Orbost Drought Response Plan - East Gippsland WaterOrbost Drought Response Plan AECOM 21 October...

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

60144336

© AECOM Australia Pty Ltd 2010

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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

Authorised

Name/Position Signature

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

Associate Director -

Water

Original Signed

B 16-Sep-2010 Issue for Technical

Committee Review

Elisa Hunter

Elisa Hunter

C 21-Oct-2010 Final Elisa Hunter

Elisa Hunter


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


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


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.


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.


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

source.

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.


21 October 2010 4

3.1.3 Storage

The system has a total storage capacity of approximately 52 ML, consisting of a 45 ML clear water storage dam, 6

ML raw water dam and 0.9 ML storage tank. This is roughly equivalent to two and a half weeks of peak

unrestricted summer demand (assuming no further extraction).

3.1.4 Water Treatment Plant

The water from the Orbost 6 ML raw water basin is treated at the water treatment plant in Orbost that was built in

1998 and upgraded to increase capacity in 2001. The conventional water treatment plant has capacity to treat

45 L/s (3.89 ML/d). The treatment process employs the coagulation and flocculation process followed by filtration

before being disinfected with sodium hypochlorite.

When demand is less than the Orbost water treatment plants capacity surplus treated water is transferred into the

53 ML clear water storage dam. This is available to augment supply during peak periods. Water in the dam

requires further treatment prior to entry into the distribution system.

3.1.5 Supply

Supply to Orbost and Marlo is by gravity, but is pumped to Newmerella. The nearby community of Jarrahmond is

also supplied by gravity from the treatment plant.

3.2 Changes to the Supply System

A number of changes have occurred since previous droughts. These include:

• The decommissioning of the Young Creek storage and pipeline near Orbost and the further decrease in

capacity of the Rocky River diversion pipeline due to tree roots entering pipeline junctions

• The introduction of a two-part user-pays tariff system for urban consumers. Under this system users pay

according to the amount of water they consume

• The commissioning of a full water treatment plant for Orbost in 1998

• Upgrading the treatment plant capacity in 2001.

Further changes since the development of the previous DRP in 2006 include:

• Introduction of a single volumetric rate for water consumption in all districts in 2009.

Although the Rocky River has traditionally been the main raw water source for the Orbost water supply system,

the raw water gravity main has deteriorated and is approaching the end of its design life. EGW are planning to

install an additional bulk meter on the main to assess the extent of leakage, which will inform a decision on

whether or not to abandon the diversion.

An assessment of future supply under climate change scenarios – undertaken as part of the 2010 WSDS –

establishes that the Brodribb River alone has sufficient reliability to supply Orbost’s supply needs over the

planning horizon. The WSDS states that EGW could therefore elect to decommission the Rocky River diversion

main if it so chooses without impacting on the overall level of service to Orbost (AECOM, 2010).


21 October 2010 5

4.0 Objectives

4.1 General

A set of objectives is required for a Drought Response Plan (DRP) in order to give the plan direction and purpose,

and to facilitate an evaluation of the effectiveness of drought assessment and response activities.

Goals and objectives to be considered in a DRP are:

• Strategic – addresses the overall objectives for drought response and tie in with other strategic objectives for

a corporation

• Planning – specifically related to the creation of a definite plan

• Operational – translates the strategic objectives into specific operational objectives.

4.2 Strategic

To ensure a systematic, timely and efficient response to drought and minimise its impact on customers by:

• ensuring timely warning of any water shortages which might occur during future drought events and

improving the preparedness to deal with such shortages when they occur.

4.3 Planning

To ensure that:

• the plan identifies all the necessary steps that need to be taken throughout a drought including clear trigger

variables that instigate certain actions

• the plan is subject to regular review as the system develops and as more information becomes available

during the pre-drought phase

• the plan is reviewed throughout the course of drought and adjusted where necessary, and that all actions

taken be evaluated after the end of the drought

• the plan is consistent with the most recent revision of the Orbost WSDS.

4.4 Operational

To ensure that:

• during times of severe water shortage, ensure that as a minimum, a supply of at least 60 litres/consumer/day

is provided. This is the minimum volume required to meet basic human needs (UN, 1992)

• the most efficient use is made of water resources during periods of water shortage

• minimum flows are maintained to meet any downstream operational commitments or environmental

requirements

• a reliable assessment of drought status is provided so that East Gippsland Water is aware of what stage of

drought they are in and how severe the drought is likely to be.


21 October 2010 6

5.0 Action Plan for Responding to Drought

5.1 Introduction

To ensure that EGW’s water resources are managed effectively during times of drought and quality related water

shortages, an action plan has been developed. The action plan takes the form of a number of pre and post

drought activities along with a flowchart detailing critical actions (shown in Appendix A).

The effectiveness and need for various short term drought response options was assessed in the WSDS (2010), a

summary has been provided in Section 7.3. Analysis of the water supply system showed the Brodribb River to

be a highly reliable supply source and that the impacts of bushfires and the associated decline in water quality

after rainfall events is of greater concern for maintaining water supply to Orbost. The eWater CRC (2010) states

that:

“Quality of water from "Run of river" sources will suffer only in the short term, until the first flushes of

contaminated streamflows pass by, although these impacts can be severe locally, particularly where the

upstream disturbance is considerable, such as in agricultural areas. Little can be done to improve the quality

of this water, except to remove large organic debris and increase the dosage of disinfectant (chlorination) to

counteract the presence of higher levels of turbidity and organic matter”.

The following sections of this report outline measures to assist with the protection of Orbost’s water supply during

low streamflow and water quality related events.

5.2 Action Plan Summary and Flowchart

The flowchart contained in Appendix A summarises the action plan into a decision making framework to assist

EGW’s management and operations staff. This flowchart could also be used as an input to EGW’s ISES model to

assist with streamlining current processes.

5.2.1 Water Restriction Trigger Levels

The previous DRP (SKM, 2006) provided the following restriction triggers.

Table 1: Previous Restriction Triggers (SKM, 2006)

Flow in Brodribb River u/s

of offtake (ML/d)

Volume in Orbost

Storage (ML)

Stage of Restriction

<8.0 - Voluntary

- 50 Stage 1

- 37 Stage 2

- 25 Stage 3

- 14 Stage 4

Under current peak summer demand and cease to flow conditions within the Brodribb River, increasing levels of

mandatory restriction would be triggered every four days (i.e. four days of storage between Stage 1 and Stage 2,

four days of storage between Stage 2 and Stage 3 etc). To provide both EGW and the community with an

appropriate response time, these triggers have been consolidated and revised to provide increased response time

and flexibility.

The current restriction triggers for Orbost are shown in Table 2. These are to be considered a guide only with

EGW to use their discretion when deciding which level of restriction is most appropriate for the situation.

The trigger levels have been linked to the flow in the Brodribb River and the combined volume within the Orbost

raw water and clear water storages (total volume of 52 ML).

EGW’s Bulk Entitlement permits it to pump water from the Brodribb River as long as flows are available, so the

number of days between restrictions would depend upon the extent to which available storage can be

supplemented by the remaining flows in the river. In no-flow conditions, it is estimated there would be

approximately 8 days of storage between the Stage 1/2 and Stage 3/4 trigger levels (under restricted average

daily summer demand). A further 5 days of supply would be provided between the Stage 4 restriction trigger and


21 October 2010 7

the storage running empty. It is noted that the time between restriction triggers in the event of cease to flow

conditions is very short due to the high demand and available volume of storage. As such, at their discretion,

EGW may decide to eliminate Stage 1/2 restrictions and move directly to Stage 4.

Table 2: Restriction Triggers for the Orbost System

Flow in Brodribb River u/s of offtake

(ML/d)

Volume in Orbost Storage

(ML)

Stage of Restriction

<8.0 - Voluntary

<Demand (~3.7 ML/d in summer) - Stage 1 or 2

- <25 Stage 3 or 4

The permitted uses of water under each level of restriction are detailed within EGW’s Water Restriction By-Laws

(Appendix C). It should be noted that customers of 70 years of age or older are provided with an exemption during

Stages 1 – 3 restrictions. These customers are permitted to water gardens and lawns either between the hours of

6am and 8am or 8am and 10am (but not both) on the days nominated for their property.

Based on the restriction triggers outlined in Table 2, EGW wouldn’t have entered into restrictions during the

previous year (2009), this is also true of the previous restriction levels. Streamflows within the Brobribb River have

not dropped below 8ML/day (the voluntary restriction trigger) since March 2006 and as a result restrictions have

not been required .

5.2.2 Introduction of Voluntary Restrictions

Voluntary restrictions are to be introduced when the flow in the Brodribb River drops below or is equal to

8.0 ML/day and streamflows are expected to continue to fall. Diversions from Rocky River are also expected to

have ceased at this point due to low flows.

Before instigating these restrictions, EGW must satisfy themselves that reduced streamflow will be an ongoing

condition (i.e. not a one-off event). This can be undertaken by reviewing forecast conditions (based on information

available on the BOM website, see Section 6.4.3) to determine whether or not rainfall is anticipated and whether

streamflows are expected to continue to decline. If reduced streamflows (below 8.0ML/day) are anticipated to

continue, then voluntary restrictions shall be imposed.

The procedure for instituting voluntary restrictions is as follows:

• Prepare a media release for issue to the press informing residents of the need to commence voluntary

restrictions (not required by legislation, but should be undertaken as a best practice standard)

• Advertise voluntary restrictions in the local newsletter or paper and/or on local radio

• In the event of major and long-term impact on water quality of the Brodribb River due to bushfire and

excessive silt runoff, implement temporary treatment solutions in order to restore appropriate levels of supply

as quickly as possible

Continue to monitor the situation.

5.2.3 Introduction of Mandatory Stage 1 and 2 Restrictions

Stage 1 or 2 water restrictions are to be introduced when streamflow in the Brodribb River drops below demand (~3.7 ML/day in summer). The level of restriction adopted will depend upon the forecast for the immediate future. If the drought is expected to be ongoing with very little rainfall, then Stage 2 restrictions should be adopted. If rainfall is predicted then it may be more suitable to initially adopt Stage 1 restrictions.

The procedure for introducing Stage 1 and 2 water restrictions is as follows:

• Prepare a media release for issue to the press informing the community of the introduction of the

restrictions. This release must provide sound reasoning as to why that particular course of action has been

selected and must re-enforce the need to continue to conserve water

• Advertise restrictions in the local newsletter or paper and/or on local radio

• Assess the capacity of local groundwater bores or nearby supply systems such as Nowa Nowa, Bemm River

or Buchan to provide emergency supply by tanker

• Consult with SRW to confirm options for accessing groundwater

• Commence discussions with local water carters about the possibility of utilising their services in the future if

streamflows decrease further


21 October 2010 8

• Continue to monitor the situation.

At this stage it is critical for EGW to act quickly to minimise the need for introducing more severe water

restrictions. Actions to be considered in addition to those listed above include:

• An intensive advertising campaign using all forms of media so that consumers are fully aware of the details

of this level of restriction. Leaflets mailed to consumers could be used to provide advice and information.

Consumers should be made aware of the rules for each stage of restriction

• Implementation of Water Watch Days as a form of demand management (refer to Section 7.2.2 for further

details).

If Stage 1 restrictions are initiated and the water supply situation continues to decline, then EGW should consider

elevating restriction levels to Stage 2. This should however be undertaken in consideration of the likelihood of

requiring Stage 3 or 4 restrictions (discussed further in Section 5.2.4).

5.2.4 Mandatory Stage 3 and 4 Restrictions

Restrictions beyond Stage 2 should only be required on rare occasions. Given the historical reliability of flows in

the Brodribb River, such a situation is considered highly unlikely but could feasibly be associated with sudden

deterioration in water quality from an extreme event such as intense bushfire.

In the event that the volume of storage drops below 25ML, EGW should instigate either Stage 3 or 4 water restrictions, depending on the forecasts for the immediate future. If forecasts do not show any relief to the dry conditions then Stage 4 restrictions should be selected.

The procedure to be adopted for implementing Stage 3 and 4 restrictions includes:

• Introduction/continuance of a rigorous media campaign

• Advise customers and DSE of the current water supply situation and the need to adopt Stage 3 or 4 water

restrictions

• Confirm the ability of the previously identified alternative water sources to provide supply to Orbost

• Contact the water carters to formalise the commencement of carting from the location/s decided above.

If Stage 3 restrictions are initiated and the water supply situation continues to decline, then EGW should consider

elevating restriction levels to Stage 4. This should however be undertaken in consideration future forecasts and

the likelihood of dry conditions easing.


21 October 2010 9

6.0 Pre Drought Activities

This section of the DRP identifies a number of actions to be taken to ensure that the DRP can be implemented in

a timely and efficient manner. These actions should be undertaken prior to the onset of drought to ensure that

EGW are adequately prepared.

6.1 Staff Training and Educations

It is important for East Gippsland Water to present an informed and consistent image to its customers. To this end

all staff should at least be aware of the current status of restrictions, perhaps by reviewing updates on the EGW

website. Customer service staff would require more detailed training on the specifics of restrictions. Drought

education should be fostered on an ongoing basis. Training will also be needed for selected staff to be able to

interpret the drought warning signals. These signals will include information from various Bureau of Meteorology

publications. Operators and staff will need to be aware of the system that will be operating in order to report

information and the effect that changing conditions will have on supply.

Relevant staff also need to be made aware of the drought response procedure to ensure that the action plan can

be implemented successfully. A briefing session should be held following the finalisation of any major updates to

the plan.

6.2 Waste Minimisation

EGW will continue to implement its waste minimisation strategy which includes:

• Working with major customers to minimise their water waste

• Target significant sources of unaccounted for water throughout the system, where cost-effective

• Continued leak reduction program

• Keeping abreast of technological developments in water saving measures currently being investigated by

Melbourne’s urban water utilities through EGW’s membership of the Victorian Water Industry Association.

6.3 Promotion of Water Restrictions

Under EGW’s Water Restriction By-Laws, the corporation is required to publish a notice in an appropriate

newspaper detailing the restrictions prior to their introduction. This requirement is only applicable for Stage 1 – 4

restrictions with voluntary water restrictions being exempt.

In terms of advertising, EGW treats all levels of restrictions (including voluntary restrictions) in a similar manner.

The following mediums are used for communication:

• Local newsletter

• Local radio

• Appropriate newspapers

• Television commercials (as required).

The most effective medium for communication at Orbost will be the local newsletter, or paper, and radio. These

methods are to be adopted in the first instance with newspaper advertisements to be used where mandatory

water restrictions (Stage 1 – 4) are to be introduced. In some instances television advertisements may also be

employed as a means of communication (i.e. during extreme drought when Stage 3 or 4 water restrictions are

being introduced).

In the early stages of drought or prior to peak summer periods, EGW should send an information pack to

ratepayers to reinforce methods for conserving water around the home.

Once mandatory restrictions are in place a toll-free phone number can be set up both to answer queries and to

enable community policing of restrictions.


21 October 2010 10

EGW’s Water Restriction By-laws require that when introducing water restrictions, as a minimum, EGW must

publish a notice in a newspaper that circulates generally within that district. Generally EGW will undertake

additional advertising through the use of local radio and publications, although this is not required under current

institutional arrangements.

Under EGW’s Customer Charter they also have a responsibility to provide information to customers about the

sustainable use of Victoria’s water resources and how customers may conserve water.

When initiating restrictions, it is important to promote messages about the nature of the problem, such as the

following:

• Low streamflows and depleting storage levels indicate a strong possibility that restrictions will need to be

introduced

• There will be public and private costs associated with the introduction of restrictions

• There will be inconvenience associated with restrictions

• By introducing voluntary reductions in water use at an early stage, the possibility of future restrictions being

required will be reduced.

The messages should point to the following specific uses of water that can reduce demand without significant loss

of amenity, including:

• use of waterwise practices

• use of water efficient appliances

• reduction of obvious waste (e.g. pathway hosing, long showers etc).

6.4 Ongoing Monitoring and Reporting

The following section of the DRP sets out the monitoring and reporting requirements for the management of the

Orbost water supply system with respect to drought. A summary of actions to assist operators in tracking monthly

tasks is provided in Appendix B.

6.4.1 Regular Pre Drought Activities

The communication of the status of each supply system leading into, during and following drought conditions

forms an integral part of drought response planning. EGW prepares a monthly summary report for the Department

of Sustainability and Environment (DSE) that provides an overview of the status of each of EGW’s water supply

systems. The report details current storage levels, water restrictions and future rainfall projections (where

necessary) and identifies any potential water supply issues. This allows the Water Minister to remain informed of

the current water supply situation. In critical times of drought, more frequent communication between EGW and

DSE will take place, although this process is not formalised.

6.4.2 Water Supply System Monitoring and Reporting

EGW has comprehensive monitoring programs in place to collect data for the Orbost water supply system for

operational, reporting and planning purposes. A summary of the monitoring that should be undertaken by EGW is

provided in Table 3.


21 October 2010 11

Table 3: Summary of EGW Monitoring Programs

Monitoring Monitoring Details Reporting Frequency and Output

Calibration of

Streamflow Gauge

• Streamflow gauge 222202 (Brodribb

River) and 222214 (Rocky River)

should be calibrated to ensure

accurate measurements of

streamflow

• To be undertaken on at least an annual

basis with calibration report to be

forwarded to EGW’s manager of water

supply systems.

Bulk Water Demand • Currently measured at the Orbost

WTP

• Bulk water meter readings should be

compiled by operators and provided to

EGW’s manager of water supply

systems on a weekly basis

Water Storage

Levels

• Water storage levels are provided on

the EGW website and are updated

on a daily basis (as a minimum)

• Operators should cross check

storage levels to ensure that

automated data transfer is correct

• Water storage levels should be

manually measured and recorded by

operations staff on a weekly basis.

Discrepancies between storage levels to

be reported to EGW’s manager of water

supply systems

• EGW’s manager of water supply

systems to be notified immediately if the

water storage level drops below 75%

capacity

Streamflow

Monitoring –

Brodribb River

• Streamflow in the Brodribb River is

monitored using a data logger and

communications system that

provides close on real time updates

of river flows (This data is provided

on the EGW website)

• Operators are also required to

monitor streamflows

• Streamflow data to be updated on the

EGW website on a daily basis

• Operators to record manual streamflow

measurements on a weekly basis. Any

discrepancies with logged data should

be reported immediately to EGW’s

Manager of Water Supply Systems

It is intended that the information gathered as part of the monitoring program will be entered into EGW’s ISES

system, which will provide an overview of the water supply situation at any given point in time. Once ISES is

operational, annual auditing should be undertaken to ensure that it is producing the correct outputs.

6.4.3 Climate and Drought Outlook

Climate monitoring should be undertaken so that when the indicators of drought start to emerge, East Gippsland

Water has time to prepare for the drought. This monitoring should be undertaken on a fortnightly basis or more

frequently during critical periods (i.e. when voluntary restrictions have been invoked).

The Bureau of Meteorology provides a number of services and publishes information booklets which have the

potential to assist in the preparation for drought.

These include the following publications:

Seasonal Climate Outlook - this provides three month forecasts of likely rainfall conditions expected over Australia

(Provided by the BOM on a monthly basis at http://www.bom.gov.au/climate/ahead)

Drought Statement – this highlights areas of the continent experiencing significant rainfall deficiencies at standard

intervals varying from 3 to 36 months prior to the release of the statement (Provided by the Australian

Government and reported on the BOM website http://www.bom.gov.au/climate/drought/drought.shtml)

Monthly Weather Review - this provides a detailed review of Victorian weather patterns for each month including

information on departures of temperature and rainfall from 'normal'

(Produced by the BOM at http://www.bom.gov.au/climate/mwr/)

Weekly Rainfall Report - this provides a more detailed review of weekly rainfall throughout Australia with further

information provided on the impact of recent rains on deficits, and highest weekly totals for each state.

(Provided by the BOM at http://www.bom.gov.au/climate/current/weeklyrain.shtml)


21 October 2010 12

Rainfall Forecasts – provides maps of forecast rainfall for up to three months, with detailed five day forecasts also

available

(Can be seen at http://www.bom.gov.au/watl/rainfall/exceedance.html)

The Bureau of Meteorology has a web site on the internet at http://www.bom.gov.au/climate, which has regular

climate updates and contact numbers for further information within the bureau.

There are a number of warning signs of drought that will be obvious at a very early stage. Rainfall deciles

(expected rainfalls for various levels of probability) are also a useful indicator of drought severity. The Bureau of

Meteorology's Drought Statement is based on rainfall deciles. A drought is assumed to occur when the total

rainfall for a period of three months or more is in the first decile range (the lowest 10% of recorded rainfalls).

When this occurs the area is considered to be suffering from a serious or severe rainfall deficiency and is included

in the Drought Statement.

The Bureau of Meteorology has used the following definitions for serious and severe droughts:

• a serious rainfall deficiency exists when the rainfall lies between the lowest 5% and 10% of recorded rainfalls

for the period in question.

• a severe rainfall deficiency exists for the period in question when the rainfall is among the lowest 5% of the

recorded rainfalls.

Once an area has been classified as experiencing drought, it remains in its serious/severe rainfall deficiency

category until:

• The rainfall of the past month already amounts to above the 30th percentile for the three month period

commencing that month

• Rainfall for the past three months is above the 70th percentile for that period.

6.5 Funding Strategy for Drought Response

Dealing with drought will have impacts on the finances of East Gippsland Water, as any form of reduction in

demand will reduce revenue. Additional expenses are likely to be incurred as a result of drought and include the

cost of public relations and media liaison, the cost of enforcing and policing restrictions, the cost of pumping from

supplementary bores and the cost of water carting. East Gippsland Water should ensure that its financial

management strategy will enable it to overcome any short-term liquidity problems caused by drought.


21 October 2010 13

7.0 Drought Response Options and Lifting of Restrictions

7.1 Introduction

Response options can be classified into the two broad categories of demand management and supply

enhancement. In this section of the report, the following potential demand management and supply enhancement

options for East Gippsland Water are identified and evaluated, including options for supply during extreme

drought events:

• Voluntary restrictions

• Water watch days

• Mandatory water restrictions

• Water cartage

• Groundwater

• Increased share of river flow and transfer of entitlements.

7.2 Demand Reduction Options

The main purpose of demand reduction options is to conserve the resources within the system, so that adequate

but reduced water supplies can be maintained for the duration of the drought. Restrictions will allow water

supplies to be shared equitably between competing users.

7.2.1 Voluntary Demand Reduction

The intention of Voluntary Demand Reductions is to make consumers aware that there is a possibility that Water

Restrictions will be imposed because of forecast shortages of water. They also act to raise heightened

awareness of the need to use water wisely.

Voluntary demand reduction should be promoted before any mandatory restrictions are imposed on the

community. As part of a voluntary demand reduction program, the following should be considered:

• It is necessary to make people aware that the region is heading for a potential drought. Key indicators such

as a winter with low rainfall are a good starting point that local people can identify with. Forecasts of potential

drought conditions can also be obtained from publications produced by the Bureau of Meteorology

• Water conservation practices should be more heavily promoted than is done in normal years. The purpose

of the campaign is to make people accustomed to the idea of impending restrictions and to reduce

consumption.

This early campaign could be run by delivering educational leaflets to houses or by putting up special notices in

prominent places such as general stores or the post office. Other forms of media such as regional newspapers,

radio or television could follow up the initial campaign if necessary. At this stage the aim of the promotion

campaign is to make people aware that a drought could be imminent and to encourage water conservation on a

voluntary basis. The experience of previous droughts could be highlighted.

It was reported in the Snowy River Mail that restrictions were imposed in Orbost during January 1973 (AECOM,

2010), though it was speculated that this may have been premature (SKM, 2006), given that restrictions were

lifted within one month and prior to the end of the drought.

Since the 1973 drought, voluntary restrictions have only been implemented in Orbost during January 2003.

According to an EGW Media Notice (14 May 2003), the voluntary restrictions were implemented due to low

inflows over the summer period and were lifted in May 2003 following rain.

7.2.2 Water Watch Days

EGW do not currently employ the use of ‘Water Watch Days’ although these could be used as a means to assist

with reducing water consumption on days when demand is at its peak.


21 October 2010 14

Water Watch Days help make the community aware of the potential for more serious restrictions. These days are

announced when the temperature is forecast to exceed a specified maximum temperature (i.e. predicted

temperatures of 350

C or higher) and/or a day of total fire ban is declared. Consumers are requested not to use

fixed sprinklers and automatic watering systems.

7.2.3 Demand Reduction due to Restrictions

Reliability of supply is significantly impacted by the setting of restriction trigger levels and the demand reductions

associated with these restriction levels. Restriction trigger levels need be set in consideration of:

• the desired frequency of restrictions (defined by EGW’s LOS objectives)

• allowing sufficient time between restriction levels for community adjustment

• allowing sufficient time for EGW to arrange emergency supply arrangements in the rare event of storage

failure.

Refer to Table 2 for the restriction triggers for the Orbost water supply system.

Clauses 4.2 and 4.5 of EGW’s Water Restriction By-Law state that:

“….. East Gippsland Water must impose a stage of restriction in a district, whenever a restriction level trigger

specified in its drought response plan or its by-laws is reached. ………. East Gippsland Water may decline

to impose a stage of restriction in a district if it reasonably concludes that the circumstances indicating the

need for that stage are likely to be so temporary that the public inconvenience caused by imposing that

stage of restriction would outweigh the water conservation benefits to be gained from imposing that stage.”

The Water Restriction By-Laws also outlines the estimated monthly and annual (Table 4) reduction in demand

associated with each level of water restriction.

Table 4: Reduction in total water demand for each level of restriction

Stage of Restriction Annual Reduction of Total Demand

(%)

One 2.5

Two 8

Three 12

Four 17.5

There will be a lead time associated with implementing mandatory restrictions, because restrictions need to be

advertised before they are enforced. Knowledge of storage volumes and demands throughout the drought will

help to reduce this lead time to a few days.

Possible impacts of restrictions are as follows:

• Restriction stage one is the least severe and can be classified as mild. Consumers would experience some

inconvenience and perhaps minor losses such as lawn areas and plants

• Restriction stage two could be classified as moderate. Implementation of this stage will create a moderate

level of inconvenience to consumers and moderate losses will occur

• Restriction stage three could be classified as severe. Implementation of this stage will create a major

inconvenience to consumers and substantial losses will occur

• Restriction stage four is very severe and would only be implemented in very rare circumstances. This stage

would involve major disruption to normal lifestyles and would create major losses

• Beyond the fourth stage of restriction an emergency situation would apply with consumers being in survival

mode. Only essential supplies would be available and there would be no irrigation or external watering.

Urban consumers should however be restricted to no less than 60 litres per consumer per day, which is the

minimum water requirement for basic human activity (UN, 1992).


21 October 2010 15

7.3 Supply Enhancements during Drought

7.3.1 Water Carting

It should be noted that water carting would only be required in the most extreme of circumstances, such as a

severe decline in the quality of water in the Brodribb River resulting from bushfire. There is no historical

precedent for carting to Orbost, with the Brodribb River maintaining flows even during past drought and bushfire

conditions.

Water could be carted from one of EGW’s other water supply zones such as Nowa Nowa, Bemm River or

Buchan. Nowa Nowa would be closest location to cart from at around 37 km.

During peak summer demand under Stage 4 restrictions, approximately 2.5 ML/d would be required to meet

demand in the Orbost system. As this implies an impractical 100 tanker loads daily for a 25kL truck it is not

considered a viable emergency response option for extended outages. It is therefore recommended that EGW

assess the situation when a shortage occurs and if carting becomes impractical, procure other alternative

supplies.

The minimum amount of water necessary for basic human requirements is 60L/person/day (UN, 1992); could be

supplied with tanker water from around 7 tanker loads per day.

Should water carting be required, considerable forward planning would be needed to ensure suitable vehicles can

be secured and that water is available in nearby catchments. The lead time to arrange water carting is generally

less than one month, with tasks including considering the feasibility of loading and unloading water from the

trucks, locating an alternative water supply, obtaining water trucks and obtaining internal expenditure approval to

hire the water carters. East Gippsland Water should also consider paying water carters a retainer shortly prior to

using them if they are likely to be in high demand.

Lead times for water carting can be significantly reduced by gaining pre-approval and setting up arrangements

prior to the commencement of carting.

7.3.2 Groundwater Supply

Groundwater does not currently form part of Orbost’s water supply system. Groundwater could be used as an

emergency supply in the future although this would require construction of a bore. SKM (2006) stated that:

“Groundwater could be used as an emergency source of water in all of the towns in this DRP”. The lithology

at Orbost is likely to be characterised by sand and gravel.

“Groundwater salinity in the region of Gippsland covered by this DRP (which includes Orbost) is generally

less than 1000 mg/l, which is suitable for drinking. Yields are generally below 10 L/sec.”

While the past and current reliability of the Brodribb River indicates that it is unlikely groundwater would be

required as an alternative water supply option, it currently presents the only alternative supply source capable of

cost effectively supplying the full system demand. It is therefore recommended that EGW endeavour to formalise

access to the underlying groundwater aquifer for use in emergency situations. It is considered that any such

shortage would be of short duration and that access for a one off event would have negligible impact to the

sustainability of the aquifer.

It is recommended that in the event of an extended water shortage, EGW investigate access to existing

groundwater bores in the area or undertake hydrogeological investigations to investigate the feasibility of drilling a

drought relief bore close to the WTP.

“The lead time to drill a new groundwater bore is likely to be around one to three months, dependent on the

complexity of drilling and design construction. Tasks involve selecting a new site, obtaining internal

expenditure approval, obtaining a bore construction licence, obtaining a driller, acquiring bore materials,

drilling the bore, pump testing of the bore and water quality testing of the bore”.

Additionally, SRW will need to be contacted to determine licensing requirements as extraction licenses for the

underlying aquifer are currently capped and fully allocated.

7.3.3 Increased Share of River Flow

EGW already has full access to low flows in the Brodribb River and therefore there is no option to gain access to

additional river flows at low flows.


21 October 2010 16

7.3.4 Transfer of Surface Water Entitlements

The volume of water available to private diverters in the Orbost water supply system is 384.40 ML/year. EGW

makes up the remaining licensed volume of 2031 ML/year with their Bulk Entitlement.

The local management rules also state the following:

• Diversions are metered on the Brodribb River. Customers are not to use more than their licensed volume

• Informal rostering of the Brodribb River can occur when streamflow reduces to 8 ML/d upstream of the town

offtake, though this has not known to have occurred. There are currently only two active users on the

Brodribb River.

As there are only two other active users on the Brodribb River and EGW’s entitlement is far in excess of their

current and future predicted demand, it is not considered that there is any benefit to seeking to transfer water

these entitlements to EGW. Under the local management rules, EGW’s surface water supply to the Orbost

system should not be compromised by upstream diversions during low-flow periods.

7.4 Lifting of Restrictions

Occasionally there may be small rainfall events during drought which temporarily increase streamflow, allowing

diversions from the river and providing an increase in storage volumes. This increase in storage may result in the

triggers for a less severe level of restriction being reached. If this occurs, the level of restriction should only be

lowered if East Gippsland Water is confident that the current level of restriction will not be reached again during

the same drought.

For example, when Stage 4 restrictions are in place, an isolated summer storm may raise storage levels to just

below the Stage 2 trigger. In this case, the level of restriction would only be lowered to Stage 2 if it is unlikely that

the drought will persist and that the storages are not likely to reach the Stage 2 triggers again. This ensures that

customers are not confused by frequent raising and lowering of restrictions.

EGW’s Water Restriction By-Law states that:

“Subject to sub-clause 7.2, East Gippsland Water may:

• lift a prevailing stage of restriction and substitute a lesser stage of restriction; or

• lift a prevailing stage of restriction,

Whenever East Gippsland Water reasonably concludes that the relevant circumstances which led East Gippsland

Water to impose the prevailing stage of restriction in a district no longer exist, or are about to change, by

publishing a notice in a newspaper circulating generally in that district.

East Gippsland Water may also decline to lift a prevailing stage of restriction if it reasonably concludes that either:

• continuing that stage of restriction is necessary or desirable to increase or conserve available water; or

• the change in circumstances which would otherwise justify East Gippsland Water in lifting the stage of

restriction is likely to be so temporary that the public inconvenience caused by lifting and subsequently re-

imposing a stage of restriction would outweigh the benefits to East Gippsland Water's customers of

temporarily lifting the prevailing stage of restriction.

The lifting of Voluntary Restrictions should occur when streamflow in the Brodribb River has returned to flows

above 8.0 ML/day for a consecutive period of at least 7 days. This will ensure that the restrictions aren’t lifted

prematurely based on high streamflows for only a few days.

Stage 1 and 2 restrictions could be lifted when streamflow in the Brodribb River has exceeded demand for a

consecutive period of at least 7 days, while Stage 3 and 4 restrictions could be lifted when the storages are

restored to 80% of total capacity (approximately 41ML).

The lifting of restrictions should take into consideration current forecasts for rain; these are available on the

Bureau of Meteorology (BoM) website and are described in detail Section 6.4.3 of this DRP.


21 October 2010 17

8.0 Post Drought Activities

8.1 Evaluation of Objectives

Once the drought has broken and a degree of order and normality has returned, it is time to review the

effectiveness of the plan. The first part of the review process should be to assess the suitability of the objectives.

There are three components to the objectives (i.e. strategic, planning and operational) and each of these needs to

be critically reviewed to determine whether the objectives were appropriate and achievable. If they were not,

some comment needs to be made as to why not and new objectives set for the next drought.

8.2 Evaluation of Actions

There have been a number of actions identified for demand reduction and supply augmentation as the supply

situation worsens. In most droughts, only a few of the actions will need to be implemented. The timing and

effectiveness of each action needs to be assessed and documented. If, for example, the introduction of Stage 2

restrictions leads to a greater reduction in demand than anticipated then a decision needs to be made as to

whether this restriction is too severe or whether it should be implemented at a later date when more serious

conditions have developed. Alternatively, the appropriateness of the restriction policy and the actions tied to each

restriction stage should be evaluated and modified where necessary.

Comparisons between historic deliveries and drought deliveries will have been made as part of the monitoring

process during the drought. These need to be documented as part of the post-drought evaluation, and comments

and decisions made about the impact of each stage of restriction during a drought.

8.3 Potential Impacts of Restrictions

Other potential impacts of shortfalls in supply, based on previous drought experience in various catchments,

include the following (SKM, 1997):

• Loss of amenity for the community due to the deterioration of plants, gardens and sporting fields

• Financial loss to the community, incurred when regaining the level of amenity desired during non-drought

periods

• Inconvenience on the community caused by forcing users to alter their water-use practices

• Financial loss to tourist-based local economies, as a result of holiday makers wanting to avoid the

aforementioned loss of amenity and convenience

• Stresses on in-stream flora and fauna

• Reductions in revenue for water corporations caused by restrictions on consumption

• Increased expenses for water corporations for promoting and enforcing restrictions, and for providing

emergency supplies.

8.3.1 Impact of Restrictions on the Community

Community response to the imposition of restrictions should be sought through contact with representatives of the

major water user groups. Questions which should be asked in the wake of a drought by EGW, both of itself and

consumers, include:

• Were there other things that could have been done to help reduce demand for water?

• What were the economic and social impacts of restrictions?

• Was there enough warning that restrictions were to be imposed?

• Was the right mix of media used to disseminate information on when the restrictions were to begin and what

was and was not allowed to be done?

• Were the restrictions too severe?

• Did restrictions last too long?

• Were people confused by the number of restrictions?

• What attitude did people have during the drought?

• Was there any significant plant loss?


21 October 2010 18

• Was there any major inconvenience caused by the lower stages of restrictions?

8.3.2 Impact on East Gippsland Water

The Corporation’s actions should also be reviewed to determine how it coped with the additional burden of

drought. In particular, it will be important to identify any issues that came up that were not identified prior to the

drought and were not taken into account in the Drought Response Plan, such as:

• Were the restrictions easy to enforce?

• Were the limited watering times causing problems for supervision?

• Did the staff feel alienated from the community?

• Was the additional work load unreasonable?

• Do staff have any suggestions for improvements for the Drought Response Plan?

8.4 Revision of the DRP

Drought Response Plans are dynamic in nature and will only be appropriate for a particular system for a short

period of time. Drought Response Plans need constant revision to keep them up-to-date with changes in climate,

system configurations, demand, operational procedures, community expectations, diversion rules etc. The

revisions should be based on the results of the evaluations referred to above and carried out in a regular and

disciplined manner.

It is recommended that this drought response plan be reviewed every five years as a minimum. Specific aspects

of the plan should be updated as required after major changes to the supply system such as the construction of

new storages and/or changes to diversion rules. If modification of the plan is required in a drought event or if

particular lessons are learnt during a drought, EGW should update the plan accordingly prior to the next summer

period.


21 October 2010 19

9.0 Water Supply Context

9.1 Legal and Institutional Context

9.1.1 Bulk Water Entitlements

Section 9 of the Water Act (1989) specifies a water corporation’s right to take amounts of water that are made

available to it either:

a) under a bulk entitlement granted under that Division or part 11

b) under any entitlement to take water granted under and corresponding previous enactment and continued

by this Act.

EGW has an entitlement to extract water from the Brodribb and Rocky Rivers. Conditions of this licence are

detailed in the Bulk Water Entitlement (Orbost System) Conversion Order 1997. The annual licensed limit for

extraction is 2,031 ML/yr in total from the Brodribb River and Rocky River, and is subject to the following flow

sharing arrangements:

• When the flow immediately upstream of the Brodribb River pump station is less than or equal to

5.74 ML/day, EGW’s entitlement is equal to the flow from the Brodribb River at the pumping station

• When the flow immediately upstream of the Brodribb River pump station is greater than 5.74 ML/day, EGW’s

entitlement is equal to 5.74 ML/day from the Brodribb River at the pumping station

• When the flow immediately upstream of the Rocky River offtake weir is less than or equal to 1.0 ML/day,

EGW’s is not entitled to take any water from the Rocky River

• When the flow immediately upstream of the Rocky River offtake weir is greater than 1.0 ML/day but less

than or equal to 2.56 ML/day, EGW’s entitlement from Rocky River at the offtake weir is equal to the flow

immediately upstream of the Rocky River offtake weir less 1.0 ML/day.

• When the flow immediately upstream of the Rocky River offtake weir is greater than 2.56 ML/day, EGW’s

entitlement from the Rocky River at the offtake weir is equal to 1.56 ML/day

Further detail on this and the aforementioned flow sharing arrangements and passing flow requirements are

outlined in the Victorian Government Gazette (4 September 1997); this can be seen at:

http://gazette.slv.vic.gov.au/view.cgi?year=1997&class=general&page_num=2383&state=V&classNum=G35&sea

rchCode=475083 (page 2359).

9.1.2 Applying for Qualifications to Bulk Entitlements

East Gippsland Water may apply to the Minister to qualify its bulk water entitlement during water shortages. The

qualification may include allowance to pump from river pools or to divert greater flow volumes. Such an

application would be made under Section 33 of the Water Act (1989). The qualification would only be granted

where the Minister has declared under Section 13 of the Act that a water shortage exists in the area or supply

system and East Gippsland Water has made reasonable efforts to prevent this water shortage.

EGW has never applied for a qualification of rights for their Brodribb River or Rocky River entitlement.

9.1.3 Groundwater Entitlements

EGW do not extract groundwater to supply the Orbost water supply system, therefore no groundwater licences

are held.

9.1.4 Supply to Urban Users

Under the terms of the Water Act (1989), a Corporation does not have to meet any stated volume, capacity or

pressure requirement within a water pipeline supplying urban consumers.

In addition, under Section 141 of the Water Act (1989), a Corporation may reduce or restrict the quantity of water

supplied to any person, or discontinue the supply of water to any person, if:

a) the Corporation is, because of a shortage of water or for any other unavoidable cause, unable to supply the

quantity of water which would otherwise be supplied to the person; or


21 October 2010 20

b) the Corporation believes that the reduction, restriction or discontinuance is necessary to avoid future water

shortages.

These sections give adequate powers to East Gippsland Water to restrict water quantities in times of drought in

accordance with by-laws proclaimed under Section 171 of the Act.

9.1.5 Model Water Restriction By-law (No. 0001/08)

During May of 2008, the Water Minister issued EGW’s ‘Model Water Restriction By-Law’ under section 287Zb of

the Water Act. The intent of the By-Law is to:

• promote the conservation of water

• set out four stages of restrictions on the use of water

• specify when and how a stage of restriction may be imposed

• specify things which must not be done while each stage of restriction persists

• specify principles for considering applications for exemptions from particular restrictions

• specify principles for deciding when to lift restrictions

• prescribe offences and penalties for the contravention of the By-law

• prescribe classes of persons for the purpose of issuing infringement notices.

A copy of this By-Law is attached as Appendix C.

9.2 Levels of Service

The long term operational objective for East Gippsland Water stated that it should be aware of changes to total

levels of service and patterns of demand, and of consumer expectations in relation to desirable levels of service.

Regular updates, perhaps every three years, in relation to growth in the number of services provided needs to be

maintained and interpreted in terms of actual and 'acceptable' levels of service.

The WSDS determined that the trigger levels presented in Table 2 are appropriate for maintaining EGW’s Level of

Service (LOS) objectives. The review of expectations around LOS could be undertaken as part of the WSDS

review process which is to occur as a minimum, every five years.


21 October 2010 21

10.0 Past Drought Experience

10.1 Previous Drought and Water Restrictions

No restrictions were imposed on Orbost in 1982/83. At that time the town relied on both the Rocky River and the

Brodribb River for its supply. A summary of the 1982/83 drought is shown in Table 5 (Snowy River Mail, 1982/83).

Table 5: Summary of 1982/83 Drought in Orbost

Date Stage of Restriction Comments

08/09/82 None Flows are sufficient in the Rocky River to meet all demands. The

diversion is operating at 60% of pipeline capacity due to tree

roots penetrating pipe joints in low pressure areas of the pipeline.

No water is diverted from the Brodribb River.

11/01/83 None Peak consumption of 95 l/s (8.2 ML/d) recorded.

26/01/83 None Rocky River diversion is operating at 50 % of pipeline capacity.

The weir pool at Rocky River drops to below the weir wall.

Pumping from the Brodribb River occurs on average for 7.1

hours per day, compared with an average of 4.2 hours per day

during the same period of 1982.

09/02/83 None Sandbags are used to create a weir pool at the Brodribb River

diversion site. The water level in the Brodribb River has dropped

80-100 mm.

09/03/83 None Rocky River diversion is operating at 30% of pipeline capacity.

Depth over the pump intake is 690 mm. Pumping from the

Brodribb River averages 12 hours per day. Flow in the Brodribb

River is estimated at more than 24 ML/d.

Restrictions were imposed in Orbost in January 1973. Flow in the Rocky River at the diversion weir ceased and

pumping from the Brodribb River had been reduced to around four hours per night (Snowy River Mail, 7/2/73).

Restrictions were lifted on 7/2/73, even though the drought had not yet broken, possibly indicating that restrictions

were prematurely imposed.

In 1997/98, pumping from the Brodribb River increased throughout the drought from 4 hours per day to as much

as 15.5 hours per day. Both Rocky River and Brodribb River continued to flow throughout the drought. Flows at

Rocky River reduced to run over only 50% of the wall in early March 1998. The lowest levels reached in the

Brodribb River were 2.49 metres below the top of the inlet structure.

Voluntary water restrictions were introduced at Orbost in January 2003 and were lifted in May 2003 (DPI, 2005).

There have been no water restrictions in place in Orbost since May 2003.


21 October 2010 22

11.0 Summary of Recommendations

The following recommendations are made to EGW in order to assist with the implementation of this DRP:

• Input the flowchart presented in Appendix A into EGW’s ISES software

• Review and implement the pre-drought activities outlined in Section 6.0

• Adopt the drought response procedure outlined by the action plan in Section 5.0.


21 October 2010 23

12.0 References

AECOM (2010) Orbost Water Supply Demand Strategy

SKM (2006) East Gippsland Water Drought Response Plan - Bemm River, Buchan, Cann River, Marlo,

Newmerella and Orbost, Final 05 June 2006


21 October 2010 A

Appendix A

Drought Response Flowchart


21 October 2010 B

Appendix B

Action Plan


21 October 2010 b-1

Appendix B Action Plan

Water Supply System Monitoring and Reporting Program

Task Reference1

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Bulk water demand (manual reads) 6.4.2 W W W W W W W W W W W W Water storage levels (manual reads) 6.4.2 W W W W W W W W W W W W Streamflow (manual read) 6.4.2 W W W W W W W W W W W W Submit all manual read data 6.4.2 W W W W W W W W W W W W Monitor climate and drought forecasts 6.4.3 X* X* X* X* X* X* X* X* X* X* X* X* Communicate status of water supply to DSE

6.4.1 X* X* X* X* X* X* X* X* X* X* X* X*

Calibration of streamflow gauge 6.4.1 X

Legend: W – to be completed on a weekly basis for that month X – to be completed once within the given month 1

– Refer to relevant Section with the Drought Response Plan (AECOM, 2010) for detailed monitoring and reporting requirements * – More frequent review/monitoring required in drought events (i.e. when streamflows approach the voluntary restriction trigger)


21 October 2010

Appendix C

EGW Water Restrictions By-Laws

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