Flat land, fertile soils and proximity to water for irrigation and recreation make the lower Waitaki an attractive place to live. As a floodplain however, it is an area naturally exposed to erosion and flooding that can spread across wide areas, impacting people and property.
The goal of Otago Regional Council and Environment Canterbury’s river engineering team is to provide the community with an adequate level of safety, security and resilience from flooding and erosion. Normally, we do this by meeting with the river rating district liaison committee and setting a budget and schedule of works to meet the agreed goals. Unfortunately, we sometimes experience unplanned flood events that cause damage that cannot be remedied with the normal works plan or budget.
Waitaki Bridge
Last summer, heavy rainfall events caused significant erosion at 13 locations along the lower Waitaki River. This means we need to work together with you, and other lower Waitaki residents, to revise the budget for works and/or the level of community protection that can be provided. To fully repair each of these sites would cost about $1 million. This would restore flood and erosion protection measures for the community to the levels in place prior to last summer’s flood events.
At a community meeting in July, most of those who attended confirmed they wanted the $1m work package completed but did not want to pay for it and felt that Meridian should pay the full cost. Subsequently, a meeting was held between Meridian Energy and Environment Canterbury chief executives.
Meridian Energy has confirmed its commitment to contributing 40% of rating district costs as agreed under the current funding model, but no additional funds.
All ratepayers/residents in the lower Waitaki rating district are currently affected by a slightly increased flood risk.
Owners of the 13 directly affected sites have a significantly increased erosion and flood risk to their property.
Four of the eroded sites require a minimum level of repair as they are considered critical to residents of lower Waitaki and threaten:
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a power pylon.
Transpower has agreed to contribute funds for its protection.
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a community water supply.
The lower Waihao Rural Water Supply Scheme intake is at significant risk. Waimate District Council has agreed to consider a financial contribution to this, noting the financial constraints it is facing.
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an urupā (Māori cemetery) and
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an irrigation scheme race.
Environment Canterbury and Otago Regional Council are working together to gather the views of ratepayers to develop a solution that meets the needs of landowners (which may vary by region).
Please review the table alongside the graph below which explains the risk level for these options.
| SCENARIO |
COST |
WHAT DOES THIS MEAN FOR ME? |
|
A. Current: minimal repairs only at critical sites |
Cost: $280K
$159K already spent
on urgent repairs
|
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Critical sites: this is a short-term solution. Following minimal repairs these sites would be risk level 2 (yellow).
-
Other damaged sites: the other nine damaged sites have a higher risk of additional erosion and flooding. These sites would be risk level 3 (red).
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All lower Waitaki rating district residents: if only the minimum urgent works are done there would be a moderate risk of flooding – slightly higher than pre-flood levels. This is because the remaining eroded sites are more vulnerable to flooding, which can spread over a wide area.
|
|
B. Full repairs at the four critical sites only |
Cost: $700K |
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Critical sites: protection would be restored to pre-flood levels at critical sites only. These four sites become characterised as risk level 1 (green).
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Other damaged sites: private landholders at the other nine sites have a higher risk of additional erosion and flooding. These sites would be risk level 3 (red).
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All lower Waitaki rating district residents: repairing these sites would alleviate the majority of community flood risk. All lower Waitaki residents return to a lower risk of flooding. Risk level 1 (green).
|
|
C. Full repairs at each of the 13 sites |
Cost: $1.04 million |
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All lower Waitaki rating district residents: risk level 1 is restored for all sites. Protection restored to pre-flood levels.
|
Unless we undertake the full schedule of proposed repairs at each of the 13 damaged sites, lower Waitaki residents face a higher risk that erosion and flooding could cause damage to people and property than before.
However, we want to gauge what the community believes is an acceptable level of risk, if any.
The graph in the previous section shows the average river flow over the last 12 months, which is roughly indicative of what might happen this year. Essentially, when the river flow goes above the risk levels indicated in the graph, there is a higher chance of more erosion at the existing sites. This in turn means a greater risk of erosion and flooding, both of land adjacent to the river and the wider lower Waitaki area.
Residual risk
If scenario A, B or any other partial repair option is chosen, it should be noted that there will be an elevated level of residual risk as a consequence. Partially repaired sites and damaged sites are more vulnerable to further erosion and flood flows are less likely to be contained within the main river channel. This could cost more if it is decided to repair at a later date.
Under the current rating district funding model, individual landowners at some of the 13 sites would be asked for a one-off payment, which varies based on the work required.
All ratepayers in the lower Waitaki River rating district would be subject to an additional contribution. This would mainly affect targeted rates, with possibly a nominal increase to general rates as determined through the Long-Term Plan and Annual Plan processes.
To work out how this proposal might affect your rates bill, check your most recent rates demand. If you pay Waimate District Council rates find the ECan lower Waitaki rate that you are currently charged. If you pay Otago Regional Council rates, identify the line for Lower Waitaki River Management A and/or B. This amount is a portion of your total rates bill and is roughly equal to the dollar amount that your targeted rate would increase by to cover the cost of repairs. It could be paid back over a period of time (eg. one to five years). You can look up your current rates demand as follows:
Although rates vary depending on where your land is located, we have provided some general examples to illustrate the amount your targeted rate could increase if we proceed with the full package of repairs.
| CAPITAL VALUE |
CURRENT TARGETED RATE
(example only) |
POTENTIAL RATES INCREASE
(if we proceed with the full package of repairs)
|
| $160,000 |
$120 |
- about $120 over one year OR
- $24 per year over 5 years
|
| $290,000 |
$360 |
- about $360 over one year OR
- $72 per year over 5 years
|
| $570,000 |
$709 |
- about $709 over one year OR
- $141.80 per year over 5 years
|
| $990,000 |
$1,232 |
- about $1,232 over one year OR
- $246.40 per year over 5 years
|
Survey results, Council paper and Council decision
Print version | Lower Waitaki Erosion Survey.pdf (42.7 KB) (pdf)