New water sampling programme for Mangawhai Harbour

A new year-round water quality sampling programme at Mangawhai Harbour will help officials better understand how healthy the harbour is and allow them to track any changes over time

The Northland Regional Council says the new more-intensive monthly testing programme will provide it with a lot more information than its current ‘recreational bathing’ regime, which largely only sees sampling done at Mangawhai over the busier summer months.

Council Coastal Monitoring Manager Ricky Eyre says under the new programme, six sites will be sampled and analysed for salinity, temperature, sediment levels, nutrients and bacteria every month.

“Sample sites will range the length of the estuary, from its two causeways to the harbour mouth.”

In contrast recreational bathing testing is focused largely on checking bacterial levels to ensure water is suitable for swimming and other recreational contact and is part of a long-running programme targeting Northland’s most popular coastal and freshwater swim spots over summer.

Mr Eyre says the new programme also reflects the fact that Mangawhai has undergone a period of sustained growth in recent times.

“Economic growth is obviously important to Northland, but it can also lead to pressures on the environment, for instance potential increases in sediment levels from earthworks etc.”

He says in that regard there are already a number of initiatives underway in and around the Mangawhai Harbour, including a preliminary Kaipara District Council study investigating runoff from its two main sub-catchments.

“Our new water quality programme will complement these existing studies and collectively all this research will give us a much better understanding of the current health of the estuary.  Equally importantly, it will also allow us to track changes over time.” 

Mr Eyre says the harbour is an important asset to the community and the council and data gained through the testing programme will be invaluable when the policies and plans governing its use are reviewed.

The monthly results will be reported back to the public and councillors through month agenda items as well as the council’s State of the Environment and other reporting.