The unmodified flow graph below is estimated from adjacent catchments.
This is the flow expected at the Wairoa at Irvines site if there was no dam in place.
Catchment size: 462 km2
Period of analysis: 11 November 1957 to 1 June 2023.
Comment: The flow at the location Wairoa at Irvines was traditionally measured by a flow recorder located just below the confluence of the Wairoa and Lee rivers. This recorder has been replaced by individual recorders on the Wairoa, Lee and Roding Rivers.
The flow currently published as “Wairoa at Irvines” is the sum of the three upstream tributaries, and is considered by Council to be a continuation of the original flow site.
| Flood Flows | Drought Flow | ||
|---|---|---|---|
| Return Period | (m3/s) | 1 day average | 7 day average |
| Annual | 711.2 | 2.046 | 2.206 |
| 5 Year | 921.9 | 1.597 | 1.705 |
| 10 Year | 1065.8 | 1.445 | 1.534 |
| 20 Year | 1193.8 | 1.333 | 1.409 |
| 50 Year | 1345.9 | 1.219 | 1.282 |
| 100 Year | 1450.7 | 1.150 | 1.204 |
| Extreme Recorded | 1466.3 25/01/1986 | 1.197 03/03/1973 | 1.292 28/02/1973 |
Tasman District Council has exercised all reasonable skill and care in collecting and displaying this information. However, the data is provisional, and may be incorrect until checked by staff. Data should be used with caution where there are safety, monetary, or operational consequences if the data is incorrect. Note also, the data may be changed at a later time.
