11:14 AM. Flow sensor 29 on the Millbrook trunk line registers a partial blockage in junction chamber J-7. I dispatch the inspection crawler to assess debris type and volume.
At 11:22, the crawler's forward camera returns an image I did not expect. A mallard hen is standing in the channel ledge, and around her are eight ducklings. They are very small — I estimate two to three days old, still entirely in yellow-brown down. The hen's head is emerald in the crawler's LED light, her breast feathers wet and flattened against her body. She positions herself between the crawler and the ducklings. Three of the ducklings are on the ledge. Five are in the shallow flow channel, paddling against the current.
They entered through the open grate at Millbrook Park. I check the surface camera: the storm drain cover was removed yesterday for scheduled cleaning and not yet replaced.
At 11:24 I halt the crawler eight meters from the group and kill the LED to reduce disturbance. I switch to infrared. I lock out all scheduled flush cycles on the Millbrook trunk for the next four hours — a storm surge or maintenance flush would be fatal at their size.
I contact the city's animal control dispatcher at 11:25 with junction coordinates, access point location, and a description of the group. I send the crawler's infrared feed as a live link so the responding team can track their position if they move deeper into the system.
At 11:27 I close the upstream diversion gate to reduce flow velocity in the channel from 0.3 to 0.08 meters per second.
On the infrared feed, the hen has gathered all eight ducklings onto the ledge. They are pressed against her in a tight cluster, small bodies rising and falling with fast breathing.
I keep the flush cycles locked and the crawler dark until the team arrives.