Marco Island’s environmental consultant Turrell, Hall & Associates has spoken, and the news is not good for our waterways. The report will be presented at a workshop on March 18 to review results and answer questions. The report is comprehensive, as it discusses potential sources of nitrogen pollution, Marco Island waterways test results for the last several years, and potential ways of reducing nitrogen pollution into Marco’s waterways. It is well-established science that excessive levels of nitrogen can have adverse impacts on both water quality and the ecology of lakes, rivers and estuaries.
Turrell, Hall & Associates reported the following potential sources of nitrogen pollution:
- Background Levels: Surrounding waters both north and south of Marco Island have elevated levels of nitrogen.
- Atmospheric Deposition: As nitrogen is the main component of our atmosphere, nitrogen compounds form naturally and are deposited via rain water. A half-acre lot in Marco Island would have between one and two pounds of nitrogen per year falling on it.
- Animal Waste: Birds, bats, pets and other animals all contribute to nitrogen loading into our waterways.
- Hurricane and Storm Debris: Storms deposit organic material (leaves, etc.) into our waterways. When this debris decomposes, nutrients are released.
- Reclaimed Water: Marco Island provides reclaimed water for irrigation purposes for recreational, commercial and multi-family properties located along the western and internal portions of the island. Reclaimed water contains significant amounts nitrogen and phosphorous.
- Fertilizers and Landscape Practices: Fertilizers accidentally applied to impervious surfaces can enter our waterways. Fertilizers applied prior to heavy rain can also enter our waterways.
- Stormwater Drains: Many of Marco’s stormwater drains are improperly situated, being at the low point of the swale. Many others are incorrectly installed and need maintenance. On Marco Island there is an issue of the loss of pervious land because of land development. Impervious land is detrimental to our waterways because stormwater will have a greater chance of flowing directly into our waterways.
According to the report, in the past four years Marco Island’s waterways testing by the city has shown that nitrogen levels have increased and water in our area is considered impaired by state criteria. Immediate action by the city is clearly needed to reduce nitrogen loading from those sources that can be mitigated.
Some of the suggestions could include the following: Monitor reclaimed water usage to make sure it is not entering our waterways with its high nitrogen and phosphorous content; Consider a ban on fertilizer usage; Enforce the fertilizer ordinance; Accelerate maintenance and repositioning of stormwater drains throughout the island, locating them at the lowest point in the swale to be more effective; consider changes to the amount of pervious land required for new construction; finally, follow the report’s recommendation to test our waterways monthly and not quarterly.