Sunday, September 4, 2016

Lassoing Lake Lariat

It's hard to believe that the tiny floating tufts of vegetation in the photo here are capable of doing the work of about an acre of wetland shoreline in cleaning up pollution in a lake. These are artificial floating islands mimicking those in northern lakes. They actually do a great job in reducing nutrient and other pollution in Lake Lariat, Maryland. Since Lake Lariat covers 90 acres, a 90:1 ratio of wetland buffer to water surface seems like it wouldn't make that much difference, but the lake was significantly less polluted a year after these floating islands were introduced. 

Two small man-made floating islands are just off the point on the left.
The technology for these floating islands is described on the Maryland distributor's website. They employ a proprietary soil mix, which I can't help but wonder if it could be further enhanced by including biochar. Cycling of pollutants is principally through all the slime that accumulates on the plastic fibers and submerged roots of plants growing on the platform. 

The Lake Preservation Committee was interested in getting more of these islands, last I heard. With the latest blue-green algae bloom episode, we need to, but proactive measures to reduce runoff and seepage from septic systems would be necessary to eliminate the problem altogether. If we target a buffer zone of 1000 feet all around the lake, our campaign would probably include that many homes. I think cleaning up a lake is even more vital than cleaning up a major tidal waterbody, such as the Chesapeake Bay. For one thing, this lake flows through a dam into a bay tributary, so it is a point source of pollution. Another thing is that people living and playing in and around the lake are subjected to more risk because pollutants accumulate there, are confined to a much smaller volume, and may seep into aquifers.

Since all of Maryland's 100 lakes are man-made, using man-made islands to bring balance to those ecosystems seems like a natural fit. They can have other purposes, as well, including creating a causeway, artificial shorelines, hunting blinds, and biogas supplies. My own idea is to park them near the waterfront of property owned by anyone who balks at repairing a failed septic system and put warning signs to swimmers and fisherfolk to avoid that part of the lake. I hope it never has to come to that.

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