TOKOMARU
SHANNON & MANGAORE
FOXTON
FOXTON BEACH
LEVIN
MOUTOA
HOW TO READ YOUR METER
Urban Water Supply Areas
At it's meeting on 5 February 2008, Council formally adopted Urban Water Supply Areas for the Horowhenua District and resolved that officers are to advertise and make available to the public the adopted Urban Water Supply Area. Under the proposed Water Supply Bylaw, these Urban Water Supply Areas will define where Council is obliged to provide an ordinary supply of water and is an area serviced by a reticulated water supply system with a fire fighting capbility, that is intended to supply water to customers via on demand supplies.
Hard copies of the Urban Water Supply areas for the Horowhenua District may be viewed free of charge at the Council Customer Service Centres in Levin, Foxton and Shannon. Hard copies may be purchased from the service centres for 50 cents per colour A4 page. Maps showing the Water Supply Areas are also available here in PDF format.
Proposed Bylaw Consultation Information
The following documents are available in PDF format:
Public Notification of Statement of Proposal Trade Waste and Water Supply Bylaws (date for submissions extended to 29 February 2008)
Council Report - 5 December 2007
HDC Council Meeting Minutes - 5 December 2007
Summary of Information - Proposed Water Supply Bylaw 2008
Statement of Proposal - Proposed Water Supply Bylaw 2008
Water Supply Bylaw Submission Form
Water Connection/Disconnection Application Form
Click here for an Application Form to apply for a connection/disconnection to Council's underground water and sewerage networks.
Levin Water Treatment Plant
Chemical Use
There is a range of chemicals used at the Levin Water Treatment Plant in order to achieve the desired water quality.
Turbidity
Turbidity is a measure of how "dirty" the water is. Under normal circumstances the water is quite clear, but this does not satisfy the Drinking Water Standards, which require that the water be less than 0.5 NTU (Nephelometric Turbidity Units).
In order to reduce the amount of constituents that contribute towards turbidity a combination of chemicals are employed.
PAC (Poly Aluminium Chloride) is used to coagulate the material into larger sized particles so they can be readily trapped on the sand filters. Approximately 4 g/m3 (parts per million) is used at Levin.
A Polyelectrolyte (L3RC Polydadmac) is used to change the electrical charge on each particle so they can be attracted to and adhere to the sand particles in the filter. Approximately 1 g/m3 is used at Levin.
Soda Ash (Sodium Carbonate) is used to raise the alkalinity of the water. This assists with the coagulation process. The alkalinity is also used to limit the corrossiveness of the water, as low alkalinitiy waters will allow some metals from pipes and fittings to dissolve and appear at elevated levels in the water. Some of these metals can have quite toxic effects (ie Lead) Soda Ash is used at the rate of approximately 7 g/m3 at Levin.
Filtration
There are 10 sand filters at Levin where the water is passed through a layer of sand some 0.75m in depth. The coagulated material is trapped on the sand, and then released during a backwash procedure to return to the river though some settling basins.
Disinfection
Chlorine gas is used as a disinfectant to sterilise the water. The chlorine gas is dissolved in the water at a rate of around 1 g/m3. This level is utilised in order to ensure the minimum level stipulated in the Drinking Water Standards of 0.2 g/m3, is available at the extremities of the reticulation (pipework). The water is disinfected to ensure no bacterial or organic material is present in the water, so residents can be confident that it is safe to drink.
The Drinking Water Standards limit the maximum dose of chlorine to 6.0 g/m3.
Tokomaru
| Population: 500 |
Properties 140 |
| Average consumption |
206 m3/day |
| Peak consumption |
243 m3/day |
| Reservoir capacity |
187 m3 |
Water Source
Tokomaru River at Horseshoe Bend by an infiltration gallery under the main stream bed.
The water is pumped from a well in the river bed up to a break pressure tank located near the entrance to the Reserve. The water is gravity fed from this tank through the treatment plant into the main reservoir located in Tokomaru Road at a point some 0.5 km from the township. The water is gravity fed from here through a 150 mm pipe into the township. The Intake and Treatment Plant were constructed in 1987 replacing an earlier intake system based on a bore at a point closer to Tokomaru Village.
Consent (no 4507, 864 m3/day) expires 2019. Treatment: chlorination of the raw water into the main reservoir.
The reticulation comprises some 6.3km of pipe ranging in size from 150mm down to 25mm. It is predominantly AC pipe work with some PVC pipes. It was mostly laid in 1980 with some laid in 1990.
Current Issues
The reservoir provides less than the desirable 24 hour storage. To add an additional reservoir would cost $80,000.
No protection is provided against Giardia or chryptosporidium. Several options are available including ozone treatment and the use of very fine filters. $100,000 is the likely cost.
Shannon & Mangaore
| Population: |
Shannon 1400 |
Mangaore 100 |
Properties 600 |
| Peak consumption |
1025 m3/day |
| Average consumption |
785 m3/day |
Reservoir capacity 1150 m3 in the main reservoir and 188 m3 in tanks servicing the Mangaore Village. The reservoir is located in Mangaore Road at a point some 2km from the township. The water gravity feeds from here through a 225 mm pipe into Shannon township and is pumped up from the reservoir to the tanks servicing Mangaore Village.
Water Source: Mangaore Stream approximately 800 metres upstream of the Power Station from a weir. where a grating is in place to intercept large stones and leaves. The water is gravity fed to a sand/gravel trap. Records indicate that the intake was installed in 1925.
Consent: currently no consent, application has been lodged and submissions have closed. There are issues to be resolved with DOC and MidCentral health.
Supplementary supply. A bore has been developed west of Shannon in Bryce St. It could be used for industrial supply and for town supply in the event of an emergency. (consent no 100162, 1800 m3/day).
The Shannon reticulation comprises some 19.8km of pipe ranging in size from 250mm down to 25mm. It is predominately AC pipe work. It was mostly laid in 1970 with some more recent pipes laid in 1996. The Mangaore reticulation comprises some 1.13 km of pipe of predominantly 100mm pipes. Some PVC pipe has also been installed. It was laid in 1975 by the Electricity Corporation to service the village which was under their control at that stage. The rising main from the pump-station is a 100mm PVC pipe laid in 1991.
Current Issues
The raw water flows by gravity down the gorge in a steel pipe (225mm diameter) that has deteriorated and is now due for replacement. It is exposed to flood and landslide. Work is underway (July-August 2004) installing a new pipe on a new alignment out of the gorge which allows the pipe to be buried and thus be more secure. This will require that all water is pumped.
No protection is provided against Giardia or chryptosporidium. Several options are available but the favoured one currently is slow sand filtration. A pilot plant is currently operating. The full scale plant is assessed at $400,000. The results of the pilot work will enable this figure to be refined before final decisions are made to go ahead with the work.
The capacity of the reticulation to meet peak demands and Fire Fighting requirements needs improvement. To date the necessary investigations have not been undertaken that will identify the specific shortcomings and the necessary works needed to overcome them.
Foxton
| Population : 2700 |
Properties 1101 |
| Average consumption |
1500 m3/day |
| Peak consumption |
2100 m3/day |
Reservoir capacity is 1100 m3 at ground level plus there is capacity in the water tower of 450 m3
Water Source
Water bores at Harbour St (1994) and at Ladys Mile (2002).
Consent expires 2009 for the Harbour St bore (consent no 4201, 3600 m3/day) and in 2017 for the bore at Ladys Mile (consent no 102052, 3000 m3/day).
The reticulation comprises some 16 km of pipe ranging in size from 200mm down to 25mm. The reticulation consists of a range of materials being predominantly cast iron pipe reputedly being originally gas pipes subsequently taken over for water reticulation. Other pipe types include asbestos cement, PVC and wrought iron.
Current Issues
The bores are drawing from a deep aquifer that is expected to be of a high quality. Monitoring is proceeding that is expected to prove that the bores both meet the criteria to be considered "secure" supplies. If that is the case the treatment process does not need to be as complex to meet the drinking water standards. The treatment plant will need to be slightly modified to maintain the "secure" status through bird proofing the clarifiers and filters.
Testing to date has indicated that the water from these bores has been under-ground for in excess of 100 years which will assist in being awarded a "secure" status. There is a high level of unaccounted for water use, and work has been carried out recently to reduce this. Such work is ongoing.
The storage system and pumps do not have sufficient capacity to meet fire fighting requirements for greater than class D fires. Proposed pipeline upgrades will address this problem.
Foxton Beach
| Population: 1900 |
Properties 1143 |
| Average consumption |
535 m3/day |
| Peak consumption |
870 m3/day |
Reservoir capacity 1150 m3
Water Source
One water bore at Edinburgh Terrace (1994) and a new 200 metre deep bore has recently been commissioned at the south end of Flagstaff St. The water is pumped through a treatment plant into a storage reservoir. From there it is pumped continuously into the town reticulation.
Consent expires 2009 for the Edinburgh Terrace bore (consent no 101905, 1500 m3/day) and in 2018 (consent no 102675, 1920 m3/day) for the bore in Flagstaff St. Special conditions apply to that bore including monitoring the electrical conductivity so as to give early warning of a possible inland movement of the salt water interface.
Treatment consists of chlorination plus passing the water through pressure filters.
The reticulation comprises some 17 km of pipe ranging in size from 200mm down to 100mm. The reticulation consists of a either PVC or Asbestos cement and was nearly all installed in 1974.
Current Issues
Council is currently trialling some alternate treatment processes (including the use of Ozone) to determine the most effective and economic option. There are regular complaints that the water tastes of chlorine. The bores are also being tested to establish whether they can be considered to be "secure". If that proves to be the case it will be possible to reduce the chlorine dosage and thereby reduce the taste and odour problem. An alternative a pproach is to modify the treatment process to include an aeration process which will allow the chemicals that give rise to the odour to dissipate.
Despite regular cleaning a problem appears from time to time with the deposition of growth on the inside of the pipes. It has been sampled and identified as a bacterial slime. It is likely that this problem also gives rise to taste and odour. The regular cleaning programme will continue.
Levin
| Supply area: |
Levin, Ohau and Whirokino rural area |
| Population: 15400 |
Properties 16467 |
| Average consumption |
8300 m3/day |
| Peak consumption |
13,500 m3/day |
| Reservoir capacity |
6750 m3 |
Water Source
Ohau River 750 metres south of the intersection of Tararua and Gladstone Roads. There are two intakes. One is from the right bank of the river through a long settling race to the pumps and the other is via a pair of intake galleries under the river bed to the same pumps.
Consent has expired for the river bank intake and an application for renewal has been made. The intake gallery consent (consent no 901962, 24,000 m3/day) expires in 2011.
The treatment plant utilises direct filtration with flocculation followed by chlorination.
The various components of the system were constructed as follows:
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No. 1 Reservoir 1943
-
Surface water Intake 1962
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No. 2 Reservoir 1963
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Treatment Plant 1964
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Infiltration Gallery 1995
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Trunk main (Queen Street) 1961/2
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Trunk main(Tararua Road) 1997
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Reticulation primarily since 1950
Current Issues
Water Quality
The river is subject to periods of high flow when the water is turbid. The treatment plant is able to cope with turbidity up to around 20 units, but the river can have turbidities in the hundreds for several days on end. It is impractical to construct enough storage to last through these periods. The operators run the plant on the water through the settling race until the turbidity gets too high, and then they use the infiltration gallery which can provide another day or so of lower turbidity water. Changing to the gallery is not an automated activity because the water has a different chemical make-up and that makes it necessary to alter the treatment process.
An upgrading should be carried out on the Treatment Plant as greater protection should be provided against cryptosporidium and Giardia contamination. During 2002 and 2003 a pilot clarifier was constructed and used to determine the effectiveness of a full scale clarifier. The first trial showed that it is not easy to obtain a stable process and further trials are continuing.
Another opportunity that is being investigated is the use of the settling channel for the additional purpose of initiating the flocculation process. Most of the physical settling of material is occurring naturally at the upstream end of the channel and the experiments to date indicate that dosing the water in the channel enables a good flow to be developed and this enhances the treatment plant capability.
The treated water currently has a pH (measure of acidity) of 6.5. The drinking water standard suggests that 7 is the lowest desirable figure for pH. Levels below this can generate higher rates of corrosion of metal parts of the water system, both in the public supply and in homes and other premises. It is sometimes seen as a green stain where copper pipes are in the plumbing. It is possible to add further treatment of the water to raise the pH to a level that meets the standard. This is estimated to cost $10,000 and is planned for completion in 2004.
Improved storage requirements are warranted since there is less than 24 hours of storage available. During 2002/2003 tenders were called for the construction of an additional reservoir estimated to cost $700,000. Prices were in excess of $1million and further options are being considered.
Supplementary supply. A bore has been commissioned near the south of the town, which may be able to provide ten percent of the town's water supply demand. Results to date have not been wholly satisfactory and further work is being done.
Water metering. It is proposed that water meters be installed throughout the water supply area to minimise the demand on the water resource. This supply draws significantly on the Ohau River which comes under stress during the summer.
Moutoa
Supply area: 6 Farms in the Moutoa area. The system is primarily a private water supply arrangement that is managed and maintained by Council at the request of the participating property owners.
| Population: less than 20 |
Properties 6 |
| Average consumption |
93 m3/day |
| Peak consumption |
123 m3/day |
Water Source
Bore in Springs Road distributed into storage tanks on each property. Consent (consent no 4141, 504 m3/day)
The reticulation comprises some 1.13 km of pipe being predominantly 50mm pipes.
Issues
The water quality is known to be unable to meet NZ Drinking Water Standards, but these do not apply for water supplies as small as Moutoa.
There are often capacity difficulties during periods of high demand.
How to Read Your Meter
FONT face=Arial>These notes aim to explain:
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How water meters work.
- How can you read them to keep a track of your water consumption, and
- How you can help make our meter reader's job easier.
Most of the water meters used in Horowhenua District are of the digital metric type. They are read three monthly and from these readings we produce your account.