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MURRURUNDI, BLANDFORD

AND WILLOW TREE

FLOODPLAIN MANAGEMENT STUDY

APPENDIX A

FLOOD HYDROLOGY AND HYDRAULICS

Note: The Word version of the document was reformatted in December 2014 which has led

to minor differences in its structure when compared to the original report.

Job No: NX518

J:\NX518\docs\APPA.doc

Date: 03/06/98

Rev: 3.0 Author: SAB

Reviewer: BWL

Floodplain Management Study

Murrurundi, Blandford and Willow Tree

Appendix A – Flood Hydrology and Hydraulics

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Lyall & Macoun

Consulting Engineers

TABLE OF CONTENTS

Page No.

A.1 INTRODUCTION ......................................................................................................... A-1

A.2 SCOPE OF INVESTIGATION ...................................................................................... A-1

A.3 STUDY APPROACH ................................................................................................... A-1

A.4 STUDY RESULTS ....................................................................................................... A-2

A4.1 Existing Conditions .............................................................................................. A-2

A4.2 Testing Flood Management Proposals ................................................................. A-3




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A.1 INTRODUCTION

LMCE prepared the Flood Study for the townships of Murrurundi, Blandford and Willow Tree,

which was submitted as a draft in February 1997.

The streams investigated in the study included the 12.5 km reach of the Pages River from

Murrurundi to Blandford, as well as the 4.5 km section of Borambil Creek in the vicinity of Willow

Tree.

The Pages River has its source near the eastern end of the Liverpool Range, from where it flows

in a south-easterly direction to join the Hunter River in its headwater region several kilometres

upstream of Aberdeen. Borambil Creek rises on the northern side of the Liverpool Range in the

Namoi River catchment and flows in a northern direction parallel with the New England Highway.

A short distance upstream of Willow Tree it is joined by Chilcotts Creek which drains the foothills

of the range to the east.

The study area has been subject to nine significant floods over the past 40 years since the record

flood of October 1949. Murrurundi is the most flood prone of the three townships with residential

development on both sides of the Pages River vulnerable to flooding. On two recent occasions,

in January and October 1996, flow surcharged the right bank and flowed down the New England

Highway (Mayne Street). Blandford and Willow Tree are flood prone but to a lesser degree than

Murrurundi.

A.2 SCOPE OF INVESTIGATION

Flood behaviour in the two streams was modelled in terms of flows, levels and flooding behaviour

for flood frequencies ranging between 5 and 100 years average recurrence interval (ARI), as well

as for the Probable Maximum Flood (PMF). A preliminary assessment of flood hazard has also

been made using velocity and depth results obtained from the investigation.

A.3 STUDY APPROACH

Flood behaviour was defined using computer based hydrologic models of the study catchments

and hydraulic models of the streams. The hydrologic models were based on the RORB runoff

routing program. The Pages River model was calibrated to recorded rainfall and streamflow data.

The records at the Blandford stream gauging station on the Pages River and pluviographic data

at Scone, Murrurundi, Blandford and Gowrie North were used for this purpose. Four floods were

used for model calibration. In the order of investigation they were: January 1996, February 1992,

January 1976 and October 1996.




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The January 1996 recorded flood peak of 1030 m3/s is close to the 50 year ARI in terms of peak

discharge at Blandford on the basis of the RORB model results. Further upstream at Murrurundi

the assessed flood peak was 450 m3/s, which is near the modelled 100 year ARI peak discharge.

The February 1992 and January 1976 floods were somewhat smaller, with recorded peak flows at

Blandford of 870 m3/s and 780 m

3/s respectively. They had an assessed frequency around the

20 year ARI magnitude. In October 1996, rainfall was most intense in the Pages River catchment

above Murrurundi, with lesser falls in downstream areas. At Murrurundi, the peak discharge of

380 m3/s approximated a 50 year ARI event, but at Blandford township just below the junction

with Warlands Creek, the peak discharge of 610 m3/s was less than the design 20 year ARI

discharge. For all of these events, there was a consistent set of RORB model parameters, which

gave reproduction of the recorded hydrographs.

There are no stream gauging stations on Borambil Creek. A formal calibration of the RORB

model was not therefore possible. Based on limited flood level data for the recent flood of

January 1996, an estimate of the peak discharge was made. This discharge was used to tune

the parameters of the RORB model. The October 1996 storm did not produce significant flood

flows on this catchment.

A fully dynamic network hydraulic model was adopted for the hydraulic analysis to account for the

time varying effects of flows from the tributary streams and the routing effects of the floodplain

storage. A one-dimensional link-node model, MIKE 11, was chosen which allowed for the

interaction of flows between the channel and the floodplain, flow through culverts and flow over

road embankments. Models were set up for both the Pages River and Borambil Creek. The

Pages River model extended from upstream of Murrurundi to a point about 1.8 km downstream of

Blandford and included Halls Creek, Unnamed Gully and Cohens Gully which join the Pages

River in the township, as well as Warlands Creek which joins just downstream of Blandford. The

Borambil Creek model commenced upstream of the Hams Bridge at Merriwa Road and extended

to a point downstream of the sporting fields. The two models were calibrated and tested using

recorded streamflow and flood level data, as available.

A.4 STUDY RESULTS

A.4.1 Existing Conditions

Design storms were then applied to the RORB models to generate discharge hydrographs within

the study area as described in Chapter 5. These hydrographs constituted the inputs to the

hydraulic model for the assessment of design flood behaviour.

The hydraulic model was then used to produce water surface profiles, flood contours and flow

and velocity distribution for the design events. Tabulated peak flood levels and the distribution of

flows and velocities for each model cross section were also presented.

Preliminary delineation of the floodplains into high and low hazard areas was undertaken using

the velocity - depth criteria set out in the draft Floodplain Management Manual (DLWC, 1995).

Hydraulic modelling was also undertaken to allow preliminary hydraulic categorisation of the

floodplain into floodway and flood storage areas.




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The extent of flooding and the flood hazard delineation shown on the diagrams was approximate

only, particularly in the case of Blandford and Willow Tree. The best available contour mapping

at these two centres is at 1:25000 scale with 10 m contour spacing. Accurate delineation of

these lines would require more detailed survey. For Willow Tree any additional survey should

include the establishment of benchmarks to AHD. The cross sectional survey carried out for the

flood study adopted a local datum, as there are no reliable AHD survey marks in the township.

The local datum is about 100 m above AHD.

At Murrurundi, the survey situation is somewhat better as there is mapping at 1:1000 scale with

1 m contours. However, a flood fringe survey will need to be undertaken to confirm the extent of

flooding. This work could be carried out after the Designated Flood Event has been set.

Murrurundi is surrounded on its northern and southern sides by steeply rising hillsides, which are

drained by several gullies which have contributed to local flooding problems. Two local gullies,

Unnamed Gully and Cohens Gully drain the northern side. Halls Creek drains the southern

foothills. Flooding in these watercourses as well as overland flooding in the vicinity of Hall Street

in Willow Tree was also discussed in the Flood Study.

A4.2 Testing Flood Management Proposals

The models developed in the Flood Study were used in the Floodplain Management Study to

evaluate potential floodplain management strategies. The potential strategies modelled at

Murrurundi comprised levees along the right bank, channel improvements and enlargement of the

waterway area at Arnolds Bridge. Because the model is dynamic in nature, it was capable of

assessing the implications of each measure on downstream flood levels and flows as well as

upstream impacts. At Blandford, potential measures analysed included levees on Warlands

Creek both upstream of the Barsham Bridge, as well as enlargement of the bridge waterway area.

The results of hydraulic modelling are described in Chapter 4 of the Main Report.

Job No: NX518

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Date: 03/06/98


Reviewer: BWL


AND WILLOW TREE


APPENDIX B

ASSESSMENT OF FLOOD DAMAGES

Note: The Word version of the document was reformatted in December 2014 which has led to minor

differences in its structure when compared to the original report. No hard copy version of this

Appendix was available at the time of compiling. As a result, the figures listed in this Appendix could

not be reproduced.



Appendix B - Assessment of Flood Damages

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TABLE OF CONTENTS

Page No.

SYNOPSIS ...................................................................................................................................S-1

B1. INTRODUCTION AND SCOPE ........................................................................................... B-1

B1.1 Introduction ...............................................................................................................B-1

B1.2 Scope of Investigation ..............................................................................................B-1

B2. DESCRIPTION OF APPROACH ......................................................................................... B-2

B3. SOURCES OF DATA ............................................................................................................. B-3

B4. RESIDENTIAL DAMAGES................................................................................................... B-5

B4.1 Direct Residential Damages ....................................................................................B-5 B4.1.1 Method .........................................................................................................B-5 B4.1.2 Damage Functions .......................................................................................B-5

B4.2 Indirect Residential Damages ..................................................................................B-6

B4.3 Total Residential Damages ......................................................................................B-7

B5. COMMERCIAL AND INDUSTRIAL DAMAGES ................................................................. B-9

B5.1 Direct Commercial and Industrial Damages ...........................................................B-9 B5.1.1 Method .........................................................................................................B-9 B5.1.2 Damage Functions .......................................................................................B-9

B5.2 Indirect Commercial and Industrial Damages ......................................................B-10

B5.3 Total Commercial and Industrial Damages ..........................................................B-10

B6. DAMAGES TO PUBLIC BUILDINGS ............................................................................... B-13

B6.1 Direct Damages - Public Buildings ........................................................................B-13

B6.2 Indirect Damages - Public Buildings .....................................................................B-13

B6.3 Total Damages - Public Buildings .........................................................................B-13

B7. DAMAGES TO INFRASTRUCTURE AND COMMUNITY ASSETS ............................... B-16

B7.1 Infrastructure ...........................................................................................................B-18 B7.1.1 Electricity ....................................................................................................B-18 B7.1.2 Telecom ......................................................................................................B-19 B7.1.3 Roads, Bridges and Railway .....................................................................B-19 B7.1.4 Sewerage Reticulation...............................................................................B-21 B7.1.5 Water Supply ..............................................................................................B-21 B7.1.6 Gas .......................................................................................................B-22

No gas supply is present in either of the three townships. ...............................................B-22

B7.2 Community Assets ..................................................................................................B-22

B8. SUMMARY OF TANGIBLE DAMAGES ............................................................................ B-25

B9. REFERENCES .................................................................................................................... B-28




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FIGURES

B8.1 Total Damage - Frequency Curves Murrurundi

B8.2 Cumulative Average Annual Damages - Frequency Curves Murrurundi

B8.3 Total Damage - Frequency Curves Blandford

B8.4 Cumulative Average Annual Damages - Frequency Curves Blandford

B8.5 Total Damage - Frequency Curves Willow Tree

B8.6 Cumulative Average Annual Damages - Frequency Curves Willow Tree




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SYNOPSIS

Estimation of flood damages has been carried out to permit a "broad brush" economic

assessment of various flood mitigation options and to provide information to assist Council in the

selection of the designated flood. Damages from floods ranging between the 5 year ARI and

PMF events were assessed.

Data for the flood damages model comprised a knowledge of the depth of inundation over the

floodplain, as well as information on the value of damages to residential, commercial and

industrial property.

The depth of inundation was determined from the results of the hydraulic modelling, described

previously in Appendix A, from available mapping and from site inspection. The type of structure

and potential for property damage were assessed from a drive-by survey of the town.

There are some data available on historic flood damages in the study area. Estimates of

damages to assets incurred in the January and October 1996 flood events were made by

Murrurundi Shire Council, as well as estimates to main roads in the Shire made by RTA. This

information was collated and compared with data on damages experienced during recen t flooding

in other centres in NSW. The data were transposed and used in the assessment for the

townships of Murrurundi, Blandford and Willow Tree. To that extent the computed values are

"potential" damages rather actually experienced. A reduction has been made to allow for

property evacuation, which would reduce, the damages actually experienced to values below the

potential damages.

The estimated damages, which could occur in the three townships for various floods, are

summarised in the table below.

TABLE S1

FLOOD DAMAGES IN MURRURUNDI, BLANDFORD AND WILLOW TREE ($x103)

Flood Event

ARI (years)

Residential Commercial Public Total

5

20

50

100

200

PMF

0

12

120

245

554

4,550

0

0

205

435

850

5,240

0

14

43

95

400

3,505

0

26

368

775

1,804

13,295





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B1. INTRODUCTION AND SCOPE

B1.1 Introduction

Damages from flooding belong to two categories:

Tangible Damages

Intangible Damages

Tangible damages are defined as those to which monetary values may be assigned, and may

be subdivided into direct and indirect damages. Direct damages are those caused by physical

contact of floodwater with damageable property. They include damages to commercial and

residential building structures and contents as well as damages to infrastructure services such as

electricity and water supply. Indirect damages result from the interruption of community

activities, including traffic flows, trade, industrial production, costs to relief agencies, evacuation

of people and contents and clean up after the flood.

Generally, tangible damages are estimated in dollar values using survey procedures,

interpretation of data from actual floods and research of government files.

The various factors included in the intangible damage category may be significant. However,

these effects are difficult to quantify due to lack of data and the absence of an accepted method.

Such factors may include:

inconvenience

isolation

disruption of family and social activities

anxiety, pain and suffering, trauma

physical ill-health

psychological ill-health.

B1.2 Scope of Investigation

In the following sections, damages to residential, commercial and industrial properties as well as

public buildings have been estimated within the three townships. Damages to infrastructure and

community assets have also been assessed where data were available.





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B2. DESCRIPTION OF APPROACH

The potential damage caused by a flood to a particular property is largely a function of the depth

of flooding above floor level and the value of the property and its contents. A spreadsheet model

was used to estimate residential, commercial and public utility damages on a property by

property basis according to a probable damage category (high, medium or low value), the

location of the property and the depth of inundation.

Flood heights at locations defined by the hydraulic model results were imported to a contouring

program and the data were grided using the ‘Krigging’ method with matrix smoothing. The grided

data were then used to create flood contours through the town for each of the events of interest.

The location of each property in the flood liable area was digitised to the same reference grid

used for the hydraulic data. These locations were imported to the contouring program and a

flood height, for each event, was interpolated at each property.

The interpolated property flood levels were input to a spreadsheet model containing property

characteristics and stage-damage relationships. The depth of flooding was computed as the

difference between the interpolated flood level and the floor elevation at each property. Damage

was estimated by depth-damage curves entered as a series of points with the losses in each

property category indexed to a depth of inundation of 2 metres.

Included within the model is the ability to simulate the reduction in flood damages, which result

from flood awareness and flood warning. The reduced damages are denoted "actual" damages.

It should be understood that this approach is not intended to identify individual properties liable to

flood damages and individual values of damages, even though it appears to be capable of doing

so. The reason for this caveat lies in the various assumptions used in the procedure, the main

ones being:

assumption that computed water levels are accurate and without any error;

assumption that the water surfaces between hydraulic model sections are adequately

represented by the contouring program and are not subject to localised influences;

the use of "average" stage-damage relationships, rather than a relationship for each

property;

the uncertainty associated with assessing an accurate factor to convert potential to actual

flood damages for each property;

the accuracy of assessment of floor levels.

The consequence of these assumptions is that some individual properties may be inappropriately

classified as flood liable, while others may be excluded. Nevertheless, when applied over a broad

area these effects will tend to cancel, and the resulting estimates of overall damages, both potential

and actual, will be reasonably accurate. To minimise errors, floor levels were surveyed by a registered

surveyor for properties in the flood prone areas.





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B3. SOURCES OF DATA

To estimate average annual flood damages for a specific area it is necessary to estimate the

damages for several floods of different magnitudes, ie of different frequencies, and then to

integrate the damages over the whole range of frequencies. To do this it is necessary to have

data on the damages sustained by all types of property over the likely range of inundation. There

are several ways of doing this:

The ideal way would be to conduct specific surveys in the aftermath of a range of floods,

preferably immediately after each. This has been done in a limited fashion for Murrurundi,

Blandford and Willow Tree, with the flood review studies undertaken following the 1992 and

January 1996 floods (Bush, 1991, 1996). A recent example approaching this ideal is the

case of Nyngan where surveys were conducted in May 1990 following the disastrous flood of

a month earlier (DWR, 1990).

The second best way is for experienced adjusters to conduct a survey to estimate likely

losses that would arise due to various depths of inundation. This approach is used from time

to time, but it can add significantly to the cost of a floodplain management study (LMJ, 1985).

It was not used for the three townships.

The third way is to adapt or transpose, data from another flood liable area. This was the

approach used for Murrurundi, Blandford and Willow Tree. It involved use of the bas ic data

collected for the Nyngan survey and making adjustments to account for changes in values

due to inflation, and to account for differences in the nature of developments between the

towns. Conducting a drive-by survey in flood liable areas of the townships assisted this.

The fourth way is to use generalised data such as that published by CRES (Centre for

Resource & Economic Studies, Canberra) and used in a recent Floodplain Management

Study for Forbes (SKM, 1994) This kind of data is considered to be suitable for generalised

studies, such as broad regional studies. It is not considered to be suitable for use in specific

areas, unless none of the other approaches can be satisfactorily applied.

As indicated above, an important source of data for this study was a drive-by inspection of

properties in the study area estimated to be affected by flooding events up to and including the

PMF event. The properties were divided into three categories: residential, commercial/industrial

and public buildings. The survey covered the main commercial area in the CBD, as well as

residential areas.

For residential properties, the data obtained in the drive-by survey included:

- the location/address of each property

- a description of the residence

- an estimate of the residence's value, age and size

- an assessment of the construction type and foundations

- a description of any external buildings/structures

- an estimation of the height of floor level above the road level.





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For commercial/industrial properties and public buildings, the drive-by survey obtained

information regarding:

the location of each property

the nature of each enterprise

an estimation of the floor area

an estimation the construction type and foundations of the property

an estimation of the height of floor level above the road level.

The property descriptions were used to classify the properties into categories (ie high, medium or

low value properties) which relate to the magnitude of probable flood damages.

For planning purposes it is useful to obtain an indication of the flood level at which the properties

become:

“affected” by floodwater on the land

“damaged” by floodwater above floor level.

For Murrurundi, Blandford and Willow Tree, all residential, commercial and public properties

likely to be affected by floods were surveyed to obtain an accurate floor level. The difference

between ground and floor level (assessed during the drive-by survey) was subtracted from the

floor level to obtain an estimate of the ground level adjacent to the building.





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B4. RESIDENTIAL DAMAGES

B4.1 Direct Residential Damages

B4.1.1 Method

Within the three townships damages were estimated for an area that extended approximately to

the extent of the PMF flood event.

B4.1.2 Damage Functions

A depth-damage curve relates flood damage to depth of flooding above floor level for different

property types. In this study, depth-damage curves were used to estimate:

Direct internal damages

Structural damages

External damages

Previous studies have shown that residential depth-damage curves, both actual and potential,

can be reduced to a generalised relationship of the following form (Water Studies, 1986):

D

DH H

2

20 06 1 42 0 61 . . . for H < 1 metre

and

D

DH

2

0 75 0 12 . . for H > 1 metre

Where D = potential damages ($)

H = depth of inundation above floor level (metres)

D2 = potential damages ($) at 2 metres inundation

These equations provide an estimate of the potential damage to a property if no action is taken

by the householder to reduce damage during a flood (such as removing valuable electronic

equipment or lifting furniture onto a table). The ability of a resident to effectively reduce damage

is closely related to the degree of flood awareness and the warning time available.

With high flood awareness and adequate warning time, residents can be expected to take actions

such as lifting and removing carpets, lifting some possessions to higher levels or evacuating

them from the house, removing garden furniture, mowers, boats and trailers, etc. A p revious

study (Water Studies 1992) for the township of Eugowra found that the ratio of potential to actual

damages for a historic flood could be reduced to as low as 0.3. However, this reduction was only

achieved because a large flood had already been experienced in the town that year. It is unlikely

that such a reduction would be achieved for future floods, because the flood awareness of the

residents will decrease.





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A similar situation will probably occur in the Murrurundi area as memories of the 1996 floods

fade. Also, in the case of the study area, there is little warning time as floods are of a flash

flooding nature. It may be possible to quickly raise some items above flood level for shallow

inundation, but for deeper flooding there will be little opportunity for reducing damages.

Accordingly, the potential internal and external damages were multiplied by 0.9 for depths of

inundation above 200 mm to give estimates of actual internal and external damages. For shallow

inundation below 200 mm, the corresponding ratio adopted was 0.6.

No reduction was applied to potential structural damages when computing actual damage, as this

damage category is not sensitive to flood warning time or flood preparedness of residents.

Values of potential damage D2 are given below:

Internal External Structural

Low Value Property

Medium Value Property

High Value Property

$15,400

$18,200

$21,000

$900

$2,000

$2,000

$3,900

$6,000

$8,300

These values are based on the actual damages suffered in the 1990 flooding in Eugowra and

Forbes (Water Studies, 1992) and Nyngan (DWR, 1990), increased to allow for inflation.

The total potential damages for a high value property subject to 2 m of inundation amounts to

about $31,000. This value compares with estimated potential damages of $38,500 and $32,000

for brick and weatherboard properties respectively in Camden (in 1997 values). These damages

were estimated from an evaluation of flood liable properties undertaken by a loss adjustor (LMJ,

1985).

B4.2 Indirect Residential Damages

Indirect residential damages comprise the costs of evacuating people and contents, providing

temporary accommodation, cash grants to welfare and relief agencies, clean-up costs after the

flood and loss of wages.

Because of the lack of readily useable data on this subject, these costs are sometimes estimated

as a percentage of the direct damages. Typically, a value of 15% of actual direct damages is

adopted (LMJ, 1985, SKM, 1994).

In the Forbes Study the average indirect cost was $2,450 per flooded property. The cost of clean

up was $600 and the remaining financial cost amounted to 40% of the actual direct cost. This is

higher than often used, reflecting the low actual direct damages.

In the Nyngan study, the average indirect cost was $7,700 per flooded property. Of this amount

the cost of clean up was $2,400 and the remaining financial cost of $5,300 amounted to 28% of

the total actual direct cost to surveyed properties. The Nyngan residents were away from their

homes for a long period (21 - 28 days) and were accommodated at public expense. In other

situations, eg Georges River in 1986 where the ratio to direct damage was 5%, the flooded

individuals were away for a shorter duration, around 12 days, and found private accommodation.





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For the present study clean up costs were estimated at $1,000 per dwelling, based on the Forbes

Study and adjusted for inflation. Additional welfare and disaster relief costs were assessed at

25% of actual direct damages, based on the Forbes and Nyngan Studies.

B4.3 Total Residential Damages

Tables B4.1 to B4.3 summarise residential damages for a range of floods within the study area.

The damage estimates were carried out for floods between the 5 year ARI flood level and the

PMF, which were modelled in the Flood Study.

The properties have been listed as being flood "damaged" and "affected." Flood affected

properties include those which only have water within the allotment, as well as those having

water above floor level, while damaged properties are defined as those for which flooding above

floor level occurs.

Murrurundi

Flood affectation within Murrurundi will commence for relatively minor events due to inundation of

the backyards of residential properties fronting the Pages River. Tables B4.1, which summarises

damages to residential properties within the township, does not note these properties as being

flood affected because the adopted ground level for each property was measured at the front of

the allotment adjacent to the roadway.

TABLE B4.1

RESIDENTIAL DAMAGES IN MURRURUNDI

Flood

Event

Number of Properties Damage ($ x 103)

ARI

(years)

Flood

Affected

Damaged Direct Indirect TOTAL

5

20

50

100

200

PMF

0

2

21

36

60

127

0

0

14

24

41

121

0

0

75

160

350

2,190

0

0

30

65

130

670

0

0

105

225

480

2,860

Damages to residential properties commence at around the 50 yr ARI and are concentrated

within the CBD area of the township, on the right bank of the Pages River. Flooding within the

CBD area is caused by the surcharging of the right bank of the river at Adelaide Street. An

existing levee bank fronting Adelaide Street is overtopped and floodwaters flow down Mayne

Street before rejoining the Pages River downstream of Brooke Street.

Blandford

Table B4.2 summarises estimated damages to residential properties within the township.





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TABLE B4.2

RESIDENTIAL DAMAGES IN BLANDFORD

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

1

7

11

21

46

0

1

1

2

10

45

0

9

10

15

45

965

0

3

5

5

20

285

0

12

15

20

65

1,250

Damages to residential properties within Blandford are due mainly to the surcharging of the right

bank of Warlands Creek, with damages commencing around the 20 yr ARI event.

In the January 1996 event, Bush (1996) reported 2 residential buildings inundated with

floodwaters and numerous properties flood affected by water flowing along the roadways.

Willow Tree

Residential development within Willow Tree is located mainly to the east of the Great Northern

Railway on steadily rising ground. Floodwaters for events up to and including the 200 yr ARI are

confined to the west of the railway line and therefore damages to residential properties are

minimal for these events. In the event of a PMF flood the water will overtop the railway and flood

numerous properties along the New England Highway.

Table B4.3 summarises estimated damages to residential properties within the township.

TABLE B4.3

RESIDENTIAL DAMAGES IN WILLOW TREE

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

0

0

1

1

23

0

0

0

0

1

20

0

0

0

0

6

335

0

0

0

0

3

105

0

0

0

0

9

440





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B5. COMMERCIAL AND INDUSTRIAL DAMAGES

B5.1 Direct Commercial and Industrial Damages

B5.1.1 Method

Direct damages up to the PMF event were estimated using the approach outlined in Section B2.

Floor levels were surveyed and the depth of inundation calculated as the difference between the

floor level and the flood surface at that location.

B5.1.2 Damage Functions

The method used to calculate damages requires each property to be categorised in terms of the

following:

- damage category

- grid location

- floor area

- ground level

- floor height above ground.

The damage category assigned to each enterprise was either "low", "medium" or "high",

depending on the nature of the enterprise and the likely effects of flooding. Damages were then

determined on the basis of floor area. The following damage functions were adopted for

potential internal damages for both commercial and industrial properties:

Low value enterprise $280/m2

Medium value enterprise $420/m2

High value enterprise $650/m2

These values were based on results presented in the Forbes/Eugowra Study (Water Studies,

1992) and the Nyngan Study (DWR, 1990) adjusted for inflation.

The above values are indexed to a depth of inundation of 2 metres. At floor level and 1.2 m

inundation, zero and 70% of these values respectively were assumed to occur. The resulting

depth-damage relationship is rather similar to that used in the ANUFLOOD computer model

(SKM, 1994).

The factor for converting potential to actual damages depends on a range of variables such as

the available warning time, flood awareness and the depth of inundation. Given sufficient

warning time a well prepared business will be able to temporarily lift property above floor level.

However, unless property is actually moved to flood free areas, floods which result in a large

depth of inundation, will cause considerable damage to stock and contents.





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For the present study, the potential to actual damages was assessed by conversion factors

related to the depth of inundation. Potential damages were converted to actual damages using a

ratio of 0.9. This factor and the shape of the resulting relationship are related to the very short

warning time available.

External and structural damages were assessed as 4% and 10% of actual internal damages on

the basis of data derived from studies of flood losses in Forbes, Eugowra and Nyngan.

B5.2 Indirect Commercial and Industrial Damages

Indirect commercial and industrial damages comprise clean-up costs, costs of removal of goods

and storage, loss of trading profit and loss of business confidence.

Disruption to trade takes the following forms:

The loss through isolation at the time of the flood when water is in the business premises or

separating clients and customers. The total loss of trade is influenced by the opportunity for

trade to divert to an alternative source. There may be significant local loss but due to the

trade transfer this may be considerably reduced at the regional or state level.

In the case of major flooding, a downturn in business can occur within the flood affected

region due to the cancellation of contracts and loss of business confidence. This is in

addition to the actual loss of trading caused by closure of the business by flooding.

Loss of trading profit is a difficult value to assess and the magnitude of damages can vary

depending on whether the assessment is made at the local, regional or national level.

Differences between regional and national economic effects arise because of transfers between

the sectors, such as taxes, and subsidies such as flood relief returned to the region.

Some investigations have lumped this loss with indirect damages and have adopted total

damage as a percentage of the direct damage. In other cases, loss of profit has been related to

the gross margin of the business, ie. turnover less average wages. The former approach has

been adopted in this present study. Indirect damages have been taken as 50% of direct actual

damages.

For the purpose of the damage assessment it was assumed that clean-up cost was based on the

floor area of each enterprise, and estimated at $10/m2.

B5.3 Total Commercial and Industrial Damages

Murrurundi

Table B5.1 summarises estimated commercial and industrial damages within the township.





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TABLE B5.1

COMMERCIAL AND INDUSTRIAL DAMAGES IN MURRURUNDI

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

0

29

37

44

49

0

0

21

29

37

49

0

0

125

270

540

2,480

0

0

80

165

310

1,300

0

0

205

435

850

3,780

Damages to commercial and industrial buildings commence at around the 50 yr ARI. Flooding

for this event occurs mainly within the CBD area and is due to the overtopping of the levee on the

right bank of the Pages River upstream of Arnolds Bridge. A large portion of the water, which

overtops the levee, flows down Mayne Street at high velocity. Some floodwaters meander

between the buildings.

Blandford

Commercial properties within Blandford are flood free for design flood events up to and including

the 200 yr ARI. For the PMF event the Service Station becomes inundated. Table B5.2

summarises actual commercial and industrial damages for the study area.

TABLE B5.2

COMMERCIAL AND INDUSTRIAL DAMAGES IN BLANDFORD

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

0

0

0

0

2

0

0

0

0

0

2

0

0

0

0

0

60

0

0

0

0

0

30

0

0

0

0

0

90





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Willow Tree

Table B5.3 summarises commercial and industrial damages for the township.

TABLE B5.3

COMMERCIAL AND INDUSTRIAL DAMAGES IN WILLOW TREE

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

0

0

0

0

8

0

0

0

0

0

8

0

0

0

0

0

895

0

0

0

0

0

475

0

0

0

0

0

1,370

Commercial properties within Willow Tree are flood free for design flood events up to and

including the 200 yr ARI. The Bowling Club, which is situated on the right bank of Borambil

Creek has been built on a high section of land and floodwaters are around 1.3 m lower than the

building’s floor level at the 100 yr ARI event.

The considerable increase in depth at the PMF event leads to the inundation of 8 commercial

properties within the township, 6 of which are located to the east of the Great Northern Railway.





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B6. DAMAGES TO PUBLIC BUILDINGS

B6.1 Direct Damages - Public Buildings

Included under this heading are government buildings, churches, swimming pools and parks.

Damages were estimated individually on an areal basis according to the perceived value of the

property. Potential internal damages were assigned as follows:

Very low value $ 38/m2 (eg. park buildings)

Low value $280/m2

Medium value $420/m2 (eg. council buildings)

High value $650/m2 (eg. schools)

These values were obtained from the Nyngan Study (DWR, 1990) as well as commercial data

presented in the Forbes/Eugowra Water Studies report.

External and structural damages were taken as 12.5 and 15% of internal damages respectively.

An allowance was also made for damages to external buildings. It was estimated that 50% of

public properties had external buildings and for each, damages were taken as 25% of internal

damages to the main building.

B6.2 Indirect Damages - Public Buildings

Similar values were used to those given previously in Section B4.2, except that a value of $7,500

was adopted for the clean-up of each property. This value is based on results presented in the

Nyngan Study and adjusted for inflation. Total "welfare and disaster" relief costs were assessed

as 50% of the actual direct costs, as for commercial properties.

B6.3 Total Damages - Public Buildings

Murrurundi

Damages to public buildings commence for the 100 yr ARI. At the 100 yr ARI the Council

Chambers are inundated by a shallow depth of water. Table B6.1 summarises the damages to

public buildings in Murrurundi.

In the January 1996 flood event, floodwaters entered the rear of Chambers and damages

estimated at $17,000 were recorded. The cost of damages included:

remove and replace carpet

desilt lunchroom, stores and toilets

replacement of 2 refrigerators

remove and replace furniture

repair damaged gardens and landscaping





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With increasing severity of flooding above the 100 yr ARI event, public buildings located on the

left bank of the Pages River become flood affected. For example, the Post Office, Uniting

Church and Pre-school located along the New England Highway become flooded at the 200 yr

ARI event. Additionally, within the CBD area both the Telecom exchange and the fire brigade

become inundated by floodwaters for this same event.

TABLE B6.1

DAMAGES PUBLIC BUILDINGS AT MURRURUNDI

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

0

2

8

14

20

0

0

0

3

8

20

0

0

0

15

65

1,315

0

0

0

20

85

800

0

0

0

35

150

2,115

Blandford

Table B6.2 summarises the damages to public buildings in Blandford.

TABLE B6.2

DAMAGES PUBLIC BUILDINGS AT BLANDFORD

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

1

4

4

4

5

0

1

2

2

4

5

0

4

19

30

100

495

0

10

24

30

80

285

0

14

43

60

180

780





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Damage estimates for Public buildings commence at the 20 yr ARI with damages occurring at the

Public School to the north of the township. At the 100 yr ARI both the school and the Bottle

Museum sustain damages and St Lukes church is flood affected. At the PMF level all above

mentioned buildings are inundated as well as the local bush fire brigade building.

In the January 1996 event floodwaters surcharged the highway at Norvill Park and flowed

overland through the school grounds.

Willow Tree

Table B6.3 summarises the damages to public buildings in Willow Tree.

The Willow Tree Public School, located on Merriwa Road, is flood affected during minor storm

events. A levee located to the south of the school has been built to direct floodwaters around the

school buildings. During minor storm events floodwaters pond behind Merriwa Road and outflank

the levee while overtopping of the levee occurs during major storm events.

With increasing severity of flooding up to the 100 yr ARI the school buildings and main office

become flood affected while the school residence is flood free due to it being located on a

platform of fill. The 100 yr ARI flood level within the school grounds is marginally lower than the

floor level of the flood affected buildings. For events greater than the 100 yr ARI it would be

expected that the buildings will sustain damage due to inundation.

The school residence becomes flood affected at the 200 yr ARI flood and both it and the pre -

school become flooded at the PMF event.

TABLE B6.3

DAMAGES PUBLIC BUILDINGS AT WILLOW TREE

Flood

Event


ARI

(years)

Flood

Affected


5

20

50

100

200

PMF

0

1

2

5

6

7

0

0

0

0

5

7

0

0

0

0

22

370

0

0

0

0

48

240

0

0

0

0

70

610





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B7. DAMAGES TO INFRASTRUCTURE AND COMMUNITY ASSETS

Infrastructure in the study area, such as electrical and telephone supply, sewerage and water

supply systems, and road network, are prone to damaging flooding. Community assets such as

parks and other recreational amenities also suffer damages. Council and relevant authorities

provided some data on damages experienced in the floods of January and October 1996, which

are reviewed below. The data are not sufficiently detailed to allow a quantitative estimate of

damages for the design flood events. However, a qualitative matrix of the effects of flooding on

these categories for each township are presented in Tables B7.1 to B7.3.

Table B7.1

QUALITATIVE EFFECTS OF FLOODING ON INFRASTRUCTURE AND COMMUNITY ASSETS

AT MURRURUNDI

Damage Sector

Flood Event

(ARI)

5 20 50 100 200 PMF

Electricity 0 0 0 0 0 1

Telephone 0 0 0 0 2 1, 2

Roads 0 0 3 3, 4, 5 3, 4, 5, 1, 3, 4, 5

Bridges 0 0 6 6, 7, 8, 9 6, 7, 8, 9 1, 6, 7, 8, 9

Sewerage Reticulation 0 10 10 10 10 1, 10

Water Supply 0 0 0 0 0 1

Parks and Gardens 0 0 0 11, 12 11, 12 1, 11, 12

Notes: 0 = No significant damages likely to be incurred

1= Due to significant increase in discharge and depth for PMF event, damages likely to be incurred

2 = Murrurundi telephone exchange flooded

3 = Mayne Street in CBD acts as floodway

4 = Mayne Street west of Arnolds Bridge acts as floodway

5 = Streets to north such as Munro, Bernard and Little flooded due to local creek system surcharging

6 = Eastern approach to Arnolds Bridge flooded

7= Western approach to Arnolds Bridge flooded

8= Swinging pedestrian bridge at Murrulla Street flood affected

9= Pedestrian bridge at Mount Street flood affected

10= Sewage Treatment Plant flood affected

11= Wilson Memorial Park and recreational facilities flooded

12= Remembrance Park flooded





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Table B7.2


AT BLANDFORD

Damage Sector

Flood Event

(ARI)

5 20 50 100 200 PMF


Telephone 0 0 0 0 0 1

Roads 2 2, 3 2, 3 2, 3, 4 2, 3, 4 1, 2, 3, 4

Bridges 5 5 5 5 5 1, 5

Sewerage Reticulation N/A N/A N/A N/A N/A N/A

Water Supply N/A N/A N/A N/A N/A N/A

Parks and Gardens 6 6 6 6 6 6


1= Due to significant increase in discharge and depth for PMF event, damages likely to be incurred

2 = Timor Road and Clarke Street flooded near New England Highway

3 = New England Highway flooded

4 = Streets such as Debenham Street on right bank of Warlands Creek act as floodways

5 = Western approach to Barsham Bridge flooded

6 = Norvill Park inundated by floodwaters

Table B7.3


AT WILLOW TREE

Damage Sector

Flood Event

(ARI)

5 20 50 100 200 PMF


Telephone 0 0 0 0 0 1

Roads 2, 3 2, 3 2, 3 2, 3 2, 3 1, 2, 3

Bridges 4, 5 4, 5 4, 5 4, 5 4, 5 1, 4, 5

Sewerage Reticulation N/A N/A N/A N/A N/A N/A

Water Supply 0 0 6 6 6 1, 6

Parks and Gardens 0 7 7, 8 7, 8 7, 8 1, 7





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1 = Due to significant increase in discharge and depth for PMF event, damages likely to be incurred

2 = Merriwa Road adjacent to Public School inundated

3 = Oaklyn Road inundated at Borambil Creek

4 = Northern approach to Hams Bridge inundated adjacent to Public School

5 = Causeway at Oaklyn Road inundated by floodwaters

6 = Well dirtied by creek overflow. (Note: damage occurs due to creek flooding, not Borambil Creek

flooding)

7 = Recreational Park affected by floodwaters and tennis courts

8 = King George V Park flooded by creek overflow. (Note: damage occurs due to creek flooding, not

Borambil Creek flooding)

B7.1 Infrastructure

B7.1.1 Electricity

Murrurundi

North Power supplies electricity from Tamworth to a substation located on the New England

Highway, immediately to the west of the township. The substation is located on rising ground

and is free from river flooding for events up to and including the PMF event. During the January

1996 event, the substation experienced around 100 mm depth of stormwater runoff, which

surcharged the highway drains. This depth was insufficient to incur damages to the substation.

All electrical facilities within the town are pole mounted and hence are not at high risk. To the

east of the town, in the vicinity of Campbells Creek, a pole mounted high voltage transformer was

damaged during the January event when the pole was knocked down by floodwaters. Loss of

electricity was experienced on the eastern fringes of the township.

Floodwaters that surcharged the levee on the right bank of the Pages River, upstream of Arnolds

Bridge, caused damages to both the North Power Showroom and depot located along Mayne

Street. The Showroom was inundated by around 300 mm of water while the depot was inundated

by around 50 mm. No direct damage was caused by the flooding, but clean up costs were

incurred.

Throughout the district switch boards and pumps were damaged by the flood and required

electrical repairs.

Blandford

All electrical facilities are pole mounted and hence are not at high risk. The substation located in

Murrurundi supplies the township’s electricity.





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In the January 1996 flood, Blandford experienced power failure due to the loss of the high

voltage transformer in the vicinity of Campbells Creek. To the north of the township, some low

voltage lines were knocked out, due mainly to lightening and wind damage.

Willow Tree

All electrical facilities are pole mounted and hence are not at high risk. Willow Tree receives

electricity from the power line which feeds the Murrurundi substation from Tamworth.

During the January 1996 flood, the inundation of King George V Park caused electrical damage

to the park barbeques and the water supply pump at the adjacent well.

B7.1.2 Telecom

Murrurundi

The telecom exchange is located on Mayne Street within the CBD area. Hydraulic modelling

indicates that the exchange could be expected to be flooded in the event of a 200 yr ARI flood.

In the January 1996 flood, Bush (1996) reported a depth of flooding of approximately 350 mm at

the rear of the property.

Blandford

The township of Blandford has no telecom exchange as it is serviced by the Murrurundi

exchange.

Willow Tree

The township of Willow Tree has a telecom exchange located adjacent to the Post office on the

New England Highway. The exchange is located on rising ground and is flood free at the PMF.

B7.1.3 Roads, Bridges and Railway

In 1996, damage to roads and bridges occurred in both the January and October floods. A large

proportion of these roads and bridges are located outside the study area in rural areas. The total

cost for the restoration of roads in Murrurundi Shire as a result of the January flood was

approximately $2 million. In the later flood, damage to the road infrastructure was less severe

with restoration works costing around $330,000.

Murrurundi

Within Murrurundi roads and bridges are relatively flood free for events up to the 50 yr ARI. For

floods greater than this event the Pages River surcharges its banks and the roadways act as

floodways.





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Arnolds Bridge is flood free at the 100 yr ARI level but the approaches to the bridge are

inundated. The causeway at Murrulla Street is inundated by minor storm events but due to the

nature of flooding in Murrurundi, closure of the causeway will only be for a short period of time.

Roads to the north of the town, such as Munro, Bernard and Little Streets are susceptible to local

catchment flooding when catchment runoff surcharges both Unnamed and Cohens Gullies.

The railway line runs to the south of the township and crosses Halls Creek approximately 200 m

upstream of its confluence with the Pages River. The railway line is flood free for major storm

events.

In the January 1996 flood, clean up costs were incurred across most of the town. Damage to the

pavement within the CBD area occurred due most likely to the relatively high velocity of flow

experienced down Mayne Street. The swinging Bridge at Murrulla Street was damaged and the

cost of repair of one of the approach spans was around $13,500.

Blandford

Both Blandford Bridge on the Pages River and Barsham Bridge on Warlands Creek are flood free

at the 100 yr ARI. Hydraulic modelling indicates that Warlands Creek breaks its right bank

upstream of Barsham Bridge for events less than the 100 yr ARI. Floodwaters traverse the

floodplain and flow across the Timor Road near its intersection with the New England Highway.

In January 1996 floodwaters surcharged Warlands Creek and flowed across the New England

Highway and Timor Road. Floodwaters used the road network within Blandford as floodways and

water travelled in a southerly direction as shallow sheet flow before rejoining either the Pages

River or Warlands Creek to the east of Blandford Bridge.

Willow Tree

Due to the town being located on relatively high ground to the east of Borambil Creek a majority

of the road network is flood free. Some of the roads located to the east of the Grea t Northern

Railway are susceptible to local catchment flooding as was experienced in the January 1996

flood.

Merriwa Road crosses Borambil Creek south west of the town. The bridge, known as Hams

Bridge, is flood free for the 100 yr ARI. During flood events in excess of the 5 year ARI, the

creek breaks its banks upstream of the bridge and floodwaters traverse the right floodplain in a

northerly direction before crossing Merriwa Road between the bridge and the Public School.

During major flood events 300 m of roadway can be expected to be inundated with depths up to 1

m in the 100 yr ARI flood event.

Oaklyn Road crosses Borambil Creek immediately to the west of the township via a causeway.

Three 1000 x 600 RCBCs and 2 x 900 RCPs convey minor flows beneath the roadway. In the

event of a 100 yr ARI the causeway will be inundated by around 5 m of water. On the right bank

the road is inundated out to the intersection of Recreation Road for the 100 yr ARI. On the left

bank Borambil Creek its banks upstream of the Oaklyn Street causeway and floodwaters

traverse the floodplain at depths of around 700 mm for the 100 yr ARI event. Oaklyn Road is

inundated by this floodplain flow for a distance of around 250 m to the west of the causeway.

The Great Northern Railway runs in a north-south direction between the New England Highway

and Borambil Creek. The railway line is flood free for major storm events.





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B7.1.4 Sewerage Reticulation

Murrurundi

Murrurundi Shire Council maintains the sewerage system in the area. The Sewage Treatment

Plant (STP) is located on the right bank of the Pages River, approximately 500 m east of the

township. In the vicinity of the STP the Pages River has a wide flat floodplain and once

floodwaters break the banks of the river, the floodplain is inundated as far as the New England

Highway, a distance of around 270 m.

Results of the Flood Study indicate that inundation of the floodplain will occur for events larger

than 5 year ARI. Due to the large conveyance capacity of the floodplain depths of inundation

increase by only around 400 mm between the 5 to 100 yr ARI events.

In January 1996, areas of the STP were flooded. The STP is surrounded by a levee system

which prevented inundation by floodwater but boundary fences surrounding the plant were

damaged during the flood and the cost of repairing the fence and removing debris was estimated

at around $12,000.

A sewer main within the township was damaged during the flood and the cost of repair was

estimated at $5,500. This occurrence could be seen as a one off and may not necessarily re-

occur during a similar flood event.

Blandford & Willow Tree

Both townships have a in ground septic tank arrangement.

B7.1.5 Water Supply

Murrurundi

The township water supply is from a dam located on to the south of the township on a tributary

creek of the Pages River. Water is pumped to the dam from 2 intake wells situated on the Pages

River, approximately 5 km upstream of the township.

No damage to the dam or intake wells was reported in the January 1996 event.

Blandford

Blandford has no reticulated water supply.

No damage to water supply was reported at Blandford for the January 1996 event.

Willow Tree

The township of Willow Tree obtains its water from a groundwater well situated adjacent to King

George V Park.

During the January 1996 event, the well was dirtied by silt. Works were undertaken to clean the

well and desilt the pump station and its surrounds at a cost of around $5,500.





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B7.1.6 Gas


No gas supply is present in either of the three townships.

B7.2 Community Assets

This category comprises damages to recreational amenities, such as parks, tennis courts and

swimming pool.

Murrurundi

Wilson Memorial Park & Recreation Facilities

The park is located on the left bank of the Pages River immediately downstream of the Arnolds

Bridge. The park contains a circular playing field and amenities.

In January 1996, the Pages River broke its banks upstream of Arnolds Bridge in several locations

between Boyd Street and the Bridge. Water flooded the park via two major flow paths. The first

is the New England Highway, which acted as a floodway. Floodwaters made their way along the

Highway to Arnolds Bridge where then flowed through the park and rejoined the river downstream

of the bridge. The second flow path is a depression which runs parallel with the Highway and on

its northern side. This depression crosses Murrulla and Mount Streets before running to the

north of the oval and into the Pages River. Flood damage within the park comprised clean up

costs to remove silt and debris from the oval and amenities. This work was estimated at around

$3,000.

Both swimming and tennis facilities are located to the west of the playing field. Flooding of these

facilities occurred during the January 1996 event and clean up costs, namely for the swimming

pool, were estimated at around $2,000.

In general, flooding within the park can be expected for events, which surcharge the left bank of

the Pages River upstream of the Arnolds Bridge. Hydraulic modelling indicates that this is likely

for events greater than 50 year ARI.

Remembrance Park

The park is located on the left bank of the Pages river downstream of Mount Street.

In January 1996 it was reported that a major break out of floodwaters occurred at the Park (Bush,

1996). Water reportedly flowed overland to the New England Highway and thence onto the

Wilson Memorial Park and Recreational Facilities.

Damage to the park due to these floodwaters was minimal, with the only clean up of park toilets

being necessary.





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Blandford

Norvill Park

The park is located to the north of the township at the intersection of the New England Highway

and Timor Road.

In January 1996 floodwaters entered the park from two directions. The first was due to

surcharging of the right bank of Warlands Creek, upstream of Barsham Bridge. The second was

from floodwaters which surcharged the left bank of the Pages River upstream of Benhams

Bridge, and flowed along the northern side of the New England Highway for over 2 km before

joining floodwaters from Warlands Creek. The New England Highway is raised approximately

600 mm above natural surface in the vicinity of the park which may promote ponding and

exacerbate the extent of inundation within the area. Clean up costs in the order to $13,000 were

incurred by the 1996 January event. A large amount of tree branch debris left by the flood was

removed.

Willow Tree

Recreational Ground

The recreational ground is located on the right bank of Borambil Creek downstream of the

Oaklyn Road causeway. Available mapping and cross-sectional survey indicates that an area of

high land exists upstream of the ground in the vicinity of the Bowling Club, but natural surface

levels reduce in the vicinity of the playing fields which lead to floodwaters inundating the fields

during major flood events.

During the January 1996 event damages were incurred to the value of $37,000. This cost

included:

repairing or replacement of up to 1,200 m of fencing

the replacement of the entry control building which was flattened by the force of the

floodwaters, and

the removal of debris and silt from the playing fields.

Flood markers noted after the event (Bush, 1996) indicate that water inundated the fields by up to

800 mm depth.

King George V Park and Tennis Courts

This park is located to the east of the Great Northern Railway and is not affected from flooding

from Borambil Creek for events up to and including a 200 yr ARI event. The park is however

susceptible to local catchment flooding and in January 1996 sustained minor damages due to

surcharging of local creeks. Costs incurred by this flood totalled around $600 which included the:

removal of debris from boundary fences

removal of silt and the cleaning of the public toilets, and

removal of gravel washed onto the grassed surface from the roadway.





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The tennis courts are located adjacent to the park. During the January 1996 event, flooding

caused damage to the playing surface and was substantial enough to require its replacement.

Fencing surrounding the courts was also damaged and required repairs. The total cost of works

was estimated at around $13,500.





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B8. SUMMARY OF TANGIBLE DAMAGES

Flood damages under existing conditions have been computed for Murrurundi, Blandford and

Willow Tree for a range of flood frequencies from 5 year ARI to the PMF event. The total

damages for each flood event are shown on Tables B8.1 to B8.3. Cumulative average annual

damages were assessed and are also shown. Figure B8.1 shows the resulting damage -

frequency curves and Figure B8.2 shows the cumulative average annual damage curve for

Murrurundi. Similarly, Figures B8.3 to B8.6 show the respective curves for the townships of

Blandford and Willow Tree.

TABLE B8.1

TOTAL DAMAGES AT MURRURUNDI

Flood

Event

No. of Properties Flooded Total

Dam

Cum

AAD

ARI Residential Commercial/

Industrial

Public $x10

3 $x10

3

A D A D A D

5

20

50

100

200

PMF

0

2

21

36

60

127

0

0

14

24

41

121

0

0

29

37

44

49

0

0

21

29

37

49

0

0

2

8

14

20

0

0

0

3

8

20

0

0

310

695

1,480

8,755

0

0

6

11

19

41

Note: A - flood affected property (includes flooding in allotments and above floor flooding

D - flood damaged property (above floor flooding)





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TABLE B8.2

TOTAL DAMAGES AT BLANDFORD

Flood

Event


Dam

Cum

AAD


Industrial

Public $x10

3 $x10

3

A D A D A D

5

20

50

100

200

PMF

0

1

7

11

21

46

0

1

1

2

10

45

0

0

0

0

0

2

0

0

0

0

0

2

0

1

4

4

4

5

0

1

2

2

4

5

0

26

58

80

245

2,120

0

2.3

3.5

4

5

11

TABLE B8.3

TOTAL DAMAGES AT WILLOW TREE

Flood

Event


Dam

Cum

AAD


Industrial

Public $x10

3 $x10

3

A D A D A D

5

20

50

100

200

PMF

0

0

0

1

1

23

0

0

0

0

1

20

0

0

0

0

0

8

0

0

0

0

0

8

0

0

0

5

6

7

0

0

0

0

5

7

0

0

0

0

79

2,420

0

0

0

0

0.4

6.4

Average annual damages (also termed expected damages) are determined by integrating the

area under the damage-frequency curve. They represent the time stream of average damages,

which would be experienced year by year. Using an appropriate discount rate, average annual

damages may be expressed as an equivalent present worth value of damages and used in the

economic analysis of potential flood management measures.





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For example, the cumulative average annual value at Murrurundi of damages for all floods up to

the 100 year ARI level is around $11,000. A flood management scheme which has a 100 year

ARI level of protection will eliminate damages up to this level of flooding. If the scheme has no

mitigating effect on larger floods, then these damages represent the benefits of the scheme.

Under current Treasury guidelines, economic analyses are carried out assuming a 30 year

economic life for the project and discount rates of 7% pa. (best estimate) and 11% and 4% pa.

(sensitivity analysis).

For a discount rate of 7% pa, the present worth value of damages up to the 100 year ARI level at

Murrurundi is $140,000. Therefore a scheme costing up to $140,000 could be economically

justified if it eliminated damages up to the 100 year ARI level. More expensive schemes would

have a benefit/cost ratio less than 1, but may still be justified according to a multi -objective

approach which considers other criteria in addition to economic feasibility (see Section 6 of the

Main Report).

Unless the scheme is designed to give protection against all flood events up to the probable

maximum flood (PMF), there will be residual damages, which will still be experienced under post -

scheme conditions. From Table 8.1, the cumulative average annual value of damages for all

floods at Murrurundi would be of the order of $41,000. Therefore the residual damages for a

scheme with a 100 year ARI design flood is $41,000 - $11,000 = $30,000 per annum. These

annual damages have a present worth value of $370,000 at a 7% discount rate.

The present worth value of damages in the three townships for all floods is about $720,000 for

the 7% pa. discount rate.





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B9. REFERENCES

Bush, S. (1991) “Preparation of Flood Study Information”. Report prepared for Murrurundi Shire

Council.

Bush, S. (1996) “Preliminary Research into the Severe Flooding in Murrurundi Shire on 25th

January 1996”. Report prepared for Murrurundi Shire Council.

Department of Water Resources, NSW (1990) "Nyngan April 1990 Flood Investigation".

Lyall, Macoun and Joy, Willing and Partners Pty Ltd (1985) "Camden Floodplain Management

Study". Report for Water Resources Commission and Camden Municipal Council.

Sinclair Knight Merz (1994) "Forbes Floodplain Management Report and Draft Floodplain

Management Plan, Volume 1". Report prepared for Department of Land and Water

Conservation.

Water Studies (1986) "The Sydney Floods of August 1986", Volume I Residential Flood

Damage Survey, Report prepared for CRCE Water Studies Pty Ltd for the NSW PWD.

Water Studies (1992) “Forbes Flood Damage Survey, August 1990 Flood.” Report prepared for

Department of Water Resources.


AND WILLOW TREE


APPENDIX C

COMMUNITY CONSULTATION

Note: The Word version of the document was reformatted in December 2014 which has led to minor

differences in its structure when compared to the original report. No hard copy version of this

Appendix was available at the time of compiling. As a result, the Community Flyer and Brochure were

reproduced from a Word document which was assumed to have been used to compile the original

report.

Job No: NX518

J:\NX518\docs\APPC.doc

Date: 03/06/98


Reviewer: BWL



Appendix C - Community Consultation

J:\NX518\DOCS\APPC.DOC

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TABLE OF CONTENTS

Page No.

C1. INTRODUCTION ......................................................................................................... C-1

C2. COMMUNITY BROCHURE AND QUESTIONAIRE ...................................................... C-1

C2.1 Murrurundi ................................................................................................. C-2

C2.1.1 Summary of Community Questionnaire Responses ............................. C-2

C2.1.2 Summary of Respondent Comments ................................................... C-5

C2.1.3 Assessment of Questionnaire Responses............................................ C-5

C2.1 Blandford ................................................................................................... C-7

C2.2.1 Summary of Community Questionnaire Responses ............................. C-7

C2.2.2 Summary of Respondent Comments ................................................... C-9

C2.2.3 Assessment of Questionnaire Responses.......................................... C-10

C2.3 Willow Tree ............................................................................................. C-11

C2.3.1 Summary of Community Questionnaire Responses ........................... C-11

C2.3.2 Summary of Respondent Comments ................................................. C-13

C2.3.3 Assessment of Questionnaire Responses.......................................... C-14

C3. PUBLIC DISPLAY AND MEETINGS ......................................................................... C-15

C4. NEWSPAPER ARTICLES ......................................................................................... C-16

C5. LOCAL AUTHORITY CONSULTATION .................................................................... C-16

ATTACHMENTS

1. Community Questionnaire & Respondents

2. Public Display





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C1. INTRODUCTION

Community consultation provides critical information needed to make decisions about floodplain

management issues and remedial options. The community consultation program developed for

Murrurundi, Blandford and Willow Tree includes providing information by way of brochures and

displays, as well as opportunities for the community to express views and concerns through a

questionnaire and involvement in the Floodplain Management Committee.

These various consultation activities were ongoing throughout the preparation of the Floodplain

Management Plan.

Community concerns relating to flooding issues were identified through consultation with local

residents, relevant public utilities and the Council.

The consultation program was developed with the objectives of:

obtaining local information on flood behaviour and possible mitigation measures

obtaining feedback on community issues and concerns

informing and educating the public about the nature of the flood threat and options for

managing the threat

encouraging future ownership of the Floodplain Management Plan by local residents.

Community awareness was raised through various media including:

Community questionaries

Newspaper articles

Public displays

C2. COMMUNITY BROCHURE AND QUESTIONAIRE

An information brochure and questionnaire was prepared by LMCE and was aimed at informing

residents about the study and allowing property owners within the three townships to comment on

issues such as:

what their experience was during the flood of January 1996,

what damages were incurred and how long a warning time did they receive,

and, what they saw as effective future planning measures.

The questionnaire was delivered through the local post office and via personal delivery to all properties

in low lying areas close to Warlands and Borambil Creeks and the Pages River. A copy of the

questionnaire is provided as Attachment 1. A total of 500 questionnaires were delivered with 36

responses return mailed. A list of respondents is contained in Attachment 1. The following sections

summarise the questionnaire responses received from each township.





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C2.1 Murrurundi

C2.1.1 Summary of Community Questionnaire Responses

Total number of respondents 27

Question 1 Personal and property details

No.

% of

total

1.1 House or business House

Business

House/business

Other

Not noted

14

4

2

2

5

(52%)

(15%)

(7.5%)

(7.5%)

(18%)

1.2 Period of residency in town 1 – 70 yrs

average 22 yrs

1.3 Period of residency at current house/shop 1 – 70 yrs

average 13 yrs

1.4 Building type superstructure Weatherboard/fibro

Brick veneer

Full brick

Combination

Not noted

15

3

4

2

3

(56%)

(11%)

(15%)

(7%)

(11%)

Building type foundations

Piered

Slab on ground

Combination

Not noted

14

3

2

8

(52%)

(11%)

(7%)

(30%)





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Question 2 Experience of January 1996 flood

No.

%

of

total

2.1 Effects of the flood

a Inconvenience YES 21 (78%)

b Unable to access medical assistance YES 4 (15%)

c Dangerous depth or velocity of flow YES 17 (63%)

d Flooding of land adjacent to house/business YES 19 (70%)

e Flood water in house/business YES 5 (19%)

f Power supply cut YES 6 (22%)

g Telephone cut YES 4 (15%)

2.2 Total damages to properties

a Carpets/floor coverings $1000 1 (4%)

b House structure $24,000 2 (7%)

c Furniture and appliances $500 1 (4%)

d Belongings $1,000 1 (4%)

e Outside the house $16,800 7 (26%)

2.3 Amount of flood warning received 0 – 120 min.

average 12 min.

2.4 Source of flood warning

A Council official/SES 3 (11%)

b Neighbour 3 (11%)

c Local media 0 (0%)

d Other (eg. Observation) 18 (67%)

2.5 Time for home/business to return to normal 2 – 500 hours

average 75 hrs.





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Question 3 Future Planning

3.1 Required amount of warning 30 – 120 min.

average 80 min.

3.2 Amount prepared to pay for flood mitigation 0 – $200

average $35

Question 4 Interest in further involvement

No.

%

of

total

a Would like to receive further information YES 18 (67%)

b Would like to be involved in meetings YES 10 (37%)

c Would be willing to be interviewed YES 8 (30%)





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C2.1.2 Summary of Respondent Comments

From the comments received the people of Murrurundi noted the following issues.

Since 1932 the invert of the Pages River has risen due to the ongoing deposition of silt and

stones.

There is a strong consensus that dredging of the Pages River will lessen the severity of flooding

within the township.

The construction of levee banks is seen as a useful flood mitigation measure. The levees should

be built in areas where major breakouts occurred in the January 1996 flood. This will reduce the

amount of floodwaters flowing along the street system.

The construction of a levee on the northern side of the highway will reduce the effects of flooding

ie replacement of an old levee that has washed away on the right bank of the Pages River

immediately downstream of Arnolds Bridge. This would prevent the passage of high velocity flood

waters traversing numerous properties along the highway.

Remove trees planted by WC&IC as they are seen as restricting the passage of flood waters.

Remove weeds and rubbish from the river.

Implementation of a Flood Warning System.

Preparation and adoption of a Floodplain Management Plan. This would:

a) Allow the control of future development within flood prone/affected areas.

b) Protect existing buildings and structures.

Installation of proper kerb and guttering in town streets is required.

Continuous maintenance of creek and road culvert system should be undertaken to reduce the

amount of water surcharging the creeks and roadside drains. Also look at increasing the size of

culverts within the town.

C2.1.3 Assessment of Questionnaire Responses

Of the twenty-seven respondents, twelve were directly affected by floodwaters surcharging the banks

of the Pages River. The remaining fifteen respondents were directly affected by either a) the

surcharging of the minor creek system and/or road drainage system to the north and south of the

township or, b) inconvenienced due to the surcharging of the road system within the township.

The majority of the dollar damages reported within the township, in the vicinity of 75% of the total,

were due to main river flooding.





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On the issue of flood warning the following points are noted:

Of the 12 respondents influenced by main river flooding, 11 were warned of the flood by

either their neighbours or by “other” means, namely personally viewing the river rising.

Of the twelve, seven respondents recorded a warning time of 0 minutes. This would

seem to indicate that respondents answered this question by interpreting a warning as the

real time flooding of their properties.

No warning was heard via the local media.





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C2.1 Blandford




No.

%

of

total


School

5

1

(83%)

(17%)


average 23 yrs


average 18 yrs


Brick veneer

Full brick

Not noted

3

1

1

1

(50%)

(16.7%)

(16.7%)

(16.7%)

Building type foundations Piered

Slab on ground

4

2

(67%)

(33%)





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No.

%

of

total











b House structure $0 0 (0%)


d Belongings $0 0 (0%)


2.3 Amount of flood warning received 0 – 120 min.

average 40 min.

2.4 Source of flood warning

a Council official/SES 1 (17%)

b Neighbour 1 (17%)




average 200 hrs.





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3.1 Required amount of warning 10 – 60 min.

average 45 min.


average $25


No.

%

of

total





From the comments received the people of Blandford noted the following issues.

Levee banks are required to divert water away from homes in danger of flooding. The levees

could be built approximately 1 m in height and be situated at locations where observed breakouts

of floodwaters occurred

Dredging of both the Pages River and Warlands Creek is required due to the build up of material

in the waterways.

Halt the raising of roads in the area above the level of the floodplain, as this is seen as a cause of

flood exacerbation.





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Locating the properties of respondents was difficult due to the names of the houses being given,

rather than street numbers.

Financial damages were experienced by 67% of the respondents with all damages occurring to

structures outside the house. This is an indication of the shallow sheet flow, which was experienced

through the northern part of town, where flood waters did not reach a sufficient depth to inundate

houses.

About 75% of respondents were warned of the flood by either neighbours or personal observation. Of

these, only 1 respondent reported a warning time greater than 0 minutes. This would seem to indicate

that respondents answered this question by interpreting a warning as the real time flooding of their

properties.

Of particular concern is the location of the Blandford Public School downstream of a major surcharge

point. The school received little to no warning of the approaching flood in January 1996. The school

Head Master reported that a warning time of around 60 minutes would be required to organise the

school bus and evacuate the school children. Additionally the closure of the highway during major

flooding could hamper evacuation procedures.





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C2.3 Willow Tree




No.

%

of

total


Business

School

1

1

1

(33.3%)

(33.3%)

(33.3%)


average 4 yrs


average 4 yrs


Brick veneer

2

1

(67%)

(33%)

Building type foundations Piered

Not noted

2

1

(67%)

(33%)





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Lyall & Macoun



No.

%

of

total











b House structure $0 0 (0%)


d Belongings $200 1 (33%)


2.3 Amount of flood warning received 0 min.

2.4 Source of Flood Warning

a Council official/SES 0 (0%)

b Neighbour 0 (0%)




average 75 hrs.





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3.1 Required amount of warning 30 min.

average 30 min.


average $100


No.

%

of

total





From the comments received the following issues are of concern to the people of Willow Tree.

Floods over the past 2 years have been exacerbated due to a build up of rubbish within the creeks

and road drains.

Flows surcharge the creek and drainage systems on the east side of town and flow in an

uncontrolled manner to lower streets and Highway.





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Two of the respondents are located on the eastern side of the Main Railway and are not influenced by

major flooding on Borambil Creek. Flooding issues are related more so with the surcharging of two

small creeks, which flow in a westerly direction, passing the town to the north and south. Additionally,

overland flow from the hillside directly to the east of the town causes nuisance flooding.

One respondent indicated that a 30-minute warning time would be appropriate. Due to the nature of

flooding to the east of the railway line no official warning would seem possible.

On the western side of the railway, the Willow Tree Public School was inundated by floodwaters during

the January 1996 event. The School Master indicated that no warning was given of the approaching

flood. The existing levee to the south of the school would allow some protection during the early

stages of a major flood and the build up of floodwaters behind the levee could be used as an indication

of the need to evacuate school children. Evacuation could be possible to the north along Merriwa

Road towards the township or to the east where land behind the school rises towards the railway





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C3. PUBLIC DISPLAY AND MEETINGS

At the commencement of the Floodplain Management Study a public display piece was prepared and

viewed within Council Chambers. Attachment 2 contains a reduced version of the display pieces.

The display consisted of brief summaries of:

The Floodplain Management Process.

The Murrurundi, Blandford and Willow Tree Flood Study.

Characteristics of flooding in the three townships.

Accompanying the summary were plans of the three townships. Overlaid on the plans was the

indicative extent of inundation for the 100 yr ARI design flood event and the preliminary high hazard

associated All displays were of A1 paper size and were presented in colour. The size and colour of

the display would make it more noticeable and assist in the understanding of the information

presented.

LMCE attended Floodplain Management Committee meetings as well as meetings which were open to

the public.

At the preliminary stages of the study LMCE attended a Committee meeting where the following points

were discussed:

A report on the progress of the Floodplain Management Study, including an outline of the

“drive by” field survey for the assessment of flood damages

Possible flood mitigation measures which could be modelled hydraulically

Arrangements for consultation with the community

Procedures for decisions regarding future planning controls

The draft Floodplain Management Study was also presented to the Committee in December 1997.

Comments received from stakeholders have been incorporated in the final report.





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C4. NEWSPAPER ARTICLES

Several articles were published in regional newspapers to inform the community of the Floodplain

Management Study. Issues covered included:

An invitation to view the draft Murrurundi, Blandford and Willow Tree Flood Study Report

in Council Chambers and a notification of the commencement of the Floodplain

Management Study. The advertisement was published in the local community newsletter

called “The Links” and the Scone Advocate Newspaper.

Two articles outlining work being undertaken by LMCE within the townships. The articles

also emphasised the need to fill in and return the community questionnaires to allow

LMCE to gain a better appreciation of views held by the community. The articles

appeared in the Quirindi Advocate and the Hunter Valley News.

C5. LOCAL AUTHORITY CONSULTATION

Local public authorities and relevant statutory authorities were contacted to obtain comments on the

flooding situation in the area and/or the environmental impacts of possible flood management

measures. The following bodies were contacted:

North Power Tamworth

Murrurundi Shire Council Murrurundi

DLWC Newcastle

EPA Newcastle

Optus Sydney

Police Murrurundi and Willow Tree

RTA Tamworth

SES Local and Head Office

Telstra Newcastle

Council, DLWC and other stakeholder comments have been incorporated into the Main Report and

relevant Appendices. The SES's comments have been incorporated into Appendix D - Flood

Preparedness and Response.

ATTACHMENT 1

COMMUNITY BROCHURE AND QUESTIONNAIRE

Dear Resident,

MURRURUNDI SHIRE COUNCIL : FLOODPLAIN MANAGEMENT STUDY

Lyall & Macoun Consulting Engineers have been engaged by Council to prepare a Floodplain Management Study. This study will form the basis for Council’s Floodplain Management Plan, which will have the objective of minimising the long-term impact of flooding on the community. This brochure provides some background to the steps involved in preparing the Floodplain Management Plan and asks for your assistance in a number of ways : 1. Complete and return the attached questionnaire. 2. Attend meetings which will be held in the next 2-3 months. 3. Comment on the draft plan when it is put on public exhibition in about three months’ time. The preparation of the Floodplain Management Plan is being subsidised by the State and Federal Governments. Once a plan has been accepted by the Community and adopted by Council, further subsidy may be available from government sources to implement the plan (eg levees, channel clearing, flood warning system). The available funds for such works are severely limited and there is strong competition between the various towns and shires for these funds. One of the factors which government uses to judge between the competing requests for funds is the degree of community involvement in developing the Floodplain Management Plan.

To give the Council the best chance to obtain subsidised funding to help the community, you need to

be involved!

The attached questionnaire asks a range of questions relating to your own experiences in recent floods and the impact these have had on you and your family. One of the first steps in a Floodplain Management Study is to assess the impact of flooding on the community in terms of financial loss and social impact. The attached questionnaire will assist us in making these assessments. Later in the study we will be seeking further input and comment regarding community preferences for ways in which the impact of floods can be reduced. These opportunities will be publicised at the time, but we would like to know if you are likely to be interested in being consulted or attending meetings. Please take a moment to complete the questionnaire. Any answers given will be used to give us an idea of how floods impact on the community as a whole. All information provided will be strictly confidential and not be used in any way which identifies individual residents. We are aware that some similar information may have been provided to Council in connection with the Mayor’s Relief Appeal after the flood of January 1996. We are asking for some of it again, to ensure we have a complete picture of the overall effect of flooding on the community. We would like you to provide your street address so that we can correlate the information about the effect of floods with our own analysis of the depth and speed of flood water. If you have any concerns or questions, please provide written comments on the attached questionnaire or ring Steve Perrens at Lyall & Macoun on (02) 9413 3411 or Graeme Turnbull at Couincil on (063) ...... . I look forward to hearing from you and to working with the community to minimise the future devastation caused by flooding. Yours faithfully

LYALL & MACOUN CONSULTING ENGINEERS

Dr Stephen J Perrens FIE Aust, CPEng.

FLOODPLAIN MANAGEMENT STUDY Mail-Back Questionnaire

1. PLEASE TELL US A LITTLE ABOUT YOURSELF AND YOUR HOUSE/SHOP 1.1 This questionnaire refers to my house/shop (delete one). 1.2 How long have you lived in the town? years

1.3 How long have you lived in your current house/shop? years

1.4 How is your house/shop constructed? ( tick one on each line)

a. Weatherboard/

Fibro

Brick Veneer

Full Brick

b. Piered foundations

Slab on ground

2. WHAT WAS YOUR EXPERIENCE IN THE FLOOD OF JANUARY 1996? 2.1 What were the major effects of the flood on you?

( tick where appropriate) a. Inconvenience (eg roads closed, shops shut) b. Unable to access medical assistance c. Dangerous depth or velocity of flow d. Flooding of land adjacent to house/shop e. Flood water in house/shop f. Power supply cut g. Telephone cut 2.2 What, if any, damage was caused to your property?

(Please insert an estimate of the value of damage caused)

Carpets/flood coverings $

House structure $

Furniture and appliances (including TV, etc.) $

Belongings (eg clothes, books, etc.) $

Outside the house (garage equipment, mower, etc) $

2.3 How much warning did you have that a flood was coming? minutes

2.4 How did you get to know that a flood was coming ( tick one)

Council official/SES Neighbour Local media Other

2.5 How long after the flood did your home/business return to “normal”? hours

days

3. PLANNING FOR THE FUTURE

3.1 One of the most cost effective ways of reducing flood damage is the

installation of a flood warning system to allow residents to remove or raise movable items. How much warning would you need to take

effective action? minutes

3.2 If Council was unable to obtain sufficient funding from government sources to fully implement the proposed Floodplain Management Plan, would you be prepared to pay a special rate for flood mitigation

purposes, if so how much per year? ( tick one)

$0 $20 $50 $100 $200 $500 PLEASE NOTE: THIS QUESTION DOES NOT IMPLY THAT SUCH A

RATE WOULD BE CONSIDERED. IT IS ONLY TO TEST HOW THE COMMUNITY VALUES REDUCTION OF FLOOD DAMAGE.

3.3 DO YOU HAVE ANY SUGGESTIONS FOR EFFECTIVE WAYS TO

REDUCE THE IMPACT OF FLOODING ON THE TOWN?

................................................................................................................... ................................................................................................................... ................................................................................................................... ...................................................................................................................

4. Would you like to receive further information or be involved in

future meetings? (please tick appropriate box)

a. I would like to receive further information. b. I would like to be involved in meetings concerned with

Floodplain Management.

c. I would be happy to be interviewed about the effects on the

community (please tick)

Name ...................................................................................

Address ...................................................................................

...................................................................................

...................................................................................

Contact Phone:

......................................................................... (Work)

......................................................................... (Home)

THANK YOU FOR YOUR HELP PLEASE FILL IN YOUR NAME, ADDRESS AND PHONE NUMBER ON THE REVERSE SIDE AND

RETURN YOUR QUESTIONNAIRE IBY 31 MAY 1997

More detailed written comments are welcome. Please staple any sheets with your comments to this questionnaire and fold them together before mailing.

QUESTIONNAIRE RESPONDENTS - MURRURUNDI

Number Name Address

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Leo Purcell

David Flanagan

Heritage Hardware

JB O'Hare

Kenneth S White

Mr R Weber

Murrurundi Retirement

Homes Assoc Inc

Barry and Janene Nolan

L. Tappenden

Mrs W Saunders

Ken and Barbara Mitchell

Keith Casey

Jack Goldsmith

William Scotcher

CR Drake-Brockman

Miss RA Ellis

Mr A Gimbert

L Mathieson

Murrurundi PO and Nursery

Graham D Turnbull

Jack Wood

G and D Lamey

Peter Coffey

Elizabeth Feast

B & W Gurst

Shell Murrurundi

Miss Elizabeth Beith

13 Liverpool Street, Murrurundi

28 Cohen Street, Murrurundi

8-10 Mayne Street, Murrurundi

91 Mayne Street, Murrurundi

84 Murulla Street, Murrurundi

89 Timor Lane, Murrurundi

Murravale Hostel, 6-10 Haydon Street, Murrurundi

36 George Street, Murrurundi

Royal Hotle, 144 Mayne Street, Murrurundi

33 Wood Lane, Murrurundi

3 Wades Lane, Murrurundi


PO Box 23, Murrurundi




130 Little Street, Murrurundi




244 New England Highway, Murrurundi

40 Liverpool Street, Murrurundi

"Glenvale" New England Highway, Murrurundi

34 Haydon Street, Murrurundi

BP Murrurundi, 148 Mayne St, Murrurundi


30 Haydon Street, Murrurundi

QUESTIONNAIRE RESPONDENTS - BLANDFORD

Number Name Address

1

2

3

4

5

6

Barbara Mary Mitchell

MJ Norvill

Doug and Robin Munro

Norman and Traci Gimbert

VG Baker

Dennis Madden

Lot 1 Debenham St, Blandford

Debenham St, Blandford

"Winkle Farm", Old North Road, Blandford

"Tanona", Blandford

New England Highway, Blandford

Public School, Blandford

QUESTIONNAIRE RESPONDENTS – WILLOW TREE

Number Name Address

1

2

3

Willow Tree Public School

Ron Biffin (General Store)

Mr and Mrs R Blackmore

Merriwa Road, Willow Tree

20 New England Highway, Willow Tree

"Little Willow" Station Road, Willow Tree

ATTACHMENT 2

PUBLIC DISPLAY





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1. THE FLOODPLAIN MANAGEMENT PROCESS

The State Government's Flood Policy is directed at

providing solutions to existing flooding problems in

developed areas and to ensuring that new development is

compatible with the flood hazard and does not create

additional flooding problems in other areas. The Policy

provides for technical and financial support by the

Government through the following four sequential stages:

1. Flood Study

- determines the nature and extent of

flooding.

2. Floodplain Management Study

- evaluates management options for the

floodplain in respect of both existing and

proposed development.

3. Floodplain Management Plan

- involves formal adoption by Council of a

plan of management for the floodplain.

4. Implementation of the Plan

- construction of flood mitigation works to

protect existing development.

- use of Local Environmental Plans to

ensure new development is compatible

with the flood hazard.

2. FLOOD STUDY

The draft Murrurundi, Blandford and Willow Tree Flood

Study (1997) constitutes the first stage of the management

process for this area and has been prepared for Murrurundi

Shire Council to define flood behaviour under present day

conditions. The Floodplain Management Study (FMS) is

currently being prepared for Council. A copy of the draft

Flood Study is available at Council offices for perusal by

interested residents and will remain on exhibition for the

next 4 months. During that time Council welcomes

comments from the public on its contents and results.

The area investigated in the Flood Study included the 12.5

km long reach of the Pages River from Murrurundi to

Blandford, as well as the 4.5 km section of Borambil Creek

in the vicinity of Willow Tree. Flood behaviour in the two

streams was modelled using computer based mathematical

models to provide information on flows, levels and flooding

behaviour for floods of frequencies ranging between 5 years

and 100 years average recurrence interval (ARI).

The average recurrence interval is the average period (in

years) between the occurrence or excedence of a flood of a

given size. For example, a 5 year flood is a relatively

frequent event and would be equalled or exceeded once in 5

years on the average. On the other hand, a 100 year flood

is a much larger and rarer flood and would be exceeded

once in 100 years on the average.

The ARI is defined by the average time between floods over

a long period of time (several thousand years). Because of

the random nature of floods, the occurrence of a flood (say

100 year ARI) in any year does not mean that a larger flood

will not occur for another 100 years. The chances of such a

flood occurring next year remain exactly the same,

regardless of what has happened before.

The probable maximum flood (PMF) was also modelled.

The PMF is the largest flood, which could reasonably be

expected to occur at a particular location, and is an

exceedingly rare event. It defines the upper limit of flood

prone land.

Plans showing the extent of flooding for floods ranging

between 5 years and 100 years ARI are contained in the

flood study. These plans also show high hazard areas in

the floodplain for each flood. Flood hazard at a particular

location depends on the depth and velocity of flooding and

varies for each flood. High hazard areas are zones of deep

water and/or where the velocity of flow is high. Conversely,

low hazard areas are zones where the depth of flooding is

shallow and/or velocities are low.

The attached diagrams show the extent of flooding and

the areas of high flood hazard for a 100 year ARI flood

at Murrurundi, Blandford and Willow Tree.

3. FLOODING IN MURRURUNDI

Murrurundi is the most flood prone of the three townships

investigated in the Flood Study, with nine

significant floods experienced in the past 40 years since the

record flood of October 1949.

On two recent occasions, in January and October 1996,

floodwaters surcharged the right bank of the Pages River

(looking in the downstream direction) just upstream of

Arnolds Bridge and flowed down Mayne Street. At

Murrurundi, the January 1996 flood was a major event, with

the peak discharge approximating that of a 100 year ARI

flood, but was less severe further downstream at Blandford





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where it approximated a 50 year ARI flood. The October

flood was a smaller event, approximating 50 year ARI at

Murrurundi and 20 year ARI at Blandford.

The Pages River breaks both its left and right banks during

large flood events :

Floodwater leaves the right bank at Boyd Street

and rejoins the Pages River at the suspension

bridge at Murulla Street.

Floodwater leaves the left bank between Murulla

Street and Arnolds Bridge. Water flows down

both the New England Highway and along a

natural depression to the north of the Highway.

This flow bypasses Arnolds Bridge and rejoins

the river downstream of Wilson Memorial Park.

The river surcharges the man-made levee on the

right bank upstream of Arnolds Bridge.

Floodwaters travel through properties causing

flood damages. Floodwaters travel down Mayne

Street with a high velocity and rejoin the river

downstream of the township near Brooke Street.

Flooding occurs to the north of the New England

Highway, surcharging some of the minor creeks

and gullies. Floodwaters surcharging these

waterways follow the small drainage swales,

which border the roads, before joining the Pages

River.

4. FLOODING IN BLANDFORD

Flooding from Pages River

A steep right bank and mainly lucerne paddocks on the left

bank border the river. Upstream of the New England

Highway crossing at Blandford Bridge, floodwaters are

mainly confined to the immediate vicinity of the river,

although a property on the left bank upstream of Blandford

Bridge is susceptible to flooding eg January 1996.

Downstream of Blandford Bridge the capacity of the river

channel is smaller and floodwaters spread out towards

Warlands Creek.

The Pages River breaks its left bank upstream of Benhams

Bridge. During times of major flooding, flood waters flow

along the northern side of the New England Highway

towards Norvill Park. However, most of the flow is

conveyed over the highway before it reaches Norvi ll Park.

Flooding from Warlands Creek

Warlands Creek flows from rugged country to the north of

the township. The creek meanders past the eastern side of

the township. During times of major floods, the river breaks

its banks along most of its length and causes flooding within

the township.

The river breaks its right bank upstream of the Barsham

Bridge. Floodwaters flow into Norvill Park where they

surcharge the highway and inundate the school ground.

Floodwaters then flow over lucerne paddocks to join the

Pages River.

Downstream of Barsham Bridge floodwaters which escape

the river flow through the street system before rejoining the

combined Warlands Creek and Pages River flows.

5. FLOODING IN WILLOW TREE

Borambil Creek has a wide, sparsely developed right

floodplain in the vicinity of the township of Willow Tree.

Development has been mainly to the east of the railway line

on high ground and consequently flooding has only a minor

effect on the township.

Some development has occurred to the west of the railway

line. However, only rare events (greater than the 100 year

ARI flood) would cause flooding.

During the January 1996 flood, which was approximately a

100 year ARI event at Willow Tree, minor damage was

caused along Merriwa Road.

Flooding occurred at the Willow Tree Public School when

floodwaters surcharged the right bank upstream of Hams

Bridge and followed Merriwa Road to the school. Flooding

of this nature occurs relatively frequently but the

construction of a levee beside the school prevents all but

major flood events inundating the school grounds.

Some minor flooding was experienced due to insufficient

drainage capacity and blockage of culverts within the town,

eg the culvert on the northern side of Sisson Street.

Job No: NX518

J:\NX518\docs\appd.doc

Date: 03/06/98

Rev. No. 3.0

Author: SAB

Reviewer: BWL


AND WILLOW TREE


APPENDIX D

FLOOD PREPAREDNESS

AND RESPONSE

Note: The Word version of the document was reformatted in December 2014 which has led to

minor differences in its structure when compared to the original report. No hard copy version of

this Appendix was available at the time of compiling. As a result, Figure D.1 could not be

reproduced, while Figure D.2 was reproduced from a Word document which was assumed to

have been used to compile the original report.



Appendix D - Flood Preparedness and Response

J:\NX518\DOCS\APPD.DOC

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TABLE OF CONTENTS

Page No.

D1. INTRODUCTION AND SCOPE ..................................................................................... D-1

D1.1 Elements of Flood Warning and Response System ......................................... D-1

D1.2 Location .......................................................................................................... D-1

D1.3 SES Arrangements in Murrurundi Shire ........................................................... D-2

D1.4 Scope of Review ............................................................................................. D-2

D2. FLOOD WARNING AND RESPONSE ........................................................................... D-3

D2.1 Institutional Arrangements for Flood Warning and Response ........................... D-3

D2.2 Murrurundi and Quirindi Flood Plans................................................................ D-4

D3. REVIEW OF THE MURRURUNDI AND QUIRINDI EMERGENCY MANAGEMENT

SYSTEM ....................................................................................................................... D-6

D3.1 Identification of Areas at Risk .......................................................................... D-6

D3.2 Flood Predictions and Warning ........................................................................ D-6

D3.3 Dissemination of Warnings .............................................................................. D-7

D3.4 Response to Warnings .................................................................................... D-8

D3.4.1 Existing Situation ................................................................................. D-8

D3.4.2 Commentary ........................................................................................ D-9

D3.5 Flood Recovery ............................................................................................... D-9

D4. IMPROVEMENTS TO THE FLOOD WARNING SYSTEM ........................................... D-11

D4.1 Flood Warning ............................................................................................... D-11

D4.2 Flood Response and Communication ............................................................ D-12

D5 SUMMARY ................................................................................................................. D-14

D6. REFERENCES ............................................................................................................ D-15

FIGURES

D.1 Rainfall and Stream Gauging Stations

D.2 Distribution of Flood Warnings




J:\NX518\.DOCS\APPD.DOC

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D1. INTRODUCTION AND SCOPE

D1.1 Elements of Flood Warning and Response System

Implementation of an effective flood warning system is a strategy increasingly being used as a

means of mitigating flood damage. A flood warning system also incorporates measures for an

effective response. The overall system consists of the following elements:

forecasting the time of arrival and height of flood stages and the flood peak

interpretation of the prediction and identification of the areas at risk from flooding

the preparation and dissemination of warnings to flood prone residents

response to the warnings by the agencies involved and the community, possibly

involving the evacuation of people and possessions from flood threatened areas

the recovery of the community in the flood aftermath

review of the system after the flood event

This Appendix reviews the flood warning and response system presently in place in the Shire of

Murrurundi and examines possible measures for improving the system in the townships of

Murrurundi, Blandford and Willow Tree.

D1.2 Location

Murrurundi, Blandford and Willow Tree are situated in the foothills of the Liverpoo l Range north

of the town of Scone. The Liverpool Range, a part of the Great Dividing Range with elevations

ranging between 600 and 1200 m, forms the northern boundary of the Hunter River catchment

and is the watershed between the coastal Hunter River system and inland Namoi system.

The Pages River has its source near the eastern end of the range, from where it flows in a south -

east direction through the townships of Murrurundi and Blandford to join the Hunter River in its

headwater region. Warlands Creek flows through Blandford and joins the Pages River

immediately downstream of the township. The catchment area of the Pages River at Murrurundi

is 72 km2. Warlands Creek has a catchment area of 103 km

2 at Blandford. The combined

catchment area of the two streams at the gauging station downstream of Blandford amounts to

300 km2.

Borambil Creek, a tributary of the Mooki River, rises on the northern side of the Liverpool Range

in the Namoi River catchment and flows in a northerly direction parallel with the New England

Highway. A short distance upstream of the township of Willow Tree it is joined by Chilcotts

Creek, which drains the foothills of the range to the east. Borambil Creek continues past Willow

Tree towards Quirindi. At the junction with Chilcotts Creek the total catchment area is 183 km2 of

which Borambil Creek contributes 49 km2.

The streams within the Shire have steep gradients and floods typically rise quickly with a time to

peak of two hours or less. Flooding within the towns is classed as “flash” flooding with a very

short potential warning time.





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D1.3 SES Arrangements in Murrurundi Shire

Typically, a single SES Local Controller controls flood management within each Council area.

However, within the Shire of Murrurundi, the Liverpool Ranges is the watershed between the

Hunter and Namoi River Valleys. By agreement between the Murrurundi and Quirindi SES Local

Controllers, responsibility for flood management (including flood warning and response) has been

divided into the following two areas:

1) On tributaries of the Hunter River (east of the Liverpool Range): - Murrurundi Local

Control

2) On tributaries of the Mooki River (west of the Liverpool Range): - Quirindi Local

Control

D1.4 Scope of Review

A review of the current flood warning and response system in the three townships is presented in

this Appendix and has been prepared with input from State and Local SES officers and the

Bureau of Meteorology.

State wide arrangements for flood warning and response, which involve the interaction of seve ral

co-operating government agencies, are briefly reviewed in Section D2. A review of the

Murrurundi and Quirindi Emergency Management System is provided in Section D3, while

possible improvements to the system are discussed in Section D4.





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D2. FLOOD WARNING AND RESPONSE

D2.1 Institutional Arrangements for Flood Warning and Response

A range of Local, State and Federal Authorities participate in these processes. Flood forecasting

is the designated responsibility of the Commonwealth Bureau of Meteorology (BOM), although

water authorities, local councils and the State Emergency Service also produce flood forecasts

and play a part in the flood warning process in some areas. The warning phase is generally

under the supervision of the State Emergency Service (SES) acting through its local unit, often

with considerable local council input. The SES generally supervises evacuation, although the

Police Service will often be involved, especially if the number of evacuees is large. If necessary,

the Defence Forces will be brought in to provide assistance to the civil authorities through

Emergency Management Australia. Finally, volunteers and welfare agencies play a key role in

the recovery phase, along with councils and state government agencies.

In recent years, Flood Warning Consultative Committees have been established in all States. In

NSW membership comprises the BOM (chair), Public Works and Services Department,

Department of Land and Water Conservation, Department of Local Government, Sydney Water,

the SES and the Floodplain Management Authority. This committee provides a suitable vehicle

for the review of flood warning procedures and responsibilities. Recently, the Upper Hunter

Division Controller has been added to the Committee and Local Government represented by the

Shire and Local Government Association. Putting the Floodplain Management authority on the

Committee also enhances the community’s representation.

Flood forecasting, warning, response and recovery are crucial elements in the effectiveness of a

flood warning system. Flood warning schemes interpret and add to flood forecasts (predictions

of gauge heights) by linking them to something meaningful to the public such as flood depths in

specific areas, extents of flooding, road closures, properties inundated etc and then providing

advice on appropriate response. Warning schemes must ensure the message is effectively put

together, disseminated, understood and acted upon.

It is essential that a formal preparedness, response and recovery plan ("Flood Plan") be prepared

for each area at risk. This Plan, which is prepared by the SES covers the range of activities

relevant to real time flood management and incorporates input from various other organisations

and ideally from the community at risk. It is the critical flood education document and is available

to the public. The Plan must address wider issues such as community awareness, public

education and mock emergency practices, and most importantly, community acceptance of the

need for and involvement in management measures. Other documents, including the Operation

Manual, Resource Manual and Standing Operating Procedures, contain details of areas of

responsibility, chains of command, activities to be undertaken during floods and available

resources.

It is also imperative that flood forecasting procedures, responsibilities and the necessary

resources and their disposition be reviewed to ensure that forecasts are accurate and timely.

Such procedures and responsibilities need to be incorporated into the flood plans for affected

communities.





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Flood warning systems should also be subjected to an on-going assessment. After each

significant flood event, the performance of the particular "system" needs to be reviewed as a

matter of course and, if necessary, response planning altered.

Further detail on flood management arrangements in NSW is to be found in the State Flood Plan,

Division (Regional) flood plans and Local flood plans. The last are normally written at the level of

the individual Local Government area.

D2.2 Murrurundi and Quirindi Flood Plans

A draft Flood Sub-Plan has been prepared for the area of the Murrurundi Shire to the east of the

Liverpool ranges (Murrurundi Local Control). Due to the nature of flooding within the area, and

the relatively small number of properties affected by flooding, the document only forms an

annexure to the Murrurundi Local Disaster Plan (DISPLAN) rather than a separate document.

The plan covers the following topics:

the flood management arrangement within the Council area, dividing responsibilities

between Quirindi and Murrurundi SES,

definition of the flood threat, including flood producing mechanisms, locations of road

closures and areas inundated in Murrurundi and Blandford.

activities which are undertaken by the Local Controller with respect to flood warnings

and response.

In 1994 the draft Quirindi Local Disaster Plan (DISPLAN) was prepared. The plan includes a

Local Flood Plan for Quirindi which covers:

preparedness measures, the conduct of response operations and the co-ordination of

immediate recovery measures for flooding within the Quirindi and Murrurundi Council

(northern portion) areas.

operations for all levels of flooding and caters for both SES control of operations and,

where appropriate, the handover of control of part or all of operations from the SES

Local Controller to the Local Emergency Operations Controller.

The Plan is issued under the authority of the State Emergency and Rescue Management Act

1989 and the State Emergency Service Act 1989. It has been accepted by the State Emergency

Service Namoi Division Controller and the Quirindi Local Emergency Management Committee.

The Plan is a much larger document than its Murrurundi counterpart and covers the following

topics:

Part 1 Introduction - Purpose

- Authority

- Area Covered by the Plan

- Responsibilities

- Review of the Plan





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Part 2 Preparedness - Public Education

- Activation

- Flood Intelligence

- Warnings

- Preliminary Deployments

Part 3 Response - Control

- Operations Centres

- Liaison

- Communications

- Information

- Road Control

- Flood Rescue

- Evacuations

- Logistics and Resupply

Part 4 Recovery - Welfare

- Registration

- All Clear

- Recovery Coordination

- Debrief

Several annexures providing specific information on the flooding situation in the shire are

appended to the Local Flood Plan, as follows:

A. The Flood Threat

B. Specific Risk Areas

C. Gauges Monitored by the SES Local Controller

D. The Distribution of SES Flood Bulletins

E. Guide to the Content of Evacuation Warning Messages

F. Coepolly No. 2 Dam Failure Warning System

Within the Murrurundi and Quirindi areas, the Flood Plans provide information on the

dissemination of warnings/information to the public through the media, the Police, other

emergency services and by telephone or direct radio contact.

The respective SES Local Controllers activate the Flood Plans when flooding is predicted to

occur at either of the townships, after they obtain information on prospective and actua l flooding

from:

Bureau of Meteorology Flood Alert (previously called Confidential Flood Advice). The

information is received by telephone and fax from the SES Upper Hunter and Namoi Division

Headquarters.

flood gauges located at Arnolds Bridge at Murrurundi and Hams Bridge at Willow Tree,

neighbouring Controllers

a network of local river-watch readers, Council crews and Police.

In practice, due to the “flash flooding” behaviour of the catchments, real activity would only be

triggered by signs that flooding had actually commenced.





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D3. REVIEW OF THE MURRURUNDI AND QUIRINDI EMERGENCY MANAGEMENT

SYSTEM

D3.1 Identification of Areas at Risk

The general pattern of flooding in the townships has been identified by SES from historic

flooding. Peak water surface levels in the Pages River and Warlands and Borambil Creeks for 5,

20, 50, 100 and PMF floods have been presented in the draft Flood Study report (LMCE, 1997).

The indicative extent of flooding has been shown on plans supplied to Council. As part of this

present Floodplain Management Study, floor levels of flood affected properties have been

surveyed. Consequently, there is now sufficient information available to more precisely identify

areas at risk from flooding for the full range of events likely to tr igger flood response procedures

in the three townships. It is also to be noted that the “wall of water” effect noted on the Warlands

Creek catchment in the January 1996 flood could conceivably occur on the Pages River.

D3.2 Flood Predictions and Warning

The primary responsibility for flood prediction within NSW rests with the BOM. Through the

collection and analysis of rainfall and stream flow data from telephone telemetered rainfall and

stream flow gauges the BOM undertakes the following activities:

Provision of early indications that a meteorological situation is developing which could

lead to flood producing rains in the Hunter and Namoi catchments.

A preliminary assessment of the scale of flooding.

Ongoing predictions of river heights at key locations during flood producing rains and

until the river level has fallen below the minor flood level.

Summaries of actual rainfall and river height readings as the flood develops, peaks and

recedes.

The BOM is generally responsible for providing flood warning advice on major river systems

where warning times exceed six hours. The rapid rate of rise of floods within Murrurundi Shire

does not allow sufficient time for BOM to issue Flood Warnings, although under certain

circumstances, BOM may issue Flood Alerts or more specifically Severe Thunderstorm Advice

when there is a likelihood that predicted rainfall will be sufficient to cause flooding. Within the

Upper Hunter Valley catchment these warnings are sent to Muswellbrook and Gunnedah within

the Namoi catchment and then to Local Controllers. During the operational phase, flood

warnings are the responsibility of the Local Controller who, through a network of gauges and

river-watch readers, Council crews, Police and neighbouring Controllers, may predict the onset of

a flood event.

Within or adjacent to the Pages River catchment, there are two pluviographic rainfall gauges

located at Scone and Blandford and a HYDROMACE reporting rain gauge located at Murrurundi

(see Figure D.1). The three gauges form part of the instrumentation for the Hunter River Valley

Flood Warning System. Also located on the Pages River at Blandford, is a stream gauging

station. Two privately read daily rain gauges are located on the Pages River catchment,

upstream of Murrurundi and are denoted A and B on Figure D.1.





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Within the Borambil Creek catchment, there are presently no pluviographic rainfall gauges.

However, one BOM daily rain gauge is located upstream of Willow Tree.

D3.3 Dissemination of Warnings

Due to the rapid rise of floodwaters within the Council area , the mechanism for dissemination of

flood warnings does not follow the well established pattern for NSW shown in Figure D.2. The

short period of time of rise of flood peaks means that it is not possible for BOM to issue e ffective

flood warnings.

BOM issue a Flood Alert based on an advanced appreciation of a developing meteorological

situation which could produce flood rainfall. It contains, when possible, a preliminary assessment

of the severity of flooding which could occur in particular river valleys. It is issued for planning

purposes and is not disseminated to the media or public.

The Flood Alert is issued by BOM as an alerting mechanism for the SES and other directly

affected agencies when it is assessed that predicted rainfall will be sufficient to overcome the

moisture deficit within a catchment and cause flooding. The assessment of moisture deficit uses

a concept known as the antecedent precipitation index (A.P.I.) which is calculated on a

continuous basis from rainfalls experienced prior to issuing the flood advice.

The Flood Advices are transmitted direct to the SES Divisional Headquarters, where the relevant

Local SES units are alerted by phone.

Within the Local Flood Plans there are guidelines for the activation of the respective plans and

the issuing of warnings including lists of names of all relevant authorities and organisations,

responsibility levels of the various parties and procedures for activities and mobilisation of

Divisional and Local Headquarters.

Upon receiving information from sources such as the network of gauges and river -watch readers,

Council crews, Police and neighbouring Controllers, of the possibility of a flood event, the Local

Controllers contact all relevant authorities and organisations. East of the ranges, the Murrurundi

Local Controller informs the Murrurundi Police and Council. Information is also provided to the

Upper Hunter SES Division Headquarters which is then relayed to radio stations at Muswellbrook,

Tamworth and Gunnedah. The Division Headquarters also advises the Scone and Muswellbrook

SES Local Controllers if flooding within their Council areas appears possible as a result of

flooding in Murrurundi Shire.

West of the ranges, the Quirindi Local Controller contacts the Willow Tree Police Sector

Commander who acts as an SES agent. The Police Sector Commander then controls:

any evacuations in the area resulting from flash flooding,

road control operations in conjunction with the Quirindi and Murrurundi Councils.

The NSW Fire Brigade situated at Willow Tree may also be called upon to assist the Police in the

above activities.





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Upon receipt of information of possible flooding, the Quirindi Local Controller will contact the

Namoi Division Headquarters who will undertake similar tasks outlined above for the Upper

Hunter region. Additionally, TV stations in Tamworth are notified when deemed appropriate.

All SES Units have been issued with copies of "Flood Warning: an Australian Guide" which offers

suggestions as to how the utility of the BOM predictions can be maximised (for example, by

estimating flood effects), and deals with identifying the best methods of dissemination for

different situations. The key elements are the translation of the height predictions into likely

consequences and the effective distribution of this information and appropriate advice for people

to follow.

D3.4 Response to Warnings

D3.4.1 Existing Situation

Reaction to flood warnings and response procedures are outlined in the Local Flood Plans and

deal with the provision of a coordinated response to the flooding. Aspects covered include:

Control and Responsibilities - Most flood operations within Murrurundi Shire are

controlled by the respective SES Local Controller in accordance with the State

Emergency Service Act, 1989. This will usually include the coordination of support from

other agencies. Operations are controlled from SES Local Headquarters located at

Murrurundi and Quirindi.

Communications - The primary means of communication between SES personnel in the

field is via:

Murrurundi SES UHF radio east of the ranges

the Quirindi SES UHF Tactical radio network west of the ranges.

The Quirindi unit also operates a UHF CB radio station which provides communications

with most rural properties in the area and a station on the Namoi SES Division UHF

Strategic radio network as backup. Other valuable back-up is also provided by the radio

services of Quirindi Council, the Rural Fire Service and the Quirindi District Rescue

Squad.

Flood Advice – Both the Murrurundi and Quirindi SES Local Headquarters provide

phone-in information services to the public in relation to river heights, flood behaviour,

road closures and confirmation of evacuation warnings. The Local Controllers provide

road status reports for all roads in the Shire to the Upper Hunter and Namoi SES Division

Headquarters. Division Headquarters distributes information on major roads to SES units

and the media outlets as part of Flood Bulletins.

Road Control - Road closures are undertaken by Murrurundi Council as agents for the

RTA, as appropriate. NSW Police Services also has the authority to close and re-open

roads but will normally only do so (if the Council has not already acted) if public safety

requires such action.





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Flood Rescue - The respective SES Local Controller coordinates flood rescues. If

required, Flood Rescue Boats and Crews may be obtained through the Namoi SES

Division Headquarters. Due to the nature of flooding in the vicinity of the three towns, the

time taken to aquire the boats would negate their use and would be more appropriate

further down the valleys.

Evacuations - SES Local Controllers control evacuations which are conducted by SES,

police and Rural Fire Service personnel. In the Murrurundi area, the Local Control ler will

provide advice and assistance as required. In the Willow Tree area, evacuations will be

controlled by the Willow Tree Police Sector Commander. It is expected that evacuees

would proceed to the houses of friends and relatives until the flood subs ided, but

Evacuation Centres would be opened if necessary.

D3.4.2 Commentary

The reaction phase of the flood warning cycle depends on human nature, preparedness and the

credibility of the flood warning. Effective response to warning information will depend upon the

quality of information; the ability of people to understand it and the SES's ability to ensure they

receive it. The effectiveness of evacuation operations depends on the SES's ability to determine

in advance who will need to be evacuated and to ensure those people understand that need (eg

by door knocking). However, in the case of the three townships there is little time to carry out

evacuations and the best that could probably be achieved is an announcement over radio

stations that flooding is imminent. There is no local community radio by which flood warnings

can be disseminated to the community.

The residents of Murrurundi, Blandford and Willow Tree are part of a wider community

throughout the catchment and region. Community contacts provide a widespread informal

network of people who exchange information as a flood situation develops and then “spread the

word” amongst friends and neighbours in townships. These informal means of communication

can provide the SES with a valuable means of disseminating flood information but also provide a

vehicle by which misleading rumours can spread in the absence of “official” warnings. The SES

should seek to take charge of information dissemination, to keep the community informed from

an official source. This will allow the community to plan ahead, without necessarily taking steps

to move furniture and stock.

A further improvement would be to erect temporary signs on the major roads at the last major

intersection before arriving at the town with a contact phone number so that travellers and people

from out of town can obtain information regarding flooding. Adequate supplies of barricades and

signs are required to effect road closures.

It is recommended that the SES consults the local community to identify exactly what information

they require in relation to flood advice and the best way of communicating it. This could be

achieved by advertisement in the local press and as part of the display process of the draft

Floodplain Management Plan.

D3.5 Flood Recovery

Part 4 of the Quirindi Local Flood Plan addresses this phase. Within the Murrurundi Flood Plan,

Flood Recovery has not been addressed.





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Aspects covered within the Quirindi plan include:

Registration of evacuees and catering for their long term welfare.

Issuing "all clear" message signifying response operations are completed.

Implementing Recovery Plan and debriefing.

Experience gained through mock flood emergencies could be used to refine Flood Plans.





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D4. IMPROVEMENTS TO THE FLOOD WARNING SYSTEM

The Flood Plan formalises the procedures used in previous flood events. Due to the recent

major flood which occurred in January 1996, and previous floods in the 1990’s, the local

community is very flood aware (although the flooding mainly occurred in the Upper Hunter

catchment) and the procedures documented in the Plan are based on this flood awareness.

D4.1 Flood Warning

The effectiveness of any form of warning system is ultimately measured by the response to the

warnings. This response is affected by many factors, the most important being the need to

minimise the delays between the occurrence of the event and its subsequent notification, the

awareness of this by the forecasting authority and the initiation of the emergency response plan.

As mentioned previously, the primary responsibility for flood prediction rests with the BOM. With

the Murrurundi Shire area being located in the shadow of the Liverpool Ranges, flooding in the

area is of a “flash” flooding nature.

To provide a “flash” flood warning system it would be necessary to install several radio

telemetered rain gauges within the upper reaches of the catchment. The technology utilised in

these systems can vary depending on the needs and economies of the situation. Cheaper and

more reliable modern electronics have resulted in a trend towards more automated systems,

such as the ALERT (Automated Local Evaluation in Real Time) system. The Bureau of

Meteorology has specifically adopted the philosophy of event based radio telemetry as embodie d

in the ALERT system. This system would provide a continuous source of information of actual

rainfall events. The gauges would be linked to a base station computer which could be located at

either SES Local Controller headquarters or Council Chambers and would monitor the incoming

rainfall readings. Rainfalls would be converted to predictions of flows and water surface levels in

the streams using the computer models developed in the Flood Study. A gauge would be

required within each catchment area (Pages River above Murrurundi, Warlands Creek above

Blandford and Chilcotts Creek above Willow Tree) to monitor the areal variability of rainfall.

Installation of such a system would be undertaken by BOM at an indicative cost of around

$100,000. Upkeep of the stations would be Council’s responsibility.

Implementation of an ALERT system would not greatly increase the warning time and does not

therefore appear justified. A more cost effective measure may be to maximise the effectiveness

of the present network of local river and rain watchers. The education of these watchers in what

events may constitute a flood event and subsequent procedures for notification of relevant

authorities, namely the SES Local Controller could greatly benefit the community. One system

which has been implemented in other catchments, for example Mullumbimby, is the supply of

plots of rainfall intensity–frequency-duration to rain gauge readers. These plots allow the reader

to interpret rainfall intensities as they occur.

The flood warning system is heavily reliant on telephone contact between SES and gauge

readers. The security of this communication during a major flood should be checked with

Telstra. The possibility of a radio link between river and rain watchers could be consider ed.

The Murrurundi Council area would benefit from a Doppler Radar system which could better track

and predict flood producing rain. At present there are two Doppler Radars in the whole of

Australia with one system centred in Sydney. The range of the Sydney radar extends as far north





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as Newcastle. However, the cost of one of these radars is estimated at around $20 M and the

implementation of a radar that covers the upper reaches of the Hunter and Namoi Rivers is

therefore unlikely in the near future.

D4.2 Flood Response and Communication

During major flood events the depth of flow passing through the three townships is relatively

shallow and the act of sandbagging certain properties may prevent inundation by floodwaters. It

is advised that an adequate store of sandbags be supplied in a location which is readily

accessible to residents and shop owners. Locations of sandbags should be noted on the Flood

Plans and they should be regularly inspected and maintained by SES. A priority list of areas to

be protected should be compiled using information on flooding contained in the Flood Study for

the three townships. When planning the locations of the sandbag stockpiles the following should

be noted:

a) Murrurundi township - due to the nature of major flooding, the CBD area will be severed from

the western side of the Pages River. Stockpiles of sandbags are therefore required on each

side of the Pages River to provide adequate coverage.

b) Blandford township – during major flood events, properties located on the r ight bank of

Warlands Creek experience shallow sheet flow and storage should be concentrated in that

area. There are few flood effects from Pages River.

c) Willow Tree township - flooding is generally of a local drainage nature with the surcharging

of culverts to the east of the railway line. Flooding due to surcharging of Borambil Creek

occurs at the public school, located along Merriwa Road.

Within the townships of Murrurundi and Blandford a number of key emergency organisations are

located within the flood liable area including Fire Stations and the Murrurundi telephone

exchange. It is also to be noted that within the township of Murrurundi, inundation of the New

England Highway in the vicinity of Arnolds Bridge may effect the response ability of certain

authorities. Police, Fire and Council are located on the eastern side of the Pages River while the

SES Local Headquarters are located on the western side. The Murrurundi Flood Plan may need

to address the issue of responsibilities in the absence of SES personnel.

The main improvements to the system could be made to communications between the SES and

the local community both when a flood situation is developing and then during the flood.

The short travel time of the flood peak from the township of Murrurundi to Blandford may require

an agent of the SES to be located within Blandford, say the Fire brigade. This needs to be

formalised within the Flood Plan.

At the townships of Blandford and Willow Tree, the public schools are susceptible to flood flows

surcharging Warlands and Borambil Creeks respectively. The Murrurundi and Quirindi Flood

Plans need to appreciate that children are at risk, and an effective means of flood warning and

evacuation incorporated into the Plan.

One approach which could be considered is an alerting system similar to that adopted in Coffs

Harbour.





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When significant rain has fallen and flooding is possible, the SES Local headquarters will issue

Preliminary Flood Alerts for immediate broadcast by radio and television stations. The following

are also advised:

a. School principals

b. School bus companies

c. President, Coffs Harbour Chamber of Commerce and Industry (when flooding of

the Coffs Harbour Central Business District is possible), for transmission by

telephone to the owners of commercial premises.

The SES needs to consult the local community on their requirements for information and

improved communications and how these requirements can be fulfilled.

The Flood Plan needs to be updated to incorporate information from both the Flood Study and

this Floodplain Management Study and to cross-reference with Council’s Floodplain Management

Plan. Both Plans need to developed in partnership and complement each other.





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D5 SUMMARY

This section has reviewed the existing flood warning and response system.

In the Shire of Murrurundi, the division of responsibility is such that the Murrurundi SES Local

Controller has responsibility for flood management in Murrurundi and Blandford, while the

Quirindi Local Controller covers Willow Tree.

A draft Flood Sub-Plan has been prepared for the area east of the Liverpool Ranges which

defines the nature of the flood threat including flood producing mechanisms, locations of road

closures and areas inundated in Murrurundi and Blandford and sets out procedures undertaken

by the Local Controller with respect to flood warnings and response. A draft Quirindi Local

Disaster Plan has been prepared which covers the headwaters of the Namoi system, including

Willow Tree.

While the general pattern of flooding in the townships has been identified from historic flooding,

the results of the Flood Study along with floor levels of flood affected properties will allow more

precise identification of areas at risk from the full range of flood events likely to trigger flood

response procedures in the three townships. This information should be incorporated in the

Flood Plans. Attention should also be given to covering situations such as experienced on

Warlands Creek in January 1996 where very heavy localised rainfall resulted in a “wall of water”

type floodwave.

BOM currently issue a Flood Alert (previously called Confidential Flood Advice) as an alerting

mechanism for the SES. These advices are of a qualitative nature only. There is no formal flood

prediction system in operation for the three townships. Due to their small size and steepness,

flooding on the catchments is of a “flash flooding” nature with only around 1 -2 hours between the

occurrence of heavy rainfall and the resulting flood peak. Implementation of a flood forecasting

system based on the ALERT system is not likely to be effective for the three townships, although

it may be useful in downstream flood affected locations where the response time of the

catchments is longer.

Some formalisation and expansion of the network of local river and rain watchers, along with

training and strengthening of communications, is considered appropriate to maximise the

available warning time and the effectiveness of the system. Some suggestions are given in

Section 4.1 of this Appendix. Mock trials of the system should also be undertaken to test its

effectiveness in a real flood.

Along the Pages River, the surcharging of the New England Highway may cause difficulties in

respect to emergency response to the townships of Murrurundi and Blandford. It is

recommended that consideration be given to including in the Murrurundi Flood Plan procedures

for issuing a Preliminary Flood Alert and advice to key residents likely to be flood affected

(Section 4.2).

The relatively shallow depth of flooding for events up to and including major flood events means

that sandbagging can be an effective means of preventing inundation by floodwaters to a large

number of properties. The formalisation of sandbag storage areas, namely within the town ships

of Murrurundi and Blandford is recommended. A priority list of areas to be protected should be

compiled using information presented in the Flood Study. Due to the short flood warning time,

the stockpiles of sandbags should be readily accessible to the public to allow them to quickly

respond to any flood warning. An education plan could be implemented to make the public

aware of their locations.





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D6. REFERENCES

Australian Water Resources Council (1992). "Floodplain Management in Australia Volume 2:

Main Report." Water Management Series No. 21.

Carroll D.G. (1993). "Prophet - The Brisbane City Council Creek Flood Monitoring and

Forecasting System." National Local Government Engineering Conference Adelaide.

Emergency Management Australia (1995). "Flood Warning: An Australian Guide."

Ismes Consulting Group (May 1992). "Sydney-Newcastle-Wollongong Flash Flood Warning

System." Report No. PWD92096.

McKay G. (1991). "Flood Forecasting in New South Wales by the Bureau of Meteorology." 31st

Annual Flood Mitigation Conference, Port Macquarie.

NSW State Emergency Service (1994). "draft Quirindi Local Flood Plan.”

NSW State Emergency Service (1996). "draft Murrurundi Flood Sub-Plan.”

Sullivan, P. (1992). "New South Wales Flood Warning Consultative Committee - how it can help

you." 32nd Annual Flood Mitigation Conference, Bankstown.

Wyllie, S.J. and Ribbons, C. (1991). "Real time data acquisition systems developed by Public

Works Department's Manly Hydraulics Laboratory and its application to flood warning." 31st

Annual Flood Mitigation Conference, Port Macquarie.

INPUT INPUT

M eteorologic System Bureau DLWC { River Gauges

Antecedent Precip . o f BOM { Rain Gauges

Index M eteorology SES { Gauge Readers

Conf ident ia l Pre l iminary F lood Warnings

F lood Adv ice Warnings Bul le t ins (SES) and

Pred ict ions

SES SES SES SES MEDIA SES SES

NAT DIV NAT DIV NAT DIV

HQ HQ HQ HQ HQ HQ

SES SES SES

LOCAL LOCAL LOCALMEDIA

PUBLIC PUBLIC

MURRURUNDI, BLANDFORD & WILLOW TREE


Figure D.2

Distribution of Flood Warnings

Job No: NX518 J:\NX518\docs\APPE.doc

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Author: NK Reviewer: BWL


AND WILLOW TREE


APPENDIX E

PLANNING AND LAND USE CONTROLS

Note: The Word version of the document was reformatted in December 2014 which has led to minor differences in its structure when compared to the original report. No hard copy version of this

Appendix was available at the time of compiling. As a result, Figures E.1 and E.2 were reproduced from an AutoCADD file which was assumed to have been used to compile the original report.

Floodplain Management Study Murrurundi, Blandford and Willow Tree Appendix E – Planning and Land Use Controls

J:\nx518\doc\appende.doc 03/06/98 Rev: 3.0

Lyall & Macoun Consulting Engineers

TABLE OF CONTENTS

Page No.

E.1 INTRODUCTION .......................................................................................................... E-1

E.2 EXISTING LAND USE PLANNING CONTROLS ........................................................... E-1

E.3 COMMENTARY ON EXISTING LAND USE PLANNING CONTROLS ........................... E-2

E.4 PLANNING OPTIONS .................................................................................................. E-5

E.4.1Floodplain Management Plan/Development Control Plan ........................................ E-5

E.4.2.Environmental Protection Zone .................................................................................. E-5

E.5 SUMMARY ................................................................................................................... E-6

FIGURES

E.1 Floodplain Zoning Murrurundi Township E.2 Floodplain Zoning Blandford Township


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E.1 INTRODUCTION

Murrurundi Shire Council has resolved to prepare Floodplain Management Plans (FMPs) for the

Murrurundi, Blandford and Willow Tree town areas. As part of the preparation of those FMPs

there is a requirement that the existing planning controls which relate to those areas be reviewed,

and suggestions made regarding the means by which those controls could be amended and/or

supplemented with regard to land which is potentially impacted by flood waters.

This report provides Council with a summary of the land use planning controls which currently

apply to flood liable land in the Shire, and provides a series of options for the consideration of

Council for amendment of the existing controls.

E.2 EXISTING LAND USE PLANNING CONTROLS

Land use within the Murrurundi Shire is generally regulated by the Murrurundi Local

Environmental Plan (LEP), 1993. Advice from Council is that there are no Development Control

Plans accompanying the Local Environmental Plan.

The Murrurundi LEP, 1993 contains some references to the management of development on

flood liable land. Clauses which refer to either flooding or flood liable land are:

Clause 5 (1) - Interpretation

The following definition is contained within Clause 5:

"flood liable land" means the land within the township of Murrurundi or the

village of Blandford or Willow Tree or elsewhere which is affected by flood as

indicated on the map;"

A review of the map indicates that there are no areas within the Shire notated as being flood

liable land.

Clause 6 - Model Provisions

This clause adopts the Environmental Planning and Assessment Model Provisions, 1980 except

for, inter alia, Clause 34 which essentially states that a person shall not erect a building or carry

out work on land within a flood prone area without the consent of Council. This clause is of little

relevance in Murrurundi Shire because, except for agriculture in the rural zones, all development

in the Shire requires the consent of Council. As such, the exclusion of Clause 34 is justified.

Clause 19 - Flood Liable Land

This clause, despite the need for development consent for all development other than agriculture

in any zone within the Shire, provides for the requirement of Clause 34 of the Environmental

Planning and Assessment Model Provisions, 1980 that no development on flood liable (prone)

land shall be undertaken without the consent of Council. Clause 19 states that:



Page E-2


"19 Notwithstanding any other provision of this plan, the Council shall not

grant consent to the carrying out of any development on flood liable land, unless it

has made an assessment of:-

(a) the effect of the proposed development on the flow of flood waters on that

land or land in its immediate vicinity;

(b) the safety of the proposed development in the time of flood;

(c) whether the proposed development involves any risk to life, human safety

or private property in time of flood;

(d) whether the floor level of any dwelling-house or other habitable building

on the land will be at least 500 millimetres above the highest known f lood

in the vicinity; and

(e) whether adequate measures have been or will be taken to offset the likely

effects of flooding on the development."

E.3 COMMENTARY ON EXISTING LAND USE PLANNING CONTROLS

Apart from the above-mentioned areas within the Murrurundi LEP, 1993, there is no control on

development on flood liable land within the Shire of Murrurundi.

The following comments are made in order that Council can consider ways in which it can

strengthen the existing provisions of the Murrurundi LEP, 1993 to account for the effect of

flooding on development within the Murrurundi Shire and indeed the effect of development on the

flood regime.

Part 1 - Preliminary

The Murrurundi LEP, 1993 is an aims and objectives based planning instrument. Clause 2 detai ls

the general aims and objectives of the plan, with the specific objectives of each zone contained in

the Table to Clause 9 of the LEP.

There is no aim or objective of the plan for the control of development on flood liable land. It is

recommended that such an objective be included in Clause 2 of the LEP. A possible objective is:

"2. (1) (c) to reduce the incidence of damages and hazard in areas subject

to flooding by restricting development on flood liable land."

Clause 5 of the LEP defines "flood liable land" as:

"flood liable land" means the land within the township of Murrurundi or the

village of Blandford or Willow Tree or elsewhere which is affected by flood as

indicated on the map;"



Page E-3


As indicated above, the map shows no land within the Shire as being flood liable, and as such the

definition has little value in the control of development within the Shire.

Council commissioned Flood Studies in Murrurundi, Blandford and Willow Tree which were

submitted in draft form by Lyall and Macoun Consulting Engineers (LMCE, 1997). Those studies

have identified areas which are subject to flooding and assessed the flood hazard in accordance

with the NSW Government "Floodplain Development Manual" (PWD, 1986). As such, Council

now has information on the flood regime within those townships to enable it to resolve that certain

sections of each township fall within the definition of "flood liable land".

It is recommended that Council resolve to prepare mapping which delineates the flood liable land.

In doing so, it is also recommended that Council consider an amendment to the definition of flood

liable land contained within the LEP. At present, the definition requires the land classified as

flood liable to be denoted on the map, i.e. the LEP Map.

As Council will appreciate, the map attached to the LEP forms part of the legislation of NSW and

any amendment to that map requires an amendment to the legislation. To effect such a change,

an amending LEP must be prepared, exhibited and then made by the Minister for Urban Affairs

and Planning.

It is apparent that the land which is considered to be flood liable may alter in the light of further

flood experience and refinement of the analysis of flood patterns and hazards. It is

recommended that Council adopt a means of noting flood liable land in graphic format which

allows revision and refinement in future.

It is recommended, rather than have the flood mapping tied to the LEP map, that there be a

separate series of maps held by Council which delineate land which has been determined as

flood liable. Such an approach will allow Council to make reference to those maps in the

definition of flood liable land contained in the LEP, while at the same time allowing Council to

amend its flood mapping without the need for a formal amendment to the LEP. This approach

would also allow Council to prepare additional maps for rural areas of the Shire should Council

consider that flood related planning controls be appropriate for dwellings and certain types of

rural industries (eg. intensive animal housing) In this regard, a suggested amendment to the

definition of flood liable land is:

"flood liable land means land identified by the Council as being liable to flooding

and indicated as flood liable land on a map marked "Flood Liable Land Map".

Part 2 - General Provisions

The Table to Clause 9 of the LEP contains the objectives of each zone in the LEP. None of the

zones within the LEP contain a specific objective for the control of development on flood liable

land.

If Council adopts the Flood Study results as being the basis for the delineation of flood liable

land, and subsequently amends the LEP as indicated above, then it is recommended that Council

also considers an amendment to the objectives of each of the three zones which appl y to the

Shire to provide further re-enforcement of Council's concern for the control of development in the

flood liable areas of the Shire.



Page E-4


A possible objective for inserting into the Table for each zone is:

"To ensure that development of land which is flood liable is carried out in a

manner appropriate to the flood hazard."

Part 3 - Special Provisions

Clause 19 of the LEP contains a standard clause which controls development on flood liable land.

Whilst this clause has merit, it is considered that it can be strengthened to provide greater control

on such development. It is recommended that Council consider an amendment to that clause as

follows:

Flood liable land

19. (1) Notwithstanding any other provision of this plan, the Council shall

not grant consent to the carrying out of development or works for

any purpose on flood liable land without the consent of Council.

(2) The Council shall not grant consent to the carrying out of

development or works for any purpose on land that is flood liable

unless it is satisfied that:

(a) the development or work would not unduly restrict the flow

characteristics of flood waters; and

(b) the development or work would not unduly increase the

level of flooding on land in the vicinity; and

(c) the structural characteristics of any building or work, the

subject of the application, are capable of withstanding

flooding; and

(d) any proposed building is adequately flood proofed.

(3) The Council shall not grant consent required by this clause unless

it has taken into consideration:

(a) the cumulative effect of the development or work on flood

behaviour; and

(b) the risk of pollution to the waterways caused by the

development or work; and

(c) the availability of flood free access to the development or

work.

(4) The Council may require the floor level of habitable rooms of a

building to be erected at a height which is sufficient, in its opinion,

to obviate the frequent flooding of the building or work."



Page E-5


It is considered that the above replacement clause will allow more control over development on

flood liable land while at the same time allowing more flexibility with regard to floor levels of

buildings.

Section 149 Certificates Under the Environmental Planning and Assessment Act, 1979

Advice from Council is that Annexure Item 3 to all s.149 Certificates issued by Council simply

quotes the existing Clause 19 of the LEP. As indicated above, there is no flood liable land

identified on the LEP Map, and as such the s.149 Certificate has little or no effect in this regard.

It is recommended that Council amend the Annexure to the s.149 Certificates in accordance with

the above-recommended amendments to the LEP.

E.4 PLANNING OPTIONS

In addition to the above recommendations for the general controls within the LEP, there are other

means by which Council can further strengthen its planning controls over flood liable land.

E.4.1 Floodplain Management Plan/Development Control Plan

The Floodplain Management Plans being prepared for Council will provide for a set of specific

development and flood protection guidelines which will assist in the control of development on

flood liable land.

It is recommended that a series of graded controls apply to land which is flood liable depending

upon the flood hazard which is identified for a particular parcel of land and the proposed use of

that land. These graded controls could, and should, form the basis of a Development Control

Plan for each township.

Having regard to the limited resources available to Council, it is recommended that the completed

Floodplain Management Plan for each township be adopted by Council as a Development Control

Plan. This will allow Council to have more specific controls on development and indeed provide

for a dynamic approach to development control in flood liable areas.

The adoption of the FMPs as DCPs may require a further amendment to the LEP to provide for

the creation of those DCPs. In this regard, a further proposed objective of the LEP could be:

"2 (1) (d) to provide a basis for development control plans to supplement

the broad controls of this plan with more detailed provisions for

regulating the carrying out of development."

E.4.2. Environmental Protection Zone

The preceding sections of this report have discussed measures which should be implemented by

Council to provide for a more effective LEP as far as the control of development on flood liable

land is concerned.



Page E-6


It is recommended that Council also consider further strengthening controls on land which is

identified in the Flood Study as being “floodway” and/or “high hazard”. This could be achieved by

a further amendment to the LEP 1993 to include a new zone – Environmental 7(f) floodway.

A draft amending LEP is attached for the consideration of Council (Attachment A) . It is

recommended that, as part of the preparation and exhibition of the draft LEP, Council also exhibit

the Floodplain Management Plan (FMP) for each township as a Development Control Plan. The

provisions of this draft LEP should also be incorporated into any other changes contained within

this report which Council considers warranted. The exhibition of that FMP as a DCP will provide

detailed environmental planning controls for both the newly created 7(f) (Environmental

Protection - Floodway) Zone and other flood liable land within the Shire.

Figures E.1 and E.2 are plans of Murrurundi and Blandford respectively, which show the

approximate extent of flooding for the 100 year ARI, the high hazard areas for that flood and

existing land use zoning. The high hazard - floodway areas which are suitable for inclusion in the

7(f) (Environmental Protection-Floodway) Zone have been identified.

It is to be noted that the standard of contour mapping in Blandford and Willow Tree is poor, being

restricted to 1:25000 scale topographic maps with 10 m contours. The flood information shown on

these plans is based on the (limited) number of cross sections of the floodplain which were

surveyed for the Flood Study. There is no reliable connection to Australian Height Datum (AHD)

in the township of Willow Tree and therefore the hydraulic analysis and presentation of results

were undertaken to an arbitrary datum. Connection of the arbitrary datum to AHD and additional

survey to better define the extent of flooding are recommended for the two townships.

In the case of Murrurundi, 1:1000 scale sewer maps with 1 m contour spacing are available which

are considered to provide a reasonable base for presenting flood information, although some

additional work may be required to identify the flood extent.

Final position of the boundaries of the proposed 7(f) zoning will also need to take into account

conditions such as location of existing development, community reaction to the proposal etc.

E.5 SUMMARY

This appendix has identified a number of measures which should be taken to strengthen the flood

related planning controls available to council. In essence these include:

1) Council should resolve to prepare an amendment to the LEP 1993 to:

Add an objective related to control of development on flood liable land (Clause

2(1)(c))

Add a further objective (2(1)(d)) which would allow Council to adopt the Floodplain

Management Plan for each township as a Development Control Plan

Amend the definition of “flood liable land” (Clause 5) to refer to a separate series of

maps which are not tied to the LEP map. This will allow Council to amend such maps

in the light of future flood experience without the need for a formal amendment of the

LEP.



Page E-7


Amend the objectives for three zones to include mention of flooding considerations in

the Table to Clause 9.

Strengthen Clause 19 to provide greater control of development on flood liable land.

2) As part of the preparation and exhibition of the draft LEP, Council should also exhibit the

Floodplain Management Plan for each township as a Development Control Plan.

3) Council should also consider strengthening planning controls on land which is identified

as “floodway” or “high hazard” by further amending the LEP 1993 to include a new zone –

Environmental Protection 7(f) Floodway.

The high hazard-floodway areas in the three townships which could be affected by this

proposal are shown on Figures E1 to E3.

It is to be recognised that all existing, "lawful" development within the proposed 7(f) zone which

would be prohibited by the amending LEP would, upon gazettal of the amending LEP, be "non-

conforming uses" and as such will have "existing use rights" pursuant to the Environmental

Planning and Assessment Act, 1979. It is also to be understood that significant development

"rights" will be removed from vacant land within the newly created 7(f) zone.

It is recommended that Council implement a voluntary purchase scheme for land within the 7(f)

zone as part of the rezoning of that land. Such a scheme will provide for compensation to

landowners.



Page E-9


ATTACHMENT A – DRAFT AMENDMENT

ENVIRONMENTAL PLANNING AND ASSESSMENT ACT 1979

MURRURUNDI LOCAL ENVIRONMENTAL PLAN 1993

(AMENDMENT No.XX)

I, the Minister for Urban Affairs and Planning, in pursuance of section 70 of the Environmental

Planning and Assessment Act 1979, make the local environmental plan set out hereunder. (file

number)

CRAIG KNOWLES MP

Minister for Urban Affairs and Planning

Sydney, xxx

----------------------------

Name of plan

1. This plan is called the Murrurundi Local Environmental Plan 1993 (Amendment

No.xx).

Aims, objectives etc.

2. The aim of this plan is to provide for control of development on flood liable land

identified as floodway.

Land to which the plan applies

3. This plan applies to the land shown edged black on the map marked "Murrurundi

Local Environmental Plan 1993 (Amendment No.xx)" deposited in the office of the

Murrurundi Shire Council.

Relationship to other environmental planning instruments

4. This plan amends Murrurundi Local Environmental Plan 1993 in the manner set

out in Clause 5.

Amendment of Murrurundi Shire Local Environmental Plan 1993

5. Murrurundi Shire Local Environmental Plan 1993 is amended:

(i) by inserting into Clause 5 after the definition of "flood liable land" the

following definitions:

"floodway" means an area that carries a significant discharge of water

during a flood, and even if only partially blocked, would cause significant

redistribution of flow or a significant increase in flood levels .



Page E-10


(ii) by inserting into the definition of "the map" in Clause 5 the following:

Murrurundi Local Environmental Plan 1993 (Amendment No.xx)

(iii) by inserting into Clause 8 the following:

Zone No.7(f) (Environmental Protection - Floodway) - edged black and

lettered "7(f)"

(iv) by inserting into the Table to Clause 9 the following:

Zone No. 7(f) (Environmental Protection - Floodway)

1. Objective of zone

The objective of this zone is to provide for the proper management

of the floodway as identified in accordance with the Floodplain

Development Manual, 1986.

2. Without development consent

Nil.

3. Only with development consent

Agriculture (other than intensive livestock keeping establishments

and which does not involve the clearing of trees); camp and

caravan sites; landscaping; recreation areas; subdivision; utility

installations (other than gas generating works).

4. Prohibited

Any purpose other than a purpose included in item 3.

(v) by inserting at the end of Clause 20 the following:

20A. (1) The Council may vary the boundary between zone 7(f) and

an adjoining zone.

(2) In determining a zone boundary under subclause

(1), the Council shall not determine that zone

boundary until it has had regard to a report

prepared by an appropriately qualified Engineer

which assesses the likely impact of the variation of

the zone boundary on both the flood regime and

flooding of any development which may be

permissible on the land following any variation to

the zone boundary.

(3) In determining a zone boundary under subclause (2), the

Council shall also have regard to clause 19 of this plan.

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