Nutrients

Like grass on a lawn or paddock, aquatic plants need nutrients to grow. The two major nutrients required for plant growth are nitrogen and phosphorus. Both nitrogen and phosphorus can be present in water in a number of forms which can be measured individually or together.

In healthy rivers and streams, nutrients occur naturally in small amounts. However, the same nutrients can become an issue if they reach levels that overstimulate plant and algal growth or become toxic to aquatic life. While toxic levels of nutrient are generally not an issue in the Manawatū Catchment, nitrogen and phosphorus do exceed the levels required for controlling the growth of nuisance algae (periphyton) in some places.

Manawatū-Whanganui Regional water quality state and trends 2018
Horizons Regional Council has monitored nutrient levels in the catchment since 1989. This report was commissioned Horizons to independently assess water quality state and trends across the region and was created by Land Water People (LWP).

Monitoring of nitrate in agricultural catchments – a case study on the Manawatu River, New Zealand
This study investigated the application of high-resolution sensors to measure nitrate-N in a low nitrate-N concentration environment. The study was undertaken in the Manawatu River at the Teachers College monitoring site, for a period of one year from Feb 2016 to Jan 2017.

Te whakahaere taiora i te awa o Manawatū me ōna manga

Managing nutrients in the Manawatū Catchment

As with a lot of the priority areas identified in the Action Plan, most of the activity has a positive impact on nutrients in some way. Some of the key factors implemented to reduce nutrient levels are:

  • Stream fencing and riparian planting around waterways, which has many benefits.
  • Regulatory changes and sustainable land management programmes designed to decrease runoff of sediment, nutrients and bacteria from intensive land use.
  • Point source discharges have been combined and networks have been built to connect them to single discharge points. With less sources it is easier to monitor effects and make upgrades.

Another major contributor to reducing excessive nutrients is upgrades of wastewater treatment plants across the catchment.  Improvements to Shannon wastewater treatment plant included a new effluent storage pond and land irrigation system, and removing 144 million litres of direct discharge to the awa  every year. Land irrigation systems are also being installed in Feilding, where concentrations downstream of the wastewater treatment plants were reaching toxic levels for aquatic life. In Feilding, the effects of action taken can now been seen. Monitoring by Horizons Regional Council shows improvement across a range of water quality indicators downstream of the wastewater treatment plant, including sediment, nutrients, bacteria and algae.

 Since the start of the Accord Woodville, Pahiatua, and Kimbolton, wastewater treatment plants have also been upgraded, while changes to Foxton, Tokomaru and Palmerston North wastewater treatment plants are in varying stages of upgrades.

Take a look at the See Progress Map to see what’s been happening in your area.

GET INVOLVED

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FIND OUT HOW YOU CAN HELP

The Manawatū River is OURS and as a community we have the choice of playing a part in its enhancement and protection. Working together we can help our awa thrive and enjoy it today and for generations to come.

FIND OUT
HOW YOU CAN HELP

Slide Despite efforts to recycle, plastic waste ends up in our awa. Reduce the amount of unnecessary plastic you use to help reduce the amount of plastic waste produced locally.

REDUCE PLASTIC WASTE

REDUCE
PLASTIC WASTE

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PICK UP LITTER

Next time you’re down by the awa take on the challenge of picking up five pieces of litter. Every bit counts and it all adds up to a happier, healthier environment for everyone to enjoy.

PICK UP LITTER

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PLANT A TREE

The benefits of planting trees are many – for our awa they include filtering nutrients from land run off and providing habitat for birds, fish and insects.

PLANT A TREE

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DISPOSE OF TOXIC
CHEMICALS SAFELY

Stop hazardous waste from reaching the river by disposing of it at dedicated facilities. Remember that everything that goes down the drain will eventually end up in our rivers and streams.

DISPOSE OF TOXIC
CHEMICALS SAFELY

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SEE IT, REPORT IT,
CALL 0508 800 800

If you see a chemical spill or contaminants in waterways call Horizons’ Pollution Hotline.

SEE IT, REPORT IT,
CALL 0508 800 800

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WASH YOUR CAR
ON THE GRASS

Grass acts as a natural filter for contaminants, trapping potential pollutants such as oil, dirt and grease. Washing your car on the lawn filters run off through the soil before entering stormwater drains and ultimately the river.

WASH YOUR CAR
ON THE GRASS

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JOIN THE CONVERSATION

Join the conversation and get involved, there are a lot of things you can do to help and we have the resources to show you how. Join our community on social and find out more at manawaturiver.co.nz

JOIN THE CONVERSATION

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Find out what you can do

The Manawatū River is OURS and as a community we have the choice of playing a part in its enhancement and protection. There is a lot you can do to help our awa thrive, and we are here to help you make a difference.

Find out what you can do

Slide Erosion can have a major impact on sediment and clarity in our waterways. Reduce the amount of sediment entering our awa and keep soil on your land by planting poplar poles in erosion prone areas.

COMBAT HILL COUNTRY EROSION

COMBAT HILL COUNTRY EROSION

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FIX BARRIERS TO FISH PASSAGE

Many of the native fish species need to get back and forth between their fresh water homes and the sea to breed. Barriers to this migration seriously impact our native fish, many of which are at risk. Find out how to make dams, weirs, and overhanging culverts in your streams fish friendly.

FIX BARRIERS TO FISH PASSAGE

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PROTECT STREAMS WITH RIPARIAN PLANTING AND FENCING

Keeping stock out of waterways and protecting streams with a buffer of plants along stream margins has a major impact on water quality and stream habitat. Improve sediment, nutrient, and bacteria levels in our awa and help aquatic life thrive in your streams through effective riparian management.

PROTECT STREAMS WITH RIPARIAN PLANTING AND FENCING

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MANAGE EFFLUENT ON YOUR FARM

Nutrient and bacteria in our waterways has a major impact on water quality in our catchment. Implement sustainable systems for managing effluent on your farm and help keep our awa healthy and safe.

MANAGE EFFLUENT ON YOUR FARM

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PROTECT WETLANDS AND NATIVE BUSH ON YOUR LAND

Today only 18 per cent of the catchment remains under indigenous cover. There are many programmes in the catchment working to protect these precious ecosystems. Find out how to protect bush remnants and wetlands on your land.

PROTECT WETLANDS AND NATIVE BUSH ON YOUR LAND

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LEAD A COMMUNITY PROJECT

Every year there is $100,000 of funding for community projects that aim to enhance and protect the awa. Take advantage of the support available and galvanise your community to protect our waterways.

LEAD A COMMUNITY PROJECT

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JOIN THE CONVERSATION

Join the conversation and get involved, there are a lot of things you can do to help and we have the resources to show you how. Join our community on social and find out more at manawaturiver.co.nz

JOIN THE CONVERSATION