​​9   Taumutu Culverts

9.1       Scheme Summary

9.2       Key Issues

The following key issues are associated with the Taumutu Culverts. A list of district wide issues are located in 5Waters Activity Management Plan: Volume 1.

Table 9‑1 Taumutu Culverts Key Issues

9.3       Overview & History

The Taumutu culverts were installed in the early 1900's, these are:

• Whites Culvert (Rakaia No 1)
• McEvedys Culvert (Rakaia No 2)
• Coopers Culvert (Rakaia No 3)
• Forsythe's Culvert (Rakaia No 4)

Council undertook repairs to the Forsythe's Culvert in 2010 to concrete cap the culvert. The works cost $33,300.

Repairs to the Coopers Culvert was undertaken in 2014 and cost $120,993.

The Salmon farm (NZ King Salmon) maintain a culvert they own adjacent to Councils culverts at McEvedy's. NZ King Salmon have invested significantly in maintenance of the Culvert since it was installed. Council's adjacent culvert is used periodically as an alternative to the Salmon Farm culvert that services both them and other rate payers in the scheme. Council and the Salmon farm are discussing funding of the maintenance of these culverts.

Works on these culverts in the marine environment requires significant planning. Culverts shall be visited at low tide and a low height low tide should be used for planned maintenance works. The environment is high risk and the necessary health and safety plans are required for all works in this area. Southerly swells can prevent work even at low tide.

In 2011, a variation to the Te Waihora Water Conservation Order was made, bringing a strong cultural focus into place.  The Selwyn - Waihora Zone Committee (established under the Canterbury Water Management Strategy) also released its Zone Implementation Plan (ZIP) and ZIP addendum.

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​​ Figure 9-1
TAUMUTU CULVERTS Land drainage - Scheme map
Open larger map: 'Land drainage Scheme'

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9.4       Resource Consents

A resource consent is held to divert water from Coopers drain.

Table 9‑2 Resource Consents

The occupation of the culverts in coastal marine area is a permitted activity as per Environment Canterbury letter dated 10^th November 2010.

In addition, the follow agreement applies:

Table 9‑3 Resource Consent Agreement

Land drainage activities are controlled through Rules 5.57 and 5.58 under the Land and Water Plan. An application was lodged in November 2011, with a request that it be put on hold pending discussion with stakeholders, further monitoring and development of the Selwyn-Waihora Zone Plan priorities.

9.5       Scheme Assets

This scheme has four coastal culverts. A summary of material and diameter for pipes, where known, is shown below in Figure 9‑2 and Figure 9‑3.

Figure 9‑2 – Pipe Material – Taumutu Culverts

Figure 9‑3 Pipe Diameter – Taumutu Culverts

9.6       Operational Management

Council delegates some aspects of management of the Land Drainage network to 9 Land Drainage Committee's comprising of local residents with an interest in the Land Drainage network.  Council Service Delivery Staff work alongside the Committee's to prioritise and facilitate maintenance activities which are undertaken by a number of local contractors.

9.7       Photos of Main Assets

​ Photo 1:  Rakaia Culvert Number 1	​ Photo 2:  Rakaia Culvert Number 2
​ Photo 3: Rakaia Culvert Number 3	​ Photo 4: Rakaia Culvert Number 4

Committee members and landowners typically unblock the culverts when required and request assistance from Council as required e.g. for repairs and water blasting.

9.8       Risk Assessment

A risk assessment has been undertaken for the Taumutu Culverts. The key output from the risk assessment is the identification of any extreme and high risks which need to be mitigated. In order to mitigate these risks they have been included and budgeted for in the projects within this LTP. Table 9‑4 details the risk priority rating, Table 9‑5 outlines the risks and the list of key projects is found in Table 9‑8.

​Table 9‑4 Risk Priority Rating

Table 9‑5 Risks – Taumutu Culverts

The list of district wide risks can be found in 5Waters Activity Management Plan: Volume 1.

9.9       Asset Valuation Details

The total replacement value of assets within the Taumutu Culverts is $459,374 with further details in Table 9-6 below.

Table 9‑6 Replacement Value, Taumutu Culverts

Channels are broken down into drains, pipes and stock banks. The Taumutu Culverts is made up of  four culverts.

9.10       Renewals

The renewal profile has been taken from the 2019 5 Waters Valuation. There are no renewals for this scheme.

9.11       Critical Assets

The criticality model for has been updated for the 2021 AcMP. The methodology of the criticality model can be found in 5Waters Activity Management Plan: Volume 1 and it provides details of how the criticality has been calculated for the reticulation assets. Culverts were not included in the criticality model at this stage.

9.12       Asset Condition

The asset condition model was run for the Taumutu Culverts in 2021. The methodology of the model can be found in 5Waters Activity Management Plan: Volume 1 and it provides details of how the model has been calculated for the reticulation assets (particularly pipes). There is no known recorded condition for assets within this scheme.

9.13       Funding Program

The 10 year budgets for Taumutu Culverts are shown by Table 9‑7. Budgets are split into expenditure, renewals, projects and capital projects. Expenditure and renewals have been reported on a district-wide basis in Volume 1. ​

All figures are ($) not adjusted for CPI “inflation".  They are calculated on historical data, and population growth where relevant.

​Table 9‑7 Taumutu Culverts Budget Summary

An explanation of the categories within the budgets are as follows below:

• Expenditure consists of operation and maintenance costs;
• Renewals are replacement of assets which are nearing or exceeded their useful life;
• Projects are investigations, decisions and planning activities which exclude capital works; and
• Capital projects are activities involving physical works.
  

There are two projects for Taumutu Culverts in the LTP budget.

Table 9‑8 Key Projects

* LoS refers to Level of Service; G refers to Growth

The list of district wide projects can be found in 5Waters Activity Management Plan: Volume 1.

Discussion on Projects

Projects have been determined based on their:

• Relevance to the scheme
• Requirement to be completed under legislation
• Ability to bring the scheme up to or maintain the Level of Service required under council's Asset Management Policy. 

Many projects are jointly funded by more than one scheme and activity.  Each scheme pays a pro-rata share only, equivalent to the number of connections.

Discussion on Capital and Projects

Where relevant, Capital (Levels of Service) and Capital (Growth) projects have been included in the scheme financial details. 

Levels of Service Projects and growth splits have been provided to ensure the costs of population driven works are clear.