tampabay.com

Engineers say pipe near Lake Brant needs to go

Some residents complain of the lake's drainage problems but a homeowner disputes the need to change a pipe he installed years ago.

By BILL COATS
Published February 17, 2006


LUTZ - A homeowner's 2-foot-wide pipe likely is contributing to drainage problems around Lake Brant, and should be removed, Hillsborough County stormwater engineers have concluded following a study.

"He probably made a problem worse," said Chin-Feng Ho, a team leader among the engineers. Residents around Brant have argued their lake drains noticeably slower since Dan Donaldson installed the pipe in 2002. A run of rainy summers hasn't helped.

So the stormwater engineers surveyed the area last fall and plugged the numbers into a computer model last month.

They calculated Donaldson's pipe has 3.3 square feet of flow area, while the ditch it replaced had 35.5 square feet, a number Donaldson disputes.

The model used those measurements to compare flooding on the rainiest day that could be expected in 25 years. It predicted the pipe would cause floodwaters to rise 6 inches higher at Crenshaw Lake Road and nearly 5 inches higher at Grandaddy Lane, a half-mile north of the pipe.

The engineers say the pipe is part of the Brushy Creek system, which flows through Lutz, Northdale and Carrollwood, finally merging with Rocky Creek south of Gunn Highway.

Donaldson installed the pipe as he was building a home on Lake Charles Circle, on land that has been in his wife's family for 50 years.

He said the area has flooded three times since 1985, and only once since he installed the pipe. In that case, in 2004, the backup started downstream from the pipe, Donaldson said. He hopes to persuade officials to study the entire system, not just the area upstream.

"I have walked the whole system from where it leaves Lake Brant to where it crosses N Dale Mabry Highway and found the waterway is overgrown, silt and mud are built up and swamps have been filled," Donaldson said in a statement written for the Times.

"There are diversions, fences that have been built over water flow, and so much debris that it has clogged other pipes in the system. This has backed up the flow of water. I maintain that this 200 feet of pipe is the efficient section of the whole system simply because it runs unobstructed.

"As it stands now, Hillsborough County has issued me a permit for the 24-inch pipe, and until the work is done on the system, and not just surveying, I can see no reason to change out the existing pipe."

Officials haven't told Donaldson to change it. That decision rests with Rick Cabrera, head of stormwater review in the county's planning department, separate from the engineering department. Cabrera said he wanted to double-check some of the calculations with engineering.

Since 2002, complainers have prompted two environmental agencies to inspect the pipe. One inspector, with the county's Environmental Protection Commission, didn't realize it had replaced a ditch. Another, with the state's Department of Environmental Protection, found the pipe only a quarter full. Neither saw a problem.

Although Donaldson had not obtained a permit to install the pipe, those two inspection reports prompted Cabrera's staff a year ago to issue an after-the-fact permit authorizing the pipe. Complaints to county commissioners triggered the latest study.

Apart from the pipe, the study also explored why fields and pastures have flooded so much near Grandaddy Lane.

Answer: It's the lowest point between Lake Brant and Donaldson's pipe, and appears to be a natural wetland. Surveyors found that a drain pipe under Grandaddy is nearly 3 feet lower than the next pipe downstream, under Crenshaw Lake Road.

The report called Grandaddy "the sag of the drainage system."

That hardly appeased Stephen Walters, who with a partner has built a horse farm there. Water has intermittently flooded their paddocks in recent years, including last week, after 6 inches of rain fell on Lutz Feb. 3 and 4.

Walters thinks the county government should improve the area's elevation, since the county apparently did some drainage work in the area in the 1990s.

"They created that sag," he said. "You would think they would fix what they did. It's just a mess."

Ho said he's unclear about what the county did before. But Grandaddy is a private dirt road, and the county cannot spend money on private property unless it achieves a public purpose, such as preventing a public road from flooding, he said. There are no such plans for Grandaddy, Ho said.

Bill Coats can be reached at 813 269-5309 or coats@sptimes.com