Grovetown Lagoon

17 November 2023

An Oxbow Lake With Abundant Bird Life

Provincial, small-town New Zealand folk are well known for ‘coming together’ to achieve common goals especially when those end objectives benefit the community as a whole. Natural habitat restoration projects are particularly good examples of this community spirit with the end result seeing improvements in the quality of natural environments and subsequently creating better habitats for birds and wildlife. The Grovetown lagoon in Marlborough enjoys success through community help combined with generous funding from local authorities and businesses. 

Story + Photos Matt Winter

Grovetown lagoon is one of the few natural wetlands remaining on the Wairau plains in Marlborough. Geographically speaking the lagoon is an ‘oxbow lake’. This type of lake is formed over time when a river creates a curving, meandering path which eventually nearly cuts back onto itself. (See aerial image). As the ‘neck’ of the meander becomes narrower and narrower it becomes susceptible to breaching during the next major flood, which in this case occurred in 1861. The high waters and fast flows broke through the narrow piece of land which in effect straightened the river’s path leaving an isolated curved lake where the river once flowed.

The Lagoon
As the Wairau river continued on its new, straighter path, the Grovetown oxbow lake’s water remained clear and fresh, even in times of drought, due to the numerous nearby freshwater springs flowing into the lagoon. Fish and eels continued to thrive in the wetland while birds made their homes around the sheltered water using it for feeding, nesting and raising their young.

Unfortunately, as time went on, willows and invasive climbing vines overcame the banks of the lagoon. Adding to the environment degradation, effluent and silt from farming practices and the local Grovetown residential settlement began to pollute the waters of the loop.

Fast forward to 2002 when local people became very concerned about the state of the lagoon. Through a combined effort between local iwi groups, the Department of Conservation, Nelson Fish and Game, Marlborough District Council, New Zealand Landcare Trust and local residents, the Te Whānau Hou Grovetown Lagoon Restoration Project was launched. Two groups now oversee the direction of the overall project, each with different responsibilities: the ‘executive committee’ takes more of a planning, monitoring and strategic role, while the ‘working group’ oversees the implementation of the work.

The official launch of the project was signified by a tree-planting ceremony at dawn on Saturday February 2, 2002. Following that, the first priority was the removal and eradication of weeds. The predominant weed tree causing the bulk of the problems was the common willow. These were gradually killed off by drilling holes in the base of the trees and injecting herbicide. The list of other invasive and destructive plants was long. They included: old man’s beard, honeysuckle, periwinkle, hawthorn, elderberry, ivy, blackberry.

Other weeds including garden ‘escapees’ were targeted with weed killer. As areas were cleared of pest plants by the volunteer working groups, native species suitable for riparian and wetland habitats were planted in their place. Kōwhai, cabbage trees, kahikatea, swamp maire, native sedges, flax as well as other smaller native shrubs now thrive on the once choked and weed-infested lagoon banks.

Once the habitat restoration was well underway, the Grovetown Restoration Project began building a walking/biking track around the entire lagoon. The track was intentionally designed and built around the outside of the lagoon so the inside margins were left undisturbed to provide a refuge for birds and wildlife. The track was built in stages and finally completed after the erection of an S-shaped boardwalk over Kellys creek (one of the feeder streams) in April 2019.

Grovetown Lagoon Loop Track
Literally a five-minute drive from the centre of Blenheim, the Grovetown lagoon loop track is a very easy 60-minute, flat-terrain walk on a well-built track that circumnavigates the wetland.

After navigating to Steam Wharf Road from the centre of Blenheim, the best place to start is at the bridge that spans a creek leading into the walk. Right beside the bridge is a large information board and a beautiful wooden bench seat which overlooks the lagoon. While there is no obvious carpark, as such, the grass verge between the road and the lagoon affords ample room for many cars. If you enjoy seeing things from a more intimate and personal perspective, you can launch your kayak from the purpose-built ramp beside the carpark.

Another way of completing the walk is by parking at the end of Steam Wharf Road and starting along the stopbank beside the rowing club sheds and walking in a counter-clockwise direction.

Once over the bridge, the track continues on, running parallel to the edge of the lagoon and high enough above water level to give fantastic views. Immediately you’ll notice the hundreds of native plants adorning the land lying between the track and the lagoon. These are the areas that were once riddled with weeds and unwanted plant species, while on the left side of the track, volunteer work groups have planted the open grassy areas in an attempt to ‘enclose’ the track within a new native ecosystem.

As the track meanders along, the next feature is a curved boardwalk across one of the larger feeder streams – Kellys creek. Once over the solid and well-built boardwalk, the track skirts along the edge of vineyards while still hugging the lagoon edge. The vineyards are private properties so please respect that by staying on the walking track.

The vineyards eventually give way to a grassed but low-lying, swampy area. This spot is known as the springs wetland or the Big Bush Project. There are nine hectares of land here which the Marlborough District Council purchased and added to the lagoon conservation area. The whole area is being planted out with native trees and swamp species with the intention of restoring some of the original ‘big bush’ of the region.

After passing through the springs wetland, the track pops up onto the stopbank lining the Wairau river. From the top of the bank you will be looking down onto an area of dense but relatively young native trees. Known as the ‘riverside area’, it is well tracked and a great spot to observe native birds such as tūī and fantails.

Emerging from the riverside area, follow your nose along the stopbank past the rowing club sheds then hang a right back down onto the end of Steam Wharf Road. From here there are two options – continue on straight ahead and back to your vehicle or head right over the bridge (Cemetery road) for a short detour track which takes you to a purpose-built birdwatching hide. I strongly recommend doing the latter. This small diversion starts with a delightful grassed picnic area (with picnic tables) then continues for 240 metres to where the birdwatching hide is sited. It is a simple but effective structure that enables viewers to watch bird life while being effectively ‘hidden’, meaning you are watching birds that are acting naturally and undisturbed.

When you have had your fill of birdwatching, simply backtrack to the bridge and continue back to the carpark via the walking track beside the road.

If you are walking at a very leisurely pace, the whole walk should only take you about an hour. A couple of bench seats and picnic tables along the way give the opportunity for a rest or simply a nice spot to take in the scenery. Although dogs ‘on a leash’ are permitted on the walk, because of the plentiful amount of bird life in the area, it is recommended to leave your dog at home.

One other thing to bear in mind is that the lagoon is used by duck hunters between May 1 and July 31 each year. In most cases, hunting is usually undertaken either early morning or late in the evening so perhaps consider doing the walk nearer the middle of the day during these months. 

Article kindly provided by nztoday.co.nz