5.2       Key Issues

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

Table 5‑1 Dalethorpe Scheme Issues

5.3       Overview & History

Malvern Hills Rural Water Scheme (MHRWS) was installed from 1974 to 1978 for stock and domestic use for the area from Russell's Flat to the Selwyn River, but was extended to serve the townships of Whitecliffs, Glentunnel and Coalgate. The scheme was designed as a restricted supply with flow rates of about 90L/ha/day including domestic use.  Water is provided at low pressure and flow to the customer's storage tanks.

The MHRWS included two separate supply, treatment and distribution networks wh​ich are now known separately as Dalethorpe Water Supply and Hartleys Water Supply. The Dalethorpe Water Supply is the northern part of the MHRWS and covers approximately 8,223ha of r​ural land.  The i​ntake is located adjacent to the Hawkins River near Dalethorpe Road. 

Chlorine was originally used as the primary form of water treatment for the Dalethorpe scheme.  In 1986 a decision was made to remove chlorination.  This occurred in 1987 with the addition of UV treatment.  Chlorine was used as required mainly during times of high turbidity.

In 2016 a UV treatment upgrade occurred at the Dalethorpe scheme.  At this time Gas chlorination was introduced replacing the temperamental liquid chlorination system.

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​​ Figure 5-1
DALETHORPE Water - Scheme map
Open larger map: 'Water Scheme'

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Figure 5‑2 Scheme Schematic

5.4       System Capacity

The Dalethorpe Water Supply provides water to a large rural area.  This is used for stock and other on-farm purposes, as well as for residential drinking water.  There are no towns connected to this water supply.  Water is supplied to a tank at each point of supply via a flow restrictor that limits the daily volume to an agreed allocation (2000L/day per dwelling plus 65 L/day/ha).  Peak day demand is approaching current abstraction capacity.  Further investigation and analysis would be required to confirm the adequacy of source and distribution capacity if the scheme area were to be expanded.

Table 5‑2 Capacity Summary

*  inferred value, ** Pump flow, *** 2014​ 

​Note, the consent allows water to be shared as part of a water users group.  Refer CRC173786 & CRC173785​

5.5       Resource Consents

The Dalethorpe water supply has one resource consent​. Table 5‑3 shows the water take permitted by the resource consent for this scheme.

Table 5‑3 Resource Consents

5.6       Water Quality

The water source for Dalethorpe Water Supply is non-secure. The source, treatment plant and reticulation zone are sampled twice weekly.

The following details E. coli transgressions for the period 2012 to 2020.

Source​

There have been 234 incidences of E. coli identified in source water during this period for Dalethorpe, highlighting the importance of water treatment.

​Figure 5‑3 E. coli Transgressions – Source

Treatment

There have been six E. coli treatment transgressions during this period for Dalethorpe.

Figure 5‑4 E.coli Transgressions – Treatment Dalethorpe

Zone

There have been four transgressions during this period for Dalethorpe, two in November 2012 and two in Jan 2013.

Chemical Analysis

The following is a summary of the raw water chemical analysis carried out at the Dalethorpe Water Supply. 

Table 5‑4 Dalethorpe Water Supply Raw Water Chemical Summary

5.7       Scheme Assets

A summary of material and diameter for pipes in Dalethorpe is shown by Figure 5‑5 and Figure 5‑6.

​Figure 5‑5 Pipe Material – Dalethorpe

5.8       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.

5.9       Photos of Main Assets

​​ Photo 1: Dalethorpe Treatment Building	​ Photo 2: View of Dalethorpe treated water storage reservoirs
​ Photo 3: Bluff Road Res	Photo 4: Dalethorpe Water Treatment Plant​

5.10       Risk Assessment

A risk assessment has been undertaken for the Dalethorpe 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 5‑5 outlines the risk priority rating, Table 5‑6 outlines the risks and the list of key projects is found in Table 5‑11. The list of district wide risks can be found in 5Waters Activity Management Plan: Volume 1.

Table 5‑5 Risk Priority Rating

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Table 5‑6 Risks – Dalethorpe

5.11       Asset Valuation Details

The total replacement value of assets within the Dalethorpe water scheme is $4,711,133 with further details in Table 5‑7 below.

Table 5‑7 Replacement Value, Dalethorpe

5.12       Renewals

The renewal profile has been taken from the 2019 Waters Valuation. A graph showing the renewals for this scheme are shown by Figure 5‑7 below. The majority of renewals occur in the first ten years​.​

​Figure 5‑7 Dalethorpe Water Renewal Profile

5.13       Critical Assets

The criticality model for Dalethorpe 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 5‑8 and Figure 5‑8 below shows the calculated criticality for all of the assets within this scheme that have a recorded known length.

Table 5‑8 Length of Assets per Criticality Level

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​​​

​​ Figure 5-8
DALETHORPE Water - Criticality
Open larger map: 'Water Criticality'

5.14       Asset Condition

The asset condition model was run for Dalethorpe 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 5‑9 below shows the level of asset condition for these assets within this scheme that have a recorded known condition. Table 5‑9 provides a description of the condition rating used within the condition model.

The number of pipe faults is also measured through the asset management system. Figure 5‑10 shows the known historic pipe failures within this scheme.

Table 5‑9 Asset Condition Grading

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​​ Figure 5-9
DALETHORPE Water - Condition
Open larger map: 'Water Condition'

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​​​

​​ Figure 5-10
DALETHORPE Water - Pipe Faults map
Open larger map: 'Water Pipe Faults'

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5.15       Funding Program

The 10 year budgets are shown by Table 5‑10. Bu​dgets 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 adj​usted for CPI “inflation".  They are calculated on historical data, and population growth where relevant.​

Table 5‑10 Budget Summary

Years​	Projects	Capital Projects
2021/2022	$5,000	-
2022/2023	$10,000	$150,000
2023/2024	-	-
2024/2025	-	$100,000
2025/2026	-	-
2026/2027	-	$300,000
2027/2028	-	-
2028/2029	-	$400,000
2029/2030	-	-
2031/2032	-	-
Total	$15,000	$950,000

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.
  

​Table 5​‑11 Key Projects​​

Account Label	GL	Description​	Year 1($)	Year 2($)	Year 3($)	Years 4 to 10	Funding Split *
​Capital Projects​	-	Additional reservoir site	-	-	-	$300,000	TBC​
​Capital Projects	​-	​Second Bluff Road reservoir	​-	​-	-	​$200,000	​TBC
​Capital Projects	-	Pumping main upsized	​-	-	​-	​$100,000	TBC
​Capital Projects	​-	​Additional chlorine analysers	​-	​$150,000	​	​	​100% LoS
​Capital Projects	​-	​Treatment upgrades	​-	​-	​-	​$200,000	​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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