Every month, the District will publish a monthly feature, an in-depth look at a component of the District’s mission to prevent subsidence in Harris and Galveston counties. August’s feature explores how the District regulates groundwater to prevent subsidence.
Reasonably regulating groundwater is integral to the District’s mission to prevent subsidence in Harris and Galveston counties. In fact, regulating groundwater is the only way to stop subsidence in the region.
Registering and permitting wells allows the District to grant each permittee an allocation of groundwater they can pump and track how much groundwater is used on an annual basis. Together with aquifer water level data, climate trends, and subsidence rates, groundwater usage is a key component to predicting and monitoring subsidence.
Understanding Groundwater Use in the Region
Within Harris and Galveston counties, the District permits more than 8,350 wells. The three primary water uses in the District are public supply, industrial, and irrigation. The 2019 Annual Groundwater Report revealed that public supply is reported to be about 91 percent of the region’s overall use.
As a growing population increases water demand, projects like the Luce Bayou Project help reduce local municipalities’ reliance on groundwater and move to alternative water (such as rivers and lakes). As a result of the District’s Regulatory Plan, groundwater withdrawals have decreased since the District’s inception, with a 50 percent decline from 1976 to 2019. The corresponding drop in subsidence rates in Areas 1 and 2 are directly related to this change in groundwater use.
Groundwater withdrawals, in million gallons per day, by water use category from 1976 to 2020. The total groundwater used in the District was 208.0 MGD in 2020.
Learn how the District continually regulates usage to protect the region from subsidence:
The Rules
The District’s groundwater regulation, permits, and enforcement stem from the District’s Rules and Regulatory Plan. While the plan has been updated over the years to address a growing population and changes within the region, its purpose remains the same – to prevent subsidence and the corresponding damage to private property, infrastructure, and the region.
Any well drilled within the Harris and Galveston counties must be registered with the District. Those wells must also obtain a permit (with certain exceptions outlined in the Rules).
The amount of groundwater authorized by the permit will consider:
- The amount of groundwater requested by applicant
- Total water demand
- Availability of alternative water supply
- Participation in a groundwater reduction plan
- Use of groundwater credits to offset groundwater pumpage
The location of the groundwater well is also an important consideration. The Regulatory Plan prescribes ratios of groundwater withdrawal to total water demand in each of the three different Regulatory Areas. Groundwater withdrawals for each permittee must comprise:
- Area 1 – no more than 10% of the permittee’s annual total water demand.
- Area 2 – no more than 20% of the permittee’s annual total water demand.
- Area 3 – no more than 20% of the permittee’s annual total water demand, unless the permittee is operating under a certified groundwater reduction plan (GRP).
Groundwater Reduction Plan (GRP)
Since Regulatory Area 3 is still undergoing conversion to alternative surface water, the District Regulatory Plan provides the ability to work within a groundwater reduction plan.
Groundwater reduction plans outline the strategies and steps necessary to convert to alternative water. Each GRP must include the current and projected total water demand, as well as a timetable showing what infrastructure will be constructed by a specific date to meet projected demands, among other requirements.
The Permitting Process
Step 1: All wells within the District must be registered before they are drilled, regardless of whether a well needs a permit.
Step 2: If the well will be used for anything other than a single-family home, potential groundwater user submits a permit application. The staff then reviews the well’s location, the permittee’s need for water, availability of alternative water supplies, and prior beneficial use without waste. The permittee pays an application fee.
Step 3: The District is required by law to hold a Public Hearing on each permit application submitted to the District. Following the hearing process, the application goes before the Board of Directors for approval with staff recommendations on groundwater allocation.
Step 4: Once the Board of Directors approves the permit, the permittee pays the permit fee statement and the permit is issued.
The District conducts an annual renewal audit and preliminary compliance check for wells four to five months before the permit expires.
The Fees
The District applies relevant permit and certain disincentive fees that act as a deterrent of groundwater use. Exemptions from the disincentive fee may be granted for users with a total water demand of 10 million gallons per year (MGY) or less, if alternative water is determined by District staff to be not available.
The base permit fees cover the costs of issuing permits and performing other regulatory functions of the District. The District created the Science and Research Fund in 2015 to use some of disincentive permit fee revenue for funding science and research projects in support of the District’s Regulatory Plan.
The Results
The District has reduced or stopped subsidence from occurring in areas that have moved away from using groundwater to alternative water. In Baytown – the epicenter of subsidence since the 1970’s which saw areas sink up to 13 feet – subsidence rates have ceased altogether.
The successful prevention of further subsidence in areas of Regulatory Area 1 and 2 highlight that the District’s Regulatory Plan is working. The increase in the water level in the Chicot/Evangeline aquifers since 1977 also clearly shows the impact of District regulation on the aquifers
The District exists to provide reasonable groundwater regulation based on the best available science, and will continue to oversee the conversion of Regulatory Area 3 and the ongoing efforts to prevent future subsidence in Regulatory Area 1 and 2.
