Wetlands for a Modern Age
With minutes to go before the US EPA press conference releasing the Clean Water Rule clarifying the definition of “waters of the United States”, (aka #WOTUS) my mind is on wetlands and all that they do for us. For many, wetlands bring images of tidal marshes and duck hunting, or perhaps spring peepers in woodlands flooded with spring rains. But the importance of wetlands, which play a disproportionate role in the heated discussion around this new rule, goes well beyond nature hikes in rubber boots.
While wetlands come in many varieties, it is generally true that they play a number of absolutely critical functions such as water storage, groundwater recharge, carbon storage, and water purification. When I was with Milwaukee Riverkeeper® years ago we developed a program for elementary schools showing the importance of wetlands that included a model in which the wetlands were represented by a sponge. The kids could pour water (representing rain) onto the sponge and see that most of it was held back in the sponge. They could also pour dirty water, representing stormwater running off of streets and roofs, through the sponge and see how the water that filtered through came out cleaner on the other side. How cool is that?
We’re living in an age of technological revolution when it comes to using and purifying water, as well as reclaiming resources such as energy, nutrients, and precious metals from our wastewater, and much of that revolution is coming in the form of better understanding of the role that nature can play. Here are a few highlights to whet your appetite:
- Minoa NY, a small up-state village, is using a constructed above-ground wetland to remove drugs from its wastewater before the water is returned to a nearby stream. To be specific, it’s actually the many species of bacteria, living on the rocks and plants in the wetland, that do most of the work. While the wetland takes up more space than a cement-and-pipe treatment plant, it operates for much less money and lower energy input.
- In agricultural areas of central Illinois, farmers interested in protecting area waters from agricultural pollutants are working with The Nature Conservancy, the USDA, and university partners to determine the optimal way to reconstruct wetlands to intercept and purify fertilizer-laden waters before they enter downstream drinking water intake plants. The hope is to avoid having to build expensive and energy-intensive nitrate-removal operations at the water utility, like the one that Des Moines has had to shoulder.
- Research headed up by Dr. Richard Luthy at Stanford University found that bivalves (clams and mussels) are very effective in removing “contaminants of emerging concern”, a catch-all phrase for pollutants like pharmaceuticals, endocrine disruptors, microbeads, etc. whose impacts we don’t fully understand, from waters. (Okay, so this isn’t about wetlands, but it’s still cool.)
- There are a number of companies working to turn research into applied reality by making it their business to harness nature for water purification. One particularly imaginative example is Floating Island International which (no surprise) makes vegetated floating islands tailored to a specific location with the aim of removing nutrients and improving water quality. Others, like Natural Systems Utilities build treatment wetlands to supplement conventional wastewater treatment.
Of course, it would be much simpler to protect wetlands in the first place rather than having to recreate them, but that’s another tale for another time.