ripley said.
Surface water pulled from Lake Houston is treated at the Northeast Water Purification Plant, which is undergoing a $1.76 billion expansion, Project Manager Ravi Kaleyatodi said. This expansion will increase the number of gallons the plant can pump from 80 million to 400 million per day. This expansion, like the Luce Bayou Project, is necessary for the Houston area to transition from groundwater to surface water, he said.
The water purification plant expansion started in 2017 and will be completed in two phases. The first phase will increase the number of gallons the plant can pump per day to 160 million by 2022. The expansion to 400 million gallons per day will be completed by 2024, Kaleyatodi said.
In addition to expanding the plant—which is located near Beltway 8—the project includes the construction of a new intake station on Lake Houston that will pump water to the expanded plant. Water pumped from this station will travel through an underground pipeline—which is still under construction—that will travel under West Lake Houston Parkway near the Summerwood and Summer Lake Ranch neighborhoods, Kaleyatodi said.
The Texas Water Development Board is loaning local entities with the funds to complete these projects, but all affected entities will pay the state back.
Increased water rates
As entities work on these projects, the monthly water pumping fees and rates customers pay are increasing to help pay for the projects, said Jun Chang, deputy general manager of the North Harris County Regional Water Authority—which contracts with municipal utility districts in the Lake Houston area.
The NHCRWA increased its groundwater pumping fee from $2 per 1,000 gallons in 2015 to $3.85 per 1,000 gallons, effective April 1. In that same time, the NHCRWA’s surface water pumping fee has increased from $2.45 per 1,000 gallons to $4.30 per 1,000 gallons.
Similarly, the city of Houston, which provides water to MUDs and cities—including Humble—has increased its water rates to fund these projects, said Chang—who was the city of Houston’s deputy director of Public Works before joining the NHCRWA in 2016.
According to Houston Public Works data, the monthly rate for a household in the city of Houston using 7,000 gallons per month in 2010 was $24.89. Meanwhile, the monthly rate for the same household in 2018 was $39.78.
When water providers, such as the city of Houston and water authorities, increase their rates, local entities, like the city of Humble, then pass the increases on to residents, Humble City Manager Jason Stuebe said.
“Our rates have steadily been increasing, and the only rate they have been increasing at is the rate of which Houston is increasing,” Stuebe said.
Subsidence, water demands
The Greater Houston area’s transition from groundwater to surface water will not reverse subsidence that has already occurred, but it should prevent it from getting worse, Turco said. Addressing subsidence is necessary because decreases in land elevation can increase an area’s chance of flooding.
“[Flooding] is the big reason you want to solve the subsidence,” Turco said. “There are other things that contribute to flooding, but this is one we can solve.”
According to HGSD data, subsidence is occurring near Kingwood. From 2013-18, an area near Sorters McCllellan Road, west of Hwy. 59 and north of Kingwood Drive, has subsided an average of 1.07 centimeters per year.
In addition to mitigating subsidence, the projects being completed throughout the Greater Houston area will increase the amount of water available for the growing number of residents in places such as the Lake Houston area.
“[The Houston] area is growing at 1 million people per decade,” Kaleyatodi said. “So, in the next two decades population is projected to grow by 2 million.”