Water testing report due in June

Cooperation between community volunteers, Te Uri o Hau, Kaipara District Council (KDC) and Northland Regional Council (NRC) is resulting in the collation of a comprehensive bank of data on the key influences affecting the water quality of the Mangawhai Harbour.

Interest groups agree future decisions on management of the harbour need to be based on robust data and have integrity.

“The health and well-being of the Mangawhai Harbour are of paramount significance to the historical, cultural, spiritual and traditional values of Te Uri o Hau,” says Shereen Worthington, Te Uri o Hau representative and member of the volunteer sampling team.

Fortnightly testing of six sites from the upper reaches of the Mangawhai Harbour to the causeway bridges (by KDC volunteers) is now being complemented by testing of six sites from the causeway bridges to the harbour mouth (by the NRC), as well as the NRC’s summer recreational testing programme of two sites at Mangawhai Heads.

Upon completion of a full year’s testing, at the end of May 2017, the data set will be analysed and interpreted by a qualified testing organisation so that the interpretation stands scrutiny and can be relied on.

Test results will help guide KDC in developing a harbour management programme relating to land use to help safeguard the health of the harbour.

“It’s tempting to look at just six months of data and draw conclusions – but it’s only half the story,” says volunteer Gordon Hosking. “We believe it is better to interpret a full 12 months data. This will ensure that variables such as weather and all four seasons are taken into account and help us present a robust report to Council and the community.”

The report, due in June, will analyse 12 months of data for potential spatial (position, area) patterns, examining how water quality changes from the upper catchment to the harbour mouth. Data from the sub-catchments will be examined to determine whether the differences in inflow water quality may be related to different land use types. Analysis will be complemented using land-use data. Interpretation of time-related trends will be augmented by climate data such as rainfall and temperature.

“The purpose of the harbour water quality project is to guide harbour management from a land use perspective in the future. This project is not about trying to justify past decisions on the waste-water scheme or the recent waste-water by-law. It’s about giving us facts on which to base future land management guidelines to help protect harbour quality,” said Dr Hosking. “The harbour water quality project is future focussed”.

DATA: Water testing team members Christine Silvester, Gordon Hosking, and Mike Hay carry out fortnightly sampling.