July 28 flash flood

Debris around the staff gauge and extreme pool scour to the right are evidence of the 28 July flood

Rainy season was over by the end of July. However, a localized downpour on 28 July gave the largest flood so far this summer, with rainfall intensities of up to 65 mm/h (Takane Amedas), and a daily rainfall total of 149 mm (Miomote Amedas). The hydrograph response was rapid, reaching over 1.6 m at 10.30am one hour after rainfall intensities peaked at 17.5 mm in 10 minutes. In contrast, almost no rain fell in nearby Murakami - only 14 mm for the day.

This flood was followed by a 17 day period without any rain, giving a long flow recession.

The photos below show the large amount of sediment that was deposited at the mouth of the tributary, pushing the flow to the opposite bank and leading to fresh deep scour beneath the bedrock outcrop. Fortunately the stage-rating curve seems to be unaffected.