TEXAS WATER

WATER PLANNING

by Dr. Justin C. Thompson

HOW MUCH WATER WILL WE NEED IN THE FUTURE? ARE WATER SUPPLIES SUFFICIENT

TO MEET THESE NEEDS? IF NOT, WHAT WILL THE IMPACT OF WATER SUPPLY DEFICITS BE AND HOW MIGHT WE AVOID THEM?

Texas addresses these questions every five years through a regional water planning process. The key goal of this process is to ensure Texans have sufficient water to meet their needs during a repeat of the most severe drought on record. To accomplish this, 16 regional water planning areas—each composed of at least 12 statutorily required interest groups—evaluate population projections, water demand projections, and water supply estimates over a 50-year planning period. These identify potential water shortages and recommend water management strategies to resolve them. Regional water plans are then reviewed and approved by the Texas Water Development Board (“TWDB”) which uses the approved regional plans to prepare the state water plan.

The 2021 Brazos G Regional Water Plan and the 2022 State Water Plan–Water for Texas are complete and available from the TWDB.

What do these planning documents say about the future of water in the tri-county1 area?

Water Demand: Population growth is a critical driver of increasing water needs. The population of the tri-county area is projected to increase by 130 percent or 1.3 million people over the 2020-2070 planning period. The majority of this growth is expected in Williamson County (+1.012M) and Bell County (+316,000) while Milam County population growth is minimal by comparison (+6,000). More people generally means more water is needed. Consequently, water demand in the tri-county area (Figure 1) is projected to increase by 92 percent, or nearly 220,000 acre-feet/year with 95 percent of that increased demand arising from municipal uses. Most of the increased water demand is expected in Williamson County (+167,000 acrefeet/year) and Bell County (+52,000 acre-feet /year) with only a modest increase in demand in Milam County (+832 acre-feet/year). Water Supply & Availability: To understand the future of water in the tri-county area it is important to first understand the distinction between water supply and availability as those terms are used in Texas water planning. Simply put, water supply is legally authorized for use, has existing infrastructure to connect it to water users, and can be relied upon during drought conditions. Available water considers only whether the resource could be relied upon during drought conditions. In this way, water supply is a subset of availability and may be increased by securing new water permits and/or building new infrastructure to connect reliable water to users. Water planners in Texas ultimately compare projected supply with projected demand to determine when and where Texans will have a surplus or deficit under drought-of-record conditions. Water Deficits – Water supply in the tri-county area is projected to increase by 14 percent or 30,000 acre-feet per year over the 2020-2070 planning period (Figure 2). However, this increase in supply is insufficient to satisfy increasing demand and, under drought-of-record conditions, water deficits are projected for the area throughout the planning period (Figure 3). For example, if the tri-county area were struck by drought-

WATER PLANNING

of-record conditions in the year 2070, there would be nearly 232,000 acre-feet less water available than demanded—an approximate deficit of 167,000 acre-feet in Williamson County, 32,000 acre-feet in Bell County, and 33,000 acre-feet in Milam County. Municipal users in the tri-county area would bear 78 percent of these 2070 projected deficits. Economic Impacts of Deficits: The TWDB uses economic models to estimate what the cost to the economy would be over the course of a single year of drought-of-record conditions if projected water deficits come to pass. These analyses are considered by the regional water planning process and estimate that projected water deficits in 2030 would result in tri-county area losses of $1.598 billion in income per year. • $686 million in Williamson County; 7,832 jobs lost • $526 million in Bell County, 6,178 jobs lost • $386 million in Milam County, 31 jobs lost

By 2070 these tri-county area losses rise to $3.294 billion in lost income per year. • $1,824 million in Williamson County, 39,203 jobs lost • $1,076 million in Bell County, 6,178 jobs lost • $394 million in Milam County, 31 jobs lost

A multi-year drought-of-record would drive these per year losses even higher. Proposed Deficit Remedies: If we assume population growth is desirable and should not be dissuaded, the only way to remedy projected water deficits is to increase water supply either by reducing net water usage or tapping into available water. The current water plan for the tri-county area anticipates both approaches and, by 2070, proposes to increase water supplies by 233,000 acre-feet per year. • 186,000 acre-feet in Williamson County, $3,327 million • 43,000 acre-feet in Bell County, $2,447 million • 5,000 acre-feet in Milam County, $143 million If all of the approaches described by the regional water plan are implemented, the resultant increase in water supply is sufficient to avoid water deficits under drought-of-record conditions in Williamson County and Bell County throughout the planning period but not Milam County (which would expect a deficit of between 29,000 and 32,000 acre-feet per year, depending on when drought might strike). Of the 233,000 acre-feet per year of water supply proposed to be created by 2070, 32 percent (74,000 acre-feet/year) is to be generated by reducing demand or reusing existing water sources, 21 percent (49,000 acre-feet/year) is to come from new groundwater supplies (36 percent of which, or 17,000 acre-feet/year, will originate from outside of the tri-county area), and 47 percent (110,000 acre-feet/year) is to be sourced from new surface water supplies.

Key Takeaways

The tri-county area is expected to continue growing rapidly and with that growth comes an increasing need for water. Projected water supplies are insufficient to meet projected demand; unless action is taken there will not be enough water to go around when the next drought-of-record strikes. Failure to address this dilemma would mean billions of lost dollars in income and tens of thousands of lost jobs. The latest round of water planning provides one possible road map to avoiding this bleak future.

All data discussed in this article are synthesized from the 2021 Brazos G Regional Water Plan and are available to the public. Scan the Texas Water Development Board code to review.

DR. JUSTIN C. THOMPSON

Justin C. Thompson received his Ph.D. from the Jackson School of Geosciences at the University of Texas at Austin (UT) in December 2021. His dissertation research focused on groundwater recoverability and management in Texas and he served as a graduate research assistant at the UT Bureau of Economic Geology for over three years. He holds a Master of Science in Energy and Earth Resources from the UT Jackson School of Geosciences, a Master of Global Policy Studies from the UT LBJ School of Public Affairs, and a Bachelor of Business Administration in International Business from Texas Tech University. Dr. Thompson was an international project development and finance professional for 12 years prior to his graduate studies, is proficient in Mandarin Chinese, and has extensive experience with nonprofits bringing ground/rainwater water solutions to underserved communities in East Africa.