Flooding in Ynyshir during Storm Dennis in 2020 was caused by the Rhondda Fach river and two culverts, a council report has said. The latest section 19 report into flooding caused in February two years ago identifies the overflowing of the Rhondda Fach River and the surcharging of two culvert inlets located at Heath Terrace as the two main sources.
There was internal flooding to 26 properties, including 24 houses and two businesses, along with significant highway flooding in the area, the report said. The river overflowing was caused by a fallen tree and other debris obstructing river flow. You can see the stark images show the sheer devastation wrought by Storm Dennis two years ago here.
This took place at a highway bridge connecting Avon Terrace and Riverside Close, causing water to rise behind this obstruction. The report said very high river levels contributed to the severity of the river overflowing with NRW’s station at Maerdy (around 7.5 km upstream) recording its second-highest peak during Storm Dennis, which was 1.371m.
