by Neil Stalter | Zoom Out Mycology
The lovely smell that follows a spring rain as you sit on your porch and enjoy the sound of drips pattering on the lawn is so loved that it has earned the distinct honor of its own word, “Petrichor”. Somewhat less romantic is the source of the smell: a mix of plant oil and bacterial by-product. Despite that, when I was young, living in Conesus New York, I learned to love rainy days. There is something especially relaxing about being inside while the sky outside is unleashing millions of gallons of water onto the earth. But rain is also synonymous with sadness and difficulty; for good reason. Rain, in all of its forms, causes billions of dollars in damage in the US every year. But there is one effect of rain that is less obvious than flooding or acid rain. Every time it rains, all of those millions of gallons of water that tumble onto the ground need to go somewhere—and not all of it soaks into the soil below our feet. All that water that rolls off of your roof, through your yard, and over the street is called storm water runoff. This runoff is incredibly good at picking up whatever it comes in contact with as it travels downward to the lowest elevation. Dirt, nutrients, trash; storm water does not discriminate. By some twist of fate, the nutrients that it picks up as it travels actually cause significant damage to the surrounding ecosystem.
I spent much of my life growing up in the Finger Lakes region of New York. These beautiful bodies of water are home to thousands of species and allow for all sorts of recreation: boating, swimming, fishing, you name it. But whenever it rained the storm water would flow over farms and pick up manure and fertilizer as it traveled down to the lakes. These nutrients would then feed seaweed and phytoplankton living in the lake that make swimming and recreating much less enjoyable. The growth of this plant life due to runoff not only damages the picturesque quality of the lake, but also boxes out other important native species from growing in a healthy way. This phenomenon is called eutrophication.
The Science of the Problem
When rain falls onto the ground, it can do one of two things, flow into the ground and become groundwater, or flow on top of the ground and become runoff. As water flows into the ground, the soil acts as a “filter” catching and holding onto most anything that the rain water captured and brought with it. Trees and other plant-life also serve as important capture mechanisms for the nutrients that the water they drink brings along. However, when water has no way to enter the ground (if it falls onto a parking lot, for example) it will keep traveling above ground until it hits the nearest body of water (river, lake, or ocean). Since this water had no opportunity to deposit whatever it grabbed along the way, it deposits that matter into the water body, where it can begin to have negative effects on the ecosystem.
Somewhat diabolically, some of the organisms that most benefit from this are invasive species that are already hurting the ecosystem. As these species feed on the nutrients brought to them by storm water, they continue to outcompete other species, thus aggravating the negative effects they have on food chains. As more phytoplankton and plant life blooms and grows from the runoff nutrients (the biggest offender being nitrogen) it would be natural to think that they would at least contribute oxygen to the surrounding water, encouraging the existence of other non-photosynthetic species. Somewhat ironically, the opposite is often true. As more of this plant matter grows, more dies and sinks to the bottom of the water body. Bacteria waiting at the bottom then feeds on this dead matter while using oxygen and sending out more carbon dioxide. This creates what is widely known as a hypoxic, or “dead” zone. This oxygen free-zone pushes species of fish and other mobile species out of the area, creating an area that is almost unusable in any commercial or recreational way.
As water bodies go from a beautiful blue swimming hole to a green swampy mess, less and less people will want to use it for swimming or fishing, or even for just looking at. Quickly, important money to these communities from tourism and recreation will dry up and leave these areas with a green waterbody that is doing nothing but hosting unpleasant plant life. Endangered native species will either begin the painful road toward extinction or move on to a different, more hospitable area. In fact, due in part to the growth of this phenomenon, more than 20% of the 10,000 known freshwater fish species have either gone extinct or become endangered in the past few decades. All of this to say, runoff can be very bad for the health of our water bodies as well as the economic health of the communities that are built around them.
What's Contributing to the Problem?
The first thing we need to do to address the problem of nutrient-rich stormwater runoff is finding out what exactly is causing it. First and foremost, where are the nutrients, like nitrogen, coming from? Certainly there is some floating around the environment for water to pick up on its long journey to the sea. However, the major source by far of these nutrients, as well as other chemicals like pesticides are lawns and farms. Water captures the fertilizer that residents put on their lawns and gardens, as well as the pesticides that people apply to the plants that reside in those gardens. Farms too use massive amounts of fertilizer, and animals that are raised on these farms creates manure that also contributes to this pollution.
However, farms and lawns aren’t the only place where a difference can be made. Urban infrastructure can contribute to the problem in a major way. Earlier in the article I mentioned that the soil and trees can function as filters to prevent some of these nutrients and pollutants from reaching water bodies by catching them on their way down stream. Unfortunately our roads, buildings, and all sorts of other things humans build prevent that storm water from entering the soil at all. When water reaches the pavement, carrying everything it caught along the way, it will either run over it and reach a water body, or enter our sewer infrastructure, and eventually be diverted via pipe to our rivers and lakes. In incredibly large storms, this can even overwhelm this sewer infrastructure and send raw sewage into our fresh water bodies. This is known as a combined sewage overflow, and is unfortunately common in many cities like New York. It continues to have a negative effect on the relatively famous superfund site: the Gowanus Canal. Illegal plumbing connections in your home can even be contributing to this problem without you realizing, and could end up costing you $300 a day in fines once discovered. Having plumbing inspected regularly to ensure compliance can prevent this and go a long way to protect the environment. But even apart from combined sewer overflow, human infrastructure can contribute to a 25% increase in the volume of stormwater runoff. Not only does this development remove storm water’s ability to enter the soil, it also removes many of the trees and plants that are so instrumental in filtering runoff.
What Can We do?
Thankfully, this is a problem that scientists have been researching and deciphering for decades, and engineers and city planners have created exciting new initiatives and strategies for curbing some of the negative effects of storm water. But there are clear and easy steps that anyone with a yard or garden can take to help. The main way that both cities and homeowners can begin to address this problem is through the construction of rain gardens! It seems simple, but it really works. Rain gardens can trap and use most or all of the water captured from nearly every average storm event. An easy way to create a plan of attack and look at your yard during and after your next big rain storm. See where in the yard a lot of water seems to flow and where the grass and soil is the wettest. This is a prime location for a rain garden. Then, you can hire someone or build a rain garden yourself and fill it with whatever plants you love! Some first steps can be found at (https://www.thisoldhouse.com/how-to/how-to-build-rain-garden-to-filter-run), but many local contractors can help you with this process at your home or business. There are many different kinds of plants that work, but we here at Zoom Out Mycology humbly suggest the addition of mushrooms! They are great at filtering out nutrients and waste from storm water, and can even be later picked and used for cooking. The King Stropharia mushroom (AKA: The garden giant) would be a great addition to a rain garden or chicken coop.
Also, significant progress can be made by mitigating or eliminating the use of fertilizers, pesticides, or manures in your lawns, farms, and gardens. In fact, by some measures the average suburban lawn is applied with ten times more pesticide per acre than farmland. This is obviously done out of love for the lawn without knowing that most of this pesticide simply gets washed away into the nearest water body. So right off of the bat, the amount of pesticide used can almost always be decreased and still have the same effect. There are also other eco-friendly options for fertilizer than can be found at (http://abcnews.go.com/GMA/JustOneThing/story?id=7933235&page=1) that will still help your lawn but contribute much less to the negative impact of eutrophication.
Rain is never going away, and neither is human infrastructure. But rising technologies like permeable pavement, rain garden construction in urban centers, and public education can go a long way in protecting the beauty and ecosystem of the lakes, rivers, and oceans that so many people and animals call home. By working together to preserve plant life that filters storm water and taking steps in our everyday lives to slow runoff and instead use it for something beautiful like a rain garden, we can begin to tackle the problem of storm water pollution together. As somebody who lived on a large lake for over ten years, I know how important that lake is to me; I can only imagine how important it is for the fish who live in it. At times it can seem like these difficult problems are impossible to face, but by everyone taking small steps to help make a difference, we can make huge strides together.
About the Author
Neil Stalter is currently a student at Columbia University in New York City pursuing his Masters in Environmental Science and Policy. Neil has a background in Ecology and Evolutionary Biology at the University of Rochester. He is from the Finger Lakes region of New York, and has always been incredibly passionate about the environment, and solving environmental problems!
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