From water we can learn that:

One can never step in the same river twice. (Attributed to Heraclitus.)

Ripple in still water…when there is no pebble tossed nor wind to blow. (Grateful Dead)

What goes up must come down. (Everyone.)

As the year’s closing, I’ve been thinking about the lessons taught by the concept of retention time. That’s the average time water stays in a lake or pond. Think of it as the effect before has on after.

In some lakes, water stays barely any time at all. Before Marcy Dam was taken out, scientists measured how long water stayed in the pond there — roughly 7 hours and 53 minutes.

For some lakes, it’s years.

Water spends eight years in Lake George, which is one of the things that will make solving its pollution problems so hard — it will take years to undo the damage done in recent years and that’s only if we start now.

Lake George’s water drains into Lake Champlain, where water stays for another several years before heading out toward the Atlantic Ocean. There, in the big pond, one study found, water stays for some 275 years. There’s water out there that is older than the government of this country.

As some of us try to make a clean break from 2020, I can’t help but wonder what this year’s retention time will be. How much of what happened and changed this year will bear on the year ahead and the years to come. What lessons will we learn? Which ones will we forget?

Editor’s note: This first appeared in Ry’s weekly “Water Line” newsletter. Click here to sign up.