Stonington - A ferocious band of thunderstorms pounded southeastern Connecticut Wednesday morning and afternoon, leaving flooded roads and basements, downed trees and power lines and thousands of homes and businesses without power.

But Stonington, where 6.5 inches of rain fell in just four hours, was the epicenter of the freakish storms, which forced First Selectman Ed Haberek to declare a townwide emergency.

The most pressing matter Wednesday evening was the the Aquarion Water Co.'s reservoir and dam. The dangerously high water levels forced Aquarion to conduct an emergency release of water from the dam around 7:30 that damaged the busy intersection at Mistuxet Avenue and Jerry Browne Road.

The flood waters also trapped about 50 cars in several feet of water in the Mystic Aquarium parking lot and forced town officials to issue a voluntary evacuation order for the Birdland neighborhood off Route 1 because they feared a deteriorating dam could give way.

Numerous streets became impassable and were closed off by police. Firefighters responded to a seemingly endless number of calls to pump out flooded homes and businesses. Yards turned into lakes and some roads resembled raging rivers. Town officials will assess the damage this morning to get a better picture of what repairs will be needed.

Police Chief J. Darren Stewart said numerous buildings were struck by lightning. Several people had to be rescued from their swamped cars, while one boater had to be rescued off Barn Island by the Coast Guard and Westerly Rescue during the height of the storm.

No injuries were reported in any of the incidents.

"It really hit us hard. There's water everywhere," Stewart said early Wednesday night as he headed to the water company for the release of the dam water.

A regional deluge

Other emergency departments in the area responded to several emergencies, including downed wires and trees in the roadways.

For Groton Utilities, things started to go haywire around 11:40 a.m. At the storm's peak, around 5,400 of the company's 12,300 customers were without power, although most got it back later in the afternoon.

Around 3 p.m., Connecticut Light & Power reported that nearly 5,000 customers were without power, most in North Stonington and Stonington. And at Morgan Point in Noank, heavy rains and wind pulled trees out of the ground.

"I've never seen anything like it," said Prudence Dorazio of Morgan Point, who said it looked like a tornado had come through. "It was like a path of destruction."

WTNH-Channel 8 meteorologist Geoff Fox said the sporadic bursts of heavy rain were due to several storms passing over the same area. "You get concentrated, really heavy rain in a narrow band that runs parallel to the motion of the storm," he said.

Fox said he expected more rain overnight and today as well as continued flooding problems due to the oversaturation of the ground.

Doing their job

In Stonington, Aquarion alerted the town late in the afternoon that it would have to conduct a mandatory release of water from the reservoirs because the water level had risen to 1.1 feet above the crest gates.

Part of Aquarion's recently completed $14 million project to replace the aging Palmer dam and upgrade the facility was the addition of the crest gates to allow the release of water into the spillway. The water then flows under the road and into a small stream that can quickly flood.

According to Judy Simpanen, the company's Mystic operations manager, a failure of the dam caused by the added water pressure would have catastrophic results for those who live downstream because the water from the company's two massive reservoirs would be unleashed on their homes.

"This is exactly what the gates are designed for," she said.

The town used its reverse-911 system, while police and firefighters went door-to-door and used public-address systems to alert people who live along Cove and Wilbur roads to evacuate.

Town officials and police were at the water plant to monitor the release.

At 7:30 p.m. the gates were slowly lowered. Within seconds, water rose to the top of the spillway and waves swept over the road and though the guardrails. The intersection, stream and surrounding area quickly flooded.

About 20 minutes later, the gates were raised and the water quickly receded, leaving eels and crawfish squirming on the ground.

Before the release, Public Works Director Joe Bragaw said repairs to the bulkheads, culverts and road could reach six figures and keep the intersection closed for weeks, if not longer. Haberek said the town would seek state funds for the repairs.

The torrents of water tore sheets of asphalt from the road and eroded it underneath, although Town Engineer Larry Sullivan said it did not look too bad.

But with more rain forecast and the water still rising in the reservoir, Simpanen said the company may have to release more water today, which would necessitate another evacuation. The intersection will remain closed today.

"The water level has gone down for now but we still have water pouring in," she said.

Town officials are also monitoring the dam and bridge off Route 1 that they worry could give way and badly damage the entire Birdland neighborhood. The town issued a voluntary evacuation Wednesday afternoon and opened the emergency shelter at the high school staffed by the Red Cross.

"If it breaks there's no way we're going to be able to get people out of there," Haberek said. "It would completely destroy that area."

At about 10 on Wednesday night, the dam at Sylvia's Pond off North Main Street was breached and water flowed downhill, causing significant damage to a home on Briar Patch Road. The town is also monitoring a small bridge on Collins Road that has been damaged by the flood waters.

An interactive experience

At Mystic Aquarium in the afternoon, visitors stood by while aquarium employees tried pushing their flooded cars to dry ground. Some of them started, but many had to be hauled away on flatbed trucks.

Aquarium officials said the water rose within an hour and they made announcements to visitors that the water was rising in the parking lot. Police, meanwhile, shut down a portion of Coogan Boulevard next to the aquarium after it became impassable and some cars got stuck.

Kelly Milton, the aquarium's assistant director of guest and member services, said the aquarium called tow operators as well as Enterprise Rent-a-Car to come to the aquarium to provide cars for people. The aquarium also brought out coffee and snacks for those waiting for their cars to be removed.

As Milton talked, teams of aquarium workers, many of whom normally work with whales, sea lions and other animals, pushed cars one by one out of the water, which in some cases reached their windows. A line of cars with their hoods up stretched along the front of the aquarium. Even owners who were able to start their cars had water damage to the interiors.

Michael Covello, of Auburn, Mass., who was holding his small son in his arms while looking out at his 2006 Audi in the water, said they had arrived about 12:20 p.m. He said he was happy to find a parking spot close to the entrance because it was raining. When he came out about an hour later he found the water halfway up the side of his car. The lights on his car began blinking as the workers pushed it, which made him worry there was a problem with the electrical system. While Covello was able to start the vehicle, there was several inches of water inside.

Through it all, though, he kept smiling.

"Like I say, 'It's only a car.' That's why I have insurance," he said.

Jay Spencer, from Warwick, R.I., said when he parked his car there was just an inch of water on the ground, but when he came out two hours later, the water almost covered his wheels. And he was having no luck getting the car to start.

Promise of a new day?

A few hours later, as the crest gates were closed at the water company, Haberek got some news he didn't want to hear.

"Oh, great," he said, looking down at his BlackBerry. "The state just sent us a weather forecast. More rain and showers tomorrow. "

j.wojtas@theday.com

Day staff writers Izaskun E. Larraneta, Katie Warchut and Chuck Potter contributed to this report.