Water Resources

Texas’ relationship with water can be summarized as a battle of growing demand against dwindling supplies. The state’s population is one of the fastest growing in the United States and is projected to increase more than 70% by 2070, with water demand going up 3.2 million acre-feet^1,2. Historically, most of Texas’ water use has been for agriculture, but expanding populations are shifting focus to urban areas^2,3. The previous geographic variability of water stress across the state—traditionally with east Texas being wetter than west Texas—is only becoming more uncertain in coming years and decades under climate change^4,5,6.

In Texas, surface water resources are divided among 15 primary river basins, with networks of dams and reservoirs to collect and distribute water^2,3. Warmer and drier temperatures will increase evaporation from soils and open water bodies to reduce the total volume of lakes, rivers, streams, and reservoirs_^1,7. Surface water availability is projected to decline 10% by 2040 under more severe climate projection scenarios, combined with an estimated 5% decrease in soil moisture^4,5. These percentages may seem small, but they translate to a loss of 1.6 million acre-feet². While the number of extreme rainfall events will likely increase in the coming years, hotter temperatures negate any positive effect of excess precipitation on water availably; especially with the rise in megadrought frequency and severity^1,3,6. The occurrence of consistent soaking rains is projected to decline, decreasing the number of light showers that consistently keep soils wet and plants happy, lengthening the average time between precipitation events^8,9. A greater prevalence of drought exacerbates already water-intensive sectors such as agriculture and municipal use.

Texas primarily relies on groundwater, held under the surface in aquifers, to meet water demands^5,9. There are nine major and 22 minor aquifers spread across the state, including the southern part of the Ogallala Aquifer, the largest in the country¹⁰. Many groundwater conservation districts presently plan to pump even more water over the long term, increasing the amount of unsustainable demand in the future¹¹. Currently, groundwater is being pumped at a rate of 1.8 times over the maximum sustainable amount, increasing to 2.4 times the sustainable amount. The Ogallala is hit particularly hard, currently pumped at 6.5 times its sustainable capacity, and climbing¹¹. This rise will probably happen in tandem with a decline in groundwater storage capacity due to slower recharge rates^12,13,14. Agricultural irrigation demand will also probably increase while subsurface pumping infrastructure becomes more vulnerable from greater subsurface exposure to heating and freezing events^3,15,16. Under current management practices, these circumstances paint a dire picture.

Water management in Texas is divided among different regions. A new local planning cycle is initiated every five years, which connects with regional and state-level action plans¹⁷. The state plan focuses on addressing demand 50-years into the future by using historical records to determine future supplies². This “rear-view mirror approach” considers the worst drought events ever recorded and calculates the amount of available water at those times as the bottom-line minimum moving forwards². Updating the plan every five years allows for recent changes in climate to be considered but does not address declines in water supply in the future due to climate change³.

Considering the short and long-term impacts of climate change is vital to sustainable water management in Texas^1,3,11. A challenge to this is the spatial resolution of climate models, which require downscaling to be precise enough to accurately calculate future water availability for use in regional planning^4,18. It is also important to consider surface and groundwater resources holistically while crafting water policies, as they interact in connected and complex ways with each other and water infrastructure^3,19.

Failing to account for climate change puts Texas’ already stressed water resources, as well as its economy and people, at much greater risk²⁰. Good climate change adaptation is good water management.

Learn more about water in Texas with the resources below.

Internet of Water: A new approach to improve access and storage of water data in the United States, making water data affordable and open source to increase water equity and resiliency for both developers and end-users.

OpenET: Aims to improve water management for the western US through satellite estimates of evapotranspiration.

Texas Shows Us Our Water Future with Climate Change: It Ain’t Pretty (Natural Resources Defense Council)

Texas Water Development Board: The goal of the Board since its founding in 1957 is to study, plan, and finance Texas’ water resources for current and future use. They provide many services and reports related to groundwater and surface-water planning, data collection and dissemination, conservation, flood planning and response, and financial and technical assistance services. The Board produces water reports for all state, private business, and local community stakeholders to read and incorporate into planning. The Board is the best source of water data and forecasts for the state, accessible through their Water Data for Texas page.

Texas Water Development Boards’ Drought Dashboard: Hosts resources for understanding drought in Texas with links to datasets and tools for drought status, impacts, outlook, and responses.

When It Rains, Texas Forgets Drought and Worsening Water Scarcity (Circle of Blue)

U.S. Drought Monitor: Tracks drought severity conditions for the entire United States to monitor trends and recognizing drought conditions to help reduce impacts while providing a historical record for research and planning.