Broken River & Upper Broken Creek BROKEN RIVER & UPPER BROKEN CREEK Seasonal Watering Proposal 2017-2018 Broken River & Upper Broken Creek Publication details Published by: Simon Casanelia Goulburn Broken Catchment Management Authority, PO Box 1752, Shepparton 3632 © Goulburn Broken Catchment Management Authority, 2017. Please cite this document as: GBCMA (2017). Broken River and Upper Broken Creek Seasonal Watering Proposal 2017-2018. Goulburn Broken Catchment Management Authority, Shepparton. Disclaimer: This publication may be of assistance to you, but the Goulburn Broken Catchment Management Authority does not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequences which may arise from you relying on information in this publication. It should be noted that specific reference to funding levels in this strategy are for indicative purposes only. The level of Government investment in this plan is contingent on budgets and government priorities. For further information, please contact: Goulburn Broken Catchment Management Authority P.O. Box 1752, Shepparton 3632 Ph. (03) 5820 7700 Website: www.gbcma.vic.gov.au i Broken River & Upper Broken Creek EXECUTIVE SUMMARY The proposal identifies the environmental water requirements of the Broken River and upper Broken Creek in 2017-2018 under a range of climatic scenarios to protect or improve their environmental values and health. The Broken River has been identified as priority waterway in the Goulburn Broken Waterway Strategy (GB CMA 2014). Both the Broken and the upper Broken Creek are listed as on the Directory of Important Wetlands in Australia (Environment Australia 2001). They also support a diverse and abundant native fish community, provides water for agriculture and support a variety of recreational activities such as fishing, boating, bird watching and camping. The conditions leading into the 2016-17 year were characterised by a dry summer and autumn. However, between July and November 2016 above average rainfall across the catchment resulted in the upper Broken Creek and the Broken River experiencing several freshes and the Broken River experience a bankfull/overbank flow that had a peak discharge of approximately 20,000 ML/day at Caseys Weir. These high flows would have: increased native fish and macroinvertebrate habitat; stimulated native fish movement and breeding; helped maintain in-channel habitat diversity; and helped maintain wetland, riparian and in-channel vegetation condition. Preliminary assessment of fish movement through the fish ladders at Caseys Weir and Lake Benalla on the Broken River suggest a few golden perch moved through the fish ladder at Caseys Weir between October and November 2016 coinciding with the high flows. Based on these findings the priority watering actions in 2017-18 are: 1. Use the available environmental water to maintain water quality in the upper Broken Creek for native fish and macroinvertebrates. The upper Broken Creek may experience poor water quality as a result of floods, low and cease to flow events, intense rainfall and fire. Flows between 50-100 ML/d for 10 days may be required to respond to these events 2. Maintain Broken River minimum baseflow requirement of 15 ML/day in summer and autumn using Inter- Valley Transfer water. 3. Deliver a summer/autumn fresh (400- 500 ML/day for 2-8 days) downstream of Lake Nillahcootie on the Broken River using Inter-Valley Transfer water. The fresh is designed maintain macrophyte and native fish habitat. Under all seasonal scenarios, the volume of environmental water available is much less than the volume required to deliver the desired priority watering action in the upper Broken Creek. If Inter-Valley Transfer water (maximum of 1,500 ML) can be utilized in the Broken River, it could meet the minimum Broken River baseflow requirements and could partially deliver the fresh priority watering action. Given the small volume of environmental water available and the nature of the Broken River supply system, there is no particular need to save water for the 2018-2019 year. The proposal does not take account of competing needs of environmental water use at Moodie Swamp on the upper Broken Creek. As all of the flows proposed are well within the channel of the upper Broken Creek and Broken River, there is a very low risk of adverse outcomes to private assets or the general public from delivering the priority watering actions. The proposal was developed in consultation with the GB CMA Board, the VEWH, the CEWO, GMW, Parks Victoria and the Broken Environmental Water Advisory Group. These groups will also be consulted along with traditional owners during the implementation of the proposal. ii Broken River & Upper Broken Creek CONTENTS Executive summary .......................................................................................................................................... ii Glossary and acronyms .......................................................................................................................................... v Introduction and system overview........................................................................................................................ 1 Introduction ............................................................................................................................................................ 1 Purpose ................................................................................................................................................................... 1 System overview ..................................................................................................................................................... 1 Broken River ........................................................................................................................................................................... 1 Upper Broken Creek ............................................................................................................................................................... 2 Priority reaches and measurement points ............................................................................................................................. 3 Delivery constraints ................................................................................................................................................................ 3 Water sources ......................................................................................................................................................................... 4 Environmental objectives and flow recommendations ........................................................................................ 6 Broken River objectives and recommendations ..................................................................................................... 6 Upper Broken Creek objectives and recommendations ......................................................................................... 8 Seasonal review 2016-2017 ................................................................................................................................... 9 Broken River ........................................................................................................................................................... 9 Upper Broken Creek ............................................................................................................................................. 10 Flow recommendations delivered ........................................................................................................................ 12 Current ecological condition................................................................................................................................. 13 Key observations and lessons ............................................................................................................................... 14 Shared benefits review ......................................................................................................................................... 14 Outlook for 2017-2018 ......................................................................................................................................... 14 Priority watering actions ..................................................................................................................................... 15 Scenario planning ................................................................................................................................................. 16 Scenario planning overview .................................................................................................................................. 16 Triggers for action ................................................................................................................................................. 19 Shared benefits outcomes .................................................................................................................................... 19 Implementation arrangements ........................................................................................................................... 20 Notice and time required ....................................................................................................................................