A new study from The Meadows Center for Water and the Environment at Texas State University shows Barton Creek and Onion Creek contribute significant flows to the Colorado River.
“On a per-acre basis, the Barton and Onion creek watersheds contribute twice as much flow to the Colorado River than the Pedernales River watershed,” said Yipeng Zhang, hydrogeologist at the Meadows Center and lead author of the study. “This is helpful information when considering which land to conserve to preserve the region’s water supplies.”
The Colorado River supplies drinking water to millions of Texans and serves as an important source of water to the state’s economy, environment, agriculture and industry. The river relies on tributary flows to fill its reservoirs and support a healthy aquatic habitat. During severe droughts, when flow in the Colorado River upstream of Lake Buchanan ceases, local tributary flows may be the only contributors to the river.
The study compared streamflow contributions of the Pedernales River and Barton and Onion creeks to the Colorado River using daily discharge data from Sept. 24, 1998, to Aug. 31, 2022. This time range was selected based on the availability of data from U.S. Geologic Survey stream gages.
The research found that an average acre of land conserved in the watersheds of Barton and Onion creeks produced more than twice as much water to the Colorado River than an average acre of land in the Pedernales River watershed. Furthermore, daily flow into the Colorado River from Barton and Onion creeks surpassed that of the Pedernales River nearly half the time.
The study indicated that with a catchment area four times larger than Barton and Onion creeks combined, the Pedernales experiences flood flows larger than those in Barton and Onion creeks. However, the Pedernales River contributed no water to the Colorado River 5.3% of the time while Barton Creek consistently contributed flow to the river, including during the drought of record, thanks to groundwater flows from Barton Springs.
The study is the first to analyze the relative contributions of the Pedernales River and Barton and Onion creeks to the Colorado River. The findings can help inform decisions on efficient, effective resource allocation to ensure the long-term reliability of water supply for the region.
To read the full study, visit https://bit. ly/41Ex84k. The research was funded by the Save Our Springs Alliance.
