Northland has more than 400 dune lakes, found within old sand dune systems mostly on the west coast. Dune lakes are one of the rarest and most threatened aquatic habitats in the world. The lakes are grouped on the Aupōuri, Karikari and Poutō peninsulas, as well as the Kai Iwi group north of Dargaville. They are often dynamic, with fluctuating water levels and shorelines that are frequently changed by shifting sand dunes.
There are also a few volcanic lakes, alluvial (valley bottom) and some man-made lakes. Our largest lake is Lake Ōmāpere, north of Kaikohe - it is 1160ha in area. The largest dune lake is Lake Taharoa (one of the Kai Iwi lakes), which is 197ha and 37m deep.
Why are our lakes special?
Dune lakes are home to a wide range of native plants and animals, including the rare freshwater fish, the dune lake galaxias and dwarf inanga, which are only found in some Northland dune lakes. Some of our Northland dune lakes are the most pristine in New Zealand. Lake Taharoa is also one of the largest and deepest dune lakes of its type in the world and has the deepest growing submerged vegetation in the North Island, at 24m.
Lakes are home to a unique range of native algae and aquatic plants. Many of these plants are now threatened because there are so few lakes left with good water quality. Many fish and water birds use the surrounding reed beds, wetlands and open water, some of which, like scaup and little grebe, are rare. Lakes are important for storing clean water and can be a real asset on farms or in pine forests. They can also help reduce peak flood levels during storms.
Many of the best Northland lakes are popular for recreational swimming and boating. Duck shooting is a widespread sport in areas of shallow open water, while eels and freshwater crayfish (kewai) and reeds (kuta) are harvested for food and weaving materials.
What can you do to help look after our lakes?
Dune lakes are very sensitive to outside pressure. We need to reduce the amount of nutrients getting into our lakes to help manage water quality. Added nutrients can cause toxic algal blooms and increase aquatic weed growth. You can help by:
- Fencing lakes to keep stock out. Include a wide riparian margin to create a buffer zone between the fence and the lake. Plants help filter nutrients in water flowing off paddocks before it reaches the lake.
- Keeping a healthy sward of pasture and avoiding pugging in any paddocks within the lake catchment.
- Preventing fertiliser and effluent from reaching the water via runoff or soaking into groundwater close to the lake.
Control pest plants and animals near your lake by:
- Check, Clean, Dry - check and clean any boats, diggers or farm machinery that go into or near the water.
Find out more about Check, Clean, Dry on the Ministry for Primary Industries website.
- Setting up pest bait stations or traps around the fenced lake margins to control animals such as possums, rats, stoats, weasels etc.
More information about about stopping the spread of pest plants and animals can be found in our Biosecurity section.
Funding contributions towards fencing stock out of our lakes and/or planting riparian margins may be available through the Northland Regional Council's environment fund.
Contact a land management advisor
Contact a land management advisor for more information on 0800 002 004. One of our land management team can visit your property and offer free advice on funding and sustainable land management actions that could improve biodiversity on your property.
Hidden Gems is a three part, 25 minute documentary on the Northland region's very special coastal dune lakes and how we can help look after them for future generations.
In the north of New Zealand is found one of the rarest and most threatened aquatic habitats in the world, the dune lakes. These lakes are a geological oddity, sculpted by strong sea winds blowing across the coastal sand dunes scouring out hollows that, over time, fill with fresh water which are then colonized by an extraordinary assemblage of plant and animal life. Dune lakes occur in only a few places around the world and because they occur in the very places people like to live, work and play, they are extremely vulnerable to outside pressures and are degraded easily, but New Zealand's Northland region still has more permanent, and mostly healthy dune lakes than anywhere else on the planet.
Despite the high ecological value of these coastal dune lakes their future is by no means secure. First and foremost is the same nutrient problem facing most of New Zealand's waterways, that of nutrient enrichment with the devastating effects it has on freshwater environments. Land conversion to intensive farming, forestry, water weeds, pest fish and recreational use is also putting increasing pressure on Northland's dune lakes.
Looking after our precious Dune Lakes is something we can all take part in very easily, and just a small amount of effort and care can go a long way towards ensuring our lakes remain to enjoy for a long long time! Think of dune lakes as large beautiful aquariums – most of what you put into them stay there. Although regional council, landowners and other groups are working to monitor and look after our lakes including 12 outstanding lakes that receive special attention, one of the biggest things we can all do is prevent the spread of weeds or pests. Always take the time to check, clean and dry nets, boats, trailers and recreational gear before leaving any waterway so that you don't introduce pests to the next lake you visit.
Our dune lakes are precious, unique, and something to be proud of and look after for future generations.
Hidden Gems videos - Northland's Dune Lakes
Watch the 'Northland's Dune Lakes – Hidden Gems' videos through our YouTube channel.