Waterways approves RFP to identify source of nutrients affecting Marco Island canals
The Waterways Advisory Committee approved Thursday a request for proposal (RFP) to identify the source of elevated nutrients affecting the water canals on Marco Island. Potential sources include runoff, groundwater inflow, interconnected waterbodies, reuse water and fertilizers.
"We want to get the scientific facts to understand the reality of our water quality and to identify the sources of pollution," said chairperson Douglas R. Woodworth.
The consultant hired will be tasked to review historical water quality data, design a monitoring program to determine the source of nutrients within the waterways of the city of Marco Island and prepare a final report that includes recommendations to improve water quality, according to the RFP draft.
Excessive nutrient supply can stimulate the growth of nuisance plants, creating, on occasion, algal blooms, according to a 2019 study about nitrogen levels in Marco waters. Algal blooms can reduce water clarity and impact corals and seagrasses that provide food and shelter for fishes, crabs and shrimp.
"Once algal blooms die-off, their decomposition can reduce levels of dissolved oxygen, which is essential to most forms of aquatic life," the report reads.
The report concludes nitrogen levels have increased within Marco Island waterways over the past four years and over the past five years within the waters surrounding the Island.
"The waterways via tidal exchange may already be problematic before it enters the canals," the report reads. "Finding ways to reduce the upland sources of nitrogen, coupled with increasing the time it takes stormwater to enter the canal system would help reduce the nitrogen loading coming from the Island land uses."
Only one algal sighting in Marco Island was reported to Florida Department of Environmental Protection (DEP) in the last 30 days as of Aug. 15, according to their Algal Bloom Dashboard. On Aug. 12, DEP analyzed a sample from the water canal between N. Barfield Dr. and Juniper Ct. but no algal bloom was observed. DEP found these algal mats are made of debris, lawn clippings and some filamentous algae identified as phormidium.
"Phormidium is not listed as one of the toxin producers and as you can see there was no toxin in the sample," said Rhonda J. Watkins, principal environmental specialist at Collier County Pollution Control.
The city has been monitoring the quality of waters around the island since 2001, according to the RFP. Currently it has 12 monitoring locations around the island and the frequency of sampling has varied over the years from monthly, to bi-monthly, to quarterly. The new city budget will include funds to restart monthly water testing in 14 locations, according to Public Works Director Timothy Pinter.
At press time, the RFP was not scheduled to be considered during the Aug. 19 City Council meeting because the deadline to introduce items to the agenda had passed, according to City Manager Mike McNees. Woodworth said Thursday that he was going to request council to add the RFP item to the agenda.
Waterways Advisory Committee member Robert Roth was absent during the meeting and member Leslie Shade recently resigned from the committee, according to Pinter. Roth and Shade were both absent during the previous meeting on June 20, according to the minutes published by the city.
The next Waterways Advisory Committee meeting will be 9 a.m., Sept. 19, in the community room of the Police Department.