Ohura Water Supply

Is my water treated?

Yes, water is pumped to the nearby Ohura Water Treatment Plant on Hihi Street West where it undergoes the following treatment:

1. Sediment Settling Small unwanted particles or solids, such as fine sand and dirt, are removed from the water by adding a coagulant which gathers the solids into a cluster, creating larger solids which quickly settle to the bottom. Clean water can be taken from the top. This process takes place in a clarifier.
2. Finer Filtration Water is passed through layers of sand and gravel to further remove impurities. Small water molecules pass through the holes between sand and gravel pieces and clean water is collected in a drain at the bottom. Unwanted solids get stuck in the holes, and are thus retained in the sand and gravel medium. This medium is washed from time to time to remove the unwanted solids.
3. Chlorination & pH Correction The water is dosed with chlorine to kill off contaminants (bugs) in the reservoirs and pipes. pH correction is required to ensure effective disinfection with chlorine.

Water monitoring

Online monitoring through System Control and Data Acquisition (SCADA) provides information about the water treatment, such as chlorine. This system checks that water parameters stay within set values for 24 hours every day and will alert the Plant Operator if anything changes.

Where is my water stored?

Treated water is pumped to the Ohura reservoir (225m3) before being gravity supplied to consumers within the township. The Ohura water reservoir is unique in the Ruapehu District in that it is underground.

Our pipelines

The Ohura Water Supply Reticulation Network consists of around 9km of pipeline. Pipes are between 32mm and 50mm in diameter and mainly plastic (uPVC) although a lot of Asbestos Cement and Steel pipes remain.

The below schematic shows flow through the Ohura Water Supply scheme: