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Environmental Blog

  • 05
  • February
  • 2015

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Brackish Ground Water Emerging as a Water Management Strategy

Brackish groundwater is a promising water resource that could help Texas meet its long-term consumption needs. Brackish water is abundant in Texas. A 2003 study conducted by LBG-Guyton Associates for the Texas Water Development Board (TWDB) indicated that brackish water is present in every  major and  minor aquifer and in each of the State’s 16 regional water planning groups, with an estimated 2.7 billion acre-feet potentially available for use. Currently, Texas has 34 municipal desalination plants that use brackish water as a raw source (producing about 73 million gallons of water to date). In addition, the  2012 Water Plan estimated that desalination could supply up to 182,000 acre-feet per year (2%) of the State’s water needs by 2060.

Advanced desalination technologies, such as  reverse osmosis membranes, have made large-scale brackish groundwater desalination projects more economical than ever before. The world’s largest inland desalination plant–the  Kay Bailey Hutchison Desalination Plant in El Paso–opened in 2007 and is managed by the El Paso Water Utilities. The San Antonio Water System (SAWS) is currently constructing a  brackish groundwater desalination plant that will draw brackish water from 13 production wells above the Wilcox Aquifer in southern Bexar County. SAWS expects the plant to produce about 10 million gallons of water per day when it comes online, with planned expansions in 2021 and 2026 that will provide an additional 15 million gallons per day.

Since 2003, the Texas Legislature has made regular appropriations for desalination demonstration projects and feasibility studies. Although lawmakers initially focused on seawater desalination, groundwater desalination attracted greater attention during in the last five sessions. To date, the TWDB, with financial assistance from the Legislature, has funded  12 groundwater desalination demonstration projects. In addition, five regional water planning groups (E, F, L, M, and O) included brackish groundwater desalination as “recommended water management strategies” in the  2012 State Water Plan. Many of these projects could be eligible for financial assistance via the  State Water Implementation Fund for Texas (SWIFT).

Challenges to Further Development of Brackish Groundwater

Several technical and legal barriers need to be resolved before more extensive development of Texas’ brackish groundwater resources can occur. The most formidable obstacle is the lack of clarity regarding ownership rights and regulatory authority over brackish groundwater. It is well known that Texas groundwater is governed by the rule of capture, which recognizes the right of landowners to pump all water below the surface for use or sale (with a few narrow exceptions). While the Texas Legislature, through the  Water Code, affirms private ownership of groundwater, it has also established nearly  100 groundwater conservation districts(GCDs) with authority to set rules for conserving, protecting, recharging, and preventing waste of groundwater resources. In addition, the Water Code requires GCDs with jurisdiction over the same aquifer to cooperate and develop “desired future conditions” for the aquifer. GCDs must submit each desired future condition to the TWDB, which uses it to determine the “modeled available groundwater” for the aquifer. GCDs then use these models in permitting decisions to ensure that the aquifers attain the adopted desired future conditions.

Despite this robust regulatory scheme, GCDs’ authority to establish rules and permit conditions for brackish groundwater resources is not so clear. The problem starts with the fact that the Water Code does not define “brackish groundwater,” and there is no firm consensus on the right definition. Recent debates have turned on whether to define brackish groundwater in terms of its total dissolved solids (TDS) concentration or its hydrological connection to adjacent freshwater supplies. Lawmakers proposed a  bill during the 2013 session that would have defined brackish water as having a level of TDS between 1,000 and 10,000 parts per million (ppm). Critics, including the Texas Alliance of Groundwater Conservation Districts,  argued that this legislation would essentially deregulate large areas of groundwater currently under GCD jurisdiction since many “freshwater” aquifers feature TDS levels above 1,000 ppm. GCDs and conservation groups also claimed that overproduction of brackish water could deplete or contaminate drinking water sources. All bills related to brackish water development were left pending in committee. Proposed appropriations for new studies to better characterize Texas’ groundwater resources, assess potential consequences of increased development, and evaluate the feasibility of large-scale desalination projects also stalled in the Senate. Instead, lawmakers authorized the creation of the  Joint Interim Committee to Study Water Desalination, with the goal of resolving these issues before the next legislative session.

Proposed Legislation Related to Development of Brackish Groundwater

Less than one month into the 84th Legislative Session, lawmakers have filed several new bills designed to promote brackish groundwater development, while also addressing the criticisms that thwarted previous legislation. The most comprehensive legislation filed to date,  HB 30, would amend Chapter 36 of the Water Code to provide GCDs with clearer authority to manage brackish water, while also streamlining the permitting process for desalination projects.

In particular, HB 30 would require the TWDB to identify “Brackish Groundwater Production Zones.” Production zones boundaries would be restricted to protect freshwater quality and supplies, and zones could not be located in the Edwards Aquifer or within the boundaries of the Edwards Aquifer Authority. Once the TWDB identifies a production zone, the local GCD must adopt rules for issuing withdrawal permits. These permits would last for a minimum of 30 years, and would authorize unlimited rates and amounts of withdrawals. The permit holder would be required to submit withdrawal reports to the TWDB and the applicable GCD, and also monitor aquifers near the production zone to identify any adverse impacts. If a GCD receives a withdrawal report showing that brackish water production has depleted or impaired surrounding groundwater, the GCD could amend the permit or require the permit holder to submit a mitigation plan describing how it plans to address the impacts.

A related bill,  HB 836, would allow an interested person to petition a GCD for the creation of a “brackish groundwater production zone.” The petitioner would be required to demonstrate that groundwater production would not cause “unreasonable negative impacts” to water quality, quantity, and desired future conditions in adjacent groundwater reservoirs and existing wells. The petitioner would also be required to file a monitoring plan. If the petition meets these conditions, the GCD would be required to designate a production zone and adopt rules for permits issued therein. Finally, the bill would establish hearing procedures for issued permits and would allow petitioners to appeal a GCD decision to the TWDB.

Reflections

The proposed legislation seems to balance competing concerns about brackish groundwater that have hindered full development of this resource. Large-scale desalination facilities have received robust opposition from certain GCDs and environmental coalitions. Their objection is to these projects is that, depending on the hydrology of the aquifer, pumping brackish groundwater may cause contamination of nearby freshwater groundwater or lower the water levels in the aquifer. Since there are seldom other users of the brackish water, this is generally not an issue. However, this concern could become more urgent if demands on brackish groundwater continue to rise. In addition, the bills’ provisions giving GCDs authority to modify permits based on demonstrated negative impacts to fresh water supplies could garner support from these groups.

Notably, HB 30 departs from previous legislation by not defining “brackish groundwater” in terms of TDS concentration. Rather, brackish groundwater production zones would be designated based on their hydrological connection to other aquifers and water supplies. In addition, by directing the TWDB to work with GCDs to identify these zones, the bills address the concern that GCDs would lose their existing authority to manage portions of freshwater aquifers with TDS levels above 1,000 ppm. At the same time, these bills accommodate and encourage development of new large-scale desalination projects, as reflected by the provisions allowing long-term production with relatively few restrictions on rates or quantities of withdrawals. 

We will keep you updated on bills that pass this legislature related to desalination.  

Posted at 02/05/2015 5:35 PM

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