Long-term management of facilities on an active alluvial fan – Waiho River fan, Westland, New Zealand.
- Author
- Davies TRH
- Year
- 1997
- Journal / Source
- Journal of Hydrology (New Zealand)
- Volume
- 36
- Pages
- 127-145
- Summary
- The proglacial Waiho River, Westland, New Zealand, and its tributary the Callery River, form a large alluvial fan, at the head of which is sited the township of Franz Josef Glacier. The very dynamic geology of the area, and its climate, cause the river and fan to be very active, and this results in the facilities of the township being threatened by aggradation and flooding from the Waiho River. In addition to rainstorm flooding, the fan is also susceptible to the potentially catastrophic results of glacierburst and landslide dambreak flooding. Traditional methods of river control cannot provide an adequate degree of security for facilities, inhabitants and visitors. An example of a long-term strategy is illustrated, by means of which such security could be achieved. It is based on knowledge of the evolution of alluvial fans; on acceptance of the fundamentally aggradational nature of the Waiho fan; and on acceptance that accurate prediction of detailed behaviour of the fan is unlikely to be available in the foreseeable future. It involves sequential redevelopment of key facilities, so that immediate serious hazards are avoided and the township can continue to service the tourism industry of the area in the long term.