Our Place – Geography
What is the Upper Clutha catchment?
A catchment is an area which collects rainfall into streams and down into the soil, eventually feeding rivers, lakes and wetlands.
The Upper Clutha catchment covers a total land area of 4,600km2. It includes Lake Wānaka, Lake Hāwea and all water bodies upstream of the confluence of Luggate Creek and the mighty Mata-Au/Clutha river.
Much of the catchment area is mountainous, providing a multitude of glacier-fed waters. The headwaters of the Makarora, Mātakitaki and Ōtānenui/Wilkin Rivers are in Mount Aspiring National Park. The main rivers feeding into Lake Hāwea and much of the Lake Hāwea catchment are in the Hāwea Conservation area.
The concept of ki uta ki tai (from the mountains to the sea) is especially important in the Upper Clutha, given our location at the headwaters of te Mata-Au / the Clutha River. Those living and visiting the area have a responsibility to ensure that the water that leaves the catchment is of high quality, and that problems are not passed on to those downstream.
Lake Wānaka
One of the major glacial lakes of the Southern Alps, Lake Wānaka is 192 square kilometres in area, 45km long and 6km across at the widest point. 277m above sea level, it has an estimated maximum depth of 311m.
The Makarora and Ōtānenui/Wilkin Rivers flow into the northern end of Lake Wānaka. The Mātakitaki River and its tributary, the Motatapu River, drain into Lake Wānaka’s southwestern edge. The Mata-Au/Clutha River drains from Lake Wānaka and is met by major tributaries, the Hāwea and Ōrau/Cardrona Rivers and Luggate Creek.
Lake Hāwea
About 141 square kilometres in area, 35km long and 8km across at the widest point, Lake Hāwea is a product of glaciation which scoured out the valley it occupies, depositing moraine which forms its southern shore. 342m above sea level, it has an estimated maximum depth of 392m.
Rivers draining into Lake Hāwea are the Upokotauia/Hunter River at the head, and Whakakea/Dingle Burn and Timaru Creek from the east. The Hāwea River drains Lake Hāwea into the Mata-Au/Clutha River.
Mata-Au/Clutha River
The South Island’s longest river, the Mata-Au/Clutha River runs from Lake Wānaka to its mouth on the coast south-east of Balclutha.
Lake Wānaka is fed by the Makarora River to its north; the continuous stretch of water from the Makarora’s headwaters to the mouth of the Mata-Au is 338 km long. Though slightly shorter than the North Island’s Waikato River (354 km), the Mata-Au discharges almost twice the volume with a mean annual flow of 575 m3/second.
Biodiversity
Our native beech forests, braided rivers, wetlands and glacier-fed lakes are unique ecosystems.
They are home to rare birds and fish species. These include Kea, Kākāriki, Tomtit / Miromiro and South Island Robin / Toutouwai in the forests, and New Zealand shoveller, Pied Stilt, Black Gulls, Grebes and Black Swans.
Lake Wānaka and Lake Hāwea are home to the Kōaro (one of five white bait species at risk of extinction), Common Bully and Tuna/Long Fin Eel. The lakes support three introduced gamefish species: Chinook Salmon, Rainbow Trout and Brown Trout.
What challenges does the catchment face?
While water quality is perceived as being generally good, our waterways are no longer as pristine as they appear and face increasing pressures on five fronts: urbanisation, rural development, tourism growth, climate change and introduction and spread of flora and fauna.
Rapid urban growth offers particular challenges for freshwater management. Areas of vegetation that previously absorbed rainwater are being replaced by bare or impervious surfaces that direct runoff (and pollutants) into stormwater drains that flow directly into lakes and rivers. Future growth needs to be better managed to ensure that the combined impact of land use change, more houses, more cars and more people doesn’t automatically lead to degraded water quality.
FRESHWATER RESEARCH
University of Otago / Catchments Otago
The University of Otago is involved in a number of different research projects including studying lake snow. They are also involved in lakes 380, a five-year research project which aims to understand the environmental history of 380 lakes throughout New Zealand. This project is led by the Cawthron Institute and Geological and Nuclear Sciences.
National Institute of Water & Atmospheric Research (NIWA)
Completing a research project on water monitoring and reporting is aimed at improving regional data collection for both rivers and lakes, and improving the application of that monitoring data in practical regional water management.
Land Information New Zealand
Working on a ten-year strategy for controlling lagarosiphon weed at Lake Wānaka – largest financial contributor to Lake Wānaka management at present.
FRESHWATER IMPROVEMENT
WAI Wānaka
There is currently no single entity that drives freshwater research for the Upper Clutha catchment. WAI Wānaka has developed a research strategy and a community catchment plan which involves working with stakeholders to help deliver the evidence needed to inform and develop effective policy and management actions, to protect the ecosystem health of our deep alpine lakes and their catchments.
Queenstown Lakes District Council
Responsible for making decisions alongside and on behalf of the people living in the district including: community well-being and development, environmental health and safety, managing infrastructure, facilitating recreation and culture, resource management including land use planning and development control.
Otago Regional Council
Responsible for managing Otago’s land, air and water resources on behalf of the community. As well as looking after the environment, they take into account the people of Otago – their economic, cultural and social needs.
Recreational water quality is monitored by the ORC at Roys Bay on Lake Wānaka and at the Lake Hāwea holiday park, with monitoring results published weekly on the LAWA website.