On this page:
Why water quality is important
New Zealanders love spending time in and around the sea. We enjoy swimming in sparkling waters, relaxing at the beach, fishing off the rocks, or sailing around the many bays and islands.
A crucial part of any coastal activity is the quality of the water. High water quality is essential for coastal activities such as:
- fishing, shellfish gathering and marine farming
- traditional uses, such as pingao harvest
- swimming and other water sports
- tourism.
Our coastal plants and animals need good water quality if they are to survive. We need to maintain high water quality and restore water quality where it has been lost.
Is our coastal water clean?
Overall the quality of coastal water in our region is high. Our open coast is well-flushed and the permanent population of coastal towns is relatively small. But we still need to be careful about what we put into our coastal waters.
Runoff from the land flowing into rivers and catchments is the main source of contaminants flowing into our coastal water.
In Raglan and Thames, treated waste waster is discharged directly to the coast. In many small settlements, people use individual septic tanks to treat sewage. Seepage from tanks can cause local contamination of nearby coastal water.
Stormwater discharges, and rubbish and sewage from boats, also contaminate our coastal water.
All of these activities put contaminants into coastal water. Contaminants can include:
- bacteria
- sediment
- nutrients
- heavy metals and chemicals.
In our region, coastal water is subjected to less pressure from contaminants than inland water. Coastal water is also better at coping with contaminants than still or slow moving inland water. On the coast most contaminants are quickly diluted and dispersed by tidal flushing and waves. Also, waves constantly mix oxygen into open coastal waters, so the effects of any oxygen-depleting contaminants are not as severe as in a calm lake.
The exception is in estuaries and harbours where the coastal water is enclosed and there is less tidal flushing and wave action. Many areas of estuaries are not suitable for shellfish gathering.
Our studies show that Whangamata Harbour's water quality is high and suitable for swimming over large areas of the harbour in fine weather. But during periods of high freshwater inflows in wet weather, the harbour and nearby coastal waters are unlikely to be satisfactory for bathing.
Find out more about the harbour's water quality and major sources of contaminants by ordering our factsheet Whangamata Harbour's Water Quality.
Find out more about our coastal water quality and swimming, harvesting shellfish, and plants and animals.
Protecting water quality
Water quality monitoring
Environment Waikato monitors water quality at swimming beaches. Health Waikato and the shellfish industry monitor for the potential presence of marine biotoxins.
Point source discharges to the coastal marine area require resource consents from Environment Waikato. Resource consents and compliance monitoring minimise adverse effects. Find out more about how stormwater pollution can affect our coasts.
Our Regional Coastal Plan identifies the need for future research to determine whether coastal water should be classified for different purposes, such as swimming, shellfish gathering and ecological health.
Marine pollution controls
The Resource Management (Marine Pollution) Regulations 1998 control the discharge and disposal into the coastal marine area of:
- rubbish
- oil
- sewage
- noxious substances.
There are also voluntary controls on the discharge of ballast water in New Zealand waters.
Community and other initiatives
The Regional Coastal Plan emphasises the need for Environment Waikato to work with landowners and territorial authorities to manage land use and reduce runoff into waterways.
Streamcare and Landcare groups can protect water quality by reducing runoff to streams and rivers. For example, Whaingaroa Harbourcare work to improve Whaingaroa (Raglan) Harbour water quality.
On the Coromandel Peninsula all settlements other than Thames, with reticulated (piped) sewage, use land–based systems to treat sewage.
In Raglan and Thames, where treated waste water is discharged directly into coastal water, effluent treatment systems are being improved so that:
- effluent is treated to a higher standard
- outfall structures are improved, so waste water is dispersed more rapidly.
Want to know more?
Check out our coastal indicators for more information about the quality of our region's coastal resources and how they are changing.
You can also download the pdf of the Coastal Water Quality factsheet below.
Coastal Water Quality factsheet
(495 kb, 70 seconds to download, 56k modem)