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  • East Gippsland Water

    21 October 2010

    Orbost Drought Response Plan

  • AECOMOrbost Drought Response Plan

    21 October 2010

    Orbost Drought Response Plan

    60144336 Task 1.06

    Prepared for

    East Gippsland Water

    Prepared by

    AECOM Australia Pty Ltd

    Level 9, 8 Exhibition Street, Melbourne VIC 3000, Australia

    T +61 3 9653 1234 F +61 3 9654 7117 www.aecom.com

    ABN 20 093 846 925

    21 October 2010


    © AECOM Australia Pty Ltd 2010

    The information contained in this document produced by AECOM Australia Pty Ltd is solely for the use of the Client identified on the cover sheet

    for the purpose for which it has been prepared and AECOM Australia Pty Ltd undertakes no duty to or accepts any responsibility to any third party

    who may rely upon this document.

    All rights reserved. No section or element of this document may be removed from this document, reproduced, electronically stored or transmitted

    in any form without the written permission of AECOM Australia Pty Ltd.

  • AECOMOrbost Drought Response Plan

    21 October 2010

    Quality Information

    Document Orbost Drought Response Plan

    Ref 60144336

    Date 21 October 2010

    Prepared by Marisa Cesario

    Reviewed by Steven Wallner

    Revision History

    Revision Revision Date Details


    Name/Position Signature

    A 19-May-2010 Draft for Client Comment Andrew Grant

    Associate Director -


    Original Signed

    B 16-Sep-2010 Issue for Technical

    Committee Review

    Elisa Hunter

    Elisa Hunter

    C 21-Oct-2010 Final Elisa Hunter

    Elisa Hunter

  • AECOMOrbost Drought Response Plan

    21 October 2010

    Table of Contents

    1.0 Drought Response Preface 1 2.0 Introduction 2 3.0 System Description 3

    3.1.1 Overview 3 3.1.2 Diversion 3 3.1.3 Storage 4 3.1.4 Water Treatment Plant 4 3.1.5 Supply 4

    3.2 Changes to the Supply System 4 4.0 Objectives 5

    4.1 General 5 4.2 Strategic 5 4.3 Planning 5 4.4 Operational 5

    5.0 Action Plan for Responding to Drought 6 5.1 Introduction 6 5.2 Action Plan Summary and Flowchart 6

    5.2.1 Water Restriction Trigger Levels 6 5.2.2 Introduction of Voluntary Restrictions 7 5.2.3 Introduction of Mandatory Stage 1 and 2 Restrictions 7 5.2.4 Mandatory Stage 3 and 4 Restrictions 8

    6.0 Pre Drought Activities 9 6.1 Staff Training and Educations 9 6.2 Waste Minimisation 9 6.3 Promotion of Water Restrictions 9 6.4 Ongoing Monitoring and Reporting 10

    6.4.1 Regular Pre Drought Activities 10 6.4.2 Water Supply System Monitoring and Reporting 10 6.4.3 Climate and Drought Outlook 11

    6.5 Funding Strategy for Drought Response 12 7.0 Drought Response Options and Lifting of Restrictions 13

    7.1 Introduction 13 7.2 Demand Reduction Options 13

    7.2.1 Voluntary Demand Reduction 13 7.2.2 Water Watch Days 13 7.2.3 Demand Reduction due to Restrictions 14

    7.3 Supply Enhancements during Drought 15 7.3.1 Water Carting 15 7.3.2 Groundwater Supply 15 7.3.3 Increased Share of River Flow 15 7.3.4 Transfer of Surface Water Entitlements 16

    7.4 Lifting of Restrictions 16 8.0 Post Drought Activities 17

    8.1 Evaluation of Objectives 17 8.2 Evaluation of Actions 17 8.3 Potential Impacts of Restrictions 17

    8.3.1 Impact of Restrictions on the Community 17 8.3.2 Impact on East Gippsland Water 18

    8.4 Revision of the DRP 18 9.0 Water Supply Context 19

    9.1 Legal and Institutional Context 19 9.1.1 Bulk Water Entitlements 19 9.1.2 Applying for Qualifications to Bulk Entitlements 19 9.1.3 Groundwater Entitlements 19 9.1.4 Supply to Urban Users 19

  • AECOMOrbost Drought Response Plan

    21 October 2010

    9.1.5 Model Water Restriction By-law (No. 0001/08) 20 9.2 Levels of Service 20

    10.0 Past Drought Experience 21 10.1 Previous Drought and Water Restrictions 21

    11.0 Summary of Recommendations 22 12.0 References 23

    Appendix A Drought Response Flowchart A

    Appendix B Action Plan B

    Appendix C EGW Water Restrictions By-Laws C

  • AECOMOrbost Drought Response Plan

    21 October 2010 1

    1.0 Drought Response Preface

    East Gippsland Water’s (EGW) Statement of Obligations (SoO) requires the Corporation to develop and

    implement an effective Drought Response Plan (DRP) for each water supply system, with the intent of providing a

    framework for ensuring timely and effective response to water shortages.

    The SoO requires EGW to review, and if necessary amend its DRPs at intervals of no more than five years or

    within twelve months of either:

    • the lifting of any period of restriction imposed under the Corporation’s DRP

    • any major change occurring to works or arrangements for conserving water for, or supplying water to, any

    water supply system operated by the Corporation.

    Given that the Water Supply Demand Strategy (WSDS) for Orbost was recently revised, the DRP must also be

    updated to ensure that both documents are consistent.

    This report is intended to form an update to the previous DRP titled ‘Drought Response Plan for Bemm River,

    Buchan, Cann River, Marlo, Newmerella and Orbost’ that was prepared by SKM during 2006. This version of the

    DRP will focus on the Orbost water supply system with separate DRPs to be prepared for the other towns.

    This review and update of the Orbost DRP includes:

    • revision of the current system configuration

    • re-structuring of the DRP

    • the update of statistics relating to drought history

    • revision of restriction triggers based on the updated system configuration

    • the update of available drought response options

    • revision of the previous action plan;

    • identification of information gaps

    • recommendations.

    Text in italics are direct excerpts from the previous DRP (2006).

    This DRP should be read in conjunction with the Orbost WSDS (2010) and should be updated in the event of any

    changes to the existing water supply system or its operation.

  • AECOMOrbost Drought Response Plan

    21 October 2010 2

    2.0 Introduction

    The aim of this DRP is to ensure a timely and effective response to water shortages, with the aim of minimising

    the social, economic and environmental impacts of such shortages.

    There are two components involved in securing an adequate water supply in times of drought. These are:

    • the provision of an adequate supply system to satisfy current and future demands for design drought

    conditions, ensuring that shortfalls in supply are within 'acceptable' levels

    • the definition of the actions required when water supply shortfalls occur.

    The first component represents the long term planning actions which result in a certain level of infrastructure

    development. A high level of service (i.e. where shortages in supply are very infrequent) requires a high level of

    investment in infrastructure. This means that consumers are paying a large premium every year to insure

    themselves against potential shortfalls in supply during relatively infrequent drought events.

    The second component relates to management actions which are required to minimise the impacts of shortfalls in

    supply. These actions complement the long term planning process. While the Drought Response Plan relates

    specifically to the second component, the short term response needs to be based on a good understanding of the

    longer term security of supply for the supply system, as this defines the supply context for a DRP.

    A full drought management plan for a water corporation involves an appropriate combination of long and short

    term components, focussing on the actions to be taken and/or considered by East Gippsland Water in pre-

    drought, drought and post-drought periods.

  • AECOMOrbost Drought Response Plan

    21 October 2010 3

    3.0 System Description

    3.1.1 Overview

    Orbost, as well as Newmerella, Marlo and Jarrahmond (a small satellite settlement) are supplied with surface

    water from the Brodribb and Rocky Rivers, via a water treatment plant at Orbost. Traditionally the Rocky River

    has been the primary water supply source, however deterioration of the diversion main has resulted in an

    increase in water losses and EGW are currently investigating whether it can continue to be a sustainable water


    A schematic of the Orbost supply system is shown in Figure 1. Further details on key components of the system

    are included in the following sections of this DRP.

    Figure 1: Orbost’s Water Supply System

    3.1.2 Diversion

    Water is pumped from the Brodribb River diversion site at a maximum rate of 5.74 ML/day via an 11 km long

    rising main which transfers water to the Orbost raw water basin. The Rocky River weir gravity feeds a 21 km long

    pipeline to the Orbost raw water basin with a maximum flow rate of 1.37 ML/d.

  • AECOMOrbost Drought Response Plan

    21 October 2010 4

    3.1.3 Storage

    The system has a