NEW PORT RICHEY — Charles Grunwald heard a muffled boom Thursday night and scratched his head.
Then came the torrent of water.
"It was like a Niagara Falls roar," said Grunwald, 66, who saw water gushing across his back yard on Tottenham Drive. "You didn't have time to react to it, it was coming so fast."
Authorities say a breach occurred about 11 p.m. Thursday in a 20-acre retention pond on the east side of Seven Springs Boulevard, just north of Perrine Ranch Road. Strained by the recent addition of rainwater to the pond, the berm broke, unleashing a wave of 30 million to 35 million gallons of reclaimed water.
The waves pushed north toward Veterans Villas, east toward wetlands and south toward Grunwald's Briar Patch neighborhood.
"Within 15 minutes, it was up to the homes," he said.
As it crested, the water seeped into Grunwald's back porch.
But about 90 minutes after the breach occurred, the water leveled out, said Jim Johnston, Pasco County Emergency Management operations coordinator. The water found its way toward ditches and steadily receded Friday.
Streets, yards and patios were flooded, but no damage to homes was reported, Johnston said.
"It had potential to flood some homes, but fortunately the land around there just facilitated that water flowing out without creating any impact," he said.
Still, the sheer force of the temporary rapids washed away residents' shrubs and anything else in their path.
"It ripped down the fence," Briar Patch neighbor Jeff Biggs said, nodding toward the chain-link fence that crews had recently installed around the retention pond.
The pond is part of a wastewater treatment plant at 2850 Seven Springs Blvd. owned by the Florida Governmental Utility Authority, which acquired it last year from Aloha Utilities.
The pond holds treated wastewater that meets the state's standards for irrigating lawns, so it will not harm wildlife or landscaping, the utility said in a press release Friday.
Crews quickly patched the breach with earth and stone as a temporary repair, the utility said. Engineers are working on a permanent fix.
Johnston said the pond will lose about 1,200 gallons an hour until the repair is finished in a few days.
But he said there should be no significant damage from the incident.
"The only effect anybody's going to notice is that their yards will be greener," he said.