Dubuque City engineers installed 14 floating islands made from 67,000 recycled plastic bottles in Bee Branch Creek in 2017 as part of a flood‑control overhaul.
The creek, once buried in a storm sewer a century ago, was daylighted after the city lost 1,300 homes and businesses to flash floods in the 7‑square‑mile watershed. Each island covers roughly 190 square feet, adding up to 2,674 square feet of habitat. Prototypes were tested in a variety of shapes before final installation.
Constructed from BPA‑free bottles, the islands are anchored with stainless‑steel cables that allow them to shift with water flow. Native plants and driftwood were added to create year‑round habitat, while fencing keeps waterfowl from stripping vegetation.
The islands break up wave energy, slowing water and letting sediment settle, which keeps the creek clearer. Plants absorb nitrogen and phosphorus, curbing nutrient runoff into the Mississippi. Below the surface, roots and biofilms filter pollutants, and the structures provide shelter for fish, insects, and birds.
City officials conduct yearly buoyancy and vegetation checks; a 2019 inspection revealed thriving plants but needed fence repairs. Maintenance will continue through 2026 to ensure ecological benefits persist. Dubuque hopes the success will inspire similar projects in other watersheds.