A refresher course on how pipes work

Where will the ball go?

We have a very simple display at our office that I sometimes bring along with me to community events. It has a short length of plastic pipe screwed onto a backboard with a cartoon sketch of a street near a river and the words, “Your street connects to lakes and rivers.” Now, there’s nothing overly complicated about the pipe system on the display, and no hidden surprises either. It’s sized just right so that you can drop a bouncy ball in one end and watch it roll out the other. Yet, this display has the strange ability to capture and hypnotize children of all ages. Over and over, they will drop the ball in and then watch it roll out the other end. Over and over and over, and nothing different ever happens.

Pipes are pretty simple technology but, even so, there is a bizarre human tendency to stuff all sorts of things into them in the hopes that the pipes will make these things magically disappear. Take storm sewer pipes as an example. Way back when, if you wanted to build a street, you just lay a bunch of cobblestones in a row and… presto, a street!  The only problem was that every time it rained, the low spots in the streets would fill up with water and people’s houses often got flooded too. So, to solve this problem, cities started installing storm drains and storm pipes in their streets. Now there are drains in the streets in low spots and pipes underneath carry the water away, just like in a bathtub. The only problem, of course, is that the pipes have to come out somewhere.

In most communities built before the late 1970’s, storm pipes carry water from streets directly to nearby wetlands, lakes, streams and rivers. In Minneapolis and St. Paul, for example, most storm pipes connect to the Mississippi River. In Stillwater, some storm pipes travel to the St. Croix River, while others go to Lily, McKusick or Long Lakes. In neighborhoods built after the 1970’s, storm pipes usually connect to stormwater ponds first before emptying into nearby waterways. The ponds allow some of the dirt and debris to settle out and also slow the rate at which water flows out so that there is less flooding downstream.  In general, however, the concept is the same as in my rinky-dink educational display. Things that go in one end of a storm pipe eventually come out the other.

While staffing the “Storm Drain Goalie” booth at the Minnesota State Fair last week, a man bee-lined over to me to ask an important question, “Is it okay to dump antifreeze into my storm drain?” I gave him the simple answer, “No.” Were I a teacher responding to a question from a fourth grader, however, I probably would have coaxed him into answering the question like this:

Student: “Is it okay to dump antifreeze in the storm sewer?”

Me: “Where does the storm sewer pipe go?”

Student: “I dunno…the St. Croix River?”

Me: “Yep. Would you pour antifreeze in the St. Croix River?”

Student: “No. That would be icky and gross and might kill a fish or a bird.”

Me: “So, the answer is no. Don’t put stuff in the storm drain that you don’t want in the river.”

Along with antifreeze, there are a lot of other things that shouldn’t go into our storm drains – used engine oil, paint, cement wash water, soapy water from carpet cleaners, pool water, zebras. Some of these things, such as soapy water or wash water from paint brushes and rollers, can be safely poured into a drain connecting to the sanitary sewer (ie. a kitchen sink or utility sink.) Other items require more care. For example, it is illegal to put antifreeze, lead acid and sealed lead acid batteries, oil, oil filters, tires, and transmission and power steering fluids in the trash, onto the ground, or into drains or storm sewers. These items are considered household hazardous waste and should be dropped off at the Washington County Environmental Center in Woodbury (4039 Cottage Grove Dr.). Cement wash water should be dumped into a concrete washout facility; once the water evaporates, the remaining solids can be removed and recycled. Swimming pool water can be emptied into a storm drain, but only after the water has been de-chlorinated. Zebras should be returned to the zoo; they tend to get stuck in the storm pipes and don’t belong in the St. Croix either.