How adequately do gauged tributaries represent the hydrological behaviour of ungauged tributaries in modelling large regulated catchments?

Abstract

The issue of how adequately gauged, unregulated tributaries represent the hydrological behaviour of ungauged, unregulated tributaries is rarely considered within the context of a single large regulated catchment. We show that in a catchment where the gauging of tributaries is biased towards perennial streams, this bias can result in overestimations of the water balance. The Broken River of southeastern Australia is regulated and two gauged, unregulated tributaries comprise 49% of the catchment area downstream of the main storage. Both of these tributaries are largely perennial but short-term monitoring of other unregulated tributaries indicates that most of the remaining catchment downstream..