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5-Waters-Volume-5-Land-Drainage
3 Greenpark Drainage District
3.1 Scheme Summary
Scheme Area
| 2,243.87 ha |
Scheme Coverage -Capital value (as at 1 July 2020)
| Class B
| $17,853,000
|
Class C
| $14,534,000
|
Class D
| $1,050,900
|
Class E
| $22,519,000
|
Class E
| $22,788,000
|
Systems components
| Drain Length (m) | 21,613 |
| Pump stations (No.) | None |
| Other assets | None |
History
| Installation Date | Installed progressively from 1850's |
Value ($)
| Replacement Cost | $1,947,075
|
| Depreciated Replacement Cost | $1,947,075
|
Financial
| Annual maintenance cost % of total Land Drainage maintenance
| $3,670/year on average
2% of total Land Drainage maintenance spend
|
| Drainage Outlet | Ultimate discharge point | Te Waihora (Lake Ellesmere) |
| Sustainability | Sustainable drain management practices | Adopted and Encouraged |
3.2 Key Issues
The following key issues are associated with the Greenpark Drainage District. A list of district wide issues are located in 5Waters Activity Management Plan: Volume 1.
Table 3‑1 Greenpark Drainage District Key Issues
| Better understanding is required on the influence of the lake on the land drainage system in terms of water quality and flooding. | Visually monitor water levels in drain in relation to the lake levels. Undertake water quality samples |
3.3 Overview & History
The Greenpark scheme has a rating area of 2,244ha located between the rural L2, Hudsons Road and the Lake. The drainage outlets for this area are to Te Waihora (Lake Ellesmere). Total length of classified drains in 21.2km.
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.
3.4 Resource Consents
There are no existing consents for this land drainage scheme.
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.
3.5 Scheme Assets
This scheme is predominately Land drainage channels which are excavated open channels that intercept, convey and discharge groundwater to allow productive use of land.
No summary of material and diameter of these channels is available for this scheme.
3.6 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.
3.7 Photos of Main Assets
Photo 1: Jarvis Road Drain
|
Photo 2: Greenpark Road Drain
|
3.8 Risk Assessment
A risk assessment has been undertaken for the Greenpark scheme. 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. No high risks have been identified for this scheme.
3.9 Asset Valuation Details
The total replacement value of assets within the Greenpark Scheme is $1,947,075 with further details in Table 3‑2 . All of the value is made up of channels.
Table 3‑2 Replacement Value, Greenpark
|
Land Drainage | Channel | $1,947,075 |
Channels are broken down into drains, pipes and stock banks. The Greenpark Land drainage district is made up of classified drains.
3.10 Renewals
The renewal profile has been taken from the 2019 5 Waters Valuation. There are no renewals for this scheme. This asset has a maintained infinite life.
3.11 Critical Assets
The criticality model for Greenpark 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. Table 3‑3 and Figure 3‑2 below show the calculated criticality for all of the assets within this scheme that have a recorded known length.
Table 3‑3 Length of Assets per Criticality Level
5
| Low | 8,906
|
4
| Medium-Low | 12,345
|
3
| Medium | 211
|
2
| Medium-High | 0 |
1
| High | 0
|
3.12 Asset Condition
The asset condition model was run for Greenpark 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.
3.13 Funding Program
There are no projects specific to the Greenpark scheme in the 10 year LTP budgets, however the scheme will benefit from a number of district-wide initiatives. The list of district wide projects can be found in 5Waters Activity Management Plan: Volume 1.
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5-Waters-Volume-5-Land-Drainage
