Thmyl Wats Ab Llandrwyd 4.4.2 _verified_ (2026)
On 4 April (4.4) 1962, the THMYL (Trans-Hydro-Measurement Yard, Llandrwyd) automated weir system logged a sudden anomaly in flow rate and dissolved oxygen at the Aber Llandrwyd confluence. The event, catalogued as 4.4.2 (the second major anomaly of April 4), preceded a fish kill downstream by 6 hours.
“THMYL WATS AB Llandrwyd 4.4.2” is almost certainly a from a water management or industrial heritage context in Wales. Without access to the exact original dataset (likely paper archives or a niche SCADA manual), the most confident reading is: thmyl wats ab llandrwyd 4.4.2
The THMYL station was decommissioned in 1965. Its data drum, marked “THMYL WATS AB LLANDRWYD 4.4.2,” was rediscovered in 2010 during a barn clearance near Rhayader. The event remains a case study in karst hydrology hazards. On 4 April (4