Page 6 – Conserving rivers
Changes in public opinion
Awareness of the need to protect rivers dawned slowly. Efforts to protect river catchments as a way of preventing erosion and limiting floods began in the late 19th century. However, it was not until 1941 that the Soil Conservation and Rivers Control Act was passed. Several decades went by before all districts had set up their own catchment boards. They were supported by a central research and regulation agency based within the former Ministry of Works.
Although there was widespread support for hydroelectricity schemes, in the 1960s some people began to see the environmental threat they posed. The public campaign to save Lake Manapōuri signalled changing attitudes. However, power schemes continued. A second big hydro dam was built on Otago’s magnificent Clutha River during the 1980s at Clyde. The project went ahead despite protests from environmental and community groups.
Recreational groups also formed powerful lobbies. Tranquil rivers have always lured fishermen and swimmers, and boating is a favourite pastime. After the Second World War, canoeing, kayaking and rafting became popular with New Zealanders and overseas tourists. These activities usually took place on the wild scenic rivers that were under increasing threat from power development.
Wild and scenic rivers legislation
In 1981 the Wild and Scenic Rivers Amendment to the Water and Soil Conservation Act was passed. Since then, 12 rivers have been given the protection of national water conservation order status. Groups such as the Living Rivers Coalition continue to campaign for the protection of New Zealand’s waterways.
Flood protection and river management
Catchment boards were replaced by regional councils in 1989. The councils and the National Institute of Water and Atmospheric Research (NIWA) continuously monitor river levels and rainfall, and provide flood warnings if necessary. NIWA has also developed a River Environmental Classification to help manage waterways.
The development of the waterjet engine by New Zealander Bill Hamilton in 1954 revolutionised river transport. Using a centrifugal pump that drew in water and expelled it above the waterline, the engine does not extend under the boat like an outboard motor. Jet boats can travel along shallow rivers once inaccessible to power boats. Jet boats are used for tourism on rivers such as the Shotover in Otago.
Riparian protection: restoring the river banks
Since the 1970s, there have been schemes to plant trees and shrubs on river banks. Native species are planted, such as makomako, kotukutuku, kawakawa, māhoe, karo, patē, kōwhai and pōhutukawa. As well as stabilising the banks, they provide food for birds, and so help restore biodiversity.
Since the 1980s, Māori have declared their traditional interests in rivers, water and water quality to the Waitangi Tribunal. Cases have been taken to the Environment Court since the passing of the Resource Management Act in 1991. Two of the most significant rivers in New Zealand, the Waikato and Whanganui, both await resolution between the government and the respective tribes over management and protection.
As well as long-standing pollution and flooding, there are new threats to the health of rivers, in particular:
- the arrival of invasive species such as didymo (Didymosphenia geminata, also known as ‘rock snot’), which has now spread to many South Island rivers.
- the growth of dairying in Canterbury. This affects water quality through effluent discharge, and river levels through use of water to irrigate pastures.
- the increase in numbers of off-road vehicles. Television advertisements often show these vehicles driving through pristine rivers.
The demand for electricity is expanding rapidly, and the threat of climate change may limit the use of fossil fuels to generate energy. New Zealanders may face the difficult choice whether to develop more rivers for hydroelectric power, or to retain them in their wild state.