Happy Thought for 20 Mar 2026

Have a Happy Thought:

Dams on rivers have many benefits to humans (power generation, managing downstream flow, ensuring year-round drinking and farming water, etc). Unfortunately, dams have equal (or often greater) dis-benefits to creatures that live in and around those rivers.

One major issue is allowing fish that use the length of the river for feeding and spawning, to actually travel the length of the river!

The city of Utrecht, Netherlands, has addressed this issue by having a “fish doorbell”. When fish pass in front of a camera, the lock keeper can let the fish through. But to make sure the lock keeper doesn’t miss any fish… there is a website where you (and about 1,000 others at any given time, it seems) can watch the live feed, and press the fish doorbell on the fish’s behalf!

Image: The Utrecht canal lock keeper opens the lock. About — The Fish Doorbell

 

Many other rivers, canals, etc have had fish passages installed, such as this one on the Waikato River in New Zealand.

Image: An example of a fish ramp, constructed in 2007, next to the Waikato River. Photo: Stuart Mackay/NIWA.

And other areas are opting to remove dams entirely, allowing rivers to return to natural flows. And leading to tear-inducing headlines like this from July 2025: “Indigenous youth kayak 300 miles down restored river following largest dam removal project in the world.”

Image: Indigenous youth kayak 300 miles down restored river following largest dam removal project in the world: 'It was a really long, hard fight'

 

Thanks to @kottke on Mastodon Social for letting us know about the Fish Doorbell.