The Metservice forecast is for rain to continue at similar rates (5-10mm per hour) in the upper part of the catchment today. In particular, this will affect the South Ashburton and North Ashburton which are currently rising. Bowyers and Taylors Streams are likely to be affected to a lesser degree. The catchment was still very wet before this rain started, so we expect river flows to rise quickly. Based on the current forecast, our estimate is that the North and South Branches of the Ashburton River could both flow at between 100 and 300 cumecs today and into tomorrow.
A lot of work has been done in these rivers over the past 6 weeks to provide temporary repairs which are intended to reduce the immediate effects of erosion, and control overflows that were occurring at the start of June. The vast majority of this work is vulnerable to erosion.
- If flows in the river at the following river gauge locations exceed 100 cumecs, our assessment is that there’s a 50% chance we’ll experience overflows at some of the same locations that experienced overflows in June.
- If flows in the river at the following river gauge locations exceed 300 cumecs, our assessment is that there’s a 90% chance we’ll experience overflows at some of the same locations that experienced overflows in June.
- We consider it unlikely that we’ll see overflows in any new locations.
- We consider it unlikely that river flows will rise to a level that threatens the Valetta or Jessops Bend stopbanks which would impact the urban areas of Tinwald and Ashburton.
- River Flow Gauges to watch:
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