Wainono Lagoon Community

July 2015

The Wainono Lagoon is one of the few remaining freshwater lagoons in the South Island

The Wainono Lagoon restoration project aims to feed more and better freshwater into this 370 hectare freshwater lagoon near Waimate, separated from the coast by a shingle bank. The project involves fencing of the wetland and waterways, traps to catch sediment and earthworks to prevent erosion such as bank reshaping, as well as farm environment plans for farmers in the contributing Hook catchment. These plans take an overall look at each farm, making small changes which across the catchment can make huge improvements to water quality in the lagoon and habitats for fish and birds.

The main tactics being used to improve water quality are fencing off streams, reshaping, grassing and planting their banks and building sediment traps and bunds.

Restoration of Wainono is one of three Canterbury Water Management Strategy flagship projects, involving Environment Canterbury, Ngāi Tahu and individuals and organisations with an interest in water management.

Wainono is one of the last remaining freshwater lagoons in the eastern South Island, renowned nationally and internationally for migratory wading birds and native fish. Its margins make up the most extensive wetland in lowland South Canterbury.

The lagoon hosts over 50 species of waterfowl and fish, including threatened Canterbury mudfish/kowaro and longfin eel/tuna. Once an important mahinga kai (food gathering) area for Ngāi Tahu hapū, it is now a metre deep in mud and silt and saturated with farm run-off.

Further European settlement and farm development released large volumes of sediment into the Lagoon and since the 1970’s, more intensive farming practices and use of fertilisers have left the Lagoon cloudy and saturated in phosphorus and nitrogen with frequent algal growth and blooms.

Ngai Tahu rūnanga in the area are extremely concerned at the degradation of this important mahinga kai-food gathering area.

In 1999 farmers, residents of the area and Ngai Tahu rūnanga formed the Waihao-Wainono Water Users Group, which adopted a ground-breaking plan for environmental protection along with development.

In 2011, Wainono restoration became a flagship project under the Canterbury Water Management Strategy, promoted by the Lower Waitaki-South Coastal Canterbury Zone Committee established the previous year by Environment Canterbury. The Department of Conservation, Central South Island Fish and Game, Forest and Bird South Canterbury and Waihao-Wainono Water Users Society are all involved, together with Te Rūnanga o Waihao and Te Rūnanga o Ngāi Tahu.

Farmers have willingly joined the restoration project, fencing off and sometimes covenanting land around the Lagoon and working towards reducing sediment and nutrient runoff.

The Wainono Lagoon is a taonga to tangata whenua, treasured for its place in their history as well as its abundant fish and bird species. The name Waihao refers to the hao eel, a life-stage of the short-fin eel which has been a delicacy to generations of whanau who have gathered here. The name was given by the daughter-in-law of Waitaha ancestor Rakaihatu, renowned for digging out the lakes of the South Island.

In his great, great grandmother’s day, the Wainono Lagoon fed up to 240 permanent residents of the Waihao Pa, says John Wilkie, Waihao rūnanga representative on the upper Waitaki zone committee, Canterbury regional zone committee and also Wainono Restoration Project steering group. Generations enjoyed a diet of fish including eels-tūna, flounder-pātiki, whitebait-inanga and birdlife including moa.

This was a nohoanga-camping place where food was gathered and preserved for the winter.

Before European settlement the Lagoon was mostly freshwater. The last 160 years have seen significant change, with development of its catchment into fertile farmland. Land drainage, vegetation clearance and stock in waterways have dislodged large volumes of sediment which washed into the Lagoon.

In the last 15 years, more intensive cropping and dairy conversions have increased fertiliser use and farm runoff.

Protecting farmland from flooding is the Waihao Box, built in 1910 to replace an 1896 structure. The box opens when a big flow comes into the Waihao River, shifting shingles and creating enough pressure for water to flow out to sea. When it is closed, the river flows along a coastal channel into Wainono Lagoon.

A couple of southerlies opened the Box briefly last spring, in time for the 2014 whitebaiting season, however it has mostly stayed shut, lifting water levels in the Wainono Lagoon but blocking access to migratory fish species.

A digger can also be used to open and shut the Box.

Development of its four catchments for farming means the Lagoon has become much smaller and polluted with sediment and agricultural runoff. Draw-off of irrigation water has reduced flow into the Lagoon, in drought years leaving the riverbed dry for longer periods where it meets State Highway 1.

Today few Maori live in the Waihao area but many return to gather food and retain strong connections to the area. Some of these tangata whenua fish for whitebait under an agreement brokered in the 1880’s, as part of a Ngāi Tahu settlement allowing fishing outside the season by entitled families.

In 2012 at the request of the Waihao rūnanga, Wainono and coastal stretches of contributing waterways became a maitaitai reserve meaning commercial fishing is prohibited. Maori and Pākeha can apply for permits to exceed the recreational catch for occasions such as tangi or weddings.

The Waihao-Wainono Water Users’ Group, established in 1999, was ahead of its time in writing a strategy for conserving water quality in the catchment. It was approved by the community at a public meeting in 2008 and used for educating people about effects of irrigating. It negotiated a ground breaking deal with the Morven-Glenavy-Ikawai irrigation company to divert a portion of its take from the Waitaki River to supporting ecosystems in the lower Waihao River, below the Wainono Lagoon.

Wainono restoration project manager, Kennedy Lange of Environment Canterbury, says the Lagoon is a taonga for tangata whenua and the community. It is nationally significant for waterfowl and migratory and coastal birds living here and native fish, including threatened Canterbury mudfish/kowaro. Eels are still plentiful but there seem to be few juveniles present. Their life cycles are a good indicator of how well Lagoon ecology is functioning.

The restoration project is working towards keeping sediment and farm runoff out of Wainono Lagoon and looking after surrounding wetlands, to protect this valuable habitat for fish and birds and source of treasured kai for Waihao and Ngāi Tahu rūnanga.

It’s early days yet, with dead flounder in the Lagoon this dry summer caused by lack of oxygen as the water warms. However, benefits of changes being made on farms should soon start being picked up in regular monitoring, especially for sediment.