Authors: Damian Young and Jim Hodges
ABSTRACT
The erosion of streams in New Zealand can result in serious problems. Auckland’s North Shore City is no exception in this regard. Large stretches of stream channel are eroding, smothering sensitive aquatic plants and animals with sediments. One of the few methods available to stormwater managers, to reduce the rates of erosion, has been to reinforce eroding channels with concrete, rock and treated timber.
The implications of lining channels are that the natural habitat values of the affected waterways are reduced or in some cases eliminated. Consequently, channel-lining methods to control erosion or to improve floodwater conveyance also need to cater for the environmental health of the waterway. This effectively means that lining works in watercourses must serve to “kill two birds with one stone”.
It is the aim of this paper to provide some insight as to how this might be achieved using the observations made during the recent survey of 150 kilometres of stream network in the North Shore. A better understanding of how to manage urban waterways has been developed, simply using nature as a guide and taking note of the types of habitats created by certain linings.
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