TRIVIA: The answer behind the surge

Our Facebook page followers saw a question we posted earlier today:

Wondering how Super Bowl viewing affects water usage—would usage surge during halftime or post-game when viewers hit the restroom?—we asked a superintendent for a flow report for last Sunday. We didn’t see a game-to-flow correlation in our Westerly plant’s report, but you’ll notice little surges throughout the day (marked by arrows in the photo above). What do you think causes them? Give us your guess.

A few guesses came in, but here’s the real answer.

As flow enters our treatment facilities, it’s screened to catch large floating debris that can damage the processes: Rags, rocks, bricks, branches, all sorts of things that could flow through a sewer. Those screens are called bar screens.

Over time, the bar screens get filled, just as your shower or sink drains do at home. Every 90 minutes (as you’ll see under the arrows in the photo above), those huge bar screens are raked clear to keep water flowing smoothly. So if you think again about your shower drain, just as the water flows faster the moment you remove the clog, the water entering our plant surges slightly ever time the debris is removed from the screens.

You can see some of the screens in action in the video below at about the 5 minute mark: