A study by Our Land and Water shows how much we'll need to reduce contaminants in our waterways to meet national bottom lines.
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Coastal water quality
Coastal water quality in Waitaha/Canterbury is generally high. In some areas, activities like land development and contaminant discharges have reduced water quality in the coastal marine area.
Coastal waters also face the impact of global climate change, which includes sea level rise, increasing sea surface temperatures, marine heatwaves and ocean acidification.
Environmental impacts on our coastal waters
Our coastal waters and coastlines support a diverse array of marine fauna and flora, marine mammals, seabirds and shorebirds, as well as providing for recreation, food gathering, cultural activities and marine farming. They are the ultimate receiving environments, impacted by both natural and human activities.
The main activities that affect our coastal water quality are:
- Changes in land use and related erosion which increases the sediment discharged into our rivers and streams. This sediment settles out in the mouths of rivers and on the sheltered mudflats of estuaries, lagoons, and bays where it can smother fauna and seagrass beds.
- Municipal wastewater and industrial wastewater treatment plants that discharge contaminants through outfalls into the coastal waters.
- Stormwater carrying pollutants, including heavy metals and hydrocarbons, from residential, commercial, and industrial areas, and roads.
- Intensification of farming land use that results in an increased run-off of nutrients entering coastal waters through rivers, creeks, drains and groundwater.
- Seepage of wastewater from septic tanks and leaky or broken pipes, or contaminants from old landfills into groundwater, rivers, streams, and coastal waters.
- Discharge of contaminants from industrial activities.
- Port activities and infrastructure.
- Discharges of ballast water from vessels, which can potentially introduce exotic organisms and contaminants.
Restoring the health of the Waitarakao Lagoon is one of our priorities
Water quality monitoring
We monitor water quality at 73 sites on a monthly or quarterly basis to understand the current state of water quality. This monitoring also allows us to detect trends in water quality over time. Water quality is monitored throughout our coastal environment, covering tidal lagoons, estuaries, beaches, bays, harbours, near-shore coastal sites and off-shore open coast sites.
During the summer we monitor 47 sites weekly to determine suitability for recreational use and shellfish gathering. The latest water quality results and longer-term trends are available on the Land, Air, Water Aotearoa Can I Swim Here? website.
We also conduct water quality investigations when required, for example in response to pollution discharges or phytoplankton blooms.
How can I protect our coastal water quality?
Everyone can help to protect our water quality.
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Keep stock away from waterways (coastal, freshwater and wetland areas).
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Pick up your dog's poo on walking tracks, beaches and your section and put it in the bin. Don’t leave it to wash into stormwater drains or waterways.
- Always use toilet facilities.
- Always dispose of your rubbish in bins or take it home.
- If you observe any suspected sewerage leaks, wastewater overflows, discharges of contaminants or sediment report it to us and Christchurch City Council through Snap Send Solve.
- If you have a property near the coast, check if there are wet spots or areas where you can see sewage in your backyard. Call a drainlayer for help.
- If you have a septic tank or aerated wastewater treatment system and have any concerns, or it hasn’t been serviced for a while, contact a qualified contractor.