MANLY - Northern Beaches Council...Manly Council Updated March 2004 with addendum to Section 4.1...

Manly CouncilUpdated March 2004 with addendum to Section 4.1

Date of Adoption—19 May 2003

Date of Enforcement—16 June 2003.

MANLYSpecification for

On-site Stormwater Management 2003

CERTIFICATION

The Manly Specification for On-site Stormwater Management 2003

were adopted by Council Resolution on 19 May 2003

and came into force on 16 June 2003.

Henry T Wong

General Manager

IMPORTANT NOTES

Before you turn to the specific

requirements of this specification

please read these notes, the

guidelines, aims and objectives.

1. Applicants should bear in

mind that the requirements

in this specification have

been formulated following

Council’s wish to ensure that

development in the Manly

local government area retains

the essential qualities of the

natural and urban environment

of Manly and to give guidance

that creates compatible

infill development and

redevelopment.

The intention of this

specification is to address

issues of stormwater runoff

from development to:

. protect the environmental

qualities of Manly

. provide protection and

assure improvement

of public and private

amenities for residents and

visitors.

If you have any enquiries

regarding this specification please

contact:

Environmental

Services Division

on 9976 1500

Monday—Friday 8.30am-5pm.

2. All Development Applications

(DA) are assessed under

S79C of the Environmental

Planning and Assessment

Act 1979. This specification

are one of the ‘Matters for

Consideration’ specified

under S79C that is taken into

account by Council prior to

determining the DA.

3. The requirements of this

specification will be considered

prior to the issuing of a

Development Approval and

a Construction Certificate

prescribed under S109C of the

Environmental Planning and

Assessment Act 1979.

4. Applicants should have regard

to the:

. Manly Local Environmental

Plan 1988 (as amended)

(LEP)

. Development Control Plan

(DCP) for the Business

Zone 1989 (as amended)

. DCP for the Residential

Zone 2001 (as amended)

. Building Code of Australia

1993

. Local Government Act

1993

. All relevant Australian

Standards

where relevant when preparing

a DA.

TABLE OF CONTENTS

A. EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

B. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

B1 Adoption date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

B2 Citation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

B3 Land to which these guidelines apply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

B4 Relationship to Manly LEP, other Manly DCP’s and other policies . . . . . . . . . . . . . . . . ii

B5 Aim and objectives of this specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

C. HOW THE MANLY SPECIFICATION FOR ON-SITE STORMWATER MANAGEMENT WORKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C1 Structure of the document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C2 Understanding the specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C3 Obtaining approvals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C3.1 Pre-lodgement consultation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C3.2 The Development Application (DA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

C5 Steps in using this specification: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. STANDARD DRAWINGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3. CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

4. ZONE 1: ON-SITE STORMWATER DETENTION CONTROL . . . . . . . . . . . . . . . 4

4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4.2 Design objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4.3 Critical storm events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4.4 Permissible site discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4.5 Site storage requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.6 What must drain to the detention system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.7 Design parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.8 Hydraulic grade line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.9 Outlet control devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.9.1 Square-edged orifice plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.9.2 Pit and pipe losses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.9.3 Pipe stub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.10 Trash screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.11 Detention storage facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.11.1 Underground storage systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4.11.2 Above ground storage systems in areas other than driveways and carparks . . . 8

4.12 Surface runoff. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.13 Finished levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.14 Disposal of site runoff. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.14.1 Discharge points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.14.2 Gravity drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5. ZONE 2: ON-SITE STORMWATER RETENTION (ABSORPTION) . . . . . . 11

6. ZONE 3: SCOUR AND EROSION CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.2 Soil and water management plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

7. ZONE 4: ON-SITE STORMWATER DETENTION + SCOUR/EROSION CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.2 Design objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.3 Critical storm events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.4 Permissible site discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.5 Site storage requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.6 What must drain to the detention system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.7 Design parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.8 Hydraulic grade line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.9 Outlet control devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7.10 Trash screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.11 Detention storage facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.12 Surface runoff. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.13 Finished levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.14 Disposal of site runoff. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.14.1 Discharge points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.14.2 Gravity drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

8. MECHANICAL PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

9. CHARGED SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

10. LEGAL OBLIGATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

11. SUBMISSION OF DESIGN DETAILS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

11.1 Construction Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

11.2 Final Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

i

APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

A1: DRAINAGE POLICIES D100 DRAINAGE EASEMENTS—GENERAL + S190 STORMWATER CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

D100 Drainage easements—general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

S190 Stormwater control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A2: MECHANICAL PUMP SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

A3: ON-SITE STORMWATER RETENTION (ABSORPTION) SYSTEMS . . . . 28

A3.1 ‘Simple’ absorption system design - high/medium permeability soils . . . . . . . . . . . . . 29

A3.1.1 ‘Leaky’ well with clean water inflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

A3.1.2 Trench, part-occupied with impervious material or combinations of materials (gravel, slotted pipes, ‘milk crate’ cells, Everglas units with gravel backfill, etc) with clean water inflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

A3.2 Measurement of hydraulic conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

A4: CHARGED SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

A5: STACKED RAINFALL PATTERNS FOR USE IN THE ILSAX MODEL. . . 39

A6: ORIFICE SIZED ACCORDING TO DEPTH AND PSD . . . . . . . . . . . . . . . . . . . . . . . . . 40

A7: GRAPHS OF PSD AND SSR FOR THE RELEVANT RESIDENTIAL ZONES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

A7.1 Derivation of graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

A7.2 Use of graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

A8: TERMS OF RESTRICTION ON THE USE OF LAND AND POSITIVE COVENANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

A8.1 Existing allotments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

A8.1.1 Terms of restriction on the use of land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

A8.1.2 Terms of positive covenant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

A9.1 Terms of restriction on the use of land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

A9: LAND SUBDIVISION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

A9.2 Terms of positive covenant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

A10: DRAWINGS + MAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Drawing No. 1: Connection to kerb detail, location of foundations near easements detail

Drawing No. 2: On-site stormwater detention tank detail, trash screen detail

Drawing No. 3: Control pit in above ground on-site stormwater detention (OSD) detail, orifice detail

Drawing No. 4: On-site absorption trench detail for site areas with less than 35% impervious

Map B: Residential density sub-zones

Map D: Stormwater control zones

i

A. EXECUTIVE SUMMARY

This Manly Specification

for On-site Stormwater

Management 2003 encourages

applicants to consider the

management of on-site

stormwater runoff during the

design stage of development.

This specification reflects

Council’s concern for the need

to protect the environment from

the impact of developments to

ensure that stormwater pollution

and degradation does not occur.

In this regard, various methods

of stormwater controls are

described and the method of

application or design guidelines

provided.

The requirements described

in this specification apply to all

developments in the Manly local

government area.

ii iii

B. GENERAL INFORMATION

B1 Adoption dateThe Specification for On-site

Stormwater Management

2003, was adopted by Manly

Council on 19 May 2003 and

came into operation by public

notification on 16 June 2003.

B2 CitationThis document may be cited as

Manly Specification for On-

site Stormwater Management

2003.

B3 Land to which these guidelines apply

This specification applies to

all land within the Manly local

government area as described

in Manly Council’s DCP for

the Business Zone 1989 (as

amended) and DCP for the

Residential Zone 2001 and as

shown in Map 1.

B4 Relationship to Manly LEP, other Manly DCP’s and other policies

The Specification for On-site

Stormwater Management 2003

supplement Manly Council’s

DCP for the Business Zone 1989

(as amended) and DCP for the

Residential Zone 2001.

This specification should be read in

conjunction with the following DCP’s

and/or policies:

. Manly Local Environmental

Plan 1988 (as amended)

(LEP)

. DCP for the Residential Zone

2001

. DCP for the Business Zone

1989 (as amended)

. Specification for Stormwater

Drainage 2003

. Specification for Civil Infrastructure Works, Developments & Subdivisions 2003.

B5 Aim and objectives of this specification

The aim of this specification is to

provide:

• more specific, detailed design guidelines for development within the Manly local government area.

The objectives are to:

. provide uniform guidelines

for the control of discharge

of stormwater from

properties

. ensure that stormwater

drainage pollution and

degradation does not

occur as a result of any

development.

ii iii

C. HOW THE MANLY SPECIFICATION FOR ON-SITE STORMWATER MANAGEMENT WORKS

C2 Understanding the specification

This document is divided into the

following sections:

. 1. General provides a

general background and

objectives

. 2. Standard drawings

provides reference

to specific drawings

applicable to this document

. 3. Controls describes the

types of controls available

for the management of

stormwater runoff

. 4, 5, 6 & 7: describes in

more detail each type of

control available

. 8 & 9: describes alternative

methods of stormwater

management available in

special cases

. 10: describes the legal

obligations of property

owners where the control

systems are to be installed

. 11: provides details of the

information required for

submission to Council.

C3 Obtaining approvals

C3.1 Pre-lodgement consultation

Applicants are strongly advised

to make an appointment with

a Council Assessment Officer

before detailed plans for the

proposal are commenced. This

will help identify important issues

at an early stage.

A number of Fact Sheets are

available from Council free of

charge. They define the various

categories of development and

help an applicant through the

various Council policies that may

need to be addressed during the

design and construction phases

of any development.

C3.2 The Development Application (DA)

Council’s DA package is available from:

. Customer Service Centre

1 Belgrave St., Manly OR

. www.manly.nsw.gov.au

It contains information and

checklists required for an

application to be accepted,

processed and resolved by

Council.

C1 Structure of the document

This specification present general

guidelines which apply to all

development within the Manly

local government area.

The method of stormwater

management shall depend on the

location of the site. There are four

main types of controls available

and these are designated into

zones 1, 2, 3 or 4.

The site shall fall within one of

these zones which is read from

Map D in appendix 10.

The various types of controls

are described in Section 3 and

the application of each zone is

described in sections 4 to 7.

Apart from these zones, other

methods of stormwater control

can be used where applicable.

These are outlined in sections 8

and 9.

Design criteria, graphs, charts

and maps are given in the

appendix.

iv 1 Manly Specification for On-site Stormwater Management 2003

C5 Steps in using this specification:

Step 1

Read section 1. General.

Step 2

Read section 3. Controls.

Identify where the site is

located in reference to Map D

in appendix 10 to establish the

type of control applicable.

Step 3

Read either section 4, 5, 6, 7, 8

or 9 & the relevant appendix

to design an appropriate

system for the site.

These sections detail general

design guidelines against

which all applications must be

assessed.

iv 1 Manly Specification for On-site Stormwater Management 2003

1. GENERAL

This specification compliments

Council’s Stormwater Policy.

It has been prepared to provide

uniform guidelines for the control

and discharge of stormwater from

properties.

To ensure that stormwater

drainage pollution and

degradation does not occur as

a result of any development,

the following controls are to be

implemented:

. the provision of on-site

stormwater detention

facilities to control the rate

of stormwater runoff

. the provision of on-site

absorption systems to

reduce stormwater loading

on the receiving drainage

system

. the installation of water

quality control devices

such as trash screens,

gross pollutant traps, water

quality ponds and the like

to protect the quality of

receiving waters

. the installation of appropriate scour and erosion control devices to

attenuate flows.

Implementation of any of the

above practices is complimentary

to the operation of the natural

water cycle.

2Manly Council—June 2003

3 Manly Specification for On-site Stormwater Management 2003

2. STANDARD DRAWINGS

The following standard drawings

are relevant to this document:

. drawing no. 1: connection

to kerb detail, location

of foundations near

easements detail

. drawing no. 2: on-site

stormwater detention tank

detail, trash screen detail.

. drawing no. 3: control pit

in above ground on-site


(OSD) detail, orifice detail.

. drawing no. 4: on-site absorption trench detail for site areas with less than 35% impervious.

See appendix 10 for drawings.



3. CONTROLS

The method of stormwater control

to be applied shall depend on

the location of the site. The

stormwater control requirements

for each zone are given in the

appendices. In general the main

types of controls available (source

and discharge controls) are:

. zone 1: on-site stormwater

detention control

. zone 2: on-site stormwater

retention (absorption)

. zone 3: scour and erosion

control

. zone 4: combination of on-

site stormwater detention

and scour/erosion control

. all zones: restricted

application–mechanical

pump-out and charged

systems.



4. ZONE 1: ON-SITE STORMWATER DETENTION CONTROL

4.1 General Sites within Zone 1 shall require

the installation of On-site

Stormwater Detention (OSD)

facilities to control the rate of

runoff from the site, as a result

of development, such that the

runoff after development shall be

less than the runoff prior to the

development. Runoff from the

developed site shall be reduced

to a quantity with an impervious

portion of 35% or less.

Within Zone 1, an OSD system

shall be required for all proposed

developments, re-developments

or new land subdivisions

(‘greenfields’ subdivisions

where the condition of the site is

currently ‘state of nature’), except

where:

. the development is a

one-off extension or an

addition, involving an

increase in impervious

area, which is less than

50m2 and the total existing

impervious areas of the

site does not exceed 35%

. the developed site will

have a total impervious

percentage or area, of no

more than 35% or 250m2,

whichever is the lessor,

unless it is a new allotment

created from a ‘greenfields’

subdivision — in this

case, an OSD system

shall be required for any

development on these

allotments

‘Greenfields’ subdivisions

shall include those

allotments in Boronia Lane

North, Boronia Lane South,

Boronia Lane West and

Castle Circuit, Seaforth

recently released by The

Department of Planning,

Infrastructure and Natural

Resources (DPINR)

. the applicant can

demonstrate, to Council’s

satisfaction, that the site

is currently within a flood-

affected zone, and that the

application* of an OSD

system at the subject site

would be of no benefit

in reducing the adverse

flooding impacts

. an alternative method

of stormwater disposal,

such as an absorption

system, is used—however

the design of the on-site

absorption system must be

supported by soil data and

appropriate calculations.

(refer to appendix 3 for

guidelines).

* Note: Council may require as an alternative method of stormwater disposal, such as source control (e.g. on-site absorption) or source control used in

combination.

4.2 Design objectiveThe design objective is to

ensure that the peak flowrate

immediately downstream

of the site in development

is not increased due to the

development. This is achieved

by providing adequate storage to

compensate. All storm events up

to and including the 100-year ARI

post-development shall be limited

to the Permissible Site Discharge

(PSD).

4.3 Critical storm events

The critical storm events, which

must be considered, shall be the

5-year and 100-year Average

Recurrence Intervals (ARI).

4.4 Permissible site discharge

Runoff from the site shall be

limited to the Permissible Site

Discharge (PSD).

The PSD shall be calculated as

the peak 5-year ARI storm event

for the pre-development site

based on the following impervious

percentages:

. 0%—applies to all

‘greenfields’ developments

Greenfields developments

shall include the newly

created allotments in

Boronia Lane North,

Boronia Lane South,

Boronia Lane West and

Castle Circuit, Seaforth,



recently released by The

Department of Planning,

Infrastructure and Natural

Resources (DPINR)

. 35% or 250m2 (whichever

is the lessor)—if the total

existing site impervious

area exceeds either of

these

. X%—if the total existing site impervious area is less than 35% and where X is the percentage of the actual impervious area but less than 250m2.

The maximum discharge into

the kerb and gutter is 25l/s. This

shall be the PSD if the total site’s

runoff is to be discharged at the

kerb*.

* Note: No more than two outlets at a distance of 15m apart shall be permitted to discharge at any kerb along any one property frontage.

The maximum discharge velocity

to the kerb shall be restricted to

2.0m/s.

The PSD shall be calculated

using one of the following

methods:

. design graphs for the

relevant residential zone

given in appendix 7

. the Rational Method,

in accordance with the

Australian Rainfall and

Runoff, Volume 1, 1987 or

later editions, or

. the ILSAX program for

urban stormwater drainage

design and analysis,

Version 2.13, April 1993 or

later, or

. the DRAINS program for

urban stormwater system


Version 2001.1 by Geoffrey

O’ Loughlin and Bob Stack,

April 2001 or later.

The rainfall intensities to be used

in the Manly Council area are

given in appendix 5.

4.5 Site storage requirement

The minimum Site Storage

Requirement (SSR) or the basic

volume shall be the volume

needed to reduce the runoff from

the peak 100-year ARI storm

event for the developed site back

to the PSD or maximum discharge.

The SSR can be determined using

one of the following methods:



given in appendix 7

. ILSAX program—

hydrograph model

. DRAINS program—

hydrograph model.

Computation methods based on

approximate triangular method

or the Rational method is not

acceptable.

4.6 What must drain to the detention system

Wherever possible, the total site

runoff shall be controlled through

the OSD facility.

If not possible, some of the

pervious surfaces (grassed or

vegetated areas) may be allowed

to bypass the system.

Stormwater runoff from all new

and existing impervious areas

must be routed through the OSD

system. If this is not achievable,

a maximum 30m2 of impervious

area may be permitted to bypass

the system.

The total area allowed to bypass

the OSD system, which includes

pervious and impervious areas,

must not be greater than 20% of

the total site area. Council may

vary this requirement where site

topography prohibits reasonable

construction.

The total flows exiting the site

must be taken into consideration.

The total of the runoff bypassing

the OSD system and the flows

controlled through the OSD

system must be no greater than

the PSD or maximum discharge.

4.7 Design parameters

The following design parameters

are to be used, where applicable,

in the model analysis:

. soil type = 2.5

. antecedent moisture

content, AMC = 3

. infiltration rates:

initial paved = 1mm

grassed = 5mm

. storms, generated in

accordance with the



later editions

. time of concentration,

calculated using the

kinematic wave equation

given in the Australian



Rainfall and Runoff,

Volume 1, 1987, page 300,

or program generated.

For the purpose of

determining the time of

concentration:

- the length of flow, L, is

the distance from the

furthest point of the site

to the exit point

- The surface roughness,

n* is as given in the


Runoff, Volume 1, 1987,

page 300

- the slope is the average

gradient of the flowpath

. type ‘0’ inlets are not to be

used. supplementary areas are

not to be used

. orifice size and discharge

from the OSD system are

given in appendix 6 or can

be estimated using the

following equation:

Q = C.A.√(2.g.h

Where:

A = area of orifice outlet in m2

h = depth of water above

centreline of orifice

outlet in metres

C = discharge coefficient =

0.6**

g = acceleration due to gravity

= 9.81m/s2

Q = discharge rate in m3/s or

103l/s

* Note 1: The soil type in the

Manly local government

area is diverse. Where the

designer considers that

the site’s soil landscape

is significantly different to

the values as given above,

they may be varied upon

submission of appropriate

supporting information.

For more detailed soil

landscape information,

reference is made to Manly

Council’s State of the

Environment Report 1999

–2000, Section 1.3.1.3

Soil Landscapes.

** Note 2: This value is for

a flat plate with a circular

shaped square edge orifice

hole. ‘C’ varies between

0.5 to 1.0 depending on

the type of outlet control

to be used. A pipe stub

of approximately 100mm

long, may be permitted

for diameters greater

than 90mm. Smaller

diameter pipe stubs are

not acceptable due to

the possibility of frequent

choking and blockages.

Please note that the

accuracy of the controlled

outflow may not be

achieved when a pipe stub

is to be used instead of an

orifice plate.

4.8 Hydraulic grade line

When the OSD system is to

be connected directly into the

receiving drainage system, the

discharge rate may be affected by

the downstream water level.

Friction and head losses in pipes

and pits may affect the discharge

control, especially when the

invert level of the OSD outlet

is considerably lower than the

ground level at the connection

point. In this circumstance

hydraulic grade line calculations

must be performed to check that

the tailwater level will not affect

the rate of discharge from the

OSD system.

Outlet control or a ‘drowned

orifice’ is generally unacceptable

due to inaccuracies (too many

variables introduced) into the

model, which may inadvertently

cause discharge into the

receiving drainage system which

is greater than the PSD.

The peak flowrate in the

receiving drainage system can

be calculated using the ILSAX

or DRAINS program. Hydraulic

calculations can be performed

manually, or for more complex

models such as for determining

water surface profiles in creeks or

rivers, the HEC-RAS program can

be used.

Manual calculations are to

be carried out in accordance

with current design practices

and principals as outlined in

the Australian Rainfall and

Runoff, volume 1,1987 or later

editions and this specification

and submitted by a suitably

qualified person with experience

in hydrology and hydraulics.

4.9 Outlet control devices

Various outlet control devices

may be used to control the rate of

discharge from the OSD system.

These are specified below.



4.9.1 Square-edged orifice plate

A flat stainless steel plate, 3mm

in thickness and approximately

200mm x 200mm minimum

dimension (dependent on the

outlet size) is fixed onto an

oversized pipe outlet. The circular

shaped orifice of specified

diameter is pre-drilled centrally

into the plate. This hole is tooled

to the exact calculated dimension

to obtain the required outflow rate.

The plate is to be permanently

fixed into the wall of the control pit

with four (4) ‘dyna’ bolts to prevent

its unauthorised removal.

The advantage of using an orifice

plate is it provides the designer

greater flexibility and accuracy in

controlling the rate of outflow.

The orifice equation to be used is:

Q = C.A.√(2.g.h)

For a square-edged orifice,

C = 0.6

The above equation can be re-

arranged to obtain the required

diameter for the maximum

discharge.

For a circular shaped orifice, the

diameter:

D = √(4.A/π)

Where

A = area of orifice hole in m2

π = 3.1416

4.9.2 Pit and pipe losses

The outlet control is determined

by calculating the friction and

entry losses in the outlet pipe

and pit leading from the OSD

facility to the point of connection,

to control the discharge rate. This

method would require hydraulic

grade line calculations for various

storm events and duration.

Manual calculations are to be

carried out in accordance with

current design practices and

principals as outlined in the

Australian Rainfall and Runoff,

volume 1, 1987 or later editions.

4.9.3 Pipe stub

This type of control is not

recommended because the

diameter of the nominal pipe stub

is not as accurate as an orifice

plate, which can be machined

to the exacting dimension. A

short stub of nominal length

approximately 100mm long can

be used to control the rate of

discharge from the OSD facility.

The orifice equation can be used

to determine the outflow rate.

For a pipe stub orifice, C = 0.8

The advantage of a pipe stub

is that it is a permanent fixture

that is not easily tampered with.

However it is not acceptable for

diameters less than 90mm, as

they tend to create a choke which

is difficult to clean.

4.10Trash screensA rustproof screen or cage is to

be used to protect the outlet from

potential blockages.

This screen or cage must be

removable for maintenance and

inspections.

The screen or cage should

completely protect the outlet and

be made of Lysaghts maxi-mesh

RH3030 or similar material. The

minimum surface area of the

screen is to be 50 times the area

of the orifice outlet.

The screen or cage is to be

located at a distance 1.5 times

the orifice diameter or 200mm

away, whichever is the greater.

Where possible, the main

incoming line is to flow across

the face of the mesh.

The screen or cage should also

include a lifting handle for ease

of removal for inspection and

maintenance.

4.11Detention storage facilities

Detention storage facilities can

be provided in three main areas.

These being:

. underground storage—in

tanks or oversized pipes, or

. above ground storage—as

a shallow pond or on

driveways and carparks, or

. a combination of the two (2) above.

Above ground storage is

preferable where it can be

provided with minimal adjustment

to existing levels and where

they do not create hazards to

pedestrians and vehicular traffic.

For this reason, ponding depths

must be kept to a minimum.

Allowable ponding depths are

given below.

Storage facilities shall be

designed and located to safely

convey all stormwater flows to the

Council road gutter or drainage

system. Otherwise, the storage

facility is to be moved to a more

suitable location.



However, where likely overflow

from these facilities is across

private property and a suitable

overflow path cannot be provided,

the overflow shall be contained

within an underground piped

drainage system with a design

capacity equivalent to the peak

100-year ARI storm event.

This underground system (both

pits and pipes) shall be designed

to receive and fully contain

controlled flows and overflows

from the detention facility.

A surcharge path shall also be

defined even where the 100-year

ARI flows can be maintained

within the system in case of

blockages. Easements are to

be provided in private property

over pipe systems and surcharge

paths.

OSD systems must be located

external to all building footprints.

This includes basements, ground

floor parking areas, garages,

or patios unless all access

points and emergency overflow

provisions are external to the

structure.

4.11.1 Underground storage systems

. are not to be used where

suitable above ground

storage facility is available

. are to be designed to

be structurally sound to

adequately withstand all

service loads

. must be adequately

soundproofed to minimise

noise when stormwater is

collected or discharged

. must be graded to drain

completely—permanent

water pondage encourages

insect infestation and is not

acceptable

. are to be located where

they can be readily

accessible for inspections

and routine cleaning—for

SEPP5 developments,

the OSD facility shall

be located in common

areas and not in private

courtyards—for strata

subdivisions, the location

is subject to Council

assessment but the intent

is to ensure that the

facility is located where

it is easily accessible for

routine inspections and

maintenance requirements

. must be constructed

from reinforced concrete,

pre-fabricated material

or proprietary systems

approved by Council

. must have at least one (1)

inspection access grate

over the outlet — this

inspection access must

be a minimum 600mm x

600mm in dimension

. must be in accordance with

AS2865 – Safe Working

in a Confined Space — to

eliminate gas build-up and

for ease of maintenance

at least one (1) additional

access at the extreme

corner of the tank must be

provided

. must have additional

access points at distances

of no less than 3000mm

. clearance height in the

tank must not be less than

500mm

. must have step irons where

the tank depth exceeds

1200mm

. must be located outside

the root zones of trees that

are to be retained

. must be located in areas,

which will not impede the

flow of water or undermine

existing structures or

services.

4.11.2 Above ground storage systems in areas other than driveways and carparks

. must not be located

across the boundary of an

allotment

. must not be located such

as to restrict pedestrian

access from the public

road to the building

. must be adequately

soundproofed to minimise

noise when stormwater is

collected or discharged

. are to be located where

they can be readily

accessible for inspections

and routine cleaning—

for SEPP5 developments,

the OSD facility shall

be located in common

areas and not in private

courtyards—

for strata subdivisions,

the location is subject to

Council assessment but

the intent is to ensure

that the facility is located

in an area, which is

easily accessible for



routine inspections and

maintenance requirements

. if a built structure is to be

used to retain water, it

shall be of masonry type

construction

. control structures must be

located where they can

be easily accessed for

inspections and routine

cleaning.

§ must be graded to drain

completely—gradients

shall not be less than 1.0%

. to avoid ground saturation

in landscaped areas,

subsoil drains shall be

installed

. shall be designed

in a manner, which

minimises inconvenience,

unsightliness and hazard

. must not allow water to

pond more than 300mm

in tennis courts or other

surfaced areas

. must not allow water to

pond more than 300mm in

landscaped areas unless

access by persons can be

restricted

. must not have batter

slopes greater than 1 in 4

. where the depth of

ponding exceed 300mm

in landscaped areas, it

must be fully fenced off

with approved pool fencing

and childproof, self-closing

gates with batter slopes

into the basin, around its

perimeter, not to exceed

1 in 6

. the maximum depth of ponding in landscaped areas must not exceed 1200mm.

4.11.3 Above ground storage systems on paved driveways and carparks

• must not be located such

as to restrict pedestrian

access from the public

road to the building

• control structures must be

located where they can

be easily accessed for

inspections and routine

cleaning

. must be graded to drain

completely—gradients

shall not be less than 0.5%

. designed in a manner,

which minimises

inconvenience,

unsightliness and hazard

. must be totally

impermeable

. must not allow water to pond more than 200mm in depth.

4.12Surface runoffStormwater runoff from the site or

from upstream properties passing

through the site is not permitted

to be concentrated, increased,

re-directed or otherwise onto

any property. This may require

diverting existing surface flows

safely to the street or into the

OSD facility.

Where this runoff is to be

controlled through the OSD

facility, the OSD system must

be designed to cater for the

additional inflow.

Provision must also be made for

emergency overflows out of the

OSD facility. Overflow weirs or

spillways must be provided for

unexpected blockages or flows in

excess of the design storm. Likely

overflow from these facilities

must be fully contained within

designated flow paths. These flow

paths shall be designed for the

peak 100-year ARI storm event.

The use of open channels, kerbs,

pits and pipes may be used to

contain runoff within the flow path.

The width of overflow weirs shall

not exceed more than 2000mm

across any property frontage.

4.13Finished levelsIt is most important to ensure that

adequate freeboard or clearance

between the maximum depth of

ponding in the OSD system and

the levels of all habitable floor

areas, garages, storage facilities,

etc., are provided so that damage

to goods and materials, nuisance

flooding, or hazard is avoided.

Developments will not be

permitted within known floodways

unless it can be proven that

the development will not be

affected by floodwater nor will the

development cause flooding both

upstream or downstream of the

development. Council’s Policy is

the removal of such flood affected

developments from known

floodways and the prohibition

of future developments in such

floodways, where necessary.

For OSD facilities and overflow

paths, the following freeboard

requirements will be required:



• 150mm—warehouse,

factory and carport floor

areas

• 300mm—office, living rooms, retail space, store rooms, and show rooms.

Flood waters (100-year flood

level):

• 300mm—to enclosed

garages and carparks

• 500mm—to all internal building floor levels which includes residential, commercial and retail.

4.14Disposal of site runoff

4.14.1 Discharge points

The maximum concentrated

stormwater discharge to a formed

kerb and gutter shall be limited

to 25l/s at any single point. A

maximum of two (2) outlet points

from the site shall be permitted,

provided the outlets are spaced

no less than 15m apart.

Outlets to the kerb must be sized

adequately with at least 50mm

cover. Where cover is inadequate,

the following pipe equivalencies

shall be used:

. 100mm-dia equivalent to

one (1) 100mm x 100mm x

6mm thick RHS. 150mm-dia equivalent to

one (1) 200mm x 100mm x

6mm thick RHS. 225mm-dia equivalent to

two (2) 200mm x 100mm x

6mm thick RHS

. outlets through existing

sandstone kerbing—drilling through sandstone kerbing may be permitted but should seek advice from Council’s Heritage Officer.

The pipe class must also be

adequate to withstand traffic

loads.

All RHS are to be hot-dipped

galvanised or stainless steel

material.

Discharging into a watercourse or

channel may be permitted subject

to joint approval from Council and

other relevant authority. Where

approval is granted, adequate

protection against scouring and

erosion at the point of discharge

shall be provided. Council should

be consulted in regards to

appropriate stabilisation treatment

to be used.


into an unlined (other than

concrete) channel shall be in

accordance with the Department

of Sustainable Natural

Resources document ‘Managing

Urban Stormwater, Soils and

Construction’, table 5.1 maximum

discharge flow velocities in

waterways.

Discharge from the site is to be

taken to the nearest Council

drainage system, where the

quantity exceeds 25l/s or into an

approved piped drainage system

or stormwater channel if this

cannot be achieved.

Where an existing Council

drainage line is available,

connection into the system may

be permitted subject to Council

approval. The connection may

require the construction of new

inlet pits and the laying of a new

pipeline, to Council standards.

Council encourages minimising

the number of pits, junctions and

pipe lengths in the road reserve.

However pits are preferable

over bend joins to eliminate

blind junctions such that ease of

maintenance can be achieved.

Reference should be made to

Council’s Specification for Stormwater Drainage for details

of pipe and pit design.

4.14.2 Gravity drainage

Stormwater drainage should

follow the natural fall of the land

and be discharged by a gravity

system. Diverting stormwater

runoff from one catchment

(or sub-catchment) to another

catchment (or sub-catchment)

is generally not permitted.

Council will only approve

drainage against the natural

grade of the land in the following

circumstances:

. downstream property

owners have indicated

that they are not prepared

to grant easements to

permit the drainage of

the property to follow the

natural fall of the land, and. Council has assessed that

the proposed receiving

drainage system can

adequately cope with the

additional runoff.



5. ZONE 2: ON-SITE STORMWATER RETENTION (absorption)

On-site stormwater retention

(absorption) systems are to

be implemented in zone 2.

Absorption systems shall be

provided in soft landscape areas,

such as in garden areas, and

other vegetated on-ground areas.

Where ever possible, on-site

absorption is to be provided in

hard landscaped areas, under

driveways and other paved

surfaces. The use of porous

pavement (pervious paving) is

preferred.

Stormwater collected on the roof

and paved areas (all impervious

surfaces) are to be directed into

the absorption system. A fail safe

overflow outlet must be installed

to ensure that any overflows will

be directed to the street.

In general, absorption systems

will be required or permitted if the

following applies:

. the site is located within

zone 2 where on-site

absorption is permitted,

and

. a geotech report, showing

at least one (1) bore log

at the proposed location

of the absorption facility,

has been submitted which

indicates that the soil

has sufficient absorptive

characteristics to consider

it appropriate, or

. irrespective of whether the

site is located within zone

2, the site drains towards

the rear, and downstream

property owners have

indicated that they are

not prepared to grant

easements to permit the

drainage of the property to

follow the natural fall of the

land, and

. drainage against the

natural grade of the land

is not permitted because

Council has assessed that

the proposed receiving

drainage system cannot

adequately cope with the

additional runoff, and

• a geotech report, showing

at least one (1) bore log

at the proposed location

of the absorption facility,

has been submitted which

indicates that the soil

has sufficient absorptive

characteristics to consider

it appropriate for the site.

All sites within zone 2 must

provide for on-site absorption

unless the applicant can

demonstrate that on-site

absorption is not suitable by

the submission of relevant

evidence from a qualified geotech

engineer indicating that the soil

absorption characteristics and

site constraints prevents its

application.

Minimum design requirements for

the use of absorption systems are




6. ZONE 3: SCOUR AND EROSION CONTROL

6.1 GeneralProperties within zone 3 are

required to control its runoff to

protect adjoining properties, bush

land, roadways and receiving

waters from degradation due to

silt laden stormwater runoff as a

result of any development and/or

concentration of runoff using

appropriate scour and erosion

control devices. Reference is

made to Council’s Specification

for Stormwater Drainage.

Erosion control shall be provided

as follows:

. appropriate scour

protection devices installed

at the outlet to stormwater

conduits, and

. installation of pollution control devices at the source, on-line*, off-line or at the end of the line to control sediment laden overland stormwater flows.

* Note: stormwater management measures shall not be located on-line in water courses or within riparian zones or areas of remnant native vegetation.

Scour protection devices shall

include embankment stabilisation

e.g. rock walls, concrete aprons,

gabions, turfing, jute mesh,

energy dissipating units, or other

more appropriate erosion control

devices approved by Council.

Preference is for ‘soft engineering’

solutions.

Please note that stormwater

devices are not appropriate within

or adjacent to creek locations.

In this regard, The Department

of Infrastructure, Planning and

Natural Resources (DIPNR) and

NSW Fisheries shall be contacted

for advice about suitable erosion

control measures here.

Control devices may also

be necessary as part of a

development to remove pollutants

during the ‘first flush’. These

devices shall be installed

within the site and may include

proprietary items such as

Humeceptors or CDS units, silt

and grease arrestors approved

by Council. Installation of these

devices shall be in accordance

with the manufacturers

specification.

Other sediment control

devices such as stilling basins,

constructed wetlands shall

be required for large-scale

developments. Council will

provide guidelines as to when

these are required as part of

the Conditions of Consent.

These shall include land and

community title subdivisions.

Design of these devices shall be

in accordance with the Managing

Urban Stormwater, Soils and

Construction Manual by the

NSW Department of Housing,

August 1998.

It will also be necessary to install

silt traps in all stormwater pits to

contain silt and debris. Silt traps

shall be installed at the bottom

of pits at a depth of 200mm to

capture silts and fines. Weep

holes shall be drilled into the

base of the pit to ensure that it

does not permanently hold water

and create a breeding ground for

insects. Where the pit is located

over impervious material, subsoil

drains will also need to be laid.

6.2 Soil and water management plan

Any development in zone 3

and zone 4 shall require the

submission of a soil and water

management plan. This Plan must

be approved by Council prior to

the commencement of any works.

Sediment control measures must

be taken into consideration during

any development. Specification

shall be in accordance with the

Managing Urban Stormwater,

Soils and Construction Manual

by the NSW Department of

Housing, August 1998.

All sediment control devices

are to be installed prior to any

commencement of clearing and

earthworks on the site. Ongoing

maintenance of these devices

during construction will be

required.

Council may request a

maintenance schedule to ensure

that the devices are cleaned on a

regular basis.



7. ZONE 4: ON-SITE STORMWATER DETENTION + SCOUR/EROSION CONTROL

7.1 General A combination of on-site

stormwater detention and scour/

erosion control shall be required

for all sites within zone 4. Sites in

this zone are within the Penguin

Critical Habitat and Potential

Habitat areas and encompasses

Manly Point and Little Manly

Cove.

On-site Stormwater Detention

(OSD) shall be required to control

all runoff from the site, as a result

of any development. Runoff

from the developed site shall be

reduced to a quantity with an

impervious portion of 0%, that is,

the ‘state of nature’ condition.

Outflow shall be attenuated by

the use of appropriate scour and

erosion devices as outlined for

zone 3 in section 6.

7.2 Design objectiveThe design objective is to

ensure that the peak flowrate

immediately downstream of the

site in development is reduced

to runoff for a pre-development

‘state of nature’ situation. This is

achieved by providing adequate

storage to compensate. All storm

events up to and including the

100-year ARI post-development

shall be limited to the Permissible

Site Discharge (PSD).

7.3 Critical storm events

The critical storm events, which

must be considered, shall be the

5-year and 100-year Average

Recurrence Intervals (ARI).

7.4 Permissible site discharge

Runoff from the site shall be

limited to the Permissible Site

Discharge (PSD).

The PSD shall be calculated as

the peak 5-year ARI storm event

for the pre-development site

based on the following impervious

percentages:

. 0%—applies to all developments within Zone 4.

The maximum discharge shall be

25l/s. This shall be the PSD if the

calculated pre-development runoff

is greater than 25l/s.


to the kerb shall be limited to

2.0m/s.

The PSD shall be calculated using

one of the following methods:



given in the appendix 7

based on 0% impervious

area

. the Rational Method,




later editions, or

. the ILSAX program for

urban stormwater drainage


Version 2.13, April 1993 or

later, or

. the DRAINS program for

urban stormwater system


Version 2001.1 by Geoffrey

O’ Loughlin and Bob Stack,

April 2001 or later.

The rainfall intensities to be used

in the Manly Council area are


7.5 Site storage requirement

Refer to section 4.5.

7.6 What must drain to the detention system


7.7 Design parameters


7.8 Hydraulic grade line


7.9 Outlet control devices




7.10Trash screensRefer to section 4.10.

7.11Detention storage facilities


7.12Surface runoffRefer to section 4.12.

7.13Finished levelsRefer to section 4.13.

7.14Disposal of site runoff

7.14.1 Discharge points

The maximum concentrated

stormwater discharge shall be

limited to 25l/s at any single point.

Discharge shall not be permitted

to ‘free-fall’ over cliff faces. It must

be piped to the lowest point with

regard to aesthetics.

Discharge outlets are to have

silt/grease arrestors and trash

screens as required for zone 1

and appropriate scour/erosion

control as defined for zone 3.

Discharging into a watercourse or

channel may be permitted subject

to joint approval from Council and

other relevant authority. Where

approval is granted, adequate

protection against scouring and

erosion at the point of discharge

shall be provided. Council should

be consulted in regards to

appropriate stabilisation treatment

to be used.

7.14.2 Gravity drainage

Refer to section 4.14.2.



8. MECHANICAL PUMPS

The use of mechanical pumps

for the drainage of sub-surface,

or seepage water in a basement

car parking area or minor surface

runoff collected from weather

exposed areas less than 30m2,

is permitted.

The pumping of stormwater

runoff is generally not permitted

unless gravity drainage cannot

be achieved in accordance with

the criteria given in section 4.14

Disposal of site runoff and

that an absorption system, in

accordance with section 5

Zone 2: On-site stormwater

retention (absorption), does not

apply or is found to be unsuitable.

Minimum requirements for the

use of mechanical pump systems

are given in appendix 2.

Direct connection of the pump

rising main into the kerb will not

be permitted. Where discharge

to the kerb or road reserve is

proposed, the pumped water

must be conveyed across the

public footway by gravity.

Direct connection into an existing

pipe is discouraged due to the

possibility of back flowing. If

direct discharge into an existing

stormwater pipe is required, a pit

must be constructed at the point

of connection. A non-return valve

must be installed on the upstream

pipe of the constructed junction

pit to prevent water flowing back

into the property. Water pressure

in the system must be taken

into consideration as this may

affect the design discharge rate,

rendering it unsuitable to achieve

the required outflow.



9. CHARGED SYSTEMS

Charged systems will only be

permitted for single residential

developments and only in the

following circumstances:

. the Development

Application is for a single

residential dwelling only

and is not a Complying

Development

. downstream property

owners have indicated

that they are not prepared

to grant easements to

permit the drainage of

the property to follow the

natural fall of the land

. soil absorption

characteristics and other

physical constraints

indicate that on-site

absorption is not feasible

. mechanical pump-out

system has been assessed

as being inappropriate for

the site, and

. Council has assessed that the proposed receiving drainage system can adequately cope with the additional runoff.

Minimum design requirements for

absorption systems are given in

appendix 3.



10. LEGAL OBLIGATION

OSD facilities, pump-out and

charged systems shall require a

Positive Covenant and Restriction

on the use of land, in favour of

Manly Council on the Title.

The purpose of the Covenant

is to ensure that the registered

proprietor takes responsibility

for the control, care and

maintenance of the OSD and/or

charged system. The Restriction

ensures that the system is not

altered in any manner, shape or

form.

For newly created parcels of

land, these terms shall be

created under Section 88B of

the Conveyancing Act 1919.

For existing titles, the terms of

positive covenant and restriction

on the use of land shall be

created by an application to the

Land Titles Office using Forms

13PC and 13RPA.

Standard wording for positive

covenant and restriction on the

use of land are given in

appendix 8.

Positive covenants and restriction

on the use of land are to be

finalised prior to the issue of the

Final Certificate.



11. SUBMISSION OF DESIGN DETAILS

11.1Construction Certificate

The approval of the development

may require a submission of

some or all of the following

information prior to the issue

of the construction certificate,

certified by a suitably qualified

person:

. A1, A2 or A3 size

drawings clearly showing

basic layout of the

proposed drainage system,

this is to include the

location of all downpipes,

pits and pipes with pipe

sizes, grades, existing

and finished levels, and

dimensions, volumes,

surcharge/overflow

facilities from the OSD or

OSA system and the PSD

. all supporting computation

information including

calculations on 31⁄2”

computer disc (where

applicable) with relevant

hydrologic and hydraulic

information

. computation information

summarised as:

- total site area in m2

- total impervious area

(roof and paved) in m2

- area draining into the

proposed stormwater

(OSD or OSA) facility

- dimensions (mm),

volume (cum), and

discharge rate from the

OSD or OSA system

- maximum water depth

(mm) from centreline of

outlet to top water level

- maximum depth of

ponding for above

ground OSD systems

- type and diameter of

orifice, outlet and PSD

. where drainage easements

are required, evidence

in the form of a legal

agreement between the

affected parties or copies

of titles showing the

created easements and

a longitudinal section of

the proposed pipe to the

point of connection which

shall include pipe sizes,

gradients, flowrates and a

hydraulic grade line

. detail of the OSD control

device used including size

and shape, outlet pipe

diameter and invert level

. for underground systems,

at least one (1) detailed

section through the OSD

or OSA facility sufficient for

construction

. for above ground systems,

at least two (2) detailed

sections through the

OSD facility, which shall

include the maximum

water level, gradients and

overflow weir, sufficient for

construction

. existing and proposed

levels and details of

adjoining structures and

buildings shall be shown

on the sections through the

OSD or OSA facility

. where drainage easements

are required, copies of

titles showing the created

easements

. a longitudinal section

through the proposed

pipe along the easement

from the OSD facility to

the point of connection

or a longitudinal section

through the proposed pipe

to the discharge point

for drainage to foreshore

areas and where discharge

is permitted to waterfronts

or bushland in zones 3 and

4—this shall include pipe

sizes, gradients, flowrates

and a hydraulic grade line

. overland flow path and

PSD from the site

. plan showing the location

of OSA or OSD facilities

including dimensions,

pervious (landscape)

and paved (existing and

proposed roof and paved)

areas, and all existing and

proposed surface levels

• location of any utility

services, structures, trees,

etc., which may affect the

proposed drainage system.

Note: It is the responsibility

of the applicant to submit

full details of all relevant

services, which may

conflict with the proposed

design. The exact locations

of any crossings or connections are to be shown.



11.2Final CertificatePrior to the issue of the Final

Certificate, the following must be

submitted:

. works-as-executed

drawings: an engineering

survey of the final works

is to be submitted on one

(1) set of the approved

plans, this plan is to include

finished levels, dimensions

and volume of the built

OSA, OSD facility, the

location of all drainage

pipes, sizes and levels, etc.,

and signed by a Registered

Surveyor

. copies of titles showing

the creation of Positive

Covenants and Restriction

on the use of land

. certification of the

constructed drainage

system by a suitably

qualified and experienced

chartered professional

engineer, on the National

Professional Engineers

Register with the Australian

Institute of Engineers

. identification plate: at

Council’s request, an

identification plate of no

less than 110mm wide x

80mm high, is to be fixed

near or onto the control

structure of the OSD

system, this is to advise the

registered proprietor of their

responsibility to maintain

the OSD facility and not to

tamper with it in any manner

without written consent

this plaque shall read

“This is an On-site

Stormwater Detention

system. It is an offence to

reduce the volume of this

system or to remove the

orifice that controls the

outflow. The base of the

outlet control pit and debris

screen must be cleared

of silt and rubbish on a

regular basis. This plate

must not be removed.”


APPENDIXAppendix 1 Policies D100 Drainage Easements + S190 Stormwater Control

Appendix 2 Mechanical pump systems

Appendix 3 On-site stormwater retention (absorption) systems

Appendix 4 Charged systems

Appendix 5 Stacked rainfall patterns for use in the

ILSAX model

Appendix 6 Orifice sized according to depth and PSD

Appendix 7 Graphs of PSD and SSR for the relevant

residential zones

Appendix 8 Terms of restriction on the use of land and

positive covenant

Appendix 9 Land subdivision

Appendix 10 Drawing No. 1:

Connection to kerb detail, location of foundations near easements detail Drawing No. 2:

On-site stormwater detention tank detail, trash screen detail Drawing No. 3: Control pit in above ground on-site stormwater detention

(OSD) detail, orifice detail Drawing No. 4: On-site absorption trench detail for site areas with less

than 35% impervious Map B: Residential density sub-zones, Map D: Stormwater control zones

23Appendix—Manly Specification for On-site Stormwater Management 2003


A1:DRAINAGE POLICIES D100 DRAINAGE EASEMENTS—GENERAL + S190 STORMWATER CONTROL

D100 Drainage easements—general

The intent of this Policy is to

ensure that access to the public

drainage system on private

property, for the purpose of

inspection, repair or upgrade is

maintained and that the rights

of private easements on public

land including land owned by the

Council is restricted.

For inter-allotment drainage

systems, it is to ensure that

common law rights are attached

to the land to allow another parcel

of land the right to use part or all

of the encumbered land for the

purpose of draining stormwater.

Minimum requirements are as set

out below:

. Where there is an option

between drainage

easements being placed

across adjoining private

land and adjoining public

land, including land owned

by the Council, the Council

requires that the easement

be placed across the

adjoining private land, so

as to not burden public

land (regardless of whether

the land is operational land

or community land within

the meaning of the Local

Government Act, 1993)

with dominant private

interests.

As a matter of practice the

Council does not allow,

and does not want to

allow, any easements to

be placed over public land

which is operational and

held on behalf of the public

in favour of private land

owners.

. That stormwater drainage

easements be required for

all inter-allotment drainage

lines.


easements be required

for constructed public

drainage systems within

private properties.

. That Council will acquire

drainage easements

over constructed public

drainage systems within

private property, wherever

possible.

. That when a development

is proposed on a

property, which contains

an existing constructed

public drainage system

not contained within

a drainage easement,

development consent and/

or building approval shall

be conditional upon the

property owner agreeing to

grant Council a drainage

easement over the line.

. That when a developer

or property owner

proposes to relocate

and/or reconstruct a public

drainage system within

the site, he shall create

drainage easements in

Council’s favour, to suit the

relocated or reconstructed

drainage system at his

cost.

. That the minimum width of

any drainage easement in

Council’s favour shall be

governed by the minimum

practical width necessary

for standard machinery to

carry out reconstruction of

the public drainage system

to current standards and

requirements.

This shall be no less

than 3.0 metres or for

pipes or culverts, which

have a width greater than

1.0 metre; the drainage

easement shall have a

minimum width equal to

the external width of the

pipe or culvert plus 2.0

metres, rounded to the

nearest 0.1 metre.

. That for drainage

structures such as open

channels, the easement

shall be of sufficient

width to contain the flows

resulting from the peak

storm event of 100-years

ARI or the 1% AEP.

. That for open channels,

Council may at its

discretion require an

easement to be supported

by a “Restriction on the

use of land”, the terms of

which require that the floor

level of all habitable rooms

in any proposed dwelling



be no less than 500mm

above the 100-year flood

level.

. That construction

of buildings or other

permanent structures

over the public drainage

easement is not permitted,

unless the encroachment

still permits reasonable

access for Council to

construct and maintain the

system, that it does not

impede or re-direct flows

within the easement, that

it does not load bear onto

the underlying drainage

structure, and that the

site cannot be reasonably

developed without the

encroachment over the

easement.

Otherwise it will be

necessary to relocate the

drainage system.

. That any structural

supports such as

foundations, piers and

footings located adjacent

to an easement will only

be permitted if they do

not load bear onto the

underlying drainage

structure, and that the

built structure will not be

undermined by any future

maintenance work within

the easement.

. That planting of trees or

large shrubs, particularly

those with extensive root

systems, not be permitted

in drainage easements.

. That any construction

over a public drainage

easement may only be

permitted if it will be

unnecessary to access the

drainage structure over the

encroachment for the life of

the underlying structure.

This can be achieved

if the developer or

proprietor agrees to

undertake upgrading or

reconstruction of the public

drainage system, within

the site to satisfy current

design standards and

any other requirements

imposed by Council and

that adequate provision for

emergency access, in case

of an emergency to clear

blockages, is provided to

Council.

. That Council will not

approve the building

of a structure over a

public easement which

will result in Council

incurring additional costs

by requiring specialised

equipment or construction

techniques in order to

maintain or upgrade the

drainage system within the

easement.

. That public drainage

easements shall be free

of encroachments with a

minimum vertical clearance

from the surface level over

the drainage structure to a

height of 5.0 metres above.

Height clearance will be

governed by vertical swept

path of machinery such

as backhoes, excavators

and cranes and the loading

and unloading of standard

trucks.

. That any paved surface

over the public drain shall

include construction joints

along each longitudinal

edge of the easement to

facilitate access to the

drainage structure. Where

the pavement consists

of reinforced concrete,

the pavement within the

drainage easement shall

consist of liftable sized

panels, designed as simply

supported slabs including

lifting lugs.

. That to enable Council

unobstructed access to the

drainage structure, solid

walls or fences shall not be

permitted to be constructed

over the length of the

easement. Gates and

doors across the easement

may be acceptable subject

to Council approval.

. That to enable Council the

legal right of access to the

drainage structure, a Right

of Carriageway is required

between the public road

reserve and the drain. The

minimum dimensions of

the Right of Carriageway

shall be such as to permit

standard machinery

adequate access to the

structure.

. That all new easements

over drainage lines, shall

be “easements to drain

water” as described

in Part III of Schedule

IVA or Schedule VIII

as applicable, of the

Conveyancing Act 1919,

as amended, except where

otherwise specified by

Council. Council is to be

the body empowered to



release, vary or modify

such easements.

. That easements may

be created pursuant

to Section 88B of the

Conveyancing Act 1919,

as amended, or by Transfer

and Grant, the method

of creation dependent on

the circumstance of each

location.


easements will not be

required within or over

natural drainage systems

and watercourses. Council

does not favour nor

encourages the piping,

construction within or

over, or interference with

natural drainage systems

and watercourses. Any

proposal to carry out such

works will be subject to

an assessment pursuant

to other relevant Council

policies and joint approval

from other relevant

authorities.

. That the minimum widths

of inter-allotment private

drainage easements varies

according to the pipe sizes,

but shall be 1.0 metres

wide for pipes less than

150mm-diameter and 2.4

metres wide when greater

than 150mm-diameter.

. That Council may approve

an easement over an

existing inter-allotment

drainage structure of a

width less than 1.0 metre.

S190 Stormwater control

The aim of this Policy is to

ensure that stormwater drainage

problems do not occur as a

result of any development. All

applications for development

will be assessed against

the Specification for On-site

Stormwater Management, for

appropriate stormwater control.

The method of stormwater control

to be applied shall depend on the

location of the site. The required

method of stormwater control is

identified on map D.

The following controls may also

be required:

. provision of safe overland

flowpaths

. definition of floodways for

major storms

. provision of on-site

stormwater detention and

on-site absorption systems

to reduce and control

runoff

. removal of flood effected

development from

known floodways and

the prohibition of future

developments in such

floodways

. creation and maintenance

of safe flood paths within

developments

. recommending floor levels

to reduce the risk of flood

damage

. installation of pipe/channel

systems to minimise

hazard to pedestrian and

vehicular traffic cause

by uncontrolled surface

stormwater runoff

. installation of water quality control devices such as trash screens, gross pollutant traps, water quality ponds and the like to protect the quality of receiving waters.

The standards to achieve the

above controls are provided

in Council’s Specification for

Stormwater Drainage and

Specification for On-site

Stormwater Management.



A2:MECHANICAL PUMP SYSTEMS

Mechanical pump systems

shall only be permitted for the

drainage of subsoil water from

under-building areas as specified

in Section 8 Mechanical

pumps. Pumping of surface

stormwater runoff is generally not

permitted unless in section 4.14

Disposal of site runoff, it can

be adequately demonstrated to

Council that an easement cannot

be obtained and that Council

has assessed that the proposed

receiving drainage system

can adequately cope with the

additional runoff being diverted

to it and that on-site absorption

as given in section 5 Zone 2:

On-site stormwater retention

(absorption), is unsuitable.

The following design conditions

shall apply:

. the pump system shall

consist of two (2) pumps,

connected in parallel, with

each pump being capable

of emptying the holding

tank at a rate no greater

than the following:

- the PSD or portion of the

PSD where all or part of

the site runoff is to be

conveyed, or

- the subsoil inflow rate

where only subsoil water

is to be collected. This

shall include any minor

surface runoff collected

from weather exposed

areas of less than 30m2

the pump rate shall be

designed to be capable

of accommodating runoff

from all weather exposed

areas during a 100-year

ARI storm event for a

duration of 5 hours and

any subsurface inflow

rate during wet weather

determined by an approved

test procedure or estimated

value

. the capacity of the holding

tank shall be calculated as

above the level at which all

pumps are automatically

brought into operation

. the minimum capacity

of the holding tank well

shall be adequately

sized in accordance

with AS3500.3.2–1998,

National Plumbing

and Drainage, Part 3.2:

Stormwater drainage

—acceptable solutions

. a silt trap shall be provided

on the inlet side of the

holding tank

. the rising main from the

pump system shall be

designed and installed


pump manufacturer’s

specification

. the rising main from

the pump system shall

discharge to a stilling

sump within the property

boundary and then

gravity fed to the street or

receiving drainage system

a one-way valve is to be

installed on the rising main

outlet. The stilling sump

is to be located such that

any likely overflow is safely

directed to the street

. the switching of the pumps

shall be arranged so that

they operate alternately

. the pumps shall be

provided with automatic

level switches so that they

operate simultaneously

should the capacity of the

tank be exceeded

. an automatic alarm system

shall be provided to warn

of failure of any part of the

pump system

the alarm shall have visual

indicators and an audible

alarm siren

. a rechargeable battery

back-up system for the

alarm is to be provided in

the event of power failure

. prior to the issue of the

Final or Occupation

Certificate, the applicant

shall submit written

evidence that a contract

has been let for the regular

maintenance of the pump

system

. the creation of a positive

covenant affixed to

the title of the property

indemnifying Council

against liability in respect

of any damage sustained

as a result of the failure

of the pump system or

any other cause not in

Council’s control, and



providing for regular

inspection by the proprietor

the covenant also

identifying the person(s), or

authority responsible for the

maintenance of the system

. the following information

shall be submitted with the

application:

- ‘piping size tabulation

sheet’ for the rising main

- copy of pump

specification and

pumping curves

- graph showing the

maximum design inflow

curves and pump curves

for both pumps

- a plan of the pump

system layout showing

pits, pipes and sizes,

invert levels and

discharge point

- drawing of the holding

tank and pumps

including invert level,

pump cut in levels, alarm

level, etc.

- any other calculation

and documentation

considered necessary

in support of the

application.



A3: ON-SITE STORMWATER RETENTION (ABSORPTION) SYSTEMS

An absorption system may be

approved subject to section 5

Zone 2: On-site stormwater

retention (absorption), and the

following design criteria:

. the soils are not

predominantly loose

aeolian sands or clay soils

- a soil assessment and

permeability test is

required

. clearance distance

between all buildings,

footings, structures and

downstream boundaries

are to be at least 3.0

metres from the proposed

absorption system

. the minimum clearance

distance between sewer

mains and the proposed

absorption system is to be

at least 2.0 metres

absorption systems shall

not be located under or

over any sewer service

. absorption systems are not

to be located in rock, most

non-sedimentary rocks, or

some sedimentary rocks

such as shale, which

have zero or near-zero

permeability

. there is sufficient pervious

(open space) area to allow

complete percolation of

runoff into the ground

. absorption systems are not

permitted in shallow soil

sites this:

- is because of the

likelihood that water

stored on or near

impervious bedrock

may provide a stream

of flow along the soil/

rock interface, which

may cause emerging

seepage

- would create nuisance

or hazard downstream

suitable soils having

a uniform thickness

of at least 3.0 metres

should be available

for the location of the

absorption system

. absorption systems will

not be permitted on ‘steep’

sites with slopes greater

than 5%

. absorption trenches must

follow the line of contours

. absorption systems will

not be permitted where

there is the presence of a

high water table or that the

location of the absorption

system would likely to

cause the water table to

rise

. direct uncleansed

stormwater into the

absorption system is not

permitted

only roof runoff shall

be permitted to directly

discharge into the

absorption system, but

must pass through an

approved filter system

to remove all debris,

silts, sands, etc. prior to

absorption

. areas such as courtyards,

walkways, driveways,

carriageways, car parks,

etc., are not to be piped

directly into absorption

systems

runoff must pass across at

least 15 metres of grass or

through a sand/loam filter

at least 200mm thick with

grass cover

. suitable soils must have

hydraulic conductivity

values greater than

1 x 10-6 m/s

(measurement of hydraulic

conductivity tests in soils

is given in the attached

appendix A3.2)

. types of systems to be

used are:

- ‘leaky’ wells

- trenches

refer to attached drawings

for details on page 33

. the maximum ‘emptying’

time shall not be greater

than one (1) day

. to ensure likely overflows

are not concentrated onto

adjoining downstream

properties, a dispersion

system shall be provided at

the overflow outlet

. in some cases, a

combination of OSD and

absorption may be required

to control and detain the

site runoff



. for high to medium

permeability soils, the

design procedures for

‘simple’ systems are given

in appendix 3.1

for site areas with

impervious percentages

less than 35% or 250m2,

the attached details of a

typical disposal trench may

be used.

A3.1 ‘Simple’ absorption system design - high/medium permeability soils

Reference Stormwater

Industry Association, On-

site Stormwater Retention,

Why? When? How?, Paper on

OSR (Underground devices)

in soils of high/medium and

low permeability, by John R

Argue, 30 May 2001. There are

three basic types of absorption

systems. These being:

• devices which provide

unencumbered, perforated,

well-shaped storage

space

• trench-shaped devices

which provide storage

space, part-occupied by

a single material such as

gravel or plastic, or similar

devices occupied by a mix

of materials such as slotted

pipe with gravel backfill, etc

• soakaways: these are devices constructed and filled in the same manner as trenches, but having shallow depth, typically 0.15 m to 0.5 m, and large plan areas.

Each of these types of devices

releases stored water into the

surrounding soil medium by

percolation; they also incorporate

provision for overflows.

A3.1.1 ‘Leaky’ well with clean water inflow

The basic data requirements

are:

. ‘block’ runoff volume, ∀ m3,

passing to the holding well.

The hydrological process

involves determining the

pre and post development

volumes for critical times

of concentration (Tc

and tc) and a nominated

design storm event—the

difference in the volume

shall be the estimated ∀;

storm duration equal to Tc

or tc should be used

. two case scenarios:

Case 1

Where there is a known

flooding problem downstream

of the site and Council has data

regarding the critical storm for

flood to occur: τ = Tc. + tc (in minutes)

Case 2

Where flooding downstream is

not likely to occur:

τ = 2tc (in minutes)

where

Tc. = catchment critical time of

concentration and

tc = site time of concentration

• the design ARI used to

calculate ∀ is as follows:

Pre-development = 5-year

ARI ‘state of nature’ site

condition

Post-development = 100-

year ARI fully developed

• Hydraulic conductivity of soil, kh m/s.



Inflow volume to system = ∀ m3;

and storm period τ should be

used and ignoring outflow from

ends of trench:

∀ L = ________________ (in metres) Es .b.H + 60.kh .τ b + H

2

Each design case must be

checked for ‘emptying time’ using

the following formula:

T = -4.6.L.b.es Log10 L.b 2.kh(L + b) L.b+2.H.(L+b)

The maximum emptying time

shall be 1 day.

A3.1.3 Porous pavement

Refer to manufacturers

specification for porous pavement

design and installation.

A3.2 Measurement of hydraulic conductivity

See adjacent pages.

Design Assumptions:

. well is empty at

commencement of inflow

. well fills over time in

minutes

. percolation through floor is

at full rate of kh for period

of minutes

. percolation through walls is

distributed hydrostatically,

hence this component of

outflow is half saturated

(outflow) rate for period of

minutes

. the perforated wall offers

no restriction to outflow

. the groundwater level is significantly below the floor of the well.

For a perforated well, diameter

D in metres, height H in metres,

during filling operation (note

for practical design cases,

particularly in clay soils, require D

≈ H):

D ≈ ______________ (in metres)

π (H+120.kh. τ) 4

Each design case must be

checked for ‘emptying time’ using

the following formula:

T = 4.6D Log10 D/4 (in seconds) 4.kh H+D/4

The maximum emptying time shall

be 1 day.

A3.1.2 Trench, part-occupied with impervious material or combinations of materials (gravel, slotted pipes, ‘milk crate’ cells, Everglas units with gravel backfill, etc) with clean water inflow

The basic data requirements and

design assumptions correspond

to those given in A3.1.1. For a

trench of length L, width b, and

a depth H, part-occupied with

impervious material and providing

void space, es, where:

es = void space available

L.b.H

Typical values of the ratio es are

es = 0.35 for gravels

= 0.95 for certain plastic

structure units such as

Atlantis (‘milk crate’) cells.

= 0.5 to 0.75 for trenches

part-occupied by

perforated pipes or

everglas units backfilled

with gravel (slotted pipes)

= 0.7 (everglas units),

depending on component

sizes and trench cross-

section dimensions.

(in seconds)

∀



A4:CHARGED SYSTEMS

Charged systems may be

approved subject to section 9

Charged systems, and the

following design criteria:

. approval of charged

systems does not negate

OSD requirements

. full hydraulic analysis of

the proposed drainage

system is to be submitted

including design flowrates

and a hydraulic grade line

. the drainage system

including roof gutters,

pipes and pits is designed

for the 1 in 100-year ARI

storm event

. there is a minimum height

difference between the

roof gutter level and the

discharge pit of 2.0 metres

to allow sufficient pressure

to drain the system

. the charged line shall

discharge to a sump within

the property boundary

and then gravity fed to the

street or receiving drainage

system

. a one-way valve is to be

installed on the outlet to

the charged line

. the discharge pit is to be

located such that any likely

overflow is safely directed

to the street

. all pipes shall be minimum

150mm-dia pipes for

pressure applications and

solvent welded

. cleaning eyes must be

installed at the lowest

point in the system within

a sump, which is to be

drained into an on-site

absorption/dispersal

system

. gutter guards are to be

installed to minimise debris

entering the system

. all utility services within

the road reserve must

be located and shown on

the plan in relation to the

proposed drainage system

. a positive covenant will

be required to be placed

on the title of the property

to inform the owners of

their obligation to regularly

maintain the system

. full detailed drawings and

supporting calculations

shall be submitted

to Council with the

Development Application.



A5: STACKED RAINFALL PATTERNS FOR USE IN THE ILSAX MODEL

ILSAX rainfall files for 5 and 100 year ARI storms3 2 11 5 YR. 10 MIN. ARI MANLY (Balgowlah) 1 2 -1 0 -0.300 0 -375 0.300 1.00 5.00 2.50 3.00 1 1 0 1 5 10.00 5.00 1.00 1.000 1 5 124.0 0 5 YR. 15 MIN. ARI-1 0 3.00 1 5 15.00 5.00 1.00 1.000 1 5 108.0 0 5 YR. 20 MIN. ARI-1 0 3.00 1 5 20.00 5.00 1.00 1.000 1 5 92.4 0 5 YR. 25 MIN. ARI-1 0 3.00 1 5 25.00 5.00 1.00 1.000 1 5 82.5 0 5 YR 30 MIN. ARI-1 0 3.00 1 5 30.00 5.00 1.00 1.000 1 5 75.9 0 5 YR. 45 MIN. ARI-1 0 3.00 1 5 45.00 5.00 1.00 1.000 1 5 62.5 0 5 YR. 1 HOUR ARI-1 0 3.00 1 5 60.00 5.00 1.00 1.000 1 5 52.3 0 5 YR. 1.5 HOUR ARI-1 0 3.00 1 5 90.00 5.00 2.00 1.000 1 5 42.0 0 5 YR 2 HOUR ARI-1 0 3.00 1 5 120.00 5.00 2.00 1.000 1 5 34.7 0 5 YR 3 HOUR ARI-1 0 3.00 1 5 180.00 15.00 2.00 1.000 1 5 27.0 0 5 YR. 4.5 HOUR ARI -1 0 3.00 1 5 270.00 15.00 5.00 1.000 1 5. 21.0 0

3 2 11100 YR 10 MIN. ARI MANLY (Balgowlah) 1 2 -1 0 -0.300 0 -375 0.300 1.00 5.00 2.50 3.00 1 1.00 0 1 5 10.00 5.00 1.00 1.000 1 100 211.0 0 100 YR. 15 MIN ARI-1 0 3.00 1 5 15.00 5.00 1.00 1.000 1 100 180.0 0 100 YR. 20 MIN. ARI-1 0 3.00 1 5 20.00 5.00 1.00 1.000 1 100 161.0 0 100 YR 25 MIN. ARI-1 0 3.00 1 5 25.00 5.00 1.00 1.000 1 100 145.0 0 100 YR. 30 MIN. ARI-1 0 3.00 1 5 30.00 5.00 1.00 1.000 1 100 134.0 0 100 YR. 45 MIN. ARI-1 0 3.00 1 5 45.00 5.00 1.00 1.000 1 100 110.0 0 100 YR. 1 HOUR ARI-1 0 3.00 1 5 60.00 5.00 1.00 1.000 1 100 93.9 0 100 YR. 1.5 HOUR ARI-1 0 3.00 1 5 90.00 5.00 2.00 1.000 1 100 75.0 0 100 YR. 2 HOUR ARI-1 0 3.00 1 5 120.00 5.00 2.00 1.000 1 100 62.1 0 100 YR. 3 HOUR ARI-1 0 3.00 1 5 180.00 15.00 2.00 1.000 1 100 47.9 0 100 YR.4.5 HOUR ARI -1 0 3.00 1 5 270.00 15.00 5.00 1.000 1 100 38.0 0



A6:ORIFICE SIZED ACCORDING TO DEPTH AND PSDPSD DEPTH OF TANK ABOVE CENTRELINE OF ORIFICE

l/s 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0

2 55 46 42 39 37 35 34 33 32 31 30 30 29 28 28 28 27 27 26 26

3 67 57 51 48 45 43 41 40 39 38 37 36 36 35 34 34 33 33 32 32 Min.

4 78 65 59 55 52 50 48 46 45 44 43 42 41 40 40 39 38 38 37 37 100 mm

5 87 73 66 62 58 56 54 52 50 49 48 47 46 45 44 44 43 42 42 41 diameter

6 95 80 72 67 64 61 59 57 55 54 52 51 50 49 48 48 47 46 46 45 outlet

7 103 87 78 73 69 66 63 61 59 58 57 55 54 53 52 51 51 50 49 49 pipe

8 110 93 84 78 74 70 68 65 64 62 60 59 58 57 56 55 54 53 53 52

9 117 98 89 83 78 75 72 69 67 66 64 63 61 60 59 58 58 57 56 55

10 123 104 94 87 82 79 76 73 71 69 68 66 65 64 63 62 61 60 59 58

11 129 109 98 91 86 82 79 77 75 73 71 69 68 67 66 65 64 63 62 61

12 135 113 102 95 90 86 83 80 78 76 74 72 71 70 69 67 66 65 65 64

13 140 118 107 99 94 90 86 83 81 79 77 75 74 73 71 70 69 68 67 66

14 146 122 111 103 97 93 90 87 84 82 80 78 77 75 74 73 72 71 70 69 Min.

15 151 127 115 107 101 96 93 90 87 85 83 81 79 78 77 75 74 73 72 71 150 mm

16 156 131 118 110 104 99 96 93 90 88 85 84 82 80 79 78 77 76 75 74 diameter

17 160 135 122 113 107 103 99 95 93 90 88 86 85 83 82 80 79 78 77 76 outlet

18 165 139 125 117 110 106 102 98 95 93 91 89 87 85 84 83 81 80 79 78 pipe

19 170 143 129 120 113 108 104 101 98 95 93 91 89 88 86 85 84 82 81 80

20 174 146 132 123 116 111 107 104 100 98 96 94 92 90 88 87 86 85 83 82

21 178 150 136 126 119 114 110 106 103 100 98 96 94 92 91 89 88 87 85 84

22 183 154 139 129 122 117 112 109 105 103 100 98 96 94 93 91 90 89 87 86

23 187 157 142 132 125 119 115 111 108 105 102 100 98 97 95 93 92 91 89 88

24 191 160 145 135 128 122 117 113 110 107 105 102 100 99 97 95 94 93 91 90

25 195 164 148 138 130 124 120 116 112 109 107 105 102 101 99 97 96 94 93 92

26 198 167 151 140 133 127 122 118 115 112 109 107 105 103 101 99 98 96 95 94

27 170 154 143 135 129 124 120 117 114 111 109 107 105 103 101 100 98 97 96

28 173 156 146 138 132 127 122 119 116 113 111 108 106 105 103 101 100 99 97

29 176 159 148 140 134 129 125 121 118 115 113 110 108 107 105 103 102 100 99

30 179 162 151 143 136 131 127 123 120 117 115 112 110 108 107 105 104 102 101

31 182 165 153 145 138 133 129 125 122 119 116 114 112 110 108 107 105 104 102

32 185 167 156 147 141 135 131 127 124 121 118 116 114 112 110 108 107 105 104

33 188 170 158 150 143 137 133 129 126 123 120 118 116 114 112 110 109 107 106

34 191 172 160 152 145 140 135 131 128 125 122 120 117 115 113 112 110 109 107 Min.

35 194 175 163 154 147 142 137 133 129 126 124 121 119 117 115 113 112 110 109 225 mm

36 196 177 165 156 149 144 139 135 131 128 125 123 121 119 117 115 113 112 110 diameter

37 199 180 167 158 151 146 141 137 133 130 127 125 122 120 118 117 115 113 112 outlet

38 202 182 170 160 153 148 143 139 135 132 129 126 124 122 120 118 116 115 113 pipe

39 204 185 172 163 155 149 145 140 137 133 131 128 126 124 122 120 118 116 115

40 207 187 174 165 157 151 146 142 138 135 132 130 127 125 123 121 120 118 116

41 210 189 176 167 159 153 148 144 140 137 134 131 129 127 125 123 121 119 118

42 212 192 178 169 161 155 150 146 142 139 136 133 130 128 126 124 122 121 119

43 215 194 180 171 163 157 152 147 144 140 137 134 132 130 128 126 124 122 121

44 217 196 183 173 165 159 154 149 145 142 139 136 133 131 129 127 125 124 122

45 220 198 185 175 167 161 155 151 147 143 140 138 135 133 131 129 127 125 123

46 222 201 187 177 169 162 157 152 148 145 142 139 136 134 132 130 128 126 125

47 224 203 189 178 170 164 159 154 150 147 143 141 138 136 133 131 130 128 126

48 227 205 191 180 172 166 160 156 152 148 145 142 139 137 135 133 131 129 128

49 229 207 193 182 174 168 162 157 153 150 146 143 141 138 136 134 132 131 129

50 231 209 195 184 176 169 164 159 155 151 148 145 142 140 138 136 134 132 130

Min. 375 mm diameter outlet pipe Min. 300 mm diameter outlet pipe

For orifice diameters less than 50 mm, a 90 mm diameter plastic pipe may be used as the outlet pipeAllowable discharge to the kerb is not to exceed 25 l/s at any single point.Flow through the orifice is based on the equationQ = C A √( 2 g H ) x 103

d = √( 4 A / π ) x 103

Q = the flowrate in litres per secondWhereC = 0.6 for a circular, square-edged orificeH = the depth of water from the centreline of the orifice to the upper water surface level in metresA = the area of the orifice in square metresg = 9.81 metres per second per second (gravity)π = 3.1416d = the diameter of the orifice in millimetres



A7:GRAPHS OF PSD AND SSR FOR THE RELEVANT RESIDENTIAL ZONES

A7.1Derivation of graphs

The hydrological program, ILSAX

was used to model the site runoff

and storage volumes for typical

site areas of 250m2, 300m2,

500m2, 600m2, 750m2, 950m2,

and 1150m2, for varying slopes of

0.5%, 1%, 2%, 3%, 4%, 5%, 6%,

7%, 8%, 9%, and 10%.

ILSAX was used to determine

the minimum volume for the

nominated site areas and

varying slopes based on a

pre-development impervious

area of 0% and 35% and post-

development impervious areas of

40%, 50%, 60%, and 70%.

These values were then

extrapolated/interpolated for the

65%, 80%, 85% and 88.5% post-

development impervious areas.

Slopes were grouped into three

(3) bands; less than 4% (<4%),

between 4% and 7% (4%-7%),

and greater than 7% (>7%). For

less than 4%, the calculated 1%

slope values were used.

As sites with pre-development

impervious areas between 0%

and 35% were not assessed, if

the designer chooses, he may

interpolate between the 0% and

35% values.

Rainfall patterns and generated

storms used in the model were

obtained from ARR and IFD data

from the Bureau of Meteorology

(reference Manly Council’s

Specification for Stormwater

Drainage, appendix 1 Design

rainfall intensity diagram).

The design parameters used in

the model are given in section

4.7 of this specification.

Assumptions made:

. storage volume based on a

rectangular shaped storage

with variable length and

breadth dimensions and a

fixed depth of 1.0m

. orifice control is a fixed

square-edged orifice plate,

C = 0.6

. the entire site drains either

to the front or to the rear

. the width of the site varies:

- between 250m2 and

300m2 is 10m

- between 500m2 and

600m2 is 15m

- 750m2 is 20m

- 950m2 is 25m

- 1150m2 is 30m

. discharge is made directly

into the existing drainage

network (e.g. into a pipe

or conduit) where the

concentrated discharge

limit of 25l/s does not apply

. the estimation of the time

of concentration assumes

that the upper half of the

site is grassed and the

lower half of the site is

paved

. the discharge from the

detention system is not

affected by downstream,

tail water conditions, that

is, a ‘free outlet’ control

exists—where this is not

achievable, these graphs

are not to be used.

A7.2Use of graphsThe attached graphs are

applicable to the relevant

residential density sub-zone



which are given in Manly

Council’s Residential Control

Plan for the Residential Zone

2001, October 2001, Map B

Residential density sub-zones,

see appendix 10.

An example is given as follows:

Property address: 12 Lewis St, Balgowlah Hts

Site area: 750m2

Average slope: 6%

Pre-development impervious area: 35%

Post-development impervious area: 70%

The property is located within

Density Sub-zone 5.

To obtain the required site storage volume (SSV), select relevant graph labelled:

Density Subzones 3- 6—35% predeveloped impervious areaThe applicable curve is 4-7% slope 70% impWith site area of 750m2 Reading from the graph gives SSV = 32m3

To obtain the permissible site discharge (PSD), select relevant graph labelled:

Permissible Site DischargeThe applicable curve is 35% Predeveloped Impervious Area 4-7% slope With site area of 750m2

Reading from the graph gives PSD = 18l/s*

* Note: The use of these

graphs assumes that the

discharge is not to be

concentrated at the kerb

and gutter or channel

when 25l/s or a velocity

of 2.0m/s, is exceeded.

If the PSD exceeds 25l/s

or the discharge velocity

is greater than 2m/s, to a

kerb, then these graphs

cannot be used. To limit

the discharge or velocity,

the volume of the detention

system would need to be

increased. In this case, the

volume would be greater

than the values given

in these graphs. Other

computational methods of

determining the SSR, as

given in Section 4.5, must

be used.



Density subzone 1—0% predeveloped impervious area


0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

70

Requiredtanksize(m

3 )

Site Area (m2)

4-7% slope 88.75% imp

<4% slope 88.75% imp

<7% slope 50% imp

4-7% slope 0-70% imp

4-7% slope 60% imp,>7% slope 80%imp

4-7% slope 50% imp,>7% slope 70% imp

>7% slope 50% imp

4-7% slope 80% imp<7% slope 88.75% imp

<4% slope 80% imp

<4% slope 70% imp

<4% slope 60% imp

<4% slope 50% imp


<7% slope 50% imp>7% slope 50% imp

4-7% slope 88.75% imp

<4% slope 70% imp

<4% slope 80% imp

<4% slope 50% imp

<4% slope 60% imp



4-7% slope 0-70% imp

4-7% slope 80% imp<7% slope 88.75% imp

0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

70

Requiredtanksize(m

3 )

Site Area (m2)


<7% slope 50% imp

4-7% slope 70% imp



>7% slope 50% imp

4-7% slope 80% imp,<7% slope 88.75%

<4% slope 80% imp

<4% slope 70% imp

<4% slope 60% imp

<4% slope 50% imp

4-7% slope 88.75% imp

<4% slope 50% imp<4% slope 60% imp

<4% slope 70% imp

<4% slope 80% imp



4-7% slope 70% imp

4-7% slope 80% imp,<7% slope 88.75%

4-7% slope 88.75% imp


>7% slope 50% imp<7% slope 50% imp





0

10

20

30

40

50

60

0 200 400 600 800 1000 1200 1400

Requiredtanksize(m

3 )

Site Area (m2)

<4% slope 60% imp

<4% slope 70% imp

4-7% slope 85%imp

4-7% slope 80% imp,<4% slope 50% imp

<4% slope 85% imp

<7% slope 50% imp




>7% slope 50% imp

<4% slope 80% imp

<4% slope 85% imp

<7% slope 50% imp

4-7% slope 85%imp

4-7% slope 50% imp,>7% slope 70% imp>7% slope 50% imp

<4% slope 80% imp

<4% slope 70% imp

4-7% slope 80% imp,<4% slope 50% imp

<4% slope 60% imp



0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

70Requiredtanksize(m

3 )

Site Area (m2)

4-7% slope 85%imp

4-7% slope 80% imp

<4% slope 85% imp

<7% slope 50% imp

>7% slope 85% imp4-7% slope 70% imp,



>7% slope 50% imp

<4% slope 70% imp

<4% slope 60% imp

<4% slope 50% imp

<4% slope 80% imp


<4% slope 70% imp


4-7% slope 85%imp4-7% slope 80% imp

>7% slope 85% imp4-7% slope 70% imp,

<7% slope 50% imp>7% slope 50% imp





Density subzone 3-6—0% predeveloped impervious area

Density subzone 3-6—35% predeveloped impervious area

0

10

20

30

40

50

60

0 200 400 600 800 1000 1200 1400

Site Area (m2)

Requiredtanksize(m

3 )

<7% slope 50% imp

<7% slope 40% imp

4-7% slope, 70% imp




<4% slope 40% imp,4-7% slope 80% imp

<4% slope 80% imp

<4% slope 70% imp

<4% slope 60% imp

<4% slope 50% imp

<4% slope 50% imp

<4% slope 70% imp

<7% slope 40% imp

<4% slope 80% imp

<4% slope 60% imp

<7% slope 50% imp


4-7% slope, 70% imp

4-7% slope 60% imp,>7% slope 80%imp4-7% slope 50% imp,>7% slope 70% imp


0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

70

Requiredtanksize(m

3 )

Site Area (m2)

<7% slope 50% imp

<7% slope 40% imp

4-7% slope 70% imp

>7% slope 80%imp4-7% slope 60% imp,




<4% slope 80% imp

<4% slope 70% imp

<4% slope 60% imp

<4% slope 50% imp

<7% slope 40% imp

<4% slope 80% imp

<4% slope 70% imp

<4% slope 50% imp4-7% slope 50% imp,>7% slope 70% imp

<4% slope 60% imp

<4% slope 40% imp,4-7% slope 80% imp4-7% slope 70% imp


<7% slope 50% imp

>7% slope 80%imp4-7% slope 60% imp,





0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

Site Area (m2)

Requiredtanksize(m

3 )

<4% slope, 60% imp

<4% slope, 50% imp

<4% slope, 40% imp

4-7% slope, 40% imp,>7% slope, 50% imp

4-7% slope 50% imp

4-7% slope, 60% imp

<7% slope, 50% imp

<4% slope 65% imp

4-7% slope 65% imp

>7% slope 65% imp

<7% slope, 40% imp

<7% slope, 40% imp

<4% slope 65% imp<4% slope, 60% imp

<4% slope, 40% imp

<7% slope, 50% imp


>7% slope 65% imp

4-7% slope, 60% imp4-7% slope 65% imp

<4% slope, 50% imp

4-7% slope 50% imp

0 200 400 600 800 1000 1200 14000

10

20

30

40

50

60

Site Area (m2)

Requiredtanksize(m

3 )

<4% slope, 50% imp

<4% slope, 60% imp

<4% slope, 40% imp


4-7% slope, 50% imp

4-7% slope, 60% imp

<7% slope, 40% imp

<7% slope, 50% imp

<4% slope 65% imp

4-7% slope 65% imp

>7% slope 65% imp

<4% slope 65% imp

<7% slope, 40% imp<7% slope, 50% imp

>7% slope 65% imp

4-7% slope, 60% imp

<4% slope, 40% imp

<4% slope, 60% imp<4% slope, 50% imp

4-7% slope 65% imp

4-7% slope, 50% imp




Permissible site discharge

0 200 400 600 800 1000 1200 14000

5

10

15

20

25

30

35

40

Site Area (m2)

MaxQ5from

existingsite[PSD](litres/sec)

<4% slope 0% imp(predeveloped site)

4-7% slope 0% imp(predeveloped site)

>7% slope 0% imp(predeveloped site)












A8:TERMS OF RESTRICTION ON THE USE OF LAND AND POSITIVE COVENANT

The generic wording for the terms

of restriction on the use of land

and positive covenant are given

below:

A8.1Existing allotments

For existing allotments where

there is no land subdivision, that

is, no Section 88B instrument

required, the following wording

for the terms of restriction on the

use of land and terms of positive

covenant shall be in the form of a

request in the following format:

A8.1.1 Terms of restriction on the use of land

(Show full details of the Restriction)

The registered proprietors

covenant with Manly Council (the

Council) that they will not:

i) Do any act, matter or thing

which would prevent the

structure and works from

operating in an efficient

manner.

ii) Make any alterations

or additions to the

structure and works or

allow any development

within the meaning of the

Environmental Planning

and Assessment Act

1979 to encroach upon

the structure and works

without the express written

consent of the authority.

iii) This covenant shall bind all

persons who claim under

the registered proprietors

as stipulated in section

88E(5) of the Act.

For the purposes of this

covenant:

Structure and Works

shall mean the on-site


system constructed on

the land as set out in the

plan annexed hereto and

marked with the letter ‘A’

(or alternatively as detailed

on the plans approved by

Council No.***) including

all gutters, pipes, drains,

walls, kerbs, pits, grates,

tanks, chambers, basins

and surfaces designed

to temporarily detain

stormwater on the land.

The Act means the

Conveyancing Act 1919.

A8.1.2 Terms of positive covenant

(Show full details of Positive Covenant)



Council) that they will maintain

and repair the structure and

works on the land in accordance

with the following terms and

conditions:

i) The registered proprietor

will:

a. keep the structure and

works clean and free

from silt, rubbish and

debris

b. maintain and repair at

the sole expense of the

registered proprietors

the whole of the

structure and works so

that it functions in a safe

and efficient manner.

ii) For the purpose of

ensuring observance of the

covenant the Council may

by its servants or agents at

any reasonable time of the

day and upon giving to the

person against whom the

covenant is enforceable not

less than two days notice

(but at any time without

notice in the case of an

emergency) enter the land

and view the condition of

the land and the state of

construction maintenance

or repair of the structure

and works on the land.



iii) By written notice the

Council may require the

registered proprietors to

attend to any matter and

to carry out such work

within such time as the

Council may require to

ensure the proper and

efficient performance of the

structure and works and to

that extent section 88F(2)

(a) of the Act is hereby

agreed to be amended

accordingly.

iv) Pursuant to section 88F(3)

of the Act the authority

shall have the following

additional powers pursuant

to this covenant:

a. in the event that the

registered proprietor fails

to comply with the terms

of any written notice

issued by the Council

as set out above the

Council or its authorised

agents may enter the

land with all necessary

equipment and carry

out any work which the

Council in its discretion

considers reasonable

to comply with the said

notice referred to in

A8.1.1.III).

b. the Council may recover

from the registered

proprietor in a Court of

competent jurisdiction:

a) any expense

reasonably incurred

by it in exercising

its powers under

A8.1.1.l)—such

expense shall include

reasonable wages

for the Council’s own

employees engaged

in effecting the said

work, supervising

the said work and

administering the said

work together with

costs, reasonably

estimated by the

Council, for the use

of machinery, tools

and equipment in

conjunction with the

said work

c) legal costs on an

indemnity basis

for issue of the

said notices and

recovery of the said

costs and expenses

together with the

costs and expenses

of registration of a

covenant charge

pursuant to section

88F of the Act

or providing any

certificate required

pursuant to section

88G of the Act

or obtaining any

injunction pursuant

to section 88H of the

Act.

v. This covenant shall bind all




88E(5) of the Act.


covenant:

Structure and Works
















The Act means the


Where a subdivision has

been lodged and a Section

88B instrument created, the

following wording for the terms of

restriction on the use of land and

terms of positive covenant is to

be included:



A9:LAND SUBDIVISION


88E(5) of the Act.


covenant:

Structure and Works
















The Act shall mean the


A9.2Terms of positive covenant

(referred to in the plan mentioned above)


covenant with Manly Council (The

Council) that they will maintain

and repair the structure and

works on the land in accordance

with the following terms and

conditions:

i) The registered proprietor

will:

a. keep the structure and

works clean and free

from silt, rubbish and

debris

b. maintain and repair at

the sole expense of the

registered proprietors

the whole of the

structure and works so

that it functions in a safe

and efficient manner.

ii) For the purpose of

ensuring observance of the

covenant the Council may

by its servants or agents at

any reasonable time of the

day and upon giving to the

person against whom the

covenant is enforceable not

less than two days notice

(but at any time without

notice in the case of an

emergency) enter the land

and view the condition of

the land and the state of

construction maintenance

or repair of the structure

and works on the land.

iii. By written notice the

Council may require the

registered proprietors to

attend to any matter and

to carry out such work

within such time as the

Council may require to

ensure the proper and

efficient performance of the

structure and works and to

that extent section 88F(2)

(a) of the Act is hereby

agreed to be amended

accordingly.

iv) Pursuant to section 88F(3)

of the Act the authority

shall have the following

additional powers pursuant

to this covenant:

a. in the event that the

registered proprietor fails

to comply with the terms

A9.1Terms of restriction on the use of land

(referred to in the plan mentioned above)

The registered proprietor

covenant with Manly Council

(The Council) in respect to

the structure erected on the

land described as ‘on-site

stormwater detention system’

(which expression includes all

ancillary gutters, pipes, drains,

walls, kerbs, pits, grates, tanks,

chambers, basins and surfaces

designed to temporarily detain

stormwater) shown on plans

approved by the Council No.

(hereinafter called ‘the system’).



Council) that they will not:

i) Do any act, matter or thing

which would prevent the

structure and works from

operating in an efficient

manner.

ii) Make any alterations

or additions to the

structure and works or

allow any development

within the meaning of the

Environmental Planning

and Assessment Act

1979 to encroach upon

the structure and works

without the express written

consent of the authority.

iii) This covenant shall bind all





of any written notice

issued by the Council

as set out above the

Council or its authorised

agents may enter the

land with all necessary

equipment and carry

out any work which the

Council in its discretion

considers reasonable

to comply with the said

notice referred to in

A9.2.1.I)

b. the Council may recover

from the registered

proprietor in a Court of

competent jurisdiction :

a) Any expense

reasonably incurred

by it in exercising

its powers under

A9.2.1.l)—such

expense shall include

reasonable wages

for the Council’s own

employees engaged

in effecting the said

work, supervising

the said work and

administering the said

work together with

costs, reasonably

estimated by the

Council, for the use

of machinery, tools

and equipment in

conjunction with the

said work.

b) Legal costs on an

indemnity basis

for issue of the

said notices and

recovery of the said

costs and expenses

together with the

costs and expenses

of registration of a

covenant charge

pursuant to section

88F of the Act

or providing any

certificate required

pursuant to section

88G of the Act

or obtaining any

injunction pursuant

to section 88H of the

Act.

v) This covenant shall bind all




88E(5) of the Act.


covenant:

Structure and Works
















The Act means the



A10: DRAWINGS + MAPS

DRAWING NO. 1: CONNECTION TO KERB DETAIL, LOCATION OF FOUNDATIONS NEAR EASEMENTS DETAIL

DRAWING NO. 2: ON-SITE STORMWATER DETENTION TANK DETAIL, TRASH SCREEN DETAIL

DRAWING NO. 3: CONTROL PIT IN ABOVE GROUND ON-SITE STORMWATER DETENTION (OSD) DETAIL, ORIFICE DETAIL

DRAWING NO. 4: ON-SITE ABSORPTION TRENCH DETAIL FOR SITE AREAS WITH LESS THAN 35% IMPERVIOUS

MAP B: RESIDENTIAL DENSITY SUB-ZONES

MAP D: STORMWATER CONTROL ZONES

MANLY - Northern Beaches Council...Manly Council Updated March 2004 with addendum to Section 4.1...

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Transcript of MANLY - Northern Beaches Council...Manly Council Updated March 2004 with addendum to Section 4.1...