VENICE — A study of stormwater at several of the 16 outfalls in the city of Venice showed higher than acceptable levels of pollutants including nitrogen, phosphorus and enterococcus bacteria.
City Engineer Kathleen Weeden told the City Council Tuesday that some of the pollution is from the “first flush” of storm runoff after a relatively dry period but noted that the readings gave the city enough information to prioritize sampling of five sites with the most troublesome results for nitrogen and fecal coliform.
“We’ve spent a lot of money on the outfalls and we’ll continue to do what we can” to improve conditions, she later added.
Tests of the water outfalls by consultant Taylor Engineering, prepared by VHB Engineering, were commissioned by the city in response to last year’s prolonged red tide, due to concerns that nitrogen and phosphorous can feed harmful algae blooms.
Samples were taken Jan. 24 and Feb. 13, with follow-up sampling on April 19; altogether, water was collected at 10 of the 16 outfalls.
Total nitrogen at most sites exceeded criteria for estuaries but was below the criteria for freshwater.
All of the sites sampled were above state standards for enterococcus, with very high concentrations observed at three sites, including where The Esplanade splits into Laguna and Tarpon Center drives, where Roberts Bay meets the Intracoastal Waterway and off of the Intracoastal Waterway, north of Venice Avenue.
Fecal coliform bacteria were above the state standards at eight of the 10 sites, including two drains into the Gulf of Mexico.
Additional sampling is planned at the five outfalls with the highest counts.
Consultants were scheduled to meet with Weeden and the city engineering team to decide the next steps.
“I’d like to see some type of pre-treatment on every outfall we have,” Weeden said of measures to filter pollutants.
The city recently received a $100,000 state grant and $75,000 grant from the Southwest Florida Water Management District to help underwrite its stormwater remediation efforts.
While the city has been working to improve the quality of its stormwater runoff, efforts were redoubled last summer, during the 2018 red tide outbreak.
In addition to the outfall testing, the city’s five-year capital plan contains a commitment of $2.7 million monitor or reconstruct outfalls.
In addition to discussing stormwater outfall water quality, Weeden used information from the Sarasota County Water Atlas to show how nitrogen levels have been trending up throughout the Sarasota Bay area.
“It isn’t a Venice situation,” Weeden said.
“We’re consistent with what we’re seeing in other water bodies,” she added. “That doesn’t mean we can’t do a better job and we want to strive for that.
“We’re not going to solve it for the whole community, but let’s do everything we can.”
The City Council approved spending roughly $6,000 to buy a water goat, which will be placed in Hatchett Creek between Grove Street and U.S. 41 Bypass. Water goats act as giant filters that trap debris as it flows through the creek.
Members of the local environmental group Hands Along the Water have previously offered to help monitor the water goat to remove debris.
That same group has also been active with the city, helping to mark stormwater drains, to alert people that pollutants should not be dumped into them.