Resources
New Report: Changing Hydrology and Impacts on
Water Planning in the Highland Lakes Watershed
Texas water planning currently relies on the past to help predict how much water we’ll have in the future.
That means we expect our watersheds to turn rainfall into lake water the same way they have in the past.
But what if our watershed doesn’t respond to rainfall the way it did decades ago?
CTWC commissioned independent research to answer that question in the Highland Lakes.
The study found that our watershed is producing less water from the rainfall it receives.
What We Found
Rainfall hasn’t Significantly Changed,
but Inflows Have.
Across more than a century of records, average annual rainfall has remained statistically stable at approximately 26 inches per year, but the amount of water reaching Lakes Buchanan and Travis has declined. Nine of the 10 lowest annual inflow years on record have occurred since 2006.
The 1950s drought is a more appropriate planning benchmark than the drought currently used.
The watershed received roughly 50 inches less total rainfall during the 1950s drought than during the 2008-2016 drought period used in LCRA’s 2032 Water Management Plan analysis—meaning a repeat of the 1950s rainfall pattern today would place even greater stress on a watershed that is already producing less inflow.
The amount of water the Highland Lakes can reliably supply could be 9% to 21% lower than currently estimated.
The study tested what would happen if the rainfall of the historic 1950s drought occurred under today’s watershed conditions. Across 15 model runs using four different methods, every scenario produced a lower firm water supply than current estimates — approximately 9%-21% lower. That represents 37,524 to 88,335 fewer acre-feet of reliable water supply. For perspective, one acre-foot is approximately 326,000 gallons of water.
Peek at Our Technical Library
A quick glance shows how much of an impact we make
Want to take a deeper dive? Our Technical Library includes more information on the issues, reports, and work CTWC has amassed on behalf of water conservation and smart water planning for Central Texas and the Highland Lakes.
The economic impact of water scarcity
Report: Upper Highland Lakes Economic Impact
Report: Lake Travis Economic Impact
Some of the organizations involved in the governing process include:
Texas Commission on Environmental Quality
The Texas Commission on Environmental Quality (TCEQ) strives to protect our state’s public health and natural resources consistent with sustainable economic development. Their goal is clean air, clean water, and the safe management of waste.
Lower Colorado River Authority
The Lower Colorado River Authority’s (LCRA) mission is to enhance the quality of life of the Texans they serve through water stewardship, energy and community service. They provide public power, manage the lower Colorado River and build and operate transmission lines across the state and more. LCRA manages the Highland Lakes under a Water Management Plan (WMP) that must be approved by TCEQ.
Texas Water Development Board
The Texas Water Development Board’s (TWDB) mission is to provide leadership, information, education, and support for planning, financial assistance, and outreach for the conservation and responsible development of water for Texas.
Region K Water Planning Group
The Region K Water Planning Group was established by the TWDB to help develop and revise the long-range water plan for the Central Texas region which will be included in the State Water Plan that will meet the region’s water needs over the next 50 years.
Questions that keep us up at night
Where does our water go?
- Municipal demand, i.e. fastest growing communities in nation
- Growing business demand, i.e. new Tesla and Samsung plants
- Agriculture, primarily rice, which requires a lot of water
- Environmental flows in Colorado River and releases for inflows to Matagorda Bay
- Evaporation (higher temperatures increase evaporation)
How is our water managed?
- LCRA manages our water through a water Management Plan that is updated every 5-7 years.
- LCRA decides how much water they can sell (contract) via water availability modeling to zero inventory, based on last drought of record.
Do we have a real Water Supply problem?
- The short answer is yes. Demands on the water are rapidly increasing from growth in population and new businesses coming to the area and to Texas.
- Water supply is falling from several major factors (rainfall patterns are moving east our of our watershed; thousands of ponds have been built in watershed that are capturing and holding up inflows that used to flow into our reservoir lakes; higher temperatures are increasing evaporation; many new groundwater wells are being drilled in our watershed
Is the current path sustainable?
- No, it’s not. We need changes in water policy and changes in the State Water Codes and NEW Water Supplies.
- We have less water flowing into our basin. We need much stronger conservation measures.
- We must make tough choices on how we use our water supply.
Do we need a flood-like event to recover?
- YES! Regular and normal rainfall is no longer capable of refilling our lakes. We need a flood-like event in the right places up in our watershed to provide sufficient inflows to refill our reservoir lakes. Our water management policies need to change to extend our water supply long enough to reach the next flood.
