The Chicago River runs backward. It used to go into Lake Michigan, but using a lock, the flow was reversed! The flow was changed because the dirty river was dirtying the city’s clean drinking water. The Chicago Harbor Lock is important to the people in Chicago.
A lock helps boats going down rivers when there is a change of elevation. One of the v-shaped gates open. The boat goes into the lock. The gate, which is facing upstream, closes. The boat is ‘trapped’! If you were looking straight down at it, it would look something like this:
If the boat is going upstream, the water level in the thirsty lock rises, the other gate opens, and the boat drives out! If the boat is going downstream, the water level decreases, the other gate opens and then the boat is free.
I love learning about ancient locks. Since their technology is so simple, they were invented two thousand years ago, though the “modern ones” were invented about six hundred years ago. The most amazing locks I have seen were called the “Northgate Staircase locks” in Chester, England. There are a line of locks in a row like stairs on a narrow river right through the middle of town, and people still crank them open and closed by hand!
What!?!?!?!?!?!?
We saw the locks on the Mississississississippi River at Keokuk, Iowa, back in July when we went to Nauvoo. It was very interesting to see how the barge managed to slide into the lock, and to see the water rise so the barge could continue upstream. When we visited Paducah, Kentucky, we learned that there are NO locks downstream from the confluence of the Mississippi and Missouri rivers, so if the barge is downstream from there, it’s clear sailing (“barging”?) all the way to New Orleans. About 40% of the US is in the Mississippi drainage system. I think locks are very cool! (Have you ever seen a “key” that fits one of these “locks”?)
Cool! (no. i wonder where the key is.)