Resilience to heavier storms requires freeways that can handle flooding without becoming impassable, leading a local group to demand more of state and federal transportation officials.

Bayou City Initiative, a nonprofit aimed at raising awareness of the challenges as Houston faces more frequent and stronger storms, sent letters Wednesday to the Texas Department of Transportation, Federal Highway Administration and the U.S. Department of Transportation, urging them to quickly and aggressively address low-lying areas along interstates and highways at high risk of flooding.

“We are going to have to quit accepting that our freeway system gets shut down during floods,” said Rice University Professor Jim Blackburn, who formed the Bayou City Initiative. “It may take years to get out of this mess, but we need to start thinking about it right now.”

The group’s letter makes two demands of transportation officials: Establish a flood warning system that would shut down freeways prior to flooding so vehicles are not in harm’s way, and immediately begin work on long-term fixes to the areas most likely affected by flooding.

The letter asks TxDOT to reply by Dec. 1. State and federal transportation officials on Wednesday declined comment. TxDOT spokeswoman Raquelle Lewis said officials had not yet received the letter, dated Wednesday, and would need time to form a response.

“We can respond when we have something further to say on the matter,” Lewis said in an email.

A number of freeway locations around the Houston region commonly flood during heavy rains. Interstate 45 near White Oak Bayou, Interstate 10 near Shepherd and Texas 288 at its intersection with Loop 610 have filled with water in the past three major storms to hit the region.

Those deluged roads ruined cars and risked lives as people abandoned their vehicles.

In the past, TxDOT officials have conceded many of the spots lack the ability to handle severe storms because drainage is outdated or nearby bayous swell, meaning the system meant to carry water away has nowhere to put it. They argue, however, that flooding the depressed segments of freeway helps keep that water out of nearby homes.

Keeping the water on the freeways, however, complicates everything from evacuations to re-supply the regions. Ed Emmett, former Harris County Judge and chairman of TxDOT’s Freight Advisory Committee, said he agreed with the BCI letter’s requests.

“As for the interstates, I think the federal government should play a big role in making them resilient,” Emmett said. “They are federal highways.”

Houston is not the only region in Texas re-evaluating its transportation network. On a tour in Hidalgo County 10 days ago, Sen. John Cornyn, R-Texas, told local leaders it was “unacceptable” that Interstate 2, the region’s emergency evacuation route between Brownsville and McAllen, is impassable in heavy rains, according to press accounts.

Passivity simply is not a solution because freeways are critical to keeping people safe during the floods, Blackburn said.

“I think this is where we are going to have to have hard discussions,” he said. “Until we come to grips with these in an honest manner it is going to be hard and it is going to continue.”

WATER WORKS: TxDOT pumps up freeway drainage efforts, but cannot curtail every flash flood

In some areas, those changes already have been proposed or are under construction by TxDOT. Along Texas 288, the addition of a tollway along the highway led to a complete rebuilding of drainage at the Loop 610 interchange. Officials with Almeda Genoa Contractors, builders of the tollway, said flooding in the area has reduced greatly because of the construction of larger culvert systems and detention basins.

Those plans, however, are designed based on the now-outdated standard of a 100-year flood event being around 13 inches in 24 hours. The revised standard is 18 inches in a 24-hour period.

“I would say any design that does not explicitly address how they are going to handle these large flooding events … has to be reconsidered,” Blackburn said. “It is obsolete on arrival.”

The types of changes needed can vary, Blackburn said, noting he is not a highway engineer but has experience as an environmental lawyer addressing problems in public plans. Bayou City Initiative partners with about 40 neighborhood, environmental and community organizations.

In its letter, the group said it understands the fixes proposed will take years, but work must start now, including on upcoming planned projects along I-45. Officials also can get a head start by examining a similar flood warning system used in the Texas Medical Center that could be a template for a highway system.

TxDOT still can bury some freeways, Blackburn said, if done responsibly and with all the needed infrastructure in place. Interstate 69 in Afton Oaks, where the freeway flooded terribly during Allison in June 2001 when it was under construction, handled Harvey and other recent storms much more successfully because its pump stations did their jobs.

In other cases, elevating freeways may be the most responsible thing to do, Blackburn said, even though many neighbors object when TxDOT suggests it.

The critical step, he said, is that the state take on the challenge.

“Part of this is the state being unwilling to talk about climate change,” Blackburn said, conceding that is a political discussion TxDOT officials are reluctant to have without support from elected officials.

“If they don’t talk about it, Houston is getting shortchanged,” he said.

Solving the issue, however, means more cooperation and less conflict said Andrea French, executive director of Transportation Advocacy Group — Houston Chapter, which advocates for greater investment in all modes of travel in the region.

“The answer and the responsibility does not fall on one entity or agency alone, but rather the answer requires innovative collaboration and convening between agencies, elected officials, industry experts and community leaders, some of which are outlined in this letter,” French said.

Along I-45 north of downtown Houston, TxDOT is planning a controversial rebuild of the freeway that includes higher standards for detention and aims to remedy some of the flooding problems near North Main where the freeway is depressed.

“It is going to be massive, massive amount of work,” Elie Alkoury, hydraulics engineering supervisor for TxDOT, said of the I-45 project during a September tour of a pump station.

Still, the proposed new I-45 also comes with a lot worries for nearby residents and critics of the project. Though TxDOT officials have said they can engineer solutions, many have questioned the wisdom of three planned depressed sections of the freeway in Midtown, along the east side of the central business district and in the Near Northside.

“After all these floods and all those cars floating away, they want to make it a tunnel,” Brandon Grouse said at a meeting about the I-45 this summer. “That’s crazy.”

Blackburn said his concern is it will continue a cycle of problems.

“If we are going to survive flooding in this town in the long term we are going to have to come up with solutions in the short term,” he said.

dug.begley@chron.com