MURRAY-DARLING BASIN AUTHORITY Native Fish Strategy Scoping options for the ecological assessment of cold water pollution downstream of Keepit Dam, Namoi River MURRAY-DARLING BASIN AUTHORITY Native Fish Strategy Scoping options for the ecological assessment of cold water pollution downstream of Keepit Dam, Namoi River C.A. Boys, N. Miles and T. Rayner NSW Department of Primary Industries Published by Murray-Darling Basin Authority Postal Address GPO Box 1801, Canberra ACT 2601 Office location Level 4, 51 Allara Street, Canberra City Australian Capital Territory Telephone (02) 6279 0100 international + 61 2 6279 0100 Facsimile (02) 6248 8053 international + 61 2 6248 8053 E-Mail [email protected] Internet http://www.mdba.gov.au This report may be cited as: Boys, C., Miles, N., and Rayner, T., Scoping options for the ecological assessment of cold water pollution mitigation downstream of Keepit Dam, Namoi River, Murray-Darling Basin Commission (now Murray-Darling Basin Authority.) NSW Department of Primary Industries. MDBA Publication No. 20/09 ISBN 978-1-921257-82-7 ISSN 1449–9967 (Note: Prior to July 2004, this report series was published as the NSW Fisheries Final Report Series with ISSN number 1440–3544) © Copyright Murray-Darling Basin Authority (MDBA), on behalf of the Commonwealth of Australia 2009 This work is copyright. With the exception of photographs, any logo or emblem, and any trade marks, the work may be stored, retrieved and reproduced in whole or in part, provided that it is not sold or used in any way for commercial benefit, and that the source and author of any material used is acknowledged. Apart from any use permitted under the Copyright Act 1968 or above, no part of this work may be reproduced by any process without prior written permission from the Commonwealth. Requests and inquiries concerning reproduction and rights should be addressed to the Commonwealth Copyright Administration, Attorney General’s Department, National Circuit, Barton ACT 2600 or posted at http://www.ag.gov.au/cca. This work was originally commissioned and produced for the Murray-Darling Basin Commission (MDBC) and contains references to the MDBC. In December 2008, the MDBC's rights and its functions were transferred to the MDBA in accordance with the Water Act 2008 (Cth). The views, opinions and conclusions expressed by the authors in this publication are not necessarily those of the MDBC, MDBA or the Commonwealth. To the extent permitted by law, the Commonwealth (including the MDBA) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or in whole) and any information or material contained within it. Front cover image credit: Keepit Dam (State Water Corporation) CONTENTS List of tables ....................................................................................................................................................................................................................................................................................................v List of figures ............................................................................................................................................................................................................................................................................................... vi Acronyms used in this report ..............................................................................................................................................................................................................................................viii Acknowledgements .............................................................................................................................................................................................................................................................................ix Non-technical summary .................................................................................................................................................................................................................................................................x 1. Background ............................................................................................................................................................................................................................................................................................1 1.1 The nature and extent of cold water pollution in the Murray-Darling Basin .................................................................................. 1 1.2 Impact of CWP on native fish of the MDB .................................................................................................................................................................................. 3 1.2.1 Redistribution of species............................................................................................................................................................................................................. 3 1.2.2 Timing and success of reproduction ............................................................................................................................................................................. 4 1.2.3 Growth and metabolism ............................................................................................................................................................................................................... 5 1.2.4 Recruitment ................................................................................................................................................................................................................................................ 6 1.3 Keepit Dam and the nature of CWP in the Namoi River .......................................................................................................................................... 6 1.4 Anticipated outcomes of the construction of a multi-level offtake at Keepit Dam .................................................................. 8 1.5 Impact assessment into the mitigation of CWP in the Murray-Darling Basin ...........................................................................10 1.6 Objective of this scoping report ..........................................................................................................................................................................................................11 2. Scoping process ...........................................................................................................................................................................................................................................................................12 3. Sensitive assemblage components and development of hypotheses ...............................................................................................................14 3.1 Redistribution of species ............................................................................................................................................................................................................................15 3.2 Spawning and larval production ........................................................................................................................................................................................................17 3.3 Recruitment ...............................................................................................................................................................................................................................................................17 3.4 Growth ..............................................................................................................................................................................................................................................................................17 4. Project design considerations ..................................................................................................................................................................................................................................19 4.1 Impact assessment framework .........................................................................................................................................................................................................19 4.2 Spatial stratification .........................................................................................................................................................................................................................................20 4.2.1 Impact location .....................................................................................................................................................................................................................................20 4.2.2 Control locations ................................................................................................................................................................................................................................21 4.2.3 Reference locations ........................................................................................................................................................................................................................24