Our retention pond in our neighborhood has a lot of algae and problematic plant growth due to the surrounding farms and lawn runoff, so we’re experimenting with a floating island to pull nutrients out before they can cause problems. This will also provide some interesting flowering plants, and more fish habitats.

Will be an interesting experiment to see what survives and what does poorly.

Zinnias, sunflowers, marigolds, and a few others are in net pots, inserted into cutouts in EVA foam mats.

Design is from:
http://www.beemats.com/

More reading:
https://arstechnica.com/science/2024/02/flowers-grown-floating-on-polluted-waterways-can-help-clean-up-nutrient-runoff/

https://www.sciencedirect.com/science/article/pii/S2666765723000637?via%3Dihub

  • NataliePortlandEnglish
    17•7 months ago

    Wow that’s fascinating! How will you know if it’s working? Will you do lab samples?

    • @mipadaituOPEnglish
      19•7 months ago

      For this year, we’re only interested in seeing how the island looks, and if the plants can thrive with low effort.

      Next year, if all goes well, we’ll add a lot more islands and do water testing.

      I don’t expect a significant impact to water quality with a single mat.

      • Atelopus-zeteki
        8•7 months ago

        That was my first thought, along the lines of ‘how much plant mass will you need to significantly reduce N in the water, enough so that it has sufficient reduction of unwanted photosynthesis’? I look forward to reading of your progress.

        • @mipadaituOPEnglish
          10•7 months ago

          The projects they are doing in Florida say they are targeting 10% surface coverage, that would be unrealistic in our situation, so we’re just going to do our best and balance cost/looks/effort with effectiveness.

          • Atelopus-zeteki
            1•7 months ago

            Interesting, so less than 10% might be sufficient for your needs? That dosen’t sound too onerous. I was at Fairchild Tropical Garden in Miami, FL some years ago. They had a small pond, roughly 20X30 feet more or less, with Amazonian plants. Initially the local algae was interfering with the Amazonian species, so they put black dye in the water to inhibit the algae. At the time, there was also a showing of Dale Chihuly’s glass work in the garden, including several 1-2 ft. multicolored spheres floating the the black water of the Amazonian pond; looking like alien planets floating in the darkness of space. It may well have been this pond, pictured.

            • @mipadaituOPEnglish
              3•7 months ago

              Well, to get to 10% coverage on this pond, we would need 700 of these islands (assuming they were all the same size), which would mean we needed to prep around 37,000 plants every winter to install every spring.

              We’ll probably shoot for a more realistic target to start with.