Officials warn thousands of homes may flood as water is released from two Houston dams. Those living in the area hope for the best

Kevin Vitto only moved to Houston in February. What he didn’t realise until Harvey struck is that his family’s apartment, in a smart new complex, backs on to a reservoir with a dam that feeds a bayou.

Levels rose to record highs on Tuesday. As officials struggled to manage deliberate and uncontrolled water releases from the Barker and Addicks dams, more neighbourhoods flooded in an already badly hit area about 20 miles west of downtown.

Some parts face being submerged for weeks or even months and water could spill from Addicks for another three weeks, officials said.

Rain eased as the day wore on and the sun even emerged in the late afternoon. A more hopeful update followed from officials who said improving conditions mean the reservoirs are expected to crest about one to three feet lower than expected, the Houston Chronicle reported. Shortly before sunset, residents in the prosperous Memorial district went for walks, children played in the streets, and neighbours holding beer or wine gathered to gawp at flooded streets while drivers gingerly navigated roads with broken traffic lights.

Harris County flood control district said in a tweet on Tuesday that 2,500 homes may experience flooding from the Addicks dam and 670 homes from the Barker dam.

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Fears of what could happen to a swath of the city if the dams fail still stalked some residents. The 1940s homes are run by the federal government and were being repaired before Harvey; military helicopters buzzed overhead for much of the day, while in the evening a convoy of vehicles was parked along Interstate 10 as rescues continued in tandem with efforts by boat-owning civilian volunteers.

Vitto’s building has a swimming pool for residents in the middle – and now it has a boating lake out front where Highway 6, a major north-south route, is submitted. He lives on the second floor with his wife and their son, nearly two.

“He doesn’t understand what’s going on. He thinks we’re just having fun walking through water,” he said. “They told us that power should go out maybe some time today so because of that we decided to actually leave.”

Play Video 1:41 Houston flooding: 'we've never experienced anything like this' – video report

A tall grassy berm at Barker that doubles as the George Bush park hike and bike trail is a matter of metres from the complex. On an ordinary day it would be easy to not know that the park is a crucial cog in Houston’s teetering flood defence system. “I didn’t even know there was a reservoir there originally, levees and stuff,” the 26-year-old said. “I’d seen it but we didn’t actually compute that’s what it was.”

Hurricane Katrina made landfall near New Orleans 12 years ago on Tuesday. Vitto is from Louisiana and was living in Lafayette at the time, where he experienced only minor street flooding and power outages. For him, tropical storm Harvey has proved far worse. “We’re used to flooding there where we grew up but not on this scale,” he said.

And Vitto knows all about water: he works for the city of Houston as an engineer in the drinking water division. “There’s nothing that I can do now, since I can’t get to work,” he said at around midday, sounding calm as he sat at a table in a nearby Shell garage with four small pieces of luggage at his feet. Relatives were on the way to pick the family up – hopefully. “I know God has a plan so I’m not too worried,” he said.

Next to the garage forecourt, police had blocked the road. A black Hyundai Elantra’s malfunctioning horn blared again and again as a pickup truck driver tried to give it a jump-start. Around the corner, people in blue and yellow kayaks paddled down a residential street. Tied to a sign at the entrance warning “Armed Guard On Duty, No Soliciting”, a child’s boat in the shape of a swan gently bobbled, adding a novel twist to a scene that has played out in similar style across the region in the past couple of days.

Beyond the barrier on Highway 6, the water lapping at his feet, Steve Shipley readied his aluminum flat-bottomed fishing boat for action.

Facebook Twitter Pinterest Jack, who declined to give his last name, had spent the past two days sleeping in his Toyota, parked at the Shell station. Photograph: Tom Dart/The Guardian

The real-estate worker lives west of Austin and drove 200-odd miles to carry out rescue missions with other volunteers. “We’ve lost count” of how many people they’ve helped, he said. The boat holds six or seven. They started at noon on Monday and worked until 2am, bringing people to a national guard staging station at a supermarket.

The propeller broke – entailing another long drive halfway back to Austin, where they found a replacement part in the small city of Brenham. Then they were directed to Highway 6, where they planned to circle the numerous apartment complexes built here in the past couple of years with a view, pre-oil bust, to attracting energy industry workers. Shipley pointed to another man helping to prepare for launch. “Orthodontist … retired fireman … we’re all just piling in.”

Jack, who declined to give his last name, had spent the past two days sleeping in his Toyota, parked at the Shell station. He had nowhere to go even before Harvey.

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“I’m basically homeless,” he said. He lost his construction job when the firm was bought out. “I’ve been up at the Shell for the last two days. I had money and stuff but now I’ve run out, buying snacks and stuff in the store,” he said, standing a few hundred metres away from the flooded area at an intersection by Interstate 10, wearing a blue fleece with a logo that said “Hope”.

“I’ve run out of money, I ain’t got no gas, so I had to come back here and fly [panhandle] in order to make it, you know, get something to eat,” he said.

The 59-year-old was born and raised in Houston. “I haven’t seen this much water before, this is a lot,” he said. “I just hope it don’t rain no more.”

Amid personal struggles and an entire city’s tragedy, he radiated optimism as he stood beneath a barricaded overpass below spitting rain and a granite sky. “It’s gonna be out for a while, but it’ll pick up,” he said. “Once it stops raining and the water starts receding, everything will get back to normal.”

And he turned back to the traffic, holding a cardboard sign that said: “Do drive safely, any help welcome.”