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Why are we doing it

On this page: Water quality, Water contaminants, Nitrogen, Sediment, Phosphorous, Bacteria, Biodiversity opportunities.

Water quality is our region's number one priority

We’ve made progress and in some ways our rivers are much cleaner than they were 70 years ago. The Waikato River was once considered one of New Zealand’s dirtiest, and while not pristine today, things have improved.

Aerial HRWO shot

In the 1950s, untreated point source discharges, such as sewage from towns and waste from factories and mills, went straight into the rivers. Since the 1970s, there have been major improvements to how we treat urban and industrial wastewater in the Waikato.

Today, the biggest risk to water quality in the Waikato is from non-point source discharges, or contaminants from a wide area, such as run off from farms. Put simply, what we do on the land impacts our water, and changes in land use and intensification have led to an increase in contaminants in the water.

Managing water quality is an incredibly complex task and we still have a long way to go to make sure our rivers are swimmable and safe for food collecting along their entire length.

Healthy Rivers/Wai Ora: Proposed Waikato Regional Plan Change 1 is our opportunity to protect the environment and ensure that what we value as a community is here for future generations.

We all want healthy rivers, profitable, sustainable farms and strong communities

Water contaminants

The proposed plan change focuses on four main contaminants: nitrogen, sediment, phosphorus, and bacteria.

+  Nitrogen

All rivers and lakes naturally have nitrogen in them, however, when there is too much nitrogen present, plants are over-fertilised leading to excessive plant growth and algal blooms. These algal blooms may cause skin irritation and be toxic to animals.The main source of nitrogen is farmland, mostly from animal urine. Nitrogen loss happens when nitrogen in the soil is carried to groundwater by rainfall trickling through the soil. The groundwater eventually emerges as surface water, with the nitrogen that leaked from the soil. Nitrogen loss from the soil tends to be highest during autumn and winter and is worse with highly stocked cows on free-draining soils under high rainfall. More information about N in the rivers.

+  Sediment

Sediment makes water appear dirty and reduces the amount of light for plants and animals living in the water. Erosion and unstable land, such as slips and gullies or from streambanks, contribute a large amount of sediment to our waterways. Erosion is typically a greater risk in hilly country in the upper catchment or near streambanks. Another source of sediment is races and tracks on-farm.Pest fish, such as koi carp, also aggravate the impact of sediment because they re-suspend sediment in lakes and rivers. Sediment loss occurs when water flows over land before entering waterways. Sediment loss tends to be worse where heavy rain falls onto land that is highly erodible because of the geology, steepness or vegetation cover. More information about sediment in the rivers

+  Phosphorus

Phosphorus physically binds to soil, so when sediment is lost, phosphorus is lost too. Phosphorus affects stream life and increases algal blooms, which can make it unpleasant for swimming and drinking. Dung from stock, fertiliser, and erosion are the main culprits for phosphorus loss on-farm. Because phosphorus is found at very low levels in the natural environment, small increases in a waterway can have a big effect on water quality. However, some soils, such as volcanic soils, naturally have a higher phosphorus levels. Phosphorus loss is worse where soils have high phosphorus levels (such as from high phosphorus fertiliser use), and where there is high sediment loss too. More information about P in the rivers

+  Bacteria

Faecal matter from stock can have a big impact on water quality. Faecal matter contains bacteria, protozoans and viruses that can make both humans and stock sick. Bacteria can enter waterways when animals directly defacate into the waterways or when rainfall carries farm runoff into streams and rivers. Common sources of farm runoff include laneways, stock yards, standing areas, heavily stocked or pugged paddocks and where stock have access to unfenced waterways. More information about bacteria in rivers


Want to know more about how we measure water quality? Click here.

Biodiversity opportunities

The Waikato is home to more than 900 native plants, 124 native bird species and 22 types of native fish, crayfish and shrimps (just to name a few!) Many of our native species are under threat due to habitat loss, but what we do on the land can make a difference for these native plants and animals.


Improving the way we use the land and water quality means better homes for our native plants and animals. Landowners have an opportunity to enhance the area where they farm by planting native trees and bush, retiring areas that aren’t suitable for farming and improving local wetlands, lakes and rivers.

Managing biodiversity is not a requirement of the proposed plan change, but farms offer arguably the best opportunity to enhance biodiversity. Farmers and farming communities may choose to design their Farm Environment Plans with this in mind. In doing so they may be eligibe for funding support.

Waikato Regional Council is passionate about biodiversity and we want to help landowners find ways to include native plants and animals in their decisions and actions.

Curious about the freshwater fish you can find in the Waikato? Click here to learn more.

Want more information about the native plants and animals in the mighty Waikato?

Not sure what to plant? Take a look at our planting guides for more information.