What a day. We’re not sure which was a bigger deluge: the 3+ inches of rainfall we received or the hashtag #chswx on Twitter. Never one to underestimate Charleston’s ability to have a good time, we couldn’t help but notice the flooding downtown provided an irresistible opportunity for fun.
Charleston Waterkeeper is 100% supportive of spontaneous fun. Especially when it involves celebrating our right to clean water. But there’s an important point here not to be missed. It’s CLEAN water that’s worth celebrating, not the nasty stuff that floods our streets.
The rain that falls onto the urban and suburban areas of our watershed collects a wide range of pollutants as it floods our streets, pools in parking lots, and overflows our storm drains. In fact, there’s a name for it: polluted runoff. And it drains right to our tidal creeks and rivers without any treatment.
The stuff is terrible. It’s potentially harmful to human health. Research shows in major urban areas the median fecal coliform bacteria level in runoff was 21,000 cfu/100 milliliters. That’s more than 50 times the level considered safe for swimming.
It puts our local shellfishermen out of business for days after a major rainfall. DHEC automatically closes all open shellfish beds after 4 inches of rain in a 24 hour period because the bacteria in runoff contaminates shellfish beds. Beds are only reopened after testing indicates the shellfish are safe to eat.
It impairs the health of our small tidal creeks and rivers. Research shows that 75% of the rain that falls on an urban watershed enters local creeks and streams (it’s 20% or less in a forested watershed). This acute discharge of polluted water reduces the abundance of aquatic species like red drum and brown shrimp. And, sadly, over time, our own use of our tidal creeks and rivers is reduced as well.
Unfortunately there’s no bad guy to blame for this one. It’s all of us. But just the same, you can help keep pollutants out of stormwater. Here’s how. Take steps to allow rain water to infiltrate the ground on your property with vegetated open spaces, buffers, and swales. Limit the use of fertilizers, pesticides, and herbicides. If you do use them follow the instructions on the label. Pick up and dispose of pet waste in the toilet. Encourage new development in your community to use Low Impact Development principles.
The next time it rains, remember it’s not just the quantity of stormwater that affects our lives it’s also the quality.