You’re standing on a farm looking out over a huge group of cows to your left. The smell is pretty bad, and you’re disgusted by the cows walking around in their waste without a care in the world. You glance over to your right and notice a beautiful stream that runs along the farm and then continues on. All of the sudden the clouds open up and a downpour hits.
As the rain comes down the ground is getting saturated and the water is running down into the stream unimpeded. You notice the water getting murky, and then you start wondering where the stream goes. The water from the farm must be full of diseases and pathogens from the waste, and you hope that this stream doesn’t link up with any major waterways, but you’re pretty sure it does.
Then you start to think that maybe this stream leads to a recreation area where people are in the water swimming and having fun. Or runs behind someone’s house where their kids go down and play in it. There’s a moment of panic where you wonder if you should follow the stream to warn people about what’s in it. But then you realize you’ve been standing there for 30 minutes and have to get back to feeding all of your cows.
While this story is fictional the situation described is not. Everyday our waterways are polluted by runoff and the problem is getting worse. And it’s not just waste from animals that is a problem. Agricultural runoff adds nitrates and phosphorous from fertilizer into the water. Water is polluted by human waste in other parts of the world where open defecation is the norm. Sediment runoff also is a factor in polluting our waterways. And remember the last time you were driving down the road leaving a trail of oil? What do you think happens to that oil when it rains?
This all sounds pretty bad, and it is, but there’s a way to help protect our waterways: riparian buffers. A riparian buffer is a zone of vegetation that runs alongside of a waterway. The type of vegetation varies with the climate, but usually consists of grasses or groundcovers, trees, and shrubs. These plants act as a buffer between the water and all the nasty things that are trying to make its way into the water. As the polluted runoff moves through the plants it is filtered and the majority of it never makes it into the water. It has also been found that the plants in the buffer zone can even pull pollution out of the water running downstream. But how affective can plants really be?
The USDA has found that riparian buffer zones can lower the amount of nitrates in the water by between 65-70%. In the Chesapeake Bay scientists found that the buffer zone removed 89% of the nitrogen in runoff, and in another study in Maryland it was 95%. An additional study in the Coastal Plain of North Carolina suggest that grass buffers can reduce phosphorus loads by as much as 50-70%. Further, scientists have found that levels of bacteria from animal waste can be reduced by 70-95%. They found that even a thin strip of grass sod (2ft) reduced bacterial levels by 83%. It has also been found that buffers reduce the levels of metals such as lead, chromium, copper, nickel, zinc, cadmium, and tin that come from mining, urban runoff, cars, and industrial practices.
So why is it important to get all of this out of our water? Well most of this stuff is really bad for us. High levels of nitrates have been linked to “blue baby syndrome” (a reduction in the oxygen-carrying capacity of the blood), death in small children, birth defects, and stomach and other types of cancer. Pathogens from improperly treated sewage, wildlife, stormwater runoff, leaky septic systems, and runoff from livestock operations cause salmonellosis, mastitis, scours, anthrax, tuberculosis, brucellosis, tetanus, and colibaciliosis. These diseases can infect humans and animals alike. Toxins such as pesticides and metals can destroy an aquatic ecosystem, but also can harm humans. The EPA found that toxins can cause disorders of the immune, reproductive, developmental, and neurological systems. All of this is very bad and you don’t want to be anywhere near it let alone drinking it in your water.
A lot of waterways already have buffer zones naturally, but even more of them have been destroyed by human sprawl. People destroy the buffer zones to make their view better, because they want to have more room to grow crops or for their livestock to graze, because they’re building a pathway along the water, etc.
Also, I should mention that there are a number of other benefits to riparian buffer zones such as reducing erosion, providing habitat and nutrients for wild animals, and they help maintain fish habitats among other things.
Knowing all of this I really believe that farms and other sources of water pollution should be required by law to have some kind of buffer zone around their property to protect the rest of us from the runoff. It’s relatively simple and can have such a huge impact on the quality of water that it seems like a great solution, but I know how things go in this country so I won’t hold my breath.
One last quick but important note; in developing countries this could also help the local economy by providing jobs to install and maintain the buffer. I would also think that the plants used could be of a combination of types that produce fruits or vegetables which could be a source of income and/or food. Overall riparian buffer zones are a great way to keep our waterways clean(er) and protect us from all of the harmful pollutants that find their way into our water.
As always, thanks for reading. If you liked this post you might find an earlier post on artificial wetlands interesting.