September low flows

Very low flow conditions, equivalent to 1.17 mm/day (30 Sep)

Sand and woody debris deposited around the staff gauge

The month of September experienced exceptionally dry conditions this year, as shown by the stage hydrograph below. Only two minor precipitation events can be seen, and long periods of baseflow recession. The monthly runoff was one of the lowest on record for Takiya River, at just 46 mm. The lowest recorded monthly runoff during the period of record (2000-2019) was August 2012 with 35 mm.

Comparing the Kadec and Hobo stage data, it seems the newer Hobo logger is giving more stable data readings. Instability in the Kadec data during low flows could be due to effects of water temperature fluctuations not being compensated for adequately.

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.