AUSTIN (KXAN) – 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.

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 decision makers on more efficient, effective resource allocation to ensure the long-term reliability of water supply for the region.

Meteorologist Sean Kelly spoke with Dr. Robert Mace, the Executive Director and Chief Water Policy Officer at The Meadows Center for Water and the Environment. Mace is also a Professor of Practice in the Department of Geography and Environmental Science at Texas State University.

Sean Kelly, KXAN News: Tell me about about this study, and what are some of your findings and research?

Dr. Robert Mace, The Meadows Center for Water and the Environment: So the study was looking at how much water the Pedernales Watershed produces to the Colorado River, as compared to how much water Barton Creek and Onion Creek watersheds produce for the Colorado River. And what we found was one overall, and over the past 20 years, the Pedernales River has contributed more about two thirds more water than Barton and onion creeks. In part, not surprising, because the Pedernales Watershed is four times the size of the watersheds for Barton and Onion Creek. On the other hand, when you look on a per-acre basis, the watersheds for Barton Creek and Onion Creek contribute more than twice as much water. And so on a per-acre basis, you get a lot more bang for your buck.

Kelly: And what is the reason for that?

Mace: The reason for that is I think, in part, you know, the rainfall decreases as you go west in Texas. And although it doesn’t seem like it’s that much of a of a change, it’s definitely drier over there.

Kelly: What was the process of the research of gaining all this knowledge of all the different inflows and the water levels?

Mace: So we’re fortunate in that the U.S. Geological Survey operates an array of stream gauges across the state. And so we use that database to evaluate and compare the watersheds to each other. We looked at the last 20 years because that was the only period where there were streamflow measurements for the river and the two creeks. And then it was you know, applying some some hydrologic corrections and adjustments. And then and then doing doing the math and making the comparison.