Two decades ago, Harris County planners predicted with chilling accuracy just how devastating a storm like Hurricane Harvey would be to the Houston area. Far lesser storms, they determined, could wreck a large swath of the city and its western suburbs.

In a report dated May 1996, engineers for the Harris County Flood Control District concluded the area's reservoir system was severely insufficient and imperiled thousands of properties. The report's authors proposed a $400 million fix: constructing a massive underground conduit that would carry water out of the reservoirs and into the Houston Ship Channel more quickly.

Had the report's recommendations been heeded, the catastrophic flooding that struck Houston a week ago might have been greatly diminished, sparing thousands of homes from floodwaters.

Instead, the report got filed away and was all but forgotten. Government leaders ignored its advice.

Today, the report reads like a prophesy of the flooding that swamped west Houston and surrounding areas. Its authors knew which neighborhoods would flood and why, and in which places the flooding would be especially damaging because the water could pool for weeks.

"The primary flood threat facing the citizens of west Harris County and west Houston comes from the inability to drain the Addicks and Barker reservoirs in an efficient manner," the report said.

When built in the 1940s, the area's reservoir system was adequate, the report said. But because of changes made to the system, and given the pace of urban development 50 years later, "the project's original design parameters and assumptions are severely outdated and invalid."

In addition to the report's main proposal of a conduit, its authors raised other alternatives, such as digging the reservoirs deeper, buying out properties at risk and creating new regulations on development.

And then there was a final, stark alternative: "Do nothing and accept risk of flooding."

Asked Monday about the report, Harris County flood control officials said they could not immediately locate a copy and were unfamiliar with the details.

"What I recall is, and I haven't read the report since back then, was that it was going to be very difficult to do physically," said Steve Fitzgerald, the flood control district's longtime chief engineer.

But Harris County's flood control director at the time the report was created, Arthur Storey, said Monday that he remembered the proposal well.

"This, what we have before us, is a massive engineering and governmental failure. I'm both angry about it and embarrassed about it," said Storey, who after his time as flood control director went on to lead the county's public infrastructure department. He retired in 2015 at 78 years old.

"My embarrassment is that I knew enough that this was going to happen," he said, referring to the destruction Harvey inflicted on west Harris County. "And I was not smart enough, bold enough to fight the system, the politics, and stop it."

Rising threat

After deadly floods in 1929 and 1935, the U.S. Army Corps of Engineers built two large reservoirs in what was then ranchland west of Houston. The idea was to store up water from heavy rains, rather than let it gush straight into the Buffalo Bayou, which runs through the city and carries stormwater to the Houston Ship Channel.

Most of the time, the Barker and Addicks reservoirs would be dry, and the land could be used for soccer fields, golf courses and dog parks. Only in heavy rains would they hold water.

After a rain subsides, water within the reservoirs can be released into the bayou slowly. Originally, the earthen dams that hold water in the reservoirs were designed without floodgates. Once the water reached a certain level, it could spill out at up to 15,700 cubic feet per second.

But the threat of flooding in areas below the dams rose during the 1940s and 1950s, as urban development crowded the Buffalo Bayou upstream of Houston. To avoid such flooding, the corps installed floodgates that could release the water more slowly, at no more than 4,000 cubic feet per second. Any faster than that, the corps knew, and homes near the bayou would flood.

During hard rains in March 1992, the reservoirs reached record levels. State Highway 6, which runs through Addicks Reservoir, had to be shut down for 10 days while officials waited for the water to drain.

The event worried Harris County flood control planners. Letting the water out too fast endangered development downstream from the reservoirs, because the bayou running toward Houston would overflow.

But letting the water out too slowly created another risk, because development was encroaching on the upstream fringes of the reservoirs. Entire neighborhoods were being built inside the reservoir bowls - in places that the Corps of Engineers and Harris County planners knew would flood if the reservoir levels got high enough.

The corps purchased all the land inside the reservoirs that would be covered by water in a 100-year rain event (one with a 1-in-100 chance of happening any given year). But on land at the western fringes of the reservoirs, which would be covered in water during a greater than 100-year rain, developers were replacing pastures with neat rows of brick homes.

Action urged

In 1996, the planning department of the Harris County Flood Control District created its report urging action.

"Of primary concern is the fact that the reservoirs do not function as originally intended which translates into increased risk of flooding upstream of the reservoirs and less protection downstream," the report said. "As development continues behind the reservoirs, there is the potential to expose as many as 25,000 homes and businesses in the reservoir fringe areas to flooding."

The conceptual plan proposed a single underground conduit consisting of perhaps eight channels, each 12 feet by 12 feet in size, to carry water out of the reservoirs and safely past developed areas downstream.

The timing, the report said, was right. The Texas Department of Transportation was embarking on a reconstruction of the Katy Freeway, the stretch of Interstate 10 west of downtown Houston. It would be a good route for the drainage channel.

"The potential flood control problems are severe enough to consider this magnitude of project, and the major transportation construction in the Katy Freeway corridor presents a unique, once-in-a-lifetime opportunity to consider this type of flood control option," the report said. "To determine if a conduit system under the freeway is justified, it needs to be evaluated against other options."

Without such a conduit, the reservoirs posed an increasing risk, the report said. Because they had to be drained so slowly, there might not be time to empty the water between storms. That meant a series of smaller storms could raise the water level just as could one big storm, a danger the report called "ratcheting."

"It is conceivable and not hard to imagine that a single storm event could have a catastrophic impact to several thousand people in the reservoirs and the fringe areas," the report said. "But, it's just as important to realize that a rainy season consisting of several 'normal' rain storms ... could be just as catastrophic because of the ratcheting effect."

1 / 6The Addicks Reservoir floods before buildings lining the Energy Corridor near Katy, Texas, Wednesday, August 30, 2017.(Tom Fox / The Dallas Morning News) 2 / 6A flooded neighborhood off North Eldridge Parkway near the Addicks Reservoir in West Houston, Texas, was inundated with water, Wednesday, August 30, 2017. Hurricane Harvey inundated the Houston area with several feet of rain.(Tom Fox / The Dallas Morning News) 3 / 6A flooded neighborhood off North Eldridge Parkway near the Addicks Reservoir in West Houston, Texas, was inundated with water, Wednesday, August 30, 2017. Hurricane Harvey inundated the Houston area with several feet of rain.(Tom Fox / The Dallas Morning News) 4 / 6A kayaker paddles through the flooded Lakes on Eldridge neighborhood near the Addicks Reservoir in Houston, Texas, Wednesday, August 30, 2017. Hurricane Harvey inundated the Houston area with several feet of rain. (Tom Fox / The Dallas Morning News) 5 / 6A flooded neighborhood off North Eldridge Parkway near the Addicks Reservoir in West Houston, Texas, was inundated with water, Wednesday, August 30, 2017. Hurricane Harvey inundated the Houston area with several feet of rain. (Tom Fox / Staff Photographer) 6 / 6A flooded neighborhood near the Addicks Reservoir in West Houston, Texas, was inundated with water, Wednesday, August 30, 2017. Hurricane Harvey inundated the Houston area with several feet of rain. (Tom Fox / Staff Photographer)

Slow drainage from the reservoirs also exacerbated the duration of flooding that would be experienced in the fringes of the reservoirs.

"Flood levels would not recede over the course of several hours like typically experienced with flooding from channels," the report said. Rather, houses being flooded by slow-draining reservoir waters "could be inundated for an extended period."

Tragic reality

Last week, the report's predictions became a tragic reality. The reservoirs became vast lakes, working as designed to spare Houston from a flood. But by Aug. 28, the reservoirs were nearly full.

The water had spread to the edge of the government-owned land and was overtaking the neighborhoods beyond.

Rather than let the water keep rising, the corps opened the floodgates to let a controlled amount escape. And instead of the normal 4,000 cubic feet per second, corps officials opened the gates wide to let water spill out at more than 13,000 cubic feet per second. They had to begin to get rid of it. They did so knowing it would flood neighborhoods downstream.

And just as the 1996 report described, water in many of the flooded homes would not drain for days or even weeks.

Storey, the former county flood control director, took a break from recovering belongings from his own flooded home Monday when reached by phone.

Long ago, Storey said, one of his best engineers came to him and an elected official about the reservoir problems. "He said, 'Let me draw you a picture.'"

"We both said, 'Oh s---, no kidding, really?' " Storey recalled.

"We really knew that at that time it would be a wise thing to stop development of any land upstream of the reservoir, have the feds buy it out, and make it part of the federally owned system," he said.

Storey said he laments that he and others did not do more.

"I wish I had gone to the commanding general of the Southwestern Division of the Corps of Engineers, and sat in his office, and said, 'Sir, I'm not going to leave your office until we come up with a better solution, because it damn well is gonna rain, and it's darn well gonna hurt people,'" Storey said. "I didn't do that."

He added: "Would I have been fired before I got halfway out of town? Maybe, but I didn't do it. And the irony is my house flooded. And all of my neighbors' did. And it was by intentional discharge by the people in command and in charge of the infrastructure."

Storey said the conduit proposal didn't go anywhere because it had no funding and required the cooperation of many agencies, and because the highway reconstruction was too far along to be slowed by another study.

"Anytime anybody comes up with a good idea, there are lots of studies and information about why it won't work, it can't be afforded, or it's not practical or politically expedient, and there was all of that," he said.

"They built the highway, and there's no storm sewer under it, and don't we wish it were today."

No funding

Richard Long has worked for the Army Corps of Engineers for more than three decades, much of it overseeing operations of the Addicks and Barker reservoirs.

"Sure, it would have been nice if we'd have had all the land necessary to hold the water on, and sure, it'd have been nicer if we had a conveyance system that would carry all these large releases that we have," Long said when asked about the 1996 report.

"Without federal funding we can't do anything like that," he said. But the county is "welcome to do that if they can work with whatever partners they need to do that, and we would encourage it to happen."

Steve Radack is Harris County commissioner of the precinct that contains the reservoirs, and has been since 1989. He said he and many others have long understood the reservoirs' problems. Radack said blame for the lack of a fix falls on the U.S. Congress, which never allocated the money.

"The corps has done an outstanding job of managing this reservoir, outstanding," Radack said. "But the problem is if you don't give them the money to do what they need to do, they can't do it.

"They knew, they asked, they didn't receive," he said.

1 / 11Heavy equipment is staged on an embankment leading up to the levee of the Addicks Reservoir near IH-10 and Eldridge Parkway as flood water from Hurricane Harvey remains next to the roadway on Monday, Sept. 4, 2017, in Houston.(Smiley N. Pool / The Dallas Morning News) 2 / 11Franklin Moor tows a couple behind his canoe as he helps residents of a west Houston apartment complex check on their homes and retrieve belonging on Sunday, Sept. 3, 2017, in Houston. The area remains flooded from Hurricane Harvey.(Smiley N. Pool / The Dallas Morning News) 3 / 11Dinah Moor (facing camera) hugs a resident of a west Houston apartment complex after she and her husband helped a couple check on their homes and retrieve belonging on Sunday, Sept. 3, 2017, in Houston. The area remains flooded from Hurricane Harvey. (Smiley N. Pool / Staff Photographer) 4 / 11Robin Cardona retrieves belongings from his west Houston apartment through flood water from Hurricane Harvey, on Saturday, Sept. 2, 2017, in Houston. (Smiley N. Pool / Staff Photographer) 5 / 11After loading a paddle boat with belongings from his apartment, Jeff Liu is helped by his mother Rhoda as he retrieves items from his car at his west Houston apartment, still inundated with flood waters from Hurricane Harvey, on Saturday, Sept. 2, 2017, in Houston. (Smiley N. Pool / Staff Photographer) 6 / 11Jeff Liu pauses while retrieving his belongings from his west Houston apartment which was still flooded with about a foot of water from Hurricane Harvey on Saturday, Sept. 2, 2017, in Houston.(Smiley N. Pool / Staff Photographer) 7 / 11Jeff Liu is helped by his mother Rhoda as they float his belongings from his west Houston apartment through flood waters from Hurricane Harvey using a paddle boat on Saturday, Sept. 2, 2017, in Houston. (Smiley N. Pool / Staff Photographer) 8 / 11Cinco Ranch Canyon Gate subdivision resident Pia Anand holds her head as she joins demonstrators who gathered at a police road clock outside their neighborhood on Saturday, Sept. 2, 2017, in Katy, Texas. The area remains cordoned off due to flood waters left by Hurricane Harvey. (Smiley N. Pool / Staff Photographer) 9 / 11Fort Bend County Judge Robert Hebert raises his hand as he takes questions from Cinco Ranch Canyon Gate subdivision residents who gathered to demonstrate at a police road clock outside their neighborhood on Saturday, Sept. 2, 2017, in Katy, Texas. The area remains cordoned off due to flood waters left by Hurricane Harvey. (Smiley N. Pool / Staff Photographer) 10 / 11A resident of the Cinco Ranch Canyon Gate subdivision holds the American Flag during a demonstration at a police road clock outside their neighborhood on Saturday, Sept. 2, 2017, in Katy, Texas. The area remains cordoned off due to flood waters left by Hurricane Harvey. (Smiley N. Pool / Staff Photographer) 11 / 11Boats from US Customs and Border Protection pass a submerged pickup truck as the perform search patrols in the Cinco Ranch Canyon Gate subdivision on Saturday, Sept. 2, 2017, in Katy, Texas. The area remains cordoned off due to flood waters left by Hurricane Harvey. (Smiley N. Pool / Staff Photographer)

Many of the thousands of homeowners who live near the reservoirs, however, didn't understand the risks those reservoirs posed. Aaron Voges lives with his wife and two kids, 7 and 12, in a flooded neighborhood called South Park, one of those located inside the reservoir.

"For some stupid reason I thought that levee that I see on my way home, I thought that protected me," he said. "I had no idea that there were plans in place to flood me to protect other people, which blows my mind."

Voges says even if he can restore his home, it now won't be worth near what he owes on his mortgage.

"Why did they build the neighborhood? Why did they let people buy out there?" he said. "It lowers what little faith I have in my government."

Correction, 11:50 a.m., Sept. 5, 2017: An earlier version of this story incorrectly described the size of the proposed underground conduit. The proposal suggested a conduit of perhaps eight channels, each 12 feet by 12 feet in size.