Att 30 12STRAT005 Engineering Guidelines - Part 4 Handbook of Drainage Design Criteria

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Handbook of Drainage Design Criteria – Lake Macquarie City Council

Handbook of Drainage Deisgn CriteriaPage 1 – F2009/00952February 2012 – Exhibiti on Draft

TABLE OF CONTENTS:

1 INTRODUCTION....................................................................................................................................... 4 2 DESIGN GUIDELINES FOR ON-SITE STORMWATER MANAGEMENT............................................... 5

2.1 INTRODUCTION ............................................................................................................................... 5 2.2 SITE DISCHARGE INDEX ................................................................................................................ 5 2.3 GENERAL PRINCIPLES ................................................................................................................... 5 2.4 GENERAL REQUIREMENTS............................................................................................................ 5 2.5 DEVICE SPECIFIC REQUIREMENTS.............................................................................................. 7

2.5.1 ON-SITE STORMWATER DETENTION (OSD) 7 2.5.1.1 Detention Systems................................................................................................................. 7 2.5.1.2 Design Guidelines for OSD Systems..................................................................................... 7

2.5.2 RAINWATER TANKS – ROOFWATER 8 2.5.3 STORMWATER TANKS 9 2.5.4 INFILTRATION 9 2.5.5 POROUS PAVING 11 2.5.6 RUNOFF CONTROLS FOR STREETS AND CARPARKS 11 2.5.7 AQUIFER STORAGE AND RETRIEVAL 11 2.5.8 WASTEWATER REUSE 12

2.6 ALTERNATE DISCHARGE OPTIONS............................................................................................ 13 2.6.1 INTER-ALLOTMENT DRAINAGE EASEMENTS 13 2.6.2 PUMP SYSTEMS 13 2.6.3 CHARGED SYSTEMS 13

3 SCHEDULE 1 - RECOMMENDED SOURCES FOR DESIGN AND BEST PRACTICES...................... 15 4 APPENDICES ......................................................................................................................................... 16

4.1 OVERLAND FLOW TIME - TABLE ................................................................................................. 17 4.2 OVERLAND FLOW TIME – GRAPH............................................................................................... 18 4.3 GUTTER FLOW TIME..................................................................................................................... 19 4.4 INTENSITY/FREQUENCY/DURATION DIAGRAM ........................................................................ 20 4.5 RUNOFF COEFFICIENTS .............................................................................................................. 21 4.6 HYDROLOGICAL DESIGN SHEET 1 ............................................................................................. 22 4.7

HYDROLOGICAL DESIGN SHEET 2 ............................................................................................. 23

4.8 HYDROLOGICAL DESIGN SHEET 3 ............................................................................................. 24 4.9 HYDRAULIC DESIGN SHEET ........................................................................................................ 25 4.10 KERB INLET CAPACITY 2.4m LINTEL .......................................................................................... 26 4.11 KERB INLET CAPACITY 3.0m LINTEL .......................................................................................... 27 4.12 KERB INLET CAPACITY 3.7m LINTEL .......................................................................................... 28 4.13 KERB INLET CAPACITY 4.3m LINTEL .......................................................................................... 29 4.14 SAG INLET CAPACITY – CROSSFALL ......................................................................................... 30 4.15 INTERALLOTMENT DRAINAGE CONNECTION FOR INDIVIDUAL PROPERTY ........................ 31 4.16 DOUBLE GRATE EXTENDED KERB – INLET PIT DETAIL – BARRIER KERB ........................... 32 4.17 DOUBLE GRATE EXTENDED KERB – INLET PIT DETAIL – LAYBACK KERB........................... 33





Summary

Provides requirements and guidance for drainage of public assets or infrastructure that will become a publicasset. Tables and graphs listed in the appendices provide Lake Macquarie City Council specific data andmust be used in the analysis. Section 2 provides detailed guidance for private developments to supplementthe information in DCP No.1.

Disclaimer

Lake Macquarie City Council has made reasonable effort to ensure that the information contained in thisdocument was current and accurate at the time the document was created and last modified. The Councilmakes no guarantee of any kind, and no legal contract between the Council and any person or entity is to beinferred from the use of or information in this document.

The Council gives no warranty and accepts no responsibility for the accuracy or completeness of theinformation. No user should rely on the information, but instead should check for confirmation with theoriginating or authorising body. The Council reserves the right at any time to make such changes as itdeems appropriate to that information.

Any links to external web-sites and/or non Lake Macquarie City Council information provided in thisdocument are provided as courtesy. They should not be construed as an endorsement by Lake MacquarieCity Council of the content or condition or views of the linked materials.

Copyright © 2002 Lake Macquarie City Council

This document and its contents are subject to copyright under the laws of Australia and, throughinternational treaties, other countries. The copyright information and materials in this document are ownedby the Lake Macquarie City Council although the copyright in some materials incorporated within thisdocument may be owned by third parties.

You are permitted to print extracts of this information and materials for your personal use only. None of thismaterial may be used for any commercial or public use. You must not modify the copy from how it appears

in this document and you must include the copyright notice "© 2002 Lake Macquarie City Council" on the

copy.You must not otherwise exercise the copyright in the whole or any part of this document for any otherpurpose except with the written permission of the Council or as expressly permitted by statute.

Department Name: Integrated Planning Lake Macquarie City Council126-138 Main Road Speers Point, NSW 2284Box 1906, Hunter Region Mail Centre, NSW 2310Telephone: 02 4921 0333Facsimile: 02 4958 7257email: [email protected]: www.lakemac.com.au





Revision History

Rev.No.

DateChanged

ModifiedBy

Details/Comments

1 2011 IntegratedPlanning

Master 29/01/2008 LMC2

ConsultingGroup

Master Document - adopted by Council on 29 January 2008





1 INTRODUCTION

This guideline must be read in conjunction with:

• DCP 1

• the Engineering Specification, Aus-Spec 1, Part D5 Stormwater Drainage Design and

• Lake Macquarie City Council’s Stormwater Treatment Framework & Stormwater Quality ImprovementDevice Guidelines.

For drainage of public assets or infrastructure that will become a public asset, these documents provide therequirements and guidance. The tables and graphs listed in the appendices (section 4) provide LakeMacquarie City Council specific data that must be used in the analysis.

For private developments, section 2 provides detailed guidance to supplement the information in DCP 1.





2 DESIGN GUIDELINES FOR ON-SITE STORMWATER MANAGEMENT

2.1 INTRODUCTION

The following guidelines are to be adopted for Residential Development, Industrial and CommercialDevelopments. Where works are proposed to become public assets and handed over to Council, the worksshall be designed in accordance with the Lake Macquarie City Council subdivision and DevelopmentEngineering Guidelines Part 1 Design Specification D5 Stormwater Drainage Design. These guidelines areto be used in conjunction with DCP No.1. Reference is made to the Lower Hunter and Central CoastRegional Environmental Strategy (LMCC REMS) practice notes 1-11. (Authored by Ian Donovan, PeterCoombes and associates).

DCP 1 prescribes a step-wise approach to the application of on-site stormwater management based on thenumber of dwellings (on equivalent tenements).

These plans may be prepared, based on guidelines and practice notes, by a competent designer.

For larger developments, a detailed design is to be prepared and certified by a practicing Civil Engineerbeing a member of the Institute of Engineers (Australia). Certain specialist in-puts may also be requireddepending on the solutions proposed. Eg Geotechnical Engineer, Landscape Architect.

2.2 SITE DISCHARGE INDEX

Ref LH & CC REMS Practice Note 11.

Site Discharge Index (SDI) is defined as the ratio of the impermeable area that drains directly to a drainagesystem (DC) to the total site area (S).

SDI = DC / S

DCP No.1 sets a performance criteria of 0.1 (10%) for the maximum allowable SDI (Practice Note 11explains how to determine the SDI in some detail).

Therefore, 90% of stormwater runoff from any site must be managed through suitably designed stormwatersource controls. These guidelines assist in the design of these controls, porous paving, infiltration devices,water tanks and associated water re-use. The guidelines supplement LHCC REMS Practice notes 1-11.

2.3 GENERAL PRINCIPLES

All designs should:

• Consider the local constraints, eg. catchment lie of the land, soil types, geotechnical conditions,adjoining development, available drainage capacity and easements and vegetation.

• Manage stormwater so that there is no nuisance flows to adjoining properties.

• Cater for runoff from outside the site and from adjoining properties, ensuring that outside runoffbypasses the onsite detention storage (if applicable). The design shall ensure that no works such as;filling, retaining walls etc. will impede the flow from upstream properties.

• Conveyance of the 100 year ARI runoff onto and from the site must be considered, with particularregard to the effect on site floor levels and any off site structures downstream.

• Consultation with Council’s Development Assessment and Compliance Department should be madeto determine design criteria for individual drainage systems and to establish whether Council hascarried out investigations and designs in the vicinity, or has a local management plan.

2.4 GENERAL REQUIREMENTS1. Roof water and site drainage is to be sized in accordance with the Building Code of Australia and

AS/NZS 3500.3.2.







2.5 DEVICE SPECIFIC REQUIREMENTS

2.5.1 ON-SITE STORMWATER DETENTION (OSD)For residential developments larger than a dual occupancy and for all commercial and industrialdevelopments, Council may require on site detention of stormwater.

2.5.1.1 DETENTION SYSTEMS

A number of on-site detention systems will be considered by Council. These may include in-ground tanks,aboveground tanks, above ground depressions in driveways or landscaped areas etc. The following listdetails some items that should be considered in design solutions.

In-Ground tanks

• Ease of access for maintenance and visual inspection shall be a design consideration. Access shallbe available via a lockable grate (min 600 * 600mm). For tanks deeper than 1.2 metres step irons

shall be provided.• Tanks shall incorporate at least a grate at each end of the tank for ventilation and ease of cleaning.

The preferred location for the grates would be above the inlet and outlets pipes.

• Any orifice for the control of discharge from the tank shall be screened to prevent blockage of theorifice.

• A high-level relief overflow pipe shall be provided to cater for flows in the event that the main outletfrom the tank becomes blocked.

• Tanks are not to store water permanently unless specifically designed for water reuse applications,and having a dedicated detention volume.

Above Ground Storages in Driveway & Parking Areas

• Shall not exceed 200mm in depth.

Above Ground Storages in Landscaped Areas

• Generally should not exceed 300mm for storage depth. For detention basins deeper than 300mm, orbasins that also store permanent water, personal safety measures (fencing, low batter slopes etc.)shall be incorporated.

• Shall be located in areas of high visibility to ensure regular maintenance

• Shall be designed to include measures to discourage unauthorised future modifications. Regardlessof this the volume shall be increased by 20% over the design volume to cover losses caused byvegetation growth, topsoiling etc.

Rainwater Tanks

• Rainwater tanks and the reuse of site water is encouraged in residential development. These systemswill be assessed by Council on a site-specific basis. OSD capacity can be accommodated by adedicated detention volume.

2.5.1.2 DESIGN GUIDELINES FOR OSD SYSTEMS

The following guidelines are acceptable design procedures for the computation of OSD systems with storagevolumes less than 100m

3. If this method produces a storage volume of greater than 100m

3, a recognised

routing method must be used.

1. Inflow

Inflow shall be based on runoff from the developed site.

A 1 in 20 year average recurrence interval storm shall be adopted for inflow calculations. (Q20dev)

2. Outflow





The maximum outflow from the basin shall be computed on a 1 in 5 year average recurrence interval storm,based on runoff from the undeveloped site. (Q

5und).

The Undeveloped site is the site in its natural state. ie 0% impervious.

Detention Volume Calculation.

The following formula can be used to estimate the detention volume.

Detention Volume (m3) = (Q

20dev - Q

5und) x t

c20 dev x 0.06 (eq 1)

where:- Q20

dev (litres/sec) Q5und (litres/sec) t

cdev (minutes)

NB. The flow from the site for the Q100

dev shall be checked to ensure that it does not exceed the Q100

und. Thefollowing formula may be used:-

Q100

dev - Q20

dev + Detention outflow (normally = Q5und) ≤ Q

100und (eq 2)

If the above equation is not satisfied then generally the detention outflow may need to be further constricted

with a corresponding increase in detained volume. The First check would be to assess the volumedifference between the Q

100dev & - Q

100und.

ie Vol = (Q100

dev - Q100

und) * 0.06 * x tc

100 dev (eq 2a)

Restraints

1. Minimum surface fall shall be 1%;

2. Charged drainage systems will not be accepted in most instances (see “Section F – AlternateDischarge Systems” below)

3. Non-habitable floor levels shall be a minimum of 150mm above the stored water level or 100mmabove the overflow level, which ever is greater;

4. Notwithstanding (i), (ii), (iii) and (iv) the standards outlined in AR & R 1987 shall be adopted, in regard

to detention systems.

Overflow

All storages shall be provided with an approved overflow facility to cater for controlled discharge of waters inexcess of the design event. Overflows shall be designed to cater for flows up to the 1 in 100 year averagerecurrence interval storm. Any overflows shall not exceed the 100 year undeveloped flow from the site.

2.5.2 RAINWATER TANKS – ROOFWATER

(Ref: LHCC REMS Practice Note 4).

The tank capacity should be designed to suit the catchment and reuse demand. Council is investigatingsuitable design models, and sourcing local data for input. As a guide a typical house will require a tankcapacity between 5000 to 15000 litres.

If rainwater is to be reused for household non-potable in-house use such as toilets and hot water systems,the following requirements apply:

Supply source

• Rainwater is sourced only from roof surfaces.

• If supply is supplemented by interconnection with a reticulated system operated by a water supplyauthority, backflow prevention is provided in accordance with Australian Standard AS 3500.1.2.

Treatment and use

• The collection system incorporates an effective first flush device for removing roof surfacecontamination. This should cater for the first 1mm of rainfall.

• The tank system is connected to toilet and hot water fixtures.





• There is no connection to other indoor fixtures unless the supply is treated to potable standard by anapproved purification system.

Drainage

• Overflow discharges to an infiltration trench or a piped stormwater drainage system.

Noise

• Noise emissions from any pumps do not exceed 5dB(A) above ambient background noise levelmeasured at the allotment boundary.

Recommended sources for design and best practice

• Refer to Item 9 in Schedule 1.

2.5.3 STORMWATER TANKS

Water tanks designed for collection of surface runoff must satisfy the following requirements:Supply source

• Rainwater is sourced from a combination of roofs, driveways, paved surfaces or grassed areas.

• There is no interconnection with a reticulated system operated by a water supply authority.

Treatment and use

• The collection system incorporates suitable treatment measures, such as a first flush pit or asand/gravel filter.

• The tank system is connected to irrigation or other outdoor fixtures, but is not connected to indoorwater fixtures.

• All fixtures connected to the supply system are marked ‘NOT SUITABLE FOR DRINKING’.

Drainage

• Overflow discharges to an infiltration trench or a piped stormwater drainage system.

Noise

• Noise emissions from any pumps do not exceed 5dB(A) above ambient background noise levelmeasured at the allotment boundary.

2.5.4 INFILTRATION

Infiltration devices must be properly designed to perform satisfactorily and to avoid adverse impacts onadjoining development.

Where conditions are otherwise suitable (Refer Tables 1-3), and the site falls towards adjoining properties,the device is to be a minimum of 5m from the boundary (normal to the contours). In these situations thedevice must also have an overflow connected to an inter-allotment drainage system.

In other situations the device must be wholly within the development lot, and overflows discharged to aswale, landscaping or a piped stormwater drainage system.

The following requirements apply:

• Table 1 sets out unsuitable conditions for infiltration devices.

• The infiltration trench shall be designed by a Consulting Engineer.

• Site testing shall be undertaken to establish the permeability of the soil.

• The trench system shall be designed to infiltrate the runoff from the site for all storm durations up tothe 20 year ARI. Any surcharge from the system shall not exceed the respective undeveloped flow. Asuitable time-area computer model shall be used such as ILSAX.




Handbook of Drainage Deisgn Criteria

• The trench system shall be designed so as to avoid clogging by sediment and leaf litter and allow forcleaning and inspection. (see the attached typical diagrams)

• Should be located an adequate distance from existing, or possible future, foundation locations andadjacent property boundaries. Refer to Table 2.

Figure 1 - XXXXXXXXXXXXXXXXXXXXX

Table 2 - Unsuitable conditions for infiltration trenches

Loose sands

Heavy clays

Bedrock exposed at surface

Shallow soil (<2 metres) over rock or shale

Steep terrain (slopes > 10%)

High water table (depth <1 metre blow surface)

Contaminated sites

Page 10 – F2009/00952February 2012 – Exhibiti on Draft





Table 3 - Minimum separation between infil tration trenches and build ing

Soil Type Hydraulic conductivity Distance tofootings

Sand > 180 mm/hr 1 metre

Sandy clay 180 – 36 mm/hr 2 metres

Medium clay 36 – 3.6 mm/hr 4 metres

Reactive clay 3.6 – 0.036 mm/hr 5 metres

2.5.5 POROUS PAVING

Porous paving should satisfy acceptable standards for site suitability, installation, maintenance andprotection from material likely to hinder performance.

Site selection and protection from sediment

• The area to be paved does not receive high vehicular traffic volumes or regular use by heavy vehicles.

• The area to be paved is not located immediately downstream from areas likely to contribute significantamounts of sediment, debris or windblown material.

• Sediment traps, vegetated filter strips or specially designed gutter systems are installed upstream ofporous paving so as to reduce sediment inputs and minimise likelihood of clogging, particularly duringthe construction phase.



2.5.6 RUNOFF CONTROLS FOR STREETS AND CARPARKS

Runoff from streets, car parks or other extensive paved areas is adequately treated before discharge to aninfiltration device, piped drainage system or natural waterway.

Treatment measures

• A treatment system is designed and installed that incorporates one or more of the following measures:

o Gross pollutant trap

o Sand/gravel filter

o Grassed swales

o Vegetated filter strip

o Constructed wetland



2.5.7 AQUIFER STORAGE AND RETRIEVAL

Aquifer storage and retrieval of rainwater for outdoor, industrial or other uses satisfies acceptable standardsfor public health, environment protection, risk management, and sustainable resource utilisation.

Injection, retrieval and use

• Rainwater is suitably treated prior to aquifer injection.

• Aquifer extraction and recharge are balanced over an average year.

• The quality of water extracted from the aquifer is suitable for the proposed use.





Design, installation and maintenance

• The system is the subject of a detailed design and management plan prepared by qualified personnel

that addresses relevant hydrological, hydrogeological, soil contamination and public health issues.

Other approvals

• Water retrieval is in accordance with an access licence under the Water Management Act 2000.

• Requirements of the Department of Land and Water Conservation and the Environment Protection Authority are satisfied.



2.5.8 WASTEWATER REUSE

Wastewater treatment and utilisation (including ‘greywater’ and ‘blackwater’) satisfies acceptable standardsfor public health, environment protection and amenity of nearby properties.

Design, installation and maintenance

• The system is the subject of a detailed design and management plan prepared by qualified personnelthat addresses relevant hydrological, hydrogeological, soil contamination and public health issues.

Environment safeguards

• Design, construction and maintenance of the system incorporates effective measures to:

o Prevent the spread of pathogens or viruses to waterways, soil, air, animals or humans

o Prevent nuisance odour or other amenity impacts

o

Prevent contamination of soil or watero Discourage insect pests and vermin

Other approvals

• Installation of a sewage management facility is approved under Chapter 7 of the Local Government Act 1993.

• The system satisfies any requirements of the Department of Health and the Environment Protection Authority.







2.6 ALTERNATE DISCHARGE OPTIONS

2.6.1 INTER-ALLOTMENT DRAINAGE EASEMENTS

Interallotment Drainage Easements

An interallotment drainage easement is required to be created wherever it is necessary to conveystormwater across lands, other than the development site, to gain access to the public drainage system or anatural watercourse.

• Council will not approve a Development Consent where an easement is required for drainage until :-

o Evidence of a written agreement from the relevant landowners has been provided to Council

o A preliminary stormwater plan has been assessed by Council

• Council will not approve the corresponding Construction Certificate until:-

o Evidence has been provided to Council that the easement has been registered with the Landand Property Information NSW (formally Land Titles Office).

• Where an easement has been created on a downstream property for a development that is required tohave on site detention, the pipe in the easement shall convey the 100 year discharge from thedevelopment site. This would typically be the 100 year developed flow less the detained flow.

Flow in easement pipe = (Q100

dev - Q20

dev + Q5und) (eq 2b)

2.6.2 PUMP SYSTEMS

The use of pump systems is discouraged by Council, however Council may permit pump systems under thefollowing circumstances:-

• Evidence shall be provided to Council that all avenues to secure easements through downstream

properties has failed. Copies of letters to and from adjacent landowners, that include details of offersof financial compensation, would be the minimum evidence required.

• The associated detention storage for a pump system shall store the difference in volume of runoff fromthe 100 year developed ARI 30 minute storm and the 100 year undeveloped ARI 30 minute storm.

Volume (m3) = (Q100

dev –Q100

und ) x 30min x 0.06 (eq 3)

where:- Q100

dev (litres/sec) Q100

und (litres/sec)

• The discharge from the pump line at the kerb shall not exceed the 5 year ARI undeveloped flow fromthe site.

• The pump line shall terminate within the property at a stilling pit from which drainage is by gravity(where possible) to the kerb. This is to reduce flows to acceptable velocities.

• Pumped stormwater disposal systems shall be designed using 2 pumps operating alternatively.

• An Inspection and Maintenance schedule shall be incorporated into the Strata By-Laws orManagement Statement (if Community Title).

The design of the system shall be such that if overflow does occur, the overflow would be spread to mimicnatural sheet flow.

2.6.3 CHARGED SYSTEMS

• Are generally not acceptable for developments larger than one single dwelling

• The system must be completely sealed with an inspection/cleaning eye at the lowest point.

• The roof gutter must be no less than 2 metres above the corresponding kerb.







3 SCHEDULE 1 - RECOMMENDED SOURCES FOR DESIGN AND BEST

PRACTICESItem No Reference

1 Lake Macqaurie City Council. Stormwater Treatment Framework & Stormwater QualityImprovement Device Guidelines. WBM Oceanics Australia for Lake Macquarie CityCouncil

2 Commonwealth Department of Housing & Regional Development (1995). AMCORDPractice Notes. PND 15 – Landscape Guidelines for Water Conservation. AGPS,Canberra.

3 Department of Housing & Department of Land & Water Conservation (1998). ManagingUrban Stormwater: Soils and Construction. DoH & DLWC, Sydney.

4 Department of Housing & Department of Land & Water Conservation (1998).

DLWC, Sydney.

5 Department of Local Government, Department of Housing & Department of Land &Water Conservation (1998). Department of Health & Environmental Protection Authority(1998). Environmental Health Protection Guidelines: On-site Sewerage Management forSingle Households. Department of Local Government, Sydney.

6 Environment Protection Authority (1998). Managing Urban Stormwater: TreatmentTechniques. EPA, Sydney.

7 Geary P.M. (1998) Domestic wastewater – treatment and reuse (RAIA EnvironmentDesign Guide). Royal Australian Institute Of architects, Sydney.

8 Australian Standard AS 3500.1.2.

9 Coombes, P. (2002). Water Smart Practice Note No. 4 – Rainwater Tanks. HunterRegional Organisation of Councils, Newcastle.

10 Coombes, P. (2002). Water Smart Practice Note No. 5 - On-site Infiltration. HunterRegional Organisation of Councils, Newcastle.

11 Coombes, P. (2002). Water Smart Practice Note No. 6 – Paving. Hunter RegionalOrganisation of Councils, Newcastle.

12 Paskin, R. (2002). Water Smart Practice Note No. 2 - Site Planning. Hunter RegionalOrganisation of Councils, Newcastle.

13 Paskin, R. (2002). Water Smart Practice Note No. 7 - Landscape Measures. Hunter

Regional Organisation of Councils, Newcastle.

14 Paskin, R. (2002). Water Smart Practice Note No. 8 - Landscape Practices. HunterRegional Organisation of Councils, Newcastle.

15 Coombes, P. (2002). Water Smart Practice Note No 10 – Groundwater. Hunter RegionalOrganisation of Councils, Newcastle.





4 APPENDICES

4.1 Overland Flow Time – Table

4.2 Overland Flow Time – Graph

4.3 Gutter Flow Time

4.4 Intensity/Frequency/Duration Diagram

4.5 Runoff Coefficients

4.6 Hydrological Design Sheet 1

4.7 Hydrological Design Sheet 2

4.8 Hydrological Design Sheet 34.9 Hydraulic Design Sheet

4.10 Kerb Inlet Capacity 2.4m lintel




4.14 Sag Inlet Capacity – Crossfall

4.15 Interallotment Drainage Connection for Individual Property

4.16 Double Grate Extended Kerb Inlet Pit Detail – Barrier Kerb

4.17 Double Grate Extended Kerb Inlet Pit Detail – Layback Kerb





4.1 OVERLAND FLOW TIME - TABLE






4.2 OVERLAND FLOW TIME – GRAPH






4.3 GUTTER FLOW TIME






4.4 INTENSITY/FREQUENCY/DURATION DIAGRAM






4.5 RUNOFF COEFFICIENTS






4.6 HYDROLOGICAL DESIGN SHEET 1






4.7 HYDROLOGICAL DESIGN SHEET 2







4.8 HYDROLOGICAL DESIGN SHEET 34.8 HYDROLOGICAL DESIGN SHEET 3







4.9 HYDRAULIC DESIGN SHEET






4.10 KERB INLET CAPACITY 2.4M LINTEL
























4.14 SAG INLET CAPACITY – CROSSFALL






4.15 INTERALLOTMENT DRAINAGE CONNECTION FOR INDIVIDUAL PROPERTY






4.16 DOUBLE GRATE EXTENDED KERB – INLET PIT DETAIL – BARRIER KERB






4.17 DOUBLE GRATE EXTENDED KERB – INLET PIT DETAIL – LAYBACK KERB





Documents

Att 30 12STRAT005 Engineering Guidelines - Part 4 Handbook of Drainage Design Criteria