Water

Central Otago District Council provides potable (drinking) water to approximately 13,500 on eight public water supplies:

Alexandra Water Supply

• Resident population around 5000 people, increasing to more than 8500 in peak holiday periods.
• Reticulation network is approximately 40km in length
• Annual average water consumption approximately 2,000,000m

A town water supply fed from the Butchers Dam irrigation system was first established in the early 1900s.

Today Alexandra's water is a groundwater extraction supply, fed by a six-bore borefield sited on the true left bank of the Clutha River about 1750m upstream from the main bridge. Water is drawn from shallow ground water, typically 12m deep, is chlorinated and pumped directly into the distribution network.

The Lake Dunstan Water Supply Project is underway that will deliver better quality water to Alexandra and Clyde. More information about this can be found in on the Pipelines Project page.

Clyde Water Supply

• Resident population of just under 900 people, increasing up to around 3000 in peak holiday periods
• Approximately 8km of reticulation
• Annual average consumption of approximately 610,000m³

Clyde was originally supplied with water from the Waikerikeri Valley. The water flowed through an open race to two open reservoirs located on a terrace to the north-west of the town. Today the Clyde water supply is drawn through schist formations from a bore adjacent to Lake Dunstan. The bore is a shallow, screened casing with one submersible pump. Water is pumped by dedicated rising main and chlorinated as it enters one of two 1000 m3 concrete reservoirs above the town. The construction of the Clyde Dam saw significant upgrade work to the town water supply, when the old cast iron pipes were upgraded.

Cromwell, Bannockburn, Pisa, Lowburn and Ripponvale Water Supplies

• Resident population approximately 3400 increasing to around 7000 during peak holiday periods
• Reticulation network of approximately 52km
• Annual average water consumption approximately 2,000,000m³

Cromwell’s water is drawn from two bores close to the shore of Lake Dunstan. The bore water is chlorinated and held in a contact tank to ensure chlorine has adequate time to disinfect the water. High lift pumps then transfer the water through town reticulation to two large reservoirs above Cromwell.

Bannockburn, Lowburn, parts of the Pisa development and the private Ripponvale Scheme are fed via pipeline connections to the Cromwell reticulation.

Naseby Water Supply

• Permanent population approximately 100 permanent residents with a significant increase during peak holiday periods
• Approximately 7km of reticulation
• Annual average water consumption approximately 60,000m³

Naseby’s water is sourced from the West Eweburn and purchased from the Hawkdun Idaburn Irrigation Company. Drawn from a water race that passes through Naseby forest, this supply is fully gravity fed from intake to consumer. At the water treatment plant, located just off Swimming Dam Road, treatment is a conventional direct filtration process where liquid coagulant is applied to the incoming raw water before filtration occurs. Naseby race water can become very turbid, which makes chlorine disinfection less effective and boil water notices are not uncommon.

Omakau/Ophir Water Supply

• Resident population of just under 400 people
• Reticulation network of approximately 5km
• Annual average water consumption of approximately 130,000m³

The Omakau/Ophir water supply is a low pressure scheme. Water is sourced from the Manuherikia River through an infiltration gallery under the river bed. At the water treatment plant water is pumped through a rapid sand filter, chlorinated, pH corrected and held in contact tanks before being pumped through town reticulation to six 30m³ reservoir tanks above the campground reserve on Alton Road and two 23m³ reservoir tanks in Ophir. Water is gravity fed through the reticulation to connected properties.

Patearoa Water Supply

• The Patearoa water supply feeds both the Patearoa urban supply and the Patearoa rural water scheme The township also has a number of holiday homes and the population peaks during summer months.
• Approximately 50 properties are fed off the town supply and 283 rural units of 1m3/day each are allocated to about 40 properties (farming and residential)
• The Patearoa reticulation is approximately 20km in length
• Annual average water consumption is approximately 250,000m

Patearoa water is sourced from a gallery in the bed of the Sowburn River, a tributary of the Taieri River. Water is pumped from a pump chamber in the Sowburn to the main rural reservoir on the hill behind Patearoa. Water is chlorinated as it passes the treatment plant and eventually enters the main reservoir where disinfection and storage takes place. Water is drawn off into a bank of six farm tanks that serve the urban area of Patearoa. Water is gravity fed to all parts of the rural scheme.

Ranfurly Water Supply

• Resident population of around 800 people
• Approximately 16km of reticulation
• Annual average consumption of water of approximately 260,000m

Ranfurly water is primarily sourced from the East Eweburn. There are two intake structures - a low concrete dam where the creek leaves the hills, and gallery pipes in the creek bed gravels about 1km upstream from Smiths Road. The Hawkdun-Idaburn Irrigation Race provides a secondary source of water used during periods of dry weather when the Eweburn is too low.

The Ranfurly water supply is gravity fed from source to customer. Water flows to the reservoir via a slow sand filter. The water is disinfected by liquid chlorine prior to reservoir storage and is gravity fed to the town reticulation.

Roxburgh/Lake Roxburgh Village Water Supply

• Permanent population of around 620 in Roxburgh and 50 in Lake Roxburgh Village. The population can increase by around 500 people during peak holiday periods
• The length of the Roxburgh/Lake Roxburgh reticulation is 21.7 km
• Annual average water consumption of approximately 300,000m

Roxburgh water is drawn through two bores on the Clutha right bank, approximately 600m north of the Roxburgh township boundary. Water is chlorinated as it enters the main reservoir where disinfection and storage takes place prior to flowing to the town consumers by gravity.

The Roxburgh supply feeds both Roxburgh Township and Lake Roxburgh Village, which are connected by a water pipeline alongside State Highway 8. The pipeline also feeds approximately 20 rural properties on a restricted supply basis.

More Reading

The Story of Drinking Water (NZ Water & Wastes Association)

The Story of Drinking Water (NZ Water & Wastes Association)