Determination of flow regimes for protection of in-river values in New Zealand: an overview

Competition for water has intensified. Determining when, and how much, water needs to be left for in-river values is a challenge world-wide. In New Zealand there is now a well established connection between the flow regime, as defined by the magnitude and variability of flows, and suitability for in-river values. Physical habitat requirements of the biota have been defined and related to overall flow regimes (e.g., mountain fed, hill fed and lowland fed). Key to this is understanding both minimum flow and variability requirements of the biota. This paper overviews some of this science and illustrates how this knowledge has helped resolve river resource management issues in New Zealand.