THE FATE OF DESALINATION IN REGIONAL WATER PLANNING IN TEXAS JORGE A. ARROYO, P.E. NOVEMBER 2015 In 1957 the state created and entrusted the Texas Water Development Board (TWDB) with providing water planning, water data collection and dissemination, and financial and technical assistance services to meet the state s water needs. Water professionals are well aware of the importance of State Water Planning as a means to chart water supply development and guide the use of the state s financial assistance. Shortly after creating the TWDB, the Texas Legislature underscored the state s interest in desalination by appropriating in 1959 $20,000 for research on the scaling problems inherent in the electrodialysis desalination process [1]. Water desalination has had decidedly growing presence in water supply planning -and water supply portfolios- in Texas. This paper provides a brief overview of the history of desalination tracked through the various state water plans. The first state water plan, issued by the Texas Board of Water Engineers in 1961, was primarily focused on surface water development. However, the plan recognized the potential of demineralization of brackish water and sea water and recommended researching this potential [2]. The plan noted that there were a few areas in the State where desalination would be economically feasible, but those areas were limited. It recommended that a desalination research investigation should be carried forward in order that the lowest possible cost and the most practical methods may be developed for use in areas where the conventional methods of developing new supplies are not applicable. It is entirely possible that the present methods and procedures used in desalinization may produce water at costs acceptable to certain industries and towns that have no other supplies much research is yet to be accomplished. This research should be supported by very accurate cost figures, because it is in this field that the main concern is now centered. In 1965 the TWDB acted on this recommendation by commissioning a study of the state s saline water sources and potential sites for desalination with the Southwest Research Institute [3]. This study provided an overview of desalination technologies of the day, and examined the water desalination supplies potential for multiple Texas cities. The second state water plan, published in 1968, reflected a growing interest in desalination. The plan, again, recognized its potential but cited the high cost as a key challenge, at the same time noting that technological advances were likely to reduce the cost of desalination over time [4]. Specifically, the plan noted the possibility of using desalted water as a means of meeting water needs in some areas in Texas is attractive and one to which the Board is directing close study. High costs of desalting the water plus the continuing costs and hazards of disposing of the concentrated brines produced under present technology tends to rule out desalting as a
solution to large-scale, water supply problems. However, in local areas desalting shows great promise. Technological advances which reduce costs and solve some of the waste brine disposal problems could offer additional promise in the future. Brackish water will supply a large percentage of the water requirements for secondary oil recovery. In 1984, the third state water plan reported 71 desalting plants in operation in Texas (See Table 1), producing 52 acre-feet per day for municipal and industrial purposes. Seven plants produced about 2.5 acre-feet of water per day for municipal use in Dell City and several suburban areas [5]. The plan remarked that before desalting technology can be considered as a potential source of municipal and industrial water supplies for a specific city or industry, several conditions must be met. There must be a readily available supply of brackish or saline surface or ground water in sufficient quantity to meet the need; the desalting plant must be determined to be economically feasible when compared to available conventional water supplies; a method of brine disposal must be available; and a source and supply of energy must be available. Preliminary information indicates that these conditions prevail in several areas of West Texas, the Panhandle, Western Central Texas, and the Gulf Coast, especially the Lower Rio Grande Valley. Table 1 - Desalination Plants in Texas as of June 30, 1980 (Capacities > 25,000 gpd) USE Capacity (gpd) Membrane Desalination Plants Distillation Desalination Plants Public 824,000 7 0 Supply Industrial 13,279,000 37 6 Power 3,041,000 16 5 Total 17,144,000 60 11 Source: 1984 Water for Texas, Volume 2. The 1990 State Water Plan [6] referred back the 1984 plan regarding installed desalination production and potential, adding that given the location and amount of brackish and saline water that occurs in Texas, and the increasingly limited supply of fresh water available to meet projected demands, desalination needed to be further incorporated into the water supply plans developed in the State. It also provided the following recommendations: The Board should expand its programs to evaluate brackish water availability and should conduct workshops with local governments and utilities on desalination and its viability for extending freshwater supplies. In conjunction with this effort, the Board should coordinate with State universities to encourage inclusion of desalination technology into water resources and civil engineering curricula; The Board and the Texas Department of Health should establish an agreement on the identification of areas where desalination should be considered as the primary water supply option. The Legislature should support national efforts to promote desalination, such as are being done by the National Water Supply Improvement Association.
The 1992 State Water Plan [7], generally considered a policy update to the 1990 plan, included a section regarding desalination development policy. Echoing previous state water plans this plan noted that additional studies are needed to determine the quantities available for development at various locations as well as the locations and quantities of wastewater available for municipal and industrial purposes through application of desalting technology. The evaluation of costs and the cost-effectiveness of desalting needs to be better identified and incorporated into long-range water supply plans as an alternative. Environmental effects, especially as related to brine disposal, also need to be considered in any evaluation. In the 1997, the last of the TWDB-prepared plans, reported that the state had approximately 16 million gallons of municipal desalting capacity on line or under construction at Bayside, Dell City, El Paso, Fort Stockton, the Lake Granbury area, Kenedy, Lake Possum Kingdom, Robinson, Sherman and South Padre Island. Membrane technologies were being used in Harlingen to treat 4.0 MGD of reclaimed water from that city s wastewater treatment plant for industrial reuse. There were also nearly 30 industrial facilities using desalting technologies. The plan noted that the cost of brackish ground and surface water were under $2.00 per thousand gallons produced, making desalting of brackish water cost competitive with other more conventional new supplies in some cases. The plan reports that the city of Brownsville and El Paso Water Utilities were considering implementing desalination facilities [8]. In 1997 the Texas Legislature enacted Senate Bill 1, directing state water planning to be conducted at the regional level instead of at the State level. The Regional Water Planning Guidelines direct regional water planners to provide specific water management strategy recommendations. Such recommendations must be based on identification, analysis, and comparison of all water management strategies that the regional water planning group determines to be potentially feasible, including desalination and other innovative water management strategies. As a result of this guidance, the regional and state plans present an ever more diverse water supply portfolio designed to meet the state s future water needs and includes an increasing share of desalination. The first batch of regional water plans were delivered to the TWDB in January 2001; these plans were then compiled into a single document, the 2002 State Water Plan. Although the plan does not discuss water desalination as a supply or resource, desalination was recommended as a water management strategy in four regions. In the Far West Texas Region and Coastal Bend Region, desalination of brackish groundwater was used as a strategy to provide 66,954 AFY in additional supplies. The desalination of coastal waters was recommended by the South Central Texas Region as a water management strategy to provide an additional 84,012 AFY. Region B included desalination in two recommended water management strategies for a total of 28,808 AFY. Currently in Texas, municipal desalination capacity is 25,750 AFY.
Figure 1 - Distribution of recommended water management strategies in the 2001 regional water plans [Source: TWDB] In 2002 the TWDB engaged in a systematic approach to advance water desalination supplies, which impacted subsequent regional water plans. These efforts sought to identify and address challenges to implementing seawater and brackish groundwater desalination supplies in Texas. Additionally, the 78th, 79th and 80 th Texas Legislatures appropriated a total of $4.2 million in grants for desalination demonstration projects and other related activities; this funding allowed TWDB to furnish grants to advance desalination water supplies. Key categories of funded projects included: Guidelines for implementing desalination projects; feasibility studies; economics of desalination; regional water facility planning studies; a database of desalination systems; pilot plant studies; source water resource characterization; energy use optimization; concentrate management; alternative energy sources; and technology demonstration projects. The 2007 State Water, a composite of the second round of regional water planning completed in 2006 included recommended desalination water management strategies totaling 313,000 acre-feet per year by 2060; of these, 138,000 acre-feet per year corresponded to seawater desalination projects and 175,000 acre-feet per year to brackish groundwater desalination projects [9].
Figure 2 - Recommended water management strategies in the 2006 regional water plans [Source: TWDB] The third installment of regional water plans, completed in 2011, were consolidated into the 2012 State Water Plan. A total of 309,700 acre-feet per year of desalination supplies were recommended in the plan; 2,700 acre-feet per year of surface brackish desalination, 181,500 acre-feet per year brackish groundwater desalination, and 125,500 acre-feet per year seawater desalination [10]. The 2015 regional water plans are being adopted by the regional water planning groups and are due to be delivered to the TWDB by January 5, 2016. The presentation of this paper at the 2016 AWWA-AMTA conference will report on the inclusion of desalination water management strategies in this latest round of regional water planning. In the meantime, following is a brief overview of the draft regional water plans also referred to as the initially prepared plans:
Figure 3 - Recommended water management strategies in the 2011 regional water plans [Source: TWDB] No desalination water management strategies are recommended in the following regional water planning areas: Regions A, B, D, G, I, K; The following regions recommended desalination water management strategies: o Region C: Brackish surface water desalination (GTUA); Woodbine brackish groundwater desalination (City of Bardwell); o Region E: brackish groundwater desalination (Expansion of the KBH Desalination Plant by EPWU, Expansion of Desal Plant by Horizon MUD); o Region F: brackish surface water (CRMWD) and brackish groundwater desalination (San Angelo); o Region H: brackish groundwater desalination (BWA and Lake Conroe), seawater (Freeport); o Region J: brackish groundwater desalination (UGRA, City of Camp of Wood); o Region L: brackish groundwater desalination (CRWA, SAWS, Gonzales Co., SSWSC); seawater desalination (SAWS, GBRA); o Region M: brackish groundwater desalination (multiple entities: NCRWSC, NAWSC, City of Primera, City of Alamo, Sharyland WSC, Rio Grande RWA, Harlingen); seawater desalination (City of Brownsville, Laguna Madre WD, Willacy County); o Region N: brackish groundwater desalination (Alice); seawater (City of Corpus Christi);
o Region O: brackish groundwater desalination (City of Lubbock); o Region P: brackish groundwater desalination (LNRA) In conclusion, the state and regional water plans provide solid evidence of the growing importance of desalination. These plans have also served to identify key challenges to desalination. Through the TWDB, the state implemented research and outreach strategies to address some of these challenges. The regional water planning process, with its directive to planners to include all potentially feasible water management strategies, has provided an effective forum to consider and recommend water desalination strategies to meet future needs of the state. The current round of regional water planning will be formally closing on January 5, 2916 with the submittal of the adopted regional water plans. The presentation to be provided at the AMTA/AWWA Conference will report on the desalination aspect of these plans. REFERENCES [1] Texas Water Development Board, Statement of the Texas Water Development Board regarding continued federal support of desalination research and development; provided to the Subcommittee on Water and Power Resources, United States House of Representatives, Washington, D. C.: Texas Water Development Board, 1973. [2] Texas Board of Water Engineers, "A Plan for Meeting the 1980 Water Requirements of Texas," Texas Board of Water Engineers, Austin, Texas, 1961. [3] Southwest Research Institute, "The potential contribution of desalting to future water supply in Texas," Southwest Research Institute, US Department of Interior, 1966. [4] TWDB, "State Water Plan," TWDB, Austin, 1968. [5] TWDB, "Water for Texas - A Comprehensive Plan for the Future," TWDB, Austin, 1984. [6] Texas Water Development Board, "Water for Texas Today and Tomorrow," Texas Water Development Board, Austin, Texas, 1990. [7] T. W. D. Board, "1992 Water for Texas, Today and Tomorrow," Texas Water Development Board, Austin, Texas, 1992. [8] Texas Water Development Board, "1997 State Water Plan, Water for Texas," Texas Water Development Board, Austin, Texas, 1997. [9] Texas Water Development Board, "2007 Water For Texas," Texas Water Development Board, Austin, Texas, 2007. [10] Texas Water Development Board, "2012 Water For Texas," Texas Water Development Board, Austin, Texas, 2012.