Geologically, an 'aquafact' is a boulder worn by running water that is too large to be rolled as a pebble, worn smooth on the upstream or seaward side and exposed top and with a sharp ridge on the downstream or landward side. These 'aquafacts' are simple facts to aid understanding of a range of issues about Christchurch and Canterbury water.
Let's look at the (aqua)facts around Christchurch water
Our main urban area, Christchurch, is blessed with a plentiful supply of fresh clean drinking water. Environment Canterbury works with the community to help ensure we protect our fresh water now and for generations to come. People from across our region are working together as kaitiaki to protect and improve our water resources.
All Canterbury city and district councils are involved with protecting our water via the Canterbury Water Management Strategy, but three agencies are directly responsible.
Environment Canterbury looks after the source of our drinking water (aquifers, rivers and lakes); local councils are responsible for the supply, distribution, treatment and safe supply of drinking water (the infrastructure) and the Ministry of Health through the Canterbury District Health Board monitors the impact of water quality on health. Watch the video for more information or read through our pages on Canterbury's drinking water.
There is no risk of running out. Christchurch’s water supply is well understood by scientists and is sustainably managed. 123 billion litres of rainfall onto the areas north and west of the city, and 252 billion litres which ‘leaks’ from the Waimakariri River recharge the Christchurch aquifers each year.
In total, that's about 375 billion litres or 150,000 Olympic swimming pools which flows through the Christchurch aquifers each year. What isn’t used ends up in the ocean.
Nitrate levels are an indicator of water quality. Elevated levels can indicate the presence of compounds which may cause health issues. We know nitrate levels will increase over time due to poor land-use practices in the past.
Christchurch’s drinking water has about 1mg of nitrate per litre and strict rules are in place to keep our water at a safe level. The maximum national health level is 11.3mg per litre.
General information about nitrate in waterways
- National and local rules are in place to regulate nitrate in our freshwater
- The National Policy Statement for Freshwater Management(external link) (NPSFM) requires that freshwater quality is at least maintained, or ideally improved
- For drinking water, the New Zealand Drinking Water Standards set a Maximum Acceptable Level (MAV) of 50mg/l for nitrate, which is equivalent to 11.3 mg/l nitrate-nitrogen
- If nitrate reach half that level (5.65 mg/l) in a community supply, additional monitoring must be undertaken.
Find out more about the Annual groundwater quality survey.
Environment Canterbury’s role in reducing nitrate
- We put controls on land-use activities that could threaten water quality; for example, we control land-use to the west of Christchurch to protect the city’s drinking water supply; much of the area is used for very low intensity stock grazing and recreational parks
- We have introduced some of the strictest rules(external link) in the country to help address water quality issues and, over time, deliver the improvements the community demands
- This includes requiring farmers to operate within strict limits and adhere to industry agreed good management practice guidelines.
- Higher risk farming types are now required to measure and manage nitrate leaching via a consent to farm. They are also required to have a Farm Environment Plan and their performance against this plan is graded by independent auditors as part of Environment Canterbury’s compliance programme
- Many farmers are working hard(external link) to reduce their impact on the environment, such as fencing off water ways and planting along stream margins