Waiopehu Freshwater Management Unit

The stories of the river and the humans who live alongside it are intertwined.

The Waiopehu FMU is a patchwork of landscapes that includes market gardening and pastoral farming on the open plains, and some natural and planted forest cover. Levin is the main urban centre and there are several other coastal communities. Only 1% of the FMU is hill country but 13% of the FMU has superior quality versatile soils.

The activities that people undertake in the region have, and continue to have, an impact on freshwater in the Waiopehu FMU.

The pressures the Waiopehu waterways face today include:  

• Discharges, including wastewater to land and stormwater, can carry bacteria and excess nutrients into rivers, lakes and streams.   
• Abstraction of freshwater from rivers, lakes, streams and groundwater for human use reduces water available for aquatic life.  
• Alteration of physical aspects of the ecosystem, such as damage to river channels, can impede access to habitats for freshwater species.  
• Invasive freshwater weeds can threaten native species and degrade the quality of the water.  
• The risks associated with the impacts of climate change. 
• Land used for activities such as agriculture or urban development, contributes bacteria, nutrients and sediment (sand, soil and silt particles that have detached from the land by erosion) that enter the freshwater systems.
• Lakes are particularly sensitive to pollution as contaminants become trapped within them.

We all have a responsibility to manage our activities in a way that sustains the life-giving capacity of freshwater, safeguarding it for future generations.

Iwi/hapū, local and central government, farming, and industry leaders, along with environmental and recreational advocacy groups have, and continue to address some of the challenges facing the Waiopehu FMU.

One significant project was the Lake Horowhenua Accord established in 2013, where five parties representing Muaūpoko owners, community interests and statutory bodies agreed to work together to provide leadership and halt degradation of Lake Horowhenua and Hōkio Stream. 

Te Kakapa Manawa o Muaūpoko – The Heartbeat of Muaūpoko is a kaupapa funded from the Te Mana o te Wai Fund. This project aims to restore the mauri of Lake Horowhenua, including its waters, environment, and fishery.  

The current intervention work for the Lake was boosted by the  Mahi mō te Taiao – Jobs for Nature  project (2021-2024 ). 

There are collaboration projects that bring hapū and iwi, local government, farming and industry leaders together with academics and environmental or recreational interest groups to help improve the water quality within the FMU.

These groups have fenced and planted along the waterways (riparian planting). The fences keep wandering stock out of the water. The plants help filter nutrients, sediment and bacteria that leave the land as runoff.

Land used for grazing animals has been retired and planted with native vegetation. These actions create protective environments for wetlands, rivers and streams.

A collaboration with the horticulture sector was established to reduce nutrient and sediment loss from horticultural farms.

Barriers to fish passage are being remediated or removed, in some instances improving the connectivity of habitats for aquatic life.

Actions like these reduce the impact of human activities on freshwater environments. Over time, these initiatives will gradually improve the health of Waiopehu’s waterways.

Every water body (rivers, lakes, streams, wetlands and aquifers) has a unique ecosystem consisting of all living things and the physical habitat that they interact with.

Ecosystem health is the ability of water bodies to support all life, including fish, birds, insects, plants and microbes. Pressures from human activities can impact ecosystem health.

We, the people that live, work and play around the river, form part of the Waiopehu ecosystem and have a duty to care for it.

The Waiopehu FMU has several places where locals can use the waterways to cool off on a hot day.

But how do we know when the quality of the water is good enough for our whānau to enjoy?

If you splash about at your local swimming spot or fall out of your kayak into the river, you are making direct contact with the water. 

At times, rivers and lakes may contain elevated levels of  faecal bacteria  and potentially toxic algae, making them unsafe for direct contact. Encountering high levels of these bacteria can cause stomach upsets, vomiting and other signs of gastrointestinal illness.

Horizons collect two sets of data:

1. Weekly monitoring at popular swim spots over the bathing season (November – April) to help you decide where to cool off on a summer day. 
2. Monthly monitoring where staff check representative sites across the FMU year-round.

The indicators that determine the grading for direct contact are E. coli for freshwater sites and Enterococci at coastal sites. These indicators of faecal contamination can increase significantly with high rainfall causing contaminants from urban and rural settings to be washed into water bodies. In the future,  cyanobacteria  will also be included in our reporting.

Freshwater is precious; it makes up only 3% of all the water on earth.

During summer or in periods of drought, demand for water increases and river levels are at their lowest. Rivers and streams cannot afford to have too much water removed as low levels threaten ecosystem health.

People use freshwater for human and stock drinking water, irrigation for agricultural land or horticulture, hydroelectric power generation, and processes in other industries.

Freshwater plays a significant role in supporting communities across the Waiopehu FMU. 

The Waiopehu FMU is divided into eight surface water allocation sub-zones. Each zone has a water allocation limit to protect the river and its environment. The amount of water allocated to users against these limits varies across the FMU.

 A considerable amount of the country's freshwater is stored as groundwater in aquifers.

Aquifers are large areas of layered gravel, sand and rock that act as a sponge, removing and holding water away from the surface. Water stored in aquifers is replenished by rainfall.

Aquifers can be connected to surface water, sometimes supplying lakes, rivers and wetlands with freshwater from below. Other times groundwater is replenished through interaction with surface water bodies. There is a high degree of connection between surface water and groundwater within the Waiopehu FMU; many streams and Lake Horowhenua rely on groundwater for replenishment.

The Waiopehu FMU constitutes a single groundwater management zone - it is currently 13% allocated.

Groundwater quality is monitored in eight bores across the FMU. The grades (grades A-D) have not yet been developed to allow us to report on these as we do for surface water. This is currently part of Horizons Regional Council's scientific work programme.

Explore more about groundwater on the  LAWA website .

If you have any further questions about freshwater you can call us on freephone 0508 800 800 or email us at   info@ourfreshwaterfuture.nz.