Watershed Texas

We are moving closer to installing floating wetland islands in what may be the first such project at a school in Texas, and one of the first public installations anywhere in the state. The floating wetlands will be in the storm water detention basin (aka “the pond”) of the Education Village campus in League City TX, part of the Clear Creek Independent School District (CCISD).

Left: Floating wetland islands in Canada. Source: Biohavens International. Right: A pilot project in Baltimore Harbor. Source: Waterfront Partnership of Baltimore.

What is a floating wetland? It’s a small buoyant man-made island that grows wetland plants. CCISD’s islands will be made of a dense mesh of recycled plastic fibers produced by Martin Ecosystems. These floating wetlands have plant, soil and root interactions similar to a natural wetland and provide surfaces for colonies of beneficial water-cleaning microorganisms.

Although the first installation at CCISD will only be three islands of 80 square feet each (water quality improvements may not be measurable in the 6-acre pond), they will demonstrate a new way to reduce non-point source pollution and contribute cleaner water to the system. Floating wetlands are being used to reduce nitrogen and phosphorous from fertilizer  washes into waterways, which can cause low dissolved oxygen levels in the water, algae blooms, and fish kills. Wetlands can also reduce fecal bacterial populations which can be characteristic of urban storm water runoff.

This is good news for the Dickinson Bayou watershed, which has been identified as impaired by the Environmental Protection Agency for low levels of dissolved oxygen and high levels of bacteria.  The Education Village’s detention basin drains into Gum Bayou, then Dickinson Bayou, and then into Galveston Bay.

The wetlands planted by TCWP on the shallow margins of the Education Village stormwater basin are establishing, but the pond also holds acres of open water. The schools are visible in the background.

Floating wetlands are anchored to stay in one area of the pond but can rise and fall as the water level changes with storm water inflows.  This makes the CCISD pond a good test site. It is deep for a storm water basin, having an approximate 3’ depth at the center, and deeper after it rains. Few plant species in a natural wetland could tolerate this depth and fluctuation. Currently, there are acres of open, plant-free water in the detention basin, which drastically reduces the water quality improvements which would take place compared to a planted wetland.  However, depth is not critical for floating wetlands, which are able to rise and fall with the water level.

A section drawing of a floating wetland island.

Besides water improvements, floating wetlands give little chunks of habitat for native species of plants and animals which depend on the wetlands. But best of all, the floating wetlands will be a part of the students’ curriculum and outdoor experience. CCISD teachers have expressed an interest in developing the detention basin’s potential as an outdoor classroom. There is a desire to reinforce class materials on ecology, the water cycle, local flora, fauna and ecotypes, etc., with direct observation and engaging lab experiments in nature. Soon, the floating wetlands project will give students experiences in growing, propagating, and planting wetland species together. Later projects could include a competition to design and install new floating wetlands, and seeing how water quality changes as wetlands are added.

The floating wetlands are the focus of a planning meeting on Thursday, September 12 at 6:30pm in the Clear Falls High School library. The school community, students, staff, parents, and volunteers are invited to attend. For more information, please contact us.