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5-Waters Volume 2 - Water Supplies
15 Lincoln Water Supply
15.1 Scheme Summary
Estimated Population Served
| 7,442
|
Scheme Coverage (1 Jan 2021)
| Full Charges | 2,544
|
Half Charges | 0
|
>1 Charges
| 28
|
System Components
|
Bores/Intakes (No.) |
5 |
Treatment/Disinfection |
1
(Filtration and UV treatment is only in place on the Veuve Drive well, the other wells provide untreated groundwater) |
Reservoirs (No.) |
0 |
Pump Stations (No.) |
4 |
Piped (m) | 104,160
|
History |
Original scheme installation date |
1983 |
Value ($)
|
Replacement Cost |
$13,555,301.15 |
Depreciated Replacement Cost |
$10,730,350.06 |
Financial | Operator cost (scheduled and reactive maintenance) per connection
|
$66.72/connection |
Demand (m3)
(1 Jan – 31 Dec 2020)
|
Average daily |
2,484
|
Peak daily |
5,615 |
Minimum daily |
32.5 |
Average daily per connection |
0.97 |
Type of Supply | |
High pressure and unrestricted |
Target Pressure & Flow at boundary
|
Pressure |
>310kPa |
Flow |
>20L/min |
Sustainability |
Well Security |
Secure |
15.2
Key Issues
The following key issues are associated with the Lincoln water supply. A list of district wide issues are located in 5Waters Activity Management Plan: Volume 1.
Table 15‑1 Lincoln Scheme Issues
The Lincoln Water Supply will require additional source capacity as population and associated demand increases. | The source capacity will be managed by Council, but generally onsite pipe works will be undertaken by developers as part of their subdivision work. Council will monitor growth and demand and initiate increased capacity upgrades through the schemes Infrastructure Plan. Councl are looking at an update to the bulk water extraction policy across the district.
|
The Kildare Terrace pumps are nearing the end of their economic life and pump renewals is expected within the life of this plan. | Council will monitor the pump condition and develop and implement a renewal programme, subject to new wells replacing the need for this well.
|
Catchment management
| Council are investigating groundwater quality within the water supply protection zones, and working with ECan on this matter
|
Pressure zoning will be required within Lincoln's reticulation network, because it is growing so large
| Council are planning to install more pressure monitoring devices within the reticulation network, and we are developing a Target Pressure Plan and Network Management Strategy
|
The water supply is becoming more vulnerable to contamination from backflow, because there are more commercial and irrigation sites in Lincoln
| Council are underway with a district-wide backflow prevention project
|
The scheme has no ability to chlorinate if required in an emergency
| Council are planning for upgrades to the Lincoln water supply to allow on-demand chlorination, if there is an emergency or transgression/contamination event.
|
15.3 Overview & History
The township was originally supplied water by individual bores on each property. Individual water supplies were established for the Murray Place and Cole Street (now named Millstream Drive) subdivisions in 1975/76. A community supply was installed in 1983 after nitrogen levels in the groundwater became elevated. The Murray Place bore was abandoned and the Millstream Drive bore incorporated to the new system. A new bore was drilled at Kildare Terrace utilising surface pumps to provide the bulk of the demand. By 1988 groundwater levels had dropped due to peak summer demand and the surface pumps at Kildare Terrace were replaced with a single bore pump. A third bore was drilled at West Belt in 1998 to accommodate the increasing population, and a standby generator was installed at Kildare Terrace the following year to ensure continuity of supply.
A fourth source on Eastfield Drive was drilled in 2014 and brought online in 2016 to accommodate the continued population growth. The new source consisted of a deep bore consented at 100 L/s along with the ability to automatically flush the bore during any high turbidity events. The Eastfield Drive source now serves as the main point of supply for the Lincoln Water Supply Scheme, supplying over 60% of the total volume of water consumed.
In 2020 a fifth source, Veuve Drive, was brought online. The source consisted of a deep bore consented for 140L/s. A temporary container treatment plant was installed to allow the source to be brought online immediately and cater for the increasing summer water demand. A well at Vernon Drive has been drilled but is not yet online.
The Lincoln township is also home to Lincoln University, who have their own water supply and are not supplied from the Lincoln Water Supply Scheme.
Figure 15‑2 Scheme Schematic
15.4 System Capacity
Lincoln is planned to experience significant growth over the next 30-years, which will result in a significant increase in new water connections. Figure 15‑3 shows the projected growth in water demand for Lincoln to 2051, based on the latest housing projections.
Hydraulic models have been used to plan future water infrastructure for Lincoln, as part of a master planning exercise. The master planning provides an assessment of the sizing and timing of new infrastructure for new water sources (wells) and pipelines to service growth. Part of the master planning requires a water balance to be developed to forecast growth, using historical peak demand per household. The water balance forecasts the peak instantaneous flow per year versus the water resources available to determine the staging of new wells. The well staging assumes that one well is redundant for each water supply, to take into consideration maintenance of wells, planning/timing of new wells and security of supply i.e. to maintain average/peak demand. The master planning exercise has identified that 4 new wells be required in Lincoln, to service growth and to allow for older, less productive wells to be decomissioned (Table 15-3).
There are no reservoirs within the Lincoln Water Supply. The use of reservoir storage in Lincoln in future may reduce the total number of wells required and/or defer the timing of new wells.
Figure 15‑3 Lincoln Water Demand
Table 15‑2 Existing Water Source Capacity
Kildare Tce | 1 | 36 | To be decommissioned |
Millstream Drive | 1 | 10 | To be decommissioned
|
West Belt | 1 | 35
|
|
Eastfield Drive
| 1 | 60 | Consented for 100 L/s
|
Veuve Drive
| 1
| 65
| Consented for 140 L/s
|
Vernon Drive
| 1
| 60 (TBC)
| Not yet online
|
Table 15‑3 Future Water Source Capacity
Linc4 | Decommission Kildare Terrace
| 2020/21
| -36
|
Linc5
| Decommission Millstream
| 2020/21
| -10
|
Linc7 | Veuve Drive #2
| 2025/26
| 65
|
Linc8
| Decommission West Belt
| 2025/26
| -35
|
Linc9
| Vernon Drive #2
| 2032/33
| 60
|
Linc10
| ODP5/ODP8 (site TBC)
| 2046/47
| 60
|
Figure 15‑4 Lincoln Master Plan
15.5 Resource Consents
The Lincoln water supply has a number of resource consents. Table 15‑4 shows the water take permitted by the resource consents for this scheme.
Table 15‑4 Resource Consents
CRC090427
| To take and use water.
| North Belt, Lincoln
| 14-May-08
| 12-Aug-39
| M36/0108
| 20
| 3,600 m3per 7 consecutive days
|
CRC161472
| To take and use groundwater
| Liffey Domain, Coles Street and Eastfield Drive, Lincoln
| 25-Sep-15
| 31-Jan-35
| M36/1862 M36/1965 BX23/0300
| 50 18.9 100
| 892,944 m3 between 1 July and the following 30 June
|
CRC183459
| To take and use groundwater for community water supply
| Section 1 SO 483818
| 31-Oct-18
| 20-May-33
| M36/5377 BX23/0510
| 35 70
| 453,600 m3 between 1 July and the following 30 June
|
CRC200826
| To take and use groundwater
| Liffey Domain, Coles Street, Eastfield Drive & Burnett Lane, Lincoln
| 27-Sep-19
| 31-Jan-35
| M36/1862 M36/1965 BX23/0300 BX23/0862
| 50 18.9 100 140
| 892,944 m3 between 1 July and the following 30 June; no more than 8,640 m3/day from bore BX23/0862
|
15.6 Water Quality
The Lincoln water supply is fed by 5 operational wells, which are sampled
twice weekly and one is sampled quarterly. The reticulation is sampled weekly. All wells except Veuve Drive are currently deemed to be secure groundwater (as at 20 July 2020). Treatment is in place at Veuve Drive (filtration and UV), but the other wells provide untreated groundwater
The following details E. coli transgressions for the period 2012 to 2020. No E. coli was identified in sampling of source water during this period.
Treatment
There have been no E. coli treatment transgressions during this period.
Zone
There have been no E. coli transgressions during this period.
Chemical Analysis
The following is a summary of the raw water chemical analysis carried out at the Lincoln Water Supply.
Table 15‑5 Raw Water Chemical Analysis: Eastfield Drive Well
Total Lead (g/m3)
| 0.01 (Maximum Acceptable Value)
| 0.000125
| <0.00011
| <0.00011
| <0.000111
| ✓
|
pH (pH units)
| 7 - 8.5 (Guideline Value)
| 7.9
| 7.8
| 7.8
| 7.9
| ✓
|
Total Hardness (g/m3 as CaCO3)
| <200 (Guideline Value)
| 48.8
| 49.9
| 50.1
| 47.1
| ✓
|
Total Calcium (g/m3)
| None
| 16.56
| 16.94
| 16.83
| 15.97
| ✓
|
Total Iron (g/m3)
| <0.2 (Guideline Value)
| <0.021
| <0.021
| <0.021
| <0.021
| ✓
|
Total Sodium (g/m3)
| <200 (Guideline Value)
| 8.71
| 8.46
| 8.31
| 8.50
| ✓
|
Nitrate - Nitrogen (g/m3)
| 11.3 (Maximum Acceptable Value)
| 1.100
| 1.089
| 1.154
| 1.181
| ✓
|
Table 15‑6 Raw Water Chemical Analysis: Veuve Drive Well
Total Lead (g/m3)
| 0.01 (Maximum Acceptable Value)
| 0.00015
| ✓
|
pH (pH units)
| 7 - 8.5 (Guideline Value)
| 7.8
| ✓
|
Total Hardness (g/m3 as CaCO3)
| <200 (Guideline Value)
| 49
| ✓
|
Total Calcium (g/m3)
| None
| 17.1
| ✓
|
Total Iron (g/m3)
| <0.2 (Guideline Value)
| 0.039
| ✓
|
Total Sodium (g/m3)
| <200 (Guideline Value)
| 8
| ✓
|
Nitrate - Nitrogen (g/m3)
| 11.3 (Maximum Acceptable Value)
| 0.84
| ✓
|
Table 15‑7 Raw Water Chemical Analysis: Kildare Terrace Well
Total Lead (g/m3)
| 0.01 (Maximum Acceptable Value)
| 0.00099
| 0.00016
| <0.00011
| 0.00026
| 0.00020
| 0.000205
| <0.00011 | 0.000379
| ✓
|
pH (pH units)
| 7 - 8.5 (Guideline Value)
| 7.7
| 7.5
| 7.7
| 7.9
| 8.2
| 7.7
| 7.9
| 7.9
| ✓
|
Total Hardness (g/m3 as CaCO3)
| <200 (Guideline Value)
| 41
| 59
| 54
| 50
| 29
| 51.8
| 47.5
| 52.4
| ✓
|
Total Calcium (g/m3)
| None
| 14
| 18.9
| 17.9
| 16.5
| 10.0
| 17.05
| 15.73
| 17.64
| ✓
|
Total Iron (g/m3)
| <0.2 (Guideline Value)
| <0.02
| <0.021
| <0.021
| 0.52
| 0.57
| <0.021
| 3.52
| 0.179
| X
|
Total Sodium (g/m3)
| <200 (Guideline Value)
| 8
| 10.5
| 9.1
| 9.4
| 8.8
| 9.08
| 9.55
| 9.04
| ✓
|
Nitrate - Nitrogen (g/m3)
| 11.3 (Maximum Acceptable Value)
| 1.4
| 1.65
| 1.51
| 1.24
| <0.05
| 1.62
| 0.815
| 1.66
| ✓
|
Table 15‑8 Raw Water Chemical Analysis: West Belt Well
Total Lead (g/m3)
| 0.01 (Maximum Acceptable Value)
| <0.0001
| <0.00011
| 0.00013
| <0.00011
| <0.00011
| <0.00011
| <0.00011
| <0.00011
| ✓
|
pH (pH units)
| 7 - 8.5 (Guideline Value)
| 7.6
| 7.6
| 7.6
| 7.9
| 7.8
| 7.7
| 7.8
| 7.9
| ✓
|
Total Hardness (g/m3 as CaCO3)
| <200 (Guideline Value)
| 50
| 61
| 58
| 57
| 51.8
| 57.1
| 61.2
| 56.2
| ✓
|
Total Calcium (g/m3)
| None
| 16
| 19.7
| 18.5
| 18.2
| 16.91
| 18.71
| 19.83
| 18.04
| ✓
|
Total Iron (g/m3)
| <0.2 (Guideline Value)
| <0.02
| <0.021
| <0.021
| <0.021
| <0.021
| <0.021
| <0.021
| <0.021
| ✓
|
Total Sodium (g/m3)
| <200 (Guideline Value)
| 9.5
| 10.8
| 10.6
| 10.6
| 9.75
| 10.45
| 10.32
| 10.11
| ✓
|
Nitrate - Nitrogen (g/m3)
| 11.3 (Maximum Acceptable Value)
| 1.3
| 1.68
| 1.53
| 1.63
| 1.63
| 1.75
| 1.96
| 1.87
| ✓
|
15.7 Scheme Assets
A summary of material and diameter for pipes in Lincoln is shown by Figure 15‑5 and Figure 15‑6.
Figure 15‑5 Pipe Material – Lincoln
Figure 15‑6 Pipe Diameter – Lincoln
15.8 Operational Management
The water supply is operated and maintained under two maintenance contracts as follows:
- Contract 1241: Water Services Contract. Contract is with SICON who undertakes investigations, conditions inspections, proactive and reactive maintenance and minor asset renewals; and
- Contract 1202: Parks and Reserves Contract. Contract is with SICON who undertakes the maintenance of land scape features related to water services e.g. mowing, gardens etc.
Water quality sampling is completed under an agreement with Food and Health Ltd as required.
15.9 Photos of Main Assets
15.10 Risk Assessment
A risk assessment has been undertaken for the Lincoln 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. Table 15‑9 outlines the risk priority rating, Table 15‑10 outlines the risks and the list of key projects is found in Table 15‑15.
Table 15‑9 Risk Priority Rating
> 50 | Extreme | Awareness of the event to be reported to Council. Urgent action to eliminate / mitigate / manage the risk. Document risk and action in the AMP. |
35-50 | Very High | Risk to be eliminated / mitigated / managed through normal business planning processes with responsibility assigned. |
14-35 | High | Manage risk using routine procedures. |
3.5-14 | Moderate | Monitor the risk. |
< 3.5 | Low | Awareness of the event to be reported to Council. Immediate action required to eliminate / mitigate / manage the risk. Document risk and action in the AMP. |
Table 15‑10 Risks – Lincoln
Insufficient water supply capacity for growth
| Design reservoir and bore, site behind Lincoln New World Supermarket
| 2014
| 90
| 90 | 27
|
Insufficient water supply capacity for growth | Construct bore and reservoir | 2014 | 90 | 90 | 27 |
Electrical failure due to lightning or network spikes | Install surge diverters | 2014 | 20 | 20 | 20 |
Failure to meet NES water meter standards | NES Water Meter Compliance | 2014 | 20 | 6 | 6 |
Inability to collect income from non-metered properties | Install property water meters | 2014 | 45 | 45 | 3.5 |
Non-compliance with the DWSNZ | DWSNZ - Age Testing | 2014 | 20 | 0.7 | 0.7 |
Non-compliance with the DWSNZ | DWSNZ - Bore-head security | 2014 | 20 | 20 | 20 |
Non-consented activities | Renewal of consents | 2014 | 27 | 27 | 6 |
Inadequate treatment under all conditions | UV treatment
| 2017
|
| 5
| 5
|
Inadequate capacity into the future |
| 2017 |
| 45 | 10
|
The list of district wide risks can be found in 5Waters Activity Management Plan: Volume 1.
15.11 Asset Valuation Details
The total replacement value of assets within the Lincoln water scheme is $13,555,301 with further details in Table 15‑11 below.
Table 15‑11 Replacement Value, Lincoln
Plant and Equipment | $647,556
|
Water Reticulation
| Hydrant
| $870,974
|
Lateral | $414,706
|
Pipe | $8,438,457
|
Supply Point | $2,231,457
|
Valve | $952,152
|
15.12 Renewals
The renewal profile has been taken from the 2019 5 Waters Valuation. A graph showing the renewals for this scheme is shown in Figure 15‑7 below. There is a backlog of assets due for renewal now, and a further peak in renewals due in
2033/2034.
Figure 15‑7 Lincoln Water Renewal Profile
15.13 Critical Assets
The criticality model for Lincoln has been updated for the 2021 AcMP. The methodology of the criticality model can be found in 5Waters Activity Management Plan: Volume 1 and it provides details of how the criticality has been calculated for the reticulation assets. Table 15‑12 and Figure 15‑8 below shows the calculated criticality for all of the assets within this scheme that have a recorded known length.
Table 15‑12 Length of Assets per Criticality Level
5
| Low | 43,432
|
4
| Medium-Low | 23,321
|
3
| Medium | 20,379
|
2
| Medium-High | 14,139
|
1
| High | 1,648
|
15.14 Asset Condition
The asset condition model was run for Lincoln in 2021. The methodology of the model can be found in 5Waters Activity Management Plan: Volume 1 which provides details of how the model has been calculated for the pipe reticulation assets. Figure 15‑9 below shows the level of asset condition for these assets within this scheme that have a recorded known condition.
Table 15‑13 provides a description of the condition rating used within the condition model.
Table 15‑13 Asset Condition Grading
1.0 | Excellent |
2.0 | Good |
3.0 | Moderate |
4.0 | Poor |
5.0+ | Fail |
The number of pipe faults is also measured through the asset management system. Figure 15‑10 shows the known historic pipe failures within this scheme.
15.15 Funding Program
The 10 year budgets for Lincoln are shown by Table 15‑14. Budgets are split into expenditure, renewals, projects and capital projects. Expenditure and renewals have been reported on a district-wide basis in Volume 1.
All figures are ($) not adjusted for CPI “inflation". They are calculated on historical data, and population growth where relevant.
Table 15‑14 Lincoln Budget Summary
2021/2022 | $1,000
| $2,417,110
|
2022/2023 | $2,000
| $199,425
|
2023/2024 | -
| -
|
2024/2025 | -
| $144,425
|
2025/2026 | -
| $200,000
|
2026/2027 | -
| $48,600
|
2027/2028
| -
| -
|
2028/2029
| -
| -
|
2029/2030
| -
| -
|
2030/2031
| -
| -
|
Total |
$3,000
|
$3,009,560
|
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 several major projects for Lincoln water scheme in the LTP budget.
Table 15‑15 Key Projects
Capital Projects | 404790032 | Construct reservoir and pumps | $2,000,000
| -
| -
| -
| 90% G
|
Capital Projects | 404790035 | Lincoln growth
| $417,110
| $144,425
| -
| $393,025
| 100% G |
Capital Projects
| -
| SCADA and Monitoring
| -
| $40,000
| -
| -
| 100% LoS
|
Capital Projects
| - | Treatment Upgrades
| -
| $15,000
| -
| -
| 100% LoS
|
* Where LoS refers to Level of Service and 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.
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5-Waters Volume 2 - Water Supplies