A tube fixed upright in the water, closed except for a small intake near the bottom, so that waves and chop are filtered out while the slower tide passes freely. A float, acoustic sensor or other device inside measures the calm level. Intakes clog with silt and growth, and density differences between the water inside and outside can bias readings, so wells need regular cleaning and staff checks.
Stilling well intake is half blocked with mussels, the trace is lagging the staff by ten minutes.
Also heard as
- well
- stilling pipe
- protective well
Related terms
Tide gauge
An instrument that records water level continuously at a fixed point, the basic tool of tidal measurement.
Tide house
The small shelter on a pier or wharf that houses a tide gauge's well, recorder and electronics.
Staff shot
A set of tide staff readings taken alongside the gauge to check that the gauge is still reading true.
Tide staff
A graduated board fixed vertically in the water and read by eye to check a gauge against datum.