How San Antonio-Austin could be the next Dallas-Fort Worth

Why it matters: Communities along the I-35 corridor from San Antonio to Austin, including New Braunfels, Kyle and San Marcos, are consistently some of the fastest-growing in the country.

• That can create economic opportunities, but also lead to challenges as environmental and other resources are strained and housing costs rise.

Driving the news: Cisneros moderated a Texas Tribune panel this week about the interconnected future of San Antonio and Austin.

By the numbers: The combined San Antonio and Austin metro areas are now home to just over 5 million people.

• That's expected to grow to about 8.3 million people by 2050, per Cisneros — more than the current Dallas-Fort Worth metro population of about 7.9 million.

What they're saying: "The mega-region exists whether people think about it or not," said Jenna Saucedo-Herrera, president and CEO of greater: SATX, an economic development group. "It is already happening.

• "The growth is really these regions coming together," Ed Latson, CEO of Opportunity Austin, said.

State of play: Earlier this year, San Antonio and Austin economic development leaders announced a collaboration to lobby for business-friendly programs.

• The Greater Austin-San Antonio Corridor Council, a public-private partnership, has advocated for better infrastructure and economic development for the corridor since the 1980s.

Details: Two main challenges face the growing region, according to Cisneros: transportation and water availability.

Transportation: The area needs regional mass transit, in addition to better highways to feed into I-35, Cisneros said.

• Cisneros has pushed for a public bus route along I-35 between San Antonio and Austin. It hasn't come to fruition.
• And many residents have long hoped for a rail connection between the two cities, only to have their hopes dashed.
• While a bullet train from Dallas to Houston is again in the picture, there's no immediate plan for Central Texas.
• "If we're going to have an Austin-San Antonio connection, we need to do it on our own," Cisneros said.

Water: San Antonio gets most of its water from the Edwards Aquifer. Austin largely relies on the Colorado River. Both are strained by the ongoing drought and growing populations.

• The San Antonio Water System has worked to diversify its sources in recent years, including with the Vista Ridge Pipeline bringing in water from Burleson County northeast of Austin.
• "Available and affordable water, available and affordable power … if you can't get that right, we can't talk about a lot of the growth we're discussing today," Saucedo-Herrera said.
• "We're going to be facing bigger droughts and more extreme weather in the future," according to Latson.

The big picture: Other major challenges include housing affordability, workforce training, energy reliability and access to green spaces.

• As housing prices in Austin have jumped, people have looked to San Antonio and other I-35 cities for cheaper places to live — but those communities have their own burgeoning affordability concerns.
• In the case of San Marcos and New Braunfels, newcomers are often attracted by the natural springs and rivers.
• But more development and people could threaten the future of such natural resources if local agencies don't coordinate and communicate their plans, Cisneros said.

The bottom line: "We know we're going to grow. Are we going to allow that to be haphazard, eclectic, congested, environmentally toxic?" Cisneros said. "Or is this something that can be coordinated with integrated thinking and planning?"