Environmental Flows for the Lower Derwent River

Abstract

This document is the final report of the lower Derwent environmental flows assessment project. The results represent an initial position on minimum environmental flows for the lower Derwent, which can be used for scoping the design/potential for abstraction under the initiatives of the State Water Development Plan. It also presents results of an initial scoping of environmental high/flood flows the lower Derwent. It then integrates them into a recommendation on an environment flow regime incorporating both minimum and high flows for the maintenance of key environmental values in the lower Derwent system. The overall aims of this project were to: 1. To define key elements of an environmental flow regime for the lower Derwent; 2. To assess a minimum environmental flow regime for the system; 3. To scope a high flow/flood flow regime for the system. A principle aim of environmental flow management adopted for this project is to maintain existing environmental values of the river and estuary. This project was not tasked to develop an environmental flow regime aimed at restoring the historical condition of the river or estuary (eg 'pre-Hydro' or 'pre-European').