Sump is an experiment to capture sediment

Turkey Creek, as seen from the air, is a tributary to the Indian River Lagoon.

Photo Credit: Mat O'Malley

John Mongioi was boating near the mouth of Turkey Creek one day when he noticed "a tremendous hole in the water." He learned from the St. Johns River Water Management District that the hole, or "sump," was designed to capture sediment from stormwater runoff, a chronic problem in the creek, during environmental dredging that the St. Johns River Water Management District completed in 2001.

"I said, ‘That's a great idea,'" Mongioi recalls. "I knew that what we needed was a miniature sump to catch runoff before it reaches Turkey Creek."

Convincing environmental permitting agencies that digging a hole in an aquatic preserve was a challenge, but Mongioi was undeterred. He and fellow members of Friends of Turkey Creek relied on a grassroots effort to convince officials that a sediment trap or sump could abate the volume of material accumulating at the mouth of Turkey Creek.

"John thought it would be a good idea (to create a sediment sump)," recalls Palm Bay Deputy City Manager Sue Hann. "We talked to FDEP and they weren't too excited about the idea."

The sediment problem in Turkey Creek is symptomatic of many tributaries along Florida's east coast that dump freshwater into the briny 156-mile-long lagoon. The creek receives water from a large canal known as the C-1. The C-1, in turn receives stormwater runoff from a 100-square-mile network of canals. In essence, most of the pollutants, nutrients, dirt and debris carried from this large urban area into the canal system eventually make their way to the creek.

In 2001, more than 400,000 cubic yards of muck were dredged from Turkey Creek. Fish and manatees returned as water quality improved. The turnaround was short-lived, however, and the creek began to fill back up with sandy sediments, Mongioi says.

Friends of Turkey Creek pressed on. The group persuaded Palm Bay city officials, the U.S. Army Corps of Engineers, the St. Johns River Water Management District, the Melbourne-Tillman Water Control District, State Rep. Mitch Needelman and Congressman Dave Weldon to support the sediment sump project and other endeavors targeted to improve navigation and water quality in the creek.

"FDEP wanted science behind the project before they would support it," Hann says. "Dr. Ashok Pandit at Florida Tech conducted a study that indicated it should work."

The sediment sump took about three days to dig. The sump is simply a 50-by-300 foot hole, about 10 feet deep in the creek bed designed to capture material that would otherwise be distributed throughout the creek.

A five-year permit allows the city to clean out the sump in case it fills quickly following a major storm event.

"We're hoping to learn from this project," Mongioi says. "The sump could conceivably fill up after one storm. We'll just have to see what happens."