Leaky Pipes Help Sustain Trees During Drought

Even in dry times, Waller Creek on The University of Texas at Austin campus is never without water. That’s because a significant portion of the water that flows through it — anywhere from 25% to 50% — can be traced to wastewater from leaky city pipes.

But there’s a silver lining to the less-than-perfect plumbing, according to new research. The water flowing through the creek sustains trees growing along it, allowing them to thrive during drought conditions that take a toll on trees growing along streams in more rural areas.

The research highlights how urbanization can have unintended positive effects among more well-known negative effects, such as pollution and higher levels of illness causing bacteria.

“Those negative effects are not canceled out,” said Jay Banner, a professor in the Jackson School of Geosciences and the director of the Environmental Science Institute. “One has to weigh the unintended positive consequences with the expected and long-shown negative consequences.”

Leaky infrastructure is commonplace across cities worldwide. That means that across the world, there are probably pockets of trees being sustained by wastewater like those along Waller Creek, the researchers said. Understanding the extent of infrastructure leakage and its ecological influence can help policymakers understand the broader effects of urbanization — the good and the bad — and plan accordingly.

The findings were published in the Nature Partner Journal Urban Sustainability.