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STORMWATER MANAGEMENT Contract No.

D07-Stormwater Management- Hastings 2003 Rev 1.doc February 2004 (Copyright )

DEVELOPMENT DESIGN SPECIFICATION

D7

STORMWATER MANAGEMENT

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IPWEA MID NORTH COAST GROUP AUSPEC-1 D07-Stormwater Management- Hastings 2003 Rev 1.doc November 2003 (Copyright )

Amendment Record for this Specification Part

This Specification is Council’s edition of the AUS-SPEC generic specification part and includes Council’s primary amendments.

Details are provided below outlining the clauses amended from the Council edition of this Specification Part. The clause numbering and context of each clause are preserved. New clauses are added towards the rear of the specification part as special requirements clauses. Project specific additional script is shown in the specification as italic font.

The amendment code indicated below is ‘A’ for additional script ‘M’ for modification to script and ‘O’ for omission of script. An additional code ‘P’ is included when the amendment is project specific.

Amendment Sequence No.

Key Topic addressed in amendment Clause No. Amendment Code

Author Initials

Amendment Date

0 Customisation for Hastings Council Local Government Area

All inclusive OAM HC 31/7/03

1 Relocation of Contents page to beginning of document .

n/a AOM HC 26/02/04


HASTINGS COUNCIL AUSPEC-1 D07-Stormwater Management- Hastings 2003 Rev 1.doc February 2004 (Copyright )

Page 1

CLAUSE CONTENTS PAGE

GENERAL ................................................................................................................................3

D7.01 SCOPE .........................................................................................................................................3

D7.02 OBJECTIVES .................................................................................................................................3

D7.03 REFERENCE AND SOURCE DOCUMENTS.........................................................................................4

D7.04 PLANNING OF DESIGN ...................................................................................................................5

D7.05 DESIGN REQUIREMENTS...............................................................................................................6

D7.06 ACCEPTABLE MODELLING TOOLS AND METHODS ...........................................................................6

D7.07 TOTAL WATERCYCLE MANAGEMENT PLAN .....................................................................................8

D7.08 STORMWATER MANAGEMENT PLAN...............................................................................................8

D7.09 BUFFER ZONES ............................................................................................................................8

STORMWATER QUALITY REQUIREMENTS ......................................................................9

D7.10 STORMWATER RUNOFF .................................................................................................................9

D7.11 WATER QUALITY............................................................................................................................9

D7.12 STORMWATER TREATMENT MEASURES ........................................................................................13

STORMWATER QUALITY IMPROVEMENT DEVICES......................................................14

D7.13 SELECTION OF STORMWATER QUALITY IMPROVEMENT DEVICES ...................................................14

D7.14 MAINTENANCE COST ...................................................................................................................14

D7.15 WET RETENTION BASINS/PONDS ..................................................................................................15

D7.16 TRASH RACKS.............................................................................................................................18

D7.17 GROSS POLLUTANT TRAPS ..........................................................................................................18

D7.18 LITTER BASKETS ........................................................................................................................19

D7.19 CONSTRUCTED WETLANDS AND PONDS ......................................................................................19

D7.20 INFILTRATION SYSTEMS ..............................................................................................................23

D7.21 VEGETATED SWALES..................................................................................................................26

D7.22 BIORETENTION SYSTEMS ............................................................................................................27

EROSION AND SEDIMENT CONTROL .............................................................................28



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D7.23 EROSION AND SEDIMENT CONTROL PLAN .......................................................................................28

D7.24 SOIL DISTURBANCE .......................................................................................................................28

D7.25 “NO ACCESS” AREAS .....................................................................................................................28

D7.26 DIVERSION WORKS .....................................................................................................................29

D7.27 DROP DOWN DRAINS ...................................................................................................................30

D7.28 STOCKPILES ...............................................................................................................................30

D7.29 SEDIMENT BASINS/TRAPS/DAMS...................................................................................................30

D7.30 SEDIMENT TRAPS / BARRIERS FOR MINOR CATCHMENTS...............................................................31

D7.31 LEVEL SPREADERS .....................................................................................................................32

D7.32 THE LOCATION OF SHAKEDOWN AREAS AND ACCESS STABILISATION.............................................32

D7.33 WIND EROSION/DUST CONTROL ...................................................................................................33

D7.34 REQUIREMENTS FOR BUILDING SITES ..........................................................................................34

D7.35 EXTERNAL SITE REQUIREMENTS ..................................................................................................34

D7.36 DEFINITIONS...........................................................................................................................35

APPENDIX A.......................................................................................................................39

TABLE D7A – 2 WETLAND ZONES , TYPICAL SPECIES AND FUNCTIONAL PROCESS (Somerset et al 1996)..................39

TABLE D7A - 3 TOTAL WATERCYCLE MANAGEMENT PLAN REQUIREMENTS ................................................................44

TABLE D7A - 4 STORMWATER MANAGEMENT PLAN REQUIREMENTS - SMP.................................................................45

TABLE D7A - 5 EROSION AND SEDIMENT CONTROL PLAN REQUIREMENTS – ESCP......................................................47

TABLE D7A – 6 POLLUTANT REDUCTION EFFICIENCIES ( Brisbane City Council Design Guidelines for Stormwater Quality Improvement Devices Final Draft – 4 November 1999)...........................................................................49

TABLE D7A – 7 Brisbane City Council design guidelines for Stormwater Quality Improvement Devices Final Draft – 4 November 1999 .........................................................................................................50

Figure D7-10 Hastings and Camden Haven River Catchments water quality regions ......................................51

Table D7A – 8 Environmental Values Hastings and Camden Haven Regions..................................................52

Fig D7A - 11 Coastal Region Monthly Rainfall Distribution................................................................................53

Fig D7A - 12 Lower Inland Region Monthly Rainfall Distribution ......................................................................54

Fig D7A - 13 Upper Inland Region Monthly Rainfall Distribution .......................................................................55

Table D7A – 9 Landuse and Pollutant Concentrations .....................................................................................56



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DEVELOPMENT DESIGN SPECIFICATION D7

STORMWATER MANAGEMENT

GENERAL

D7.01 SCOPE

1. Works covered by this specification include any land development or use including Private, Council or other Authority works which may impact on the quality and quantity of runoff discharging from the site or to any natural or artificial waterway or water body. It includes, but, is not limited to construction, operation and use of:

• Subdivisions • Buildings, structures and surrounds • Earthworks, dams, lakes, roadworks and drainage works • Trenches, pipelines • Development site works (access roads, car parks, landscaping, drainage works, pedestrian facilities,

fencing etc) • Extractive industries • Mining

Land Development and Authority Works

2. This specification details the information relating to stormwater quality required to accompany development applications and construction certificate applications. Or in the case of Council or Authority works, Part V assessments and detailed engineering plans.

Specification Details

D7.02 OBJECTIVES

1. To provide detailed design provisions in line with Ecologically Sustainable Development (ESD), Water Sensitive Urban Design (WSUD) and Total Water Cycle Management (TCM) and principles.

Principles

2. Ensure retention and enhancement of natural watercourses, aquatic habitat and riparian vegetation. Retain natural watercourses

3. Ensure stormwater runoff meets specified quality objectives during the construction and occupation phase of a development.

Stormwater Quality

4. To promote scenic, landscape and recreational values for stream corridors through the integration of stormwater treatment techniques into the landscape by incorporating multiple use corridors that maximise the visual and recreational amenity of developments.

Integration

5. Provide an effective major and minor stormwater system that is cost effective and incorporates life cycle costs (LCC) of investigation, design, operation, maintenance and replacement of stormwater infrastructure.

Effective Stormwater systems



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D7.03 REFERENCE AND SOURCE DOCUMENTS

(a) Council Specifications D5 - Stormwater Drainage Design D13 - Street & Landscape Design C211 - Control of Erosion and Sedimentation C273 - Landscaping

(b) NSW State Legislation Environment Planning & Assessment Act, 1979 Dams Safety Act, 1978 Soil Conservation Act, 1938 Water Act, 1912 EPA Act, 1979 Local Government Act, 1993 Water Management Act 2000 No. 92 Protection of Environment (Administration) Act 1991 Protection of the Environment (Operations) Act 1997 Coastal Protection Act 1979 SEPP 71 Coastal Protection SEPP 14 Coastal Wetlands Environment Planning and Assessment Regulation 2000

(c) State Authorities NSW Department of Housing

- Soil and Water Management for Urban Development – August 1998

- Managing Urban Stormwater – Soils and Construction 1998 Roads and Traffic Authority - Erosion and Sedimentation Design Considerations. Soil Conservation Service - Erosion and Sediment Control - Model Policy and Code of Practice (Discussion

Paper). NSW Department of Land and Water Conservation (DLWC)

- Urban Erosion and Sediment Control. - Constructed Wetlands

NSW Acid Sulfate Soil Management Advisory Committee

- Acid Sulfate Soil Manual 1998 MUS

- Urban Design to be released February 2004. EPA

- Managing Urban Stormwater Council Handbook 1997 - Water Quality and River Flow Interim Environmental Objectives 2000



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(e) Other Tweed Shire Council

- D7 Stormwater Quality North Coast NSW Sustainable Water Model Planning Provisions (Draft – 2003) The Institution of Engineers Australia - Australian Runoff Quality Manual June 2003 (ARQ) (Draft) Cooperative Research Centre for Catchment Hydrology

- Water Sensitive Road Design- Design options for improving stormwater quality of road runoff (Report 00/1 Aug 2000)

- Water Sensitive Urban Design – A Storm Water Management Perspective. (Report 02/10 Sept. 2002)

Hastings Council - Guide for Building Sites - Erosion and Sediment control code (Code 18) - Total WC Management Strategy (Expected completion April 2004) - Hastings Stormwater Management Plan

Standards Australia - AS3500.5: 2000 National plumbing and Drainage Part 5: domestic installations

Brisbane City Council

- Water Quality Management Guidelines Ver. 1 2000 - Stormwater Quality Improvement Devices Final Draft November 1999 - Natural Channel Design Guidelines December 2000 - Guidelines For Selecting Remedial Works July 1997

Melbourne Water - Constructed Wetland Systems Design Guidelines for Developers 2002

Lower Hunter and Central Coast Regional Environmental Management Strategy (LHCCREMS)

- Draft Model Planning Provisions 1999 (Donovan, Cameron and Coombes) AUSTROADS

- AP-R232 Guidelines for treatment of stormwater runoff from road infrastructure.

D7.04 PLANNING OF DESIGN 1. Prior to commencement of design an assessment of the physical characteristics and constraints of soils, landform and drainage of the site shall be carried out. Planning and design of land development shall be based on water quality objectives to ensure there are either no negative stormwater impacts, or there is a beneficial impact, on upstream or downstream land, watercourses and receiving waters. Water quality design objectives include, but are not limited to, the following:

• Existing natural watercourses and riparian vegetation (with appropriate buffer widths) are to be retained and restored. Natural watercourses shall not be replaced with artificial drains or pipes.

• Land use development design will have regard to landform and drainage of the site, the physical characteristics and limitations of soils (including identification of actual and potential acid sulphate soils) and likely impacts on stormwater quality.

• Designs shall ensure stormwater runoff discharged from development sites conforms with water quality objectives as outlined in this specification.

Plan submission requirements include, but are not limited to the following: • Plans submitted with a development application must be sufficiently detailed to allow the feasibility of

stormwater quality management proposals to be assessed. • Plans submitted with a construction certificate must contain all appropriate engineering drawings,

operation/cleaning/monitoring/action/maintenance schedules.

Site Characteristics

Water Quality Objectives



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2. No site works shall commence prior to approval of the Erosion & Sediment Control Plan (ESCP) and/or the Stormwater Management Plan (SMP). Implementation must be supervised by personnel with appropriate qualifications and/or experience in soil conservation on construction sites.

Approval of the ESCP & SMP

D7.05 DESIGN REQUIREMENTS

Design Average Recurrence Interval (ARI)

1. Unless advised elsewhere in this specification, works to capture pollutants from stormwater runoff shall be designed to accommodate a design storm equivalent to a 3 Month ARI Storm Event (for calculation purposes 40% of the 1 year ARI storm event is to be adopted.), overflow / bypass arrangements are to be designed to accommodate a 1 in 100 year ARI storm event without erosion, scouring or structural damage to erosion or sediment control devices, or remobilisation of previously deposited sediment.

2. Erosion and sediment control works shall be designed in accordance with “Managing Urban Stormwater – Soils and Construction” NSW Dept of Housing 1998 (referred to subsequently as [REF 1] . “Australian Runoff Quality Manual” The Institution of Engineers Australia (ARQ) and “Acid Sulphate Soil Manual” NSW Acid Sulphate Soil Management Advisory Committee 1998 (ASSM).

References

D7.06 ACCEPTABLE MODELLING TOOLS AND METHODS

1. Three methods or a combination thereof are recommended to determine the requirements to maintain or enhance stormwater quality.

a. Best Management Practices (BMP).

b. An estimation of the average annual pollution loads from stormwater in kilograms of pollutant exported per year, relating land use, annual rainfall, catchment runoff characteristics and average pollutant concentrations to estimate the annual pollutant load generated from the catchment under both pre and post development conditions (refer to D7.06.8). Once the increase in pollutant loads is determined appropriate Stormwater Quality Improvement Devices (SQID’s) shall be selected to conform to the criteria specified in Table D7-7. Refer to D7.25 and Appendix A Tables D7A-6 & D7A-7 for SQID selection.

c. Comparison of water quality discharging from a proposed development catchment to predetermined water quality objectives (Tables D7-4 to D7-7). And the design of Stormwater Quality Improvement Devices (SQID’s) to enable conformance to the required water quality objectives (Tables D7A-6 to D7A-7). Refer to D7.06.04 for Water Quality Models.

Modelling Methods

2. Best Management Practices (BMP) for erosion and sediment control during construction are required for all works. Requirements are specified in sections D7.23 to D7.35 of this specification and in REF1. BMP Construction

3. For BMP’s to be applied to low risk developments such as Single Dwellings refer to D7.23. and Appendix A Table D7A-5 Low Risk Works

Single Dwellings 4. Water Quality Models. For development or development proposals which are deemed to be a High Risk to the environment. The following models and modelling approaches are acceptable for the purposes of demonstrating compliance with this specification MUSIC. AQUALM. Modelling approaches as listed in Chapter 13 of ARQ if appropriate to the requirements of water quality

objectives. Preliminary assessment using simple modelling techniques as specified in Section D7.06.8 D7.06.9

Water Quality Models

5. Drainage Models The following models and modelling approaches are acceptable to council for the purpose of demonstrating compliance with this Specification: - DRAINS, CIVILCAD or other models as approved by Council.

Drainage Models

6. Modelling Parameters. Modelling



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Refer to Appendix A and Specification D5 Stormwater Drainage Design for the parameters required for modelling of catchments within the Hastings LGA.

Parameters

7. Rainfall Data Set. Refer to Aus-Spec D5 Stormwater Drainage for IFD information for each region within the Hastings LGA The file (refer to Drains & Music Base Files) available from council provides the climatic data set to be used for modelling purposes.

Rainfall Data Set

8. For preliminary calculations, checking purposes and determination of pollutant loads for Low Risk Development the modelling technique using constant concentration levels may be used. The following formula shall apply.

L = PCvCA

Where L = average annual load (kg)

P = average annual rainfall (mm)

Cv = annual average volumetric runoff coefficient (dimensionless)

A = catchment area (km²)

C = average event mean pollutant concentration (EMC) (mg/L) (refer to Chapter 3 of ARQ for landuse & predicted pollutant loads) Refer to Table D7.4 and Appendix A Table D7A – 9

Preliminary Calculations Low Risk Developments

9. For Preliminary calculations, determination of increased annual runoff volumes and determination of increased pollutant loads for High Risk developments and works the Spreadsheet file: “Runoff Transposition V3-2.xls” shall be available from Council.

Preliminary Calculations High Risk Developments

10. For design purposes the Hastings LGA has been divided into regions with similar annual rainfall as follows:

a. Coastal Region – the area bounded by the eastern coastline, the northern & southern boundaries of the Council LGA and the area east of the Pacific Highway.

b. Lower Inland Region – the area bounded by the northern and southern boundaries of the Council LGA, all areas west of the Pacific Highway with an elevation below 150m AHD.

c. Upper Inland Region – the area as specified for the Lower Inland Region with an elevation above 150m AHD.

Rainfall Regions

11. The annual rainfall readings for the average dry, average and average wet year shall be used in calculations to determine the variation in pollutant loads and to size proposed infrastructure accordingly.

Range of Rainfall

Table D7.1a Runoff Coefficients

Table D7.1b Average Annual Rainfall Hastings Council Region Average Annual

Rainfall (mm) Coastal Region Wet Year 2062 Coastal Region Average 1526 Coastal Region Dry Year 1172 Lower Inland Wet Year 1814 Lower inland Average 1297 Lower inland Dry Year 974 Upper Inland Wet Year 1225 Upper Inland Average 1040 Upper Inland dry Year 837

Development Type Average Runoff Coefficient – Cv

Forest 0.20 Woodland 0.25 Agricultural 0.40

Open Space & Parks 0.35 Rural 0.30

Rural Residential 0.30 Low density Urban

Residential 0.60

High density Urban Residential

0.75

Industrial / Commercial 0.95



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D7.07 TOTAL WATERCYCLE MANAGEMENT PLAN TWMP

1. A Total Water Cycle Management Plan shall be required for developments consisting of greater than 100 lots or greater than 8 Hectares in area (which ever is lesser). Refer to Appendix A Table D7A - 3 for details of the requirements for a Total Watercycle Management Plan.

D7.08 STORMWATER MANAGEMENT PLAN SMP

1. A Stormwater Management Plan shall be required for all developments. For the plan requirements of High Risk Developments (Developments greater than 6 Lots and / or greater than 2500m²) and Low Risk Developments (Single dwellings and Duplexes less than 6 Lots or less than 2500m² in area). Refer to Appendix A Table D7A - 4

D7.09 BUFFER ZONES

1. Buffer zones are corridors of vegetation adjacent to ephemeral and permanent waterways or disturbed areas. The vegetation shall be retained in order to filter suspended solids and reduce the nutrient levels in run-off. Wetlands, stream and rivers adjacent to construction sites shall be protected by buffer zones.

Filters

2. Buffer zone performance increases as catchment area and slope gradient decreases. Buffer widths shall be nominated in accordance with Tables D7.2 and D7.3.

Performance

3. Where a conflict occurs in the determination of buffer widths between: slope, area, sensitivity & minor tributaries the greater distance shall be adopted. Refer to Fig. D7.1 To determine the category of drainage channel

Width

4 Buffer zones can reduce the need for other erosion and sediment control measures. However, contaminated water in a concentrated form shall require treatment both at its sources point and final disposal.

Contaminated Water

Fig. D7-1 Channel / Stream Ordering System

Table D7.2 Buffer Slope and Width Ratios Side Slope % Buffer Width in Metres

(total width) 2 15 4 20 6 30 8 40

10 50 12 60 14 70

Table D7.3 Riparian and Waterbody Buffers Catchment Area of Watercourse Buffer Distance in Metres (Distance

from each bank) <100 Ha. 20m

>100<500 Ha. 30m >500 Ha. 50m

Environmentally Sensitive 50m Minor tributaries, 1st,2ndOrder Drainage Channels/stream

10m



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STORMWATER QUALITY REQUIREMENTS

D7.10 STORMWATER RUNOFF

1. Any change of landuse within a catchment causes a variation to flow rate and duration of stormwater runoff.

Landuse

2. To maintain stormwater runoff from a catchment equivalent to the pre – developed or existing flow rate and duration a combination of detention and retention facilities shall be required.

3. Detention facilities shall be designed to attenuate the change in peak flow rate due to a change of landuse within a catchment to a level equal to the pre developed flow rate. Refer to Auspec Design Specification D5 Stormwater Drainage for details of detention requirements.

Detention

4. Retention facilities shall be designed to hold stormwater runoff within the catchment for a period of time to enable water to continue in the hydrological cycle via infiltration and evapotranspiration. Refer to Section 7.31 “Infiltration Systems” and Section 7.33 “Bioretention Systems” of this specification for further details of design requirements.

Retention

5. If the stormwater runoff flow rate and duration equivalent to the pre-developed conditions cannot be achieved an upgrade of the existing council stormwater infrastructure downstream of the discharge shall be required subject to approval by council.

Downstream Infrastructure

6. Design details shall be submitted to council to prove the adequacy of the existing system and/or the proposed upgrade works to handle the increase in flows.

7. Where the discharge point is located at a permanent natural waterway a permanent erosion control design shall be provided to prevent the erosion of the downstream waterway to which the catchment runoff is directed to. In lieu of NSW EPA documents relating to channel design (currently being developed) refer to Brisbane City Council design guidelines “Natural Channel Design December 2000” and “Guidelines for Selecting Remedial Works July 1997” .

Downstream Waterways

8. Where in-stream erosion control measures or upgrade of infrastructure works cannot be carried out by the proponent of the works a contribution (cost figures to be provided by Council) is to be provided for works to be carried out by Council. Erosion control measures shall be required from the discharge point of the catchment to the receiving waterway or to the next catchment discharge point with the shortest distance being the determinant.

D7.11 WATER QUALITY

1. Development or works that do not include water quality or quantity controls have the potential to increase pollutant loads of receiving waters, relative to those occurring under pre-development conditions.



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2. An assessment of water quality impacts and control measures to mitigate or improve the water quality shall be a carried out by the following process.

a. Identify the Water Quality Objectives (WQO).

b. Determine the Risk Category of the proposal.

c. Determine the type and condition of the receiving water ecosystem.

d. Determine the pollutant loads generated by the proposed works.

e. Determine the types of treatment measures to be used to mitigate or improve the water quality from the proposed works.

3. Water Quality Objectives (WQO) are used to describe the quality of water that is needed in a receiving water to protect or enhance Environmental Values (EV). Environmental Values are those values that a community believe a particular waterway should hold eg: ability to safely swim in a river or adjacent ocean beach, or the ability of a waterway to sustain healthy aquatic ecosystems.

Water quality objectives in this specification are based on the guidelines as specified in the “Water Quality and river flow interim Environmental Objectives for the Camden Haven and Hastings River catchments” Refer to Appendix A Fig. D7 – 10 and Table D7A – 8 and Chapter six (6) of the Australian Runoff Quality manual 2003. Aquatic ecosystem values are to be used as a base to determine the protection level required for a specified development. Unless determined otherwise by Council.

Water Quality Objectives.

4. Water quality objectives shall be evaluated over the full range of rainfall conditions (Refer to Appendix A Fig. D7A – 14 Regional Rainfall Distribution Hastings LGA)) to maintain the long-term protection of the pre determined Environmental Values (EV).

5. Water quality objectives shall be determined based on a developments “RISK” to the environment. Low Risk development (eg: single dwelling construction) will not be required to identify relevant water quality objectives for down stream receiving waters but will be required to follow Best Management Practices (BMP) in relation to the control of erosion, sediment and stormwater quality as outlined in this specification and in accordance with the document “ Managing Urban Stormwater – Soils and Construction, Department of Housing 1998” Chapter 9 – Building sites. (Or current equivalent document.)

Low Risk Development & BMPs’

6. High Risk developments are classified according to the following criteria. Any development or development proposal:

a. Located in a waterway corridor.

b. Located within the catchment of a wetland area.

c. Consisting of multiple dwellings or commercial uses with an impermeable surface area ( including roof area) in excess of 2500m² and / or

d. Subdivisions greater than 6 lots and / or

e. Industrial activities that are not impact assessable and at least 1000m² in uncovered storage/working space.

f. Uncovered car parks > 100 spaces.

High Risk Development



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7. The long-term water quality sustainability of a high-risk development shall be based on viable protection levels of aquatic ecosystems. The classification of protection levels of aquatic ecosystems is defined as:

a. Pristine ecosystem or unmodified ecosystem, having high conservation values and ‘protection’ status.

b. Slightly to moderately modified ecosystem, where the ecosystem is largely intact (habitats, limited catchment clearing) such that some ‘restoration’ of the original values is viable.

c. Highly modified ecosystem, where the original ecosystem is so disturbed that it cannot be restored to a slightly to moderately disturbed condition, but is capable of sustaining some ecological and conservation values with appropriate ‘management’. (Ref: ARQ Chapter 6)

Council shall confirm determination of the classification of the receiving ecosystem.

Ecosystem Type

8. Estimation of Sustainable Average Annual Export Load (SAAEL) is to be a risk-based process where the export loads are compared to the trigger level for the receiving waterway (ref: ARQ 6.3.1 ARQ approach to estimating sustainable catchment loads). The median insitu water quality indicator must be below the trigger level of a receiving waterway to comply with this specification. Refer to tables D7.4 to D7.7

Sustainable Average Annual Export Load

9. The assessment of potential water quality impacts shall be based on.

a. Changes in water quality discharging from a catchment and proposed management techniques to ensure no increase of or an improvement in water quality.

b. Increase in the average annual load of key pollutants, above that occurring under existing conditions or to levels compliant with predetermined water quality objectives.

10. Unmodified ecosystem median pollutant levels shall be within the or below those indicated in Table. D7.4 for compliance with this specification. (Sourced from ARQ and water quality and river flow interim environmental objectives Hastings and Camden Haven Rivers 2000 .)

Unmodified Ecosystems

Table D7.4 Unmodified Ecosystem

Receiving Water TP ug/L

TN ug/L

DO % Sr

PH Units

SS mg/L

Upland Stream 10-20 100-250 80-90 6.5-7.5 25 Lowland Stream 10-20 100-250 80-90 6.5-7.5 50 Lakes/Reservoirs 5-10 150-300 80-90 6.5-8.0 6

Estuaries 10-20 150-300 80-90 6.5-8.0 6 Marine 25 120 80-90 8.0-8.4 0.5

11. Modified ecosystem median pollutant levels shall be below those indicated in Table D7.5. for compliance with this specification.

Modified Ecosystems

Table D7.5 Modified Ecosystem

Receiving Water TP ug/L

TN ug/L

DO % Sr

PH Units

SS mg/L

Upland Stream 20 250 90-110 6.5-7.5 25 Lowland Stream 50 500 85-110 6.5-8.0 50 Lakes/Reservoirs 10 350 90-110 6.5-8.0 6

Estuaries 4 300 80-110 7.0-8.5 6 Marine 25 120 90-110 8.0-8.4 0.5

12. Highly modified ecosystem median pollutant levels shall be below those indicated in Table D7.6 for compliance with this specification.

Highly Modified Ecosystems



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Table D7.6 Highly Modified Ecosystem Receiving Water TP

ug/L TN

ug/L DO %

Sr PH

Units SS

mg/L Upland Stream 24 310 80-120 6.2-8.0 31 Lowland Stream 60 620 75-110 6.2-8.6 62 Lakes/Reservoirs 12 435 80-120 6.2-8.6 -

Estuaries 36 370 70-120 6.7-9.1 7 Marine 30 150 80-120 7.6-9.0 0.7

13. In addition to the aforementioned median pollutant levels, any stormwater treatments shall be designed to meet the minimum level of pollutant load objective in accordance with Table D7.7

Pollution Retention

Table D7. 7 Stormwater Treatment Pollutant Load (ARQ 2003)

Pollutant Objective Pollutant Objective Suspended Solids

SS 80% retention of

average annual load Sediment 100% retention of

sediment greater than 0.125mm for flows up to the 3 month ARI peak

flow Total Phosphorus

(TP) 45% retention of

average annual load Oil & Grease No visible oils for flows

up to the 3 month ARI peak flow

Total Nitrogen (TN)

45% retention of average annual load

Litter 100% retention of litter greater than 5

mm for flows up to the 3 mnth ARI peak flow



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D7.12 STORMWATER TREATMENT MEASURES

1. The main components required to enhance stormwater quality are as follows:

a. Vegetated Buffer Zones (VBZ) and filter strips, porous pavements, grass swales in landscaped areas or similarly treated areas to facilitate the natural assimilation of water pollutants and reduce run-off. Swales are not preferred as a substitute for kerb and gutter where on street parking is required, unless cars can be excluded from swale areas on roads serving small lots with numerous driveways or where gradients are <1% or >5%.

b. Where required, gross pollutant/sediment traps shall be designed to intercept litter, oil and debris to maintain visual quality in downstream waterways, and to reduce the coarse sediment load on downstream water management structures.

c. Wet retention ponds /permanent sediment ponds shall be designed to allow particulate matter to settle out operating under both sedimentation and macrophyte regimes.

d. Wetland (Nutrient) Filter shall be designed to enhance the removal of fine sediment and nutrients from stormwater run-off, (which are largely dependent on biochemical removal mechanisms).

e. Infiltration systems shall be designed to focus on the control of pollutants and the retention of stormwater.

f. Selection of stormwater quality enhancement devices and practises shall be based on current environmental guidelines and best practise management procedures. As a guide Tables D7A-6 and 7 may be used to select appropriate treatments.



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STORMWATER QUALITY IMPROVEMENT DEVICES

D7.13 SELECTION OF STORMWATER QUALITY IMPROVEMENT DEVICES SQID’s

1. The appropriate selection of Stormwater Quality Improvement Devices. (SQID’s) will assist developments meet Councils Water Quality Objectives (WQO). In selecting an appropriate SQID or combination of SQID’s the following process shall be followed:

a. Risk Category – identify whether the proposed development is ‘low risk’ eg: Single dwellings & Duplexes <6 Lots or < 2500m² or ‘high risk’ eg: Development >6 Lots and/or 2500m².

b. Pollutant Type – identify the target stormwater pollutants for the proposed land use for the construction and occupational phases of the development using tables D7A-3 And D7A-4 In appendix A

c. Construction Phase – during this phase the primary contaminant of concern is usually sediment. To identify the appropriate Best Management Practices (BMP) the guidelines contained within REF1 shall be used.

d. Occupational Phase (‘low risk’) – if the development is ‘low risk’ Water Quality Objectives (WQO) need not be identified. Table D7A-6 (Appendix A) shall be used to select which type of quality control device is appropriate. Table D7A -7 (Appendix A) may be then used to assist in sizing an appropriate device. Additional references can be used to provide alternative treatment devices if appropriate.

e. Occupational Phase (‘high risk’) – if the development is ‘high risk’ WQO’s shall be identified as outlined in section 7.06 Of this specification. Table D7A-6 (Appendix A) may be used to determine the appropriate types of devices, but detailed analysis shall be required to determine pollutant export loads and demonstrate that the device selection meets relevant WQO’s for receiving waters.

f. Maintenance Plan – where SQID’s are selected as an appropriate treatment device a maintenance plan shall be required as specified in table D7A-4 (Appendix A).

g. Documentation – the Stormwater Management Plan is to include details of the SQID’s selected, their location, the timing for installation, and the maintenance regime.

D7.14 MAINTENANCE COST

1. An evaluation of costs shall be submitted stating the initial establishment costs and the annual maintenance costs



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2. Establishment costs shall include the following:

a. Total cost of feasibility studies; grant application costs (where applicable).

b. Total conceptual, preliminary and detailed design costs.

c. Total construction costs including project management and/or contract management costs.

3. Annual maintenance costs shall include the following:

a. Administration costs.

b. Staff training.

c. Inspections.

d. Waste disposal.

e. Restoration of infrastructure within the maintenance period.

f. Monitoring of pollutant levels.

Note: costs shall include any construction difficulty associated with:

• Access requirements

• Service relocations or provision

• Geological conditions

• Shallow bedrock

• Water table level

• Permeability

• Erodibility

• stability

Establishment Costs

Maintenance Costs

D7.15 WET RETENTION BASINS/PONDS

1. Basins designed for water quality control should maximise the extent of settling. In general quiescent conditions and infiltration should be maximised.

Maximise Infiltration



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2. A wet retention basin can be located either on-line or off-line . Its capacity however needs to be considerably greater if it is located on-line. The wet retention basin usually has some form of energy dissipation at the inlet or a sufficient length-to-width ratio (greater than 2:1) to prevent short-circuiting of flow across the pond, although its shape may vary considerably. Ponds may vary in size, with the settling velocity of particles being the basis for design. Refer to chapter 11 of ARQ for details of appropriate design procedures to be adopted. Basins may be installed as smaller multiple units (in series) or as large single units. Fig D7-2 shows a typical preferred configuration of a wet retention basin.

Location and Size

Figure D7-2 - Configuration and Design of Wet Retention Basins



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3. Other design guides that will make the basin efficient in removing particles and provide for public safety include the following.

a. The minimum depth should be not less than 1.5 metres with an average depth of 2.5 metres. This discourages infiltration growth in the deeper portions of the pond and also the breeding of mosquitos.

b. The basins should have side slopes of 6(H) to 1(V).

c. If side slopes are to be steeper than 6(H) to 1(V) the basin/pond shall be enclosed by child proof security fence.

d. The maximum velocity through the pond based on a 1 in 1 year storm should not exceed 0.3 metres per second (at 2.5 metres depth, this is the maximum practical flow velocity at which optimum sediment removal can be achieved).

e. A minimum freeboard of 0.3 metres should be provided between a restricted discharge outlet for the pond and a storm overflow weir This discharge outlet should be designed so that the weir overtops on average three times per year. A freeboard of 0.5m shall be provided between the 1 in 100 year flood level and floor levels of dwellings.

f. Inlet and outlet structures should be located at extreme ends of the basin, with short-circuiting of flow further minimised by the use of baffles.

g. Depth indicators shall be provided indicating maximum depth in the basin spillway.

h. Appropriate hazard signage shall be provided for the basin and spillway.

i. Protection of the low flow intake shall be provided to prevent blockage and to prevent the risk of people being trapped.

j. Basins shall be designed so that no ponding of water occurs on to private property or roads.

Basin Safety

4. Basins should be constructed prior to the commencement of any site clearing or construction works, and should be de-silted before the design sediment depth occurs.

Construction and Maintenance

5. It is preferred that urban retention basins incorporate an outlet device that enables dewatering of the basin. This simplifies de-silting, enabling earthmoving equipment to be used for de-silting operations.

6. The high level outlet shall have capacity to contain a minimum of the 100 year ARI storm event. Additional spillway capacity may be required due to the hazard category of the structure determined by reference to ANCOLD (1986).

7. No basin spillway is to be located directly upstream of urban areas.

8. The minimum basin slope shall be 0.5%

Outlet Design

9. An all weather access track shall be provided to the basin for maintenance works. Access Track

10. Basins shall be surrounded by buffer zones, typically comprising grassed foreshores of not less than 20 metres between the nearest development and the basin. This allows for some infiltration of drainage from developments, permits the drainage authority scope to develop aesthetic surrounds and reduces the likelihood of over the fence dumping of rubbish.

Buffer Zones

11. Wet retention basins are regarded as impoundments and normal dam safety requirements should be met. A dam may be prescribed under the Dams Safety Act, 1978, depending on the recommendations of the NSW Dams Safety Committee. A dam is normally prescribed if it is:

a. 10 metres or more in height and has a storage capacity of more than 20 megalitres; or

b. 5 metres or more in height and has a storage capacity of 50 megalitres or more.

Basin Classification



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12. If the wet retention basin is a prescribed dam, the Dams Safety Committee will maintain an interest in the dam will seek information from its owner and will require that reports be prepared on the dam and submitted to the Committee.

Dam Safety Committee

D7.16 TRASH RACKS

1. Trash racks are usually permanent structures, which intercept trash and other debris to protect the aesthetic and environmental quality of water.

Environmental Quality

2. Design criteria shall ensure:-

a. vertical bar screens with bar spacing of 40 mm clear;

b. the trash rack is designed to operate during the 1 in 3 month design storm event with 50% blockage without overtopping.

c. they are as large as practicable while considering all other design criteria – a maximum height of 1.2 metres is suggested;

d. the effect on upstream water levels shall be determined based on 100% blockage during the 100 yr ARI storm event. Water levels are to comply with freeboard requirements specified in Aus-Spec D5 Stormwater Drainage

e. water can still flow past when the rack is fully blocked.

f. the structure drains by gravity to a dry condition; and

g. adequate access for maintenance which permits the use of mechanical equipment. For ramp access the maximum slope shall be 1 in 4 with provision of a concrete plinth minimum width 1.2m upstream of the trash rack to facilitate cleaning .

h. appropriate egress provision shall be included if steep side slopes exist adjacent to the trash rack.

Design Criteria

4. Trash racks may be incorporated in the design of gross pollutant traps. Gross Pollutant Trap

5. A maintenance schedule for any trash racks shall be included in the SQID’s Maintenance and Operations Procedures

Maintenance

D7.17 GROSS POLLUTANT TRAPS

1. Gross pollutant traps (GPTs) are permanent structures used to trap coarse sediments, trash, litter, and other floating materials. Usually, they are located upstream of constructed wetlands and receiving waters.

Description

2. These traps have restricted application and each should be justified on individual merits. Selection of the size and type of GPT shall be based on information and guidelines contained in Chapter 7 of ARQ and with reference to Appendix A of this specification. Confirmation from Council shall be required when a GPT type is selected to ensure consistency and conformance with catchment management plans.

Applications

3. GPTs can be defined as major or minor:

• Major gross pollutant traps can be located on major floodways and waterways to intercept medium to high flows; and

• Minor, enclosed gross pollutant traps can be located at heads of major floodways and/or where stormwater discharges into floodways or water bodies.

Definition



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4. Traps shall be designed to intercept at least 75 per cent of sediment with a grain size of 0.04mm or greater under average annual runoff conditions. Further, ensure peak flow velocities are less than 0.3 metres per second in the design storm event, and taking into account any likely backwater effect from blockages.

Sediment Interception

5. The structure shall have sufficient capacity and stability to discharge the inlet flow with the trash rack fully blocked without flooding adjacent properties.

Capacity

6. Ensure GPTs are capable of gravity drainage to a dry condition for periodic cleaning and maintenance. Maintenance Requirement

D7.18 LITTER BASKETS

1. Litter baskets are proprietary devices primarily designed to capture litter and gross pollutants. Description

2. These traps have restricted application and should be justified on individual merits. Selection of the type of location of Litter Baskets shall be based on information and guidelines contained in Chapter 7 of ARQ and with reference to Appendix A of this specification. An intention to utilise Litter Baskets shall be approved of by Council at the concept stage of a development.

Application

3. Litter Baskets are typically located within stormwater side entry drainage pits and are designed to collect and retain a range of pollutants including 95% of all solids greater than 2 mm.

Definition

4. Design loads and capture capacity shall be verified for each pit proposed from information found in Appendix A of this specification and by information supplied by the individual product manufacturer. Provision for access and OHS issues shall comply with current Australian standards.

Design

5. All costs relating to design installation and maintenance shall be provided in accordance with section D7.14 of this specification

Maintenance

D7.19 CONSTRUCTED WETLANDS AND PONDS

1. Constructed wetlands and ponds shall be designed in accordance with the requirements of:

a) The primary reference documents shall be ARQ, Chapter 11, Austroads AP – 232, Water Sensitive Road Design – Design options for improving stormwater quality of road runoff Technical report 00/1 2000 CRC

b) Pollutant loads to target levels contained within this specification;

c) Council specifications and standard drawings (where available); and

d) Any other relevant Australian Standards as specified by Hastings Council.

Design

References

2. The major elements include pre- treatment, inlet zone, ephemeral zone and macrophyte zone or wetland zone as illustrated in Fig. D7-3



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Fig. D7-3 Typical Wetland Treatment Train

3. A Pre – Treatment zone is required to remove litter and organic matter from inflows to allow easy collection by maintenance crews. A litter trap shall be capable of retaining litter of a size greater than 5 mm for all flows up to a flow rate of 1 in 3 month ARI(the design rainfall event). A sediment trap may also be located within this zone.

Pre Treatment

Zone

4. An Inlet Zone has the primary functions of energy dissipation and sedimentation. Details of methods of sizing of sediment basins may be found in the specified reference documents. The inlet zone shall have the capacity to remove 95% of all suspended sediment down to 125um during the design rainfall event. If a natural stream is used to convey the waters to a downstream wetland a 1in 2 Year ARI event shall be the design rainfall event. When the Inlet Zone is to be a pond structure the following shall apply:

a. The length to width ratio shall be between 5:1 and 10:1 with sufficient energy dissipation to reduce velocities to below 1.0m/s. The maximum width shall be 14m to allow access for maintenance plant.

b. Maximum depth between 1.5 – 2.0 m

c. The preferred top water level shall be 0.5m above the downstream wetland zone.

d. Bypass facilities shall be included in the design to allow the water level to be lowered by at least 0.5m for maintenance of the pond.

e. Access ramps and tracks must be capable of supporting maintenance plant.

f. Batter slopes shall be a maximum of 1 in 6

Inlet Zone



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5. The Ephemeral zone or marsh shall be used to trap leaf and other organic material prior to entering the wetland zone reducing the likelihood of anaerobic decomposition within the wetland zone. The design requirements are:

a. The total area shall be 250m² / m³/sec of the design flow

b. A shallow rock lined channel shall meander to maximise length of travel and allow event flows to inundate adjacent areas planted with ephemeral marsh plants.

c. Raised mounds consisting of topsoil positioned at 45° to the flow of water shall be included in the design. It is preferable to form the mounds by removing material from the location of the mounds rather than stripping the entire area and building the mounds.

d. Marsh plantings shall be arranged in offline cells to form a herringbone pattern.

e. A porous rock wall or similar shall be provided across the downstream end of the ephemeral zone to allow flow attenuation during the design flow event.

Ephemeral Zone

6. The wetland Zone shall be designed to remove sediment less than 125 um and dissolved pollutants. Design criteria shall be as outlined in the reference documents, and shall include the following specific requirements.

a. Treatment shall be obtained by retaining runoff in a macrophyte-dominated wetland.

b. A residence time in the wetland shall be at least 72 hours for the design stored event volume.

c. The maximum stored water level shall be 450mm above the normal top water level unless Hastings Council gives specific approval.

d. Provision shall be made to minimise the velocity through wetland to less than 0.2m/s during the initial stages of a storm event.

e. An accessible outlet control shall be designed to be blockage free and able to change flow rates to allow initial plant establishment and for maintenance purposes.

f. A minimum of 80% vegetated marsh is to be arranged in bands across the flow path. The remaining area shall be allowed for submerged marsh or open water areas.

Wetland Zone

7. Emphasis in planting design should be given to species growing naturally in local wetland remnants. A vegetation and weed maintenance program of at least 24 months after the initial planting of the wetland shall be incorporated in the maintenance and operation procedures. Refer to Appendix A Table D7A – 2 Wetland Vegetation Selection.

Vegetation



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8. Safety considerations shall be included in the design of all structures. The following requirements shall be used as a minimum in the design.

a. Operational depths of sediment ponds to be from 1.5 to 2.0m. Shallow marsh areas, depths to 200mm, deep marsh areas 200mm to 350mm with a periodic maximum up to 600mm.

b. Minimum offset to any allotment boundary to be 15m and up to 30m where access is available.

c. Batter slopes shall not exceed 1 in 6

d. No formal access points to water shall be included in the design unless there is appropriate safety benching.

e. All edges to waterbodies and wetlands shall have safety benches of at least 1.5m to 3.0m wide from the normal top water level except where transitions to culverts or waterways occur. Safety benches shall have maximum slopes of 1 in 8 for the first 1.5m to 3.0m, a transition to 1 in 5 over 0.5m (min.) prior to steeper grades up to 1 in 3. The safety bench shall be densely planted with emergent macrophytes to preclude access.

Safety

9. Interim fencing is recommended between the construction and vegetation establishment where water depths exceed 350mm.

Permanent fencing combined with dense impenetrable plantings shall be used adjacent to water depths exceeding 350mm (normal top water level) areas where safety benches do not conform to the width criteria, adjacent to unsafe structures, areas of high velocities or where batters are steeper than 1 in 6

Maintenance access areas shall be signed, fenced and gated where the safety measures above are not met.

Fencing

10. Natural wetlands shall not be used for improvement of urban run-off quality. Figure D7-4 shows a typical constructed wetland arrangement.

Natural Wetlands

Figure D7-4 - Sediment Trap/Constructed Wetland

11. Where wetlands are natural, the provisions of State Environmental Planning Policy No 14 – Coastal Wetlands, should be consulted. This policy protects wetlands from clearing, construction of levees, draining and filing, but does not prevent wetlands being used for run-off control, provided safeguards and operation control ensures their continued viability.

SEPP No 14

12. Wetlands are primarily to be designed to capture the ARI 3 month storm (deemed to be 40% of the ARI one year event), however overflow structures and flow paths are to be provided to pass ARI 100 year storms ensuring no damage to the wetland or associated drainage or other ancillary works and no re-mobilisation of captured sediments.

Efficiency



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13. Where possible, small islands or shoals should be constructed in the upstream areas of the wetland to reduce water velocities, prevent short-circuiting and promote aquatic plant growth.

Short Circuiting

14. These areas are best planted with vegetation native to the area, but they can be used as grassed areas and as an aesthetic feature.

Native Vegetation

15. A variety of plant species should be planted in artificial wetlands to achieve efficient colonisation and maximise pollutant removal. Establishment of plants should be through transplantation of seedlings during spring and early summer. Refer to Appendix A for a list of recommended plant species

Revegetation

16. Wetlands will serve other purposes than just improving a quality of urban run-off. They will serve to attract a large range of biota and bird habitat. In areas where they have been installed, they have become an aesthetic feature. Indeed, this may present problems as surrounding communities may resist efforts by the controlling authority to de-silt the wetland.

Aesthetic Feature

D7.20 INFILTRATION SYSTEMS

1. Infiltration systems are best utilised as part of a treatment train consisting of elements such as grassed surfaces, vegetated strips, swales, sand filters, gravel based reed beds,’ treatment train’ tanks and geotextile filters. Infiltration systems are to follow the guidelines in Chapter 10 of Ref: ARQ or similar equivalent.

. Infiltration systems are to be designed to achieve the following:

a. Reduce the peak flow and volume of storm runoff

b. Minimise pollution conveyance from urban catchments to downstream waterways and receiving waters.

c. To harvest and use storm runoff as a “ second quality” water resource.

2. The design capacity of �infiltration systems can range from designs catering for the minor system flows to the major system flows.

3. Infiltration components can be constructed from the following:

a. Single sized gravel.

b. Slotted pipes – circular or semi-circular.

c. Proprietary recycled drainage cell.



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4. Types of suitable infiltration systems include:

a. “Leaky “ wells: typically concrete or PVC or similar pipe with perforated walls covered with non-woven geotextile fabric. The well is to be surrounded with gravel, enclosed in non-woven geotextile.

b. Trenches may be gravel or gravel with a slotted pipe, drainage cell or a combination of all. All trenches embedded in host soil must be encased in non-woven geotextile fabric. Maximum floor level below ground is to be 1.5m, top of gravel should covered with 0.3m of backfill.

c. “Soakaways” similar to trenches having a large plan area with depths ranging from 0.3m to 0.5m constructed of similar materials as trenches.

d. Infiltration “dry” ponds are structures similar in design to small-scale retention wetlands. They are suited to sandy or sandy clay sites only with the screening of gross pollutants required upstream of the structure. Safe water depths during runoff events are critical in the design of this type of structure.

5. Appropriate types of runoff suitable to be directed to infiltration structures include: a. Storm runoff from roofs, cleared of leaves or other litter may be passed into a rainwater

tank(s) and the overflow piped directly into an in ground device.

b. Storm runoff from paved or hardstand areas (courtyards, walkways, carparks etc.) are not to pass directly to devices 5.a,b,c as described above. Such runoff must first pass across buffer zones or treatment devices such as 5.d above.

c. Storm runoff from suburban scale areas are to be passed through a series of treatment devices (eg; litter screens, soakaways or similar) before entering into aquifers, urban waterways or receiving waters.

d. During construction of infiltration systems appropriate measures are to be undertaken to ensure sediment is regularly removed prior to the infiltration system becoming operational.

6. The existing soil classification, permeability and water reactivity is to be determined by a geotechnical engineer or other suitably qualified person to determine how soil conditions at the project site will affect detailed design.

Table D7.8 SOIL PERMEABILITY CLEARANCES & SYSTEM SELECTION TABLE Soil Type Hydraulic Conductivity Clearance to structures

or boundaries Recommended infiltration system

m/s mm/hr m Deep confined or unconfined Sands

5 x 10-5 180 1 – 2 Leaky wells, trenches, soakaways

Sandy clays 1x10-5 to 5x10-5 36 – 180 2 Trenches, soakaways Medium clays 1x10-6 to 1x10-5 3.6 – 36 4 Leaky wells Heavy clays 1x10-8 to 1x 10-6 0.036 – 3.6 5 Dry pond,soakaways

Constructed clays 1x10-10 to 1x10-8 0.0004 – 0.036 5 Soakaways Shallow soil over rock

(sandstone) 1x10-6 to 1x10-5 3.6 – 36 2 Leaky wells



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Fig. D7- 5 Shallow retention/overflow trench Fig. D7-6 Perforated retention/overflow (Argue, 1994)

Fig. D7-7 Example of infiltration with pre-treatment provided by a grass buffer strip (Schueler, 1995)



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7. An alternative to clearance distances shown in Table D7.8 is to ensure that infiltration devices located in soils with high “heave” potential are designed to empty rapidly. This type of design would allow a reduction in the clearance distance of 50% to that recommended.

a) Conditions on selection of infiltration devices include the following:

b) Leaky wells and gravel filled trenches are not to be used in areas of wind blown sands or Aeolian sands.

c) Infiltration devices in areas of rock or shale of zero or near zero permeability are deemed to be unsuitable.

d) Areas consisting of shallow soils over rock or lower permeable sands (eg; coffee rock) detailed investigations are to be carried out to determine the existence of stored water near the lower level layers (ie. Perched water table ) and the location of the emergence point of stored water. The impact on downstream areas is to be assessed in the selection of infiltration devices in these areas.

e) A maximum slope of 5% and soil depth of at least 3m throughout a down slope area is required before infiltration devices are to be considered in areas of steep terrain.

f) Infiltration devices are not to be used in areas of high or rising water table.

g) Infiltration devices are not to be used in areas adjacent to underground Carpark areas or lower basement areas unless seepage from such devices is adequately catered for by sump pumps or similar design to transfer flows to an appropriate drainage system or lower aquifer.

h) The location of infiltration devices is to be assessed to determine the impact of upstream infiltration devices on valley floor watertables.

D7.21 VEGETATED SWALES

1. Swales are open vegetated channels that can be used as an alternative stormwater conveyance system to conventional kerb and gutter only with the approval of Council.

2. Vegetation of the swale can range from grass to native shrubs, depending on hydraulic requirements.

3. Criteria for the design of vegetated swales is to include but not confined to the following:

a. The swale dimensions or catchment ratio should be designed so as to ensure 1 year ARI peak velocities do not exceed 0.5 m/s and 100 year ARI velocities do not exceed 1 m/s. In some situations, a high-flow bypass channel or underground pipe may be required.

b. Longitudinal gradients shall be in the range from 1% min. to 4% max.

c. The swale shall be integrated into the landscape character to enhance its aesthetic value.

d. The application of swales shall match the target pollutant characteristics. Where very fine particulates, or soluble material are of concern, other treatment measures such as infiltration systems or small wetlands shall be considered.

e. Established vegetation shall not be more than 75% inundated during the major design flow.

f. Swale profiles of triangular cross section are not acceptable, wide uniform flow shall be a design objective. Maximum width shall be 2.5m unless structural measures are used to ensure uniform spread of flow.

g. Mannings n value shall be between 0.15 and 0.3 for low flow conditions where the depth of flow is below the height of the vegetation. For the major storm event the Mannings ‘n’ value shall be a lower value (eg: 0.03) where flow is above the vegetation level.



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D7.22 BIORETENTION SYSTEMS

1. Bioretention systems are designed to provide treatment of stormwater through fine filtration, extended detention and some biological uptake.

2. Treatment Processes

Runoff is filtered through a fine media layer as it percolates downward into a perforated pipe or similar and discharged either directly or via conventional stormwater conduit system.

An even flow distribution is required to allow water to infiltrate the filter media evenly and thus suited to flat terrain of less 2%.

3. Filtration Soil Media

Selection of filter media is a function of the infiltration rate required, refer to Table D7.9, and the type of vegetation utilised.

Table D7.9 Soil Hydraulic Conductivity Soil type Particle Size

(mm) Saturated Hydraulic Conductivity

(mm/hr) (m/s) Gravel 2 36000 1 x 10-2 Coarse Sand 1 3600 1 x 10-3 Sand 0.7 360 1 x 10-4 Sandy Loam 0.45 180 5 x 10-5 Sandy Clay 0.01 36 1 x 10-5

4. Vegetation Requirements

Vegetation shall be selected to complement the landscape of an area and to discourage movement and traffic over the bioretention area.

Plants selected shall be suitable to tolerate periods of inundation.

Plants having extensive fibrous root systems or a spreading, rhizomatous or suckering habit are required for efficient performance.

Plants with a clumped above ground habit shall not be used due to problems incurred by channelling, erosion and preferential flow paths.

Fig D7-10 Schematic Representation of a Bioretention system (CRC Catchment Hydrology 2002)



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EROSION AND SEDIMENT CONTROL

D7.23 EROSION AND SEDIMENT CONTROL PLAN ESCP

1. An Erosion and Sediment Control Plan shall be required for all developments. For the plan requirements of High Risk Developments (Developments greater than 6 Lots and / or greater than 2500m²) and Low Risk Developments (Single dwellings and Duplexes less than 6 Lots or less than 2500m² in area) refer to Appendix A Table D7A - 5

D7.24 SOIL DISTURBANCE

1. The erosion hazard of a development site can be minimised by scheduling activities to time periods when rainfall is lowest. The ESCP shall use soil loss class data to ensure that works are seasonally programmed to keep soil loss rate below the rate of 37.5 tonnes/hectare/year in any 2-week period. If scheduling of activities cannot be programmed to coincide with low rainfall periods, the design of erosion control measures shall be carried out using the maximum annual rainfall average for the region for design purposes. The Revised Universal Soil Loss Equation (RUSLE) Appendix A REF1 combined with Tables D7.10, D7.11, D7.12 and Figures D7A-11 to D7A –14 shall be used as a guide for planning the proposed works.

Timing of Development

Table D7.10Soil Loss Soil Loss

Class Erosion Hazard

Calculated soil loss (tonnes/ha/year as

calculated by RUSLE) 1 Very Low 0 to 250 2 Low 251 to 300 3 Low – Mod 301 to 375 4 Moderate 376 to 500 5 High 501 to 750 6 Very High 751 to 1500 7 Extreme 1501 to 3750

2. The maximum length of exposed (disturbed) slope shall be: Max. slope length = 90-48[log(%slope)] metres Length of disturbed slope

Table D7.11 Soil Class and Development Period Period Soil Classes

That May be Developed

January and February 1 – 4 February to end of April 1 – 3

May and June 1 – 4 July to end of September 1 – 6

October to end of December 1 – 5 Note: Soil Loss Class 7 not recommended for disturbance.

Table D7.12 Ratio of Slope Gradient to Disturbed Length

% Slope Max Slope Length (m)



1 (1 in 100) 90 10 (1 in 10) 42 19 29 2 (1 in 50) 75 11 40 20 (1 in 5) 28

3 67 12 38 25 (1 in 4) 23 4 (1 in 25 ) 61 13 37 30 19 5 (1 in 20) 56 14 35 35 16

6 52 15 34 40 (1 in 2.5) 13 7 49 16 32 45 11 8 47 17 31 50 (1 in 2) 8 9 44 18 30 60 5

D7.25 “NO ACCESS” AREAS

1. Retained vegetation and buffers must be protected by a suitable fence barrier. Fenced areas shall be clearly signposted “No Access Area”. A fence shall be used to exclude traffic from buffer zones to prevent damage to the vegetation, particularly during any construction phase.

Fencing



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2. The “no access” fence locations shall be shown on the detailed design. These locations will be approximate only as machinery type, topography etc will determine actual on site location.

No Access

D7.26 DIVERSION WORKS

1. Diversion works may be in the form of earth drains and banks, straw bales, sand bags or pipelines and may be permanent or temporary. All control measures must be installed prior to clearing of the site.

Diversion Types

2. Upstream run-on water shall be diverted around the site. Such flows shall discharge to a legal drainage point or open areas where level spreader banks shall ensure a broad water spread to minimise flow velocity.

Discharge Point

3. Pipelines may also be used to convey such run-on through the development site, and discharge the flow to a formal drainage point/dissipater if necessary. Such pipelines may also form part of the overall final drainage system.

Pipelines

4. Design of the diversion system should suit the following:- a. The drain should preferably be dish shaped with batter grades of less than 4:1 and in

accordance with [Ref 1]

Drain Shape b. If a piped system is selected its design capacity shall be a minimum of the capacity nominated

in the design Specification D5 STORMWATER DRAINAGE. Pipe Capacity

5. Diversion works are to be designed to carry peak flows at non-erosive velocities in bare soil, vegetated or lined drains/banks.

Peak Flows

6. Channels shall be lined with turf. Where velocities are designed in excess of 2m per second, non-erosive linings such as concrete, geotextiles, grouted rock etc or velocity reducers (check dams etc) are required. Evidence of the suitability of the proposed material to be used will be required prior to approval of the ESCP

Non-Erosive Linings

7. Diversion Structures are to generally comply with Section 5.2.4 of [Ref 1]. A typical arrangement of diversion drains and banks is shown in Figure D7-11.

8. Diversion of stormwater onto downstream properties will require legal agreement and approval by Council prior to issue of a construction certificate.

DIVERSION DRAIN DIVERSION BANK

BATTER GRADE LESS THAN 2:1

BATTER GRADE LESS THAN 2:1

Figure D7-11 - Diversion Drains/Banks



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D7.27 DROP DOWN DRAINS

1. These are temporary or permanent drains, which divert concentrated run-off down slopes such as road batters without causing erosion. They usually consist of a dished earth drain smoothly shaped, consolidated and lined with a variety of materials or they may be a flexible/rigid pipe or half pipe.

Lined Drains

2. Drop down drains shall have sufficient capacity for a minimum 1 in 5 year peak flow without eroding. Energy dissipaters may be required to reduce the flow velocity at the outlet of the drop down drain.

Capacity

D7.28 STOCKPILES

1. Location of stockpiles shall be indicated on the approved engineering plans. Approved Plan

2. Stockpile sites shall be located:

a. Clear of existing or proposed drainage lines.

b. Clear of areas likely to be disturbed during construction.

c. Clear of the drip zone of trees.

d. Preferably on reasonably flat areas.

e. Clear of public footpaths, nature strips, roads, road shoulders or any public land.

f. At least 5 metres from any hazard, including surfaces with grades greater than 15%, zones of concentrated flow, gutters, drains, driveways, swales or standing vegetation.

Location

3. Stockpiles must be protected from erosion and sediment loss by:

a. The installation of diversion works.

b. The use of silt fences, straw bales etc or other approved controls on the downstream side.

c. Compaction.

Erosion Protection

4. Site topsoil shall be isolated from subsoil material in separate stockpiles. Separate Stockpiles

5. Stockpiles if intended to be left exposed for longer than 14 days shall be revegetated immediately (see specification C273 Landscaping).

D7.29 SEDIMENT BASINS/TRAPS/DAMS

1. Sediment traps are either permanent or temporary sediment control devices that intercept sediment and run-off usually at the final discharge point of the site or at a location to protect a downstream watercourse, wetland, riparian vegetated area or receiving water. Preferably they are to be located off line.

Sediment Control

2. They are formed by excavation and/or by constructing embankments. Construction

3. There are two types, wet and dry basins. Types

4. Preferably sediment traps shall not be located directly upstream of residential areas. Location

5. Basin design must be in accordance with “Managing Urban Stormwater – Soils and Construction (1998) Section 6.3.3.

Design Criteria



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6. Where sediment retention basins are required, they shall be designed to treat the runoff from the design rainfall event emanating from the site during land development works and they must remain in place and be fully operational until removal is authorised or required by Council.

7. Where required as part of a permanent, public stormwater management system, basins located on public land (or land to be dedicated to the public), may be accepted for Council ownership.

8. Where required as part of a permanent, site stormwater management system, basins located on the site must be retained, operated and maintained in perpetuity by the landowner.

9. Where eroding soils contain more than 10% of dispersible fines:

a. all waters captured in sediment basins must be treated with an approved flocculating agent to ensure that discharges contain no more than 50 milligrams per litre of total suspended solids.

b. sediment retention basins must be maintained at a low water level in readiness for treatment and discharge of further runoff. All sediment captured in basins must be treated and discharged within 5 days of the cessation of a rainfall event.

c. a minimum stockpile of flocculating agents must be retained onsite to provide for at least three complete treatments. All materials must be stored in a secure undercover location.

10. A marker must be placed within each sediment retention basin to show the level above which design capacity occurs.

Permanent Wet Basins

11. Materials removed from sediment retention basins must be disposed of in a manner approved by Council and in accordance with current EPA guidelines.

12. Plans shall indicate whether basins are to be temporary or permanent.

D7.30 SEDIMENT TRAPS / BARRIERS FOR MINOR CATCHMENTS

1. Silt retention/filtering structures of a temporary nature shall be used in situations where the catchment does not exceed 0.25 ha.

Filtering Structures

2. Sediment traps/barriers may consist of:

a. silt fences

b. straw bales

c. blue metal groynes/sausages

d. filter fabric located beneath stormwater grates

e. gabions

f. or a combination of the above.

Barrier Types

3. The choice of material and type of treatment will depend on the size of the catchment the location and the structure being treated shall be required at:

a. surface inlet pits

b. kerb inlet pits

c. catch drain disposal areas

d. culvert inlets and outlets

e. minor construction/earthwork sites

f. check dams/velocity reducers etc.

Location of Structure



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4. The design of sediment traps/barriers shall generally in accordance with [REF 1] chapter 6.3.4 except as varied by the following criteria.

a) Maximum flow in to the silt fence from a design ARI 3 month storm is not to exceed 1.6l/sec/metre or the maximum catchment per metre of fence etc. is not to exceed 45m² and

b) The fence or structure must be structurally viable and able to support the hydraulic pressures generated during the design recurrence storm

c) Maximum post spacing 2m or 3m with wire mesh backing.

d) In fences or structures longer than 30m, spill through weirs shall be installed at 20 – 30m intervals.

e) Spill through weirs shall consist of a rock filled wall contained between an enclosed steel mesh fence retaining wall of typical dimensions of 1.2m length, 0.6m height with enclosed rock of 25 – 50 mm aggregate.

5. Sediment shall be removed and disposed/reused in accordance with Council and EPA guidelines after each rainfall event. Weirs shall be regularly maintained and cleaned to ensure effective operational condition. Straw bales and slit fence geotextiles shall be replaced when damaged or permanently blocked and fully replaced at not more than six monthly intervals.

D7.31 LEVEL SPREADERS

1. Level spreaders are outlets or “sills” having a level cross section. They convert erosive channelised flows into non-erosive sheet flow.

Convert Flows

2. Level spreaders can only be used to dissipate flows from small catchments. The area below the outlet should be stable and of even cross section so that the water will not re-concentrate into channels.

Location

3. To reduce flow velocity before the spreader, the channel grade shall not exceed 1 per cent for a minimum of 8 metres. The outlet or “sill” width depends on contributing catchment, slope and ground conditions. The minimum width should be four metres, and the maximum width 25 metres. Final discharge should be over a level surface, which may require stabilising by turfing or seeding and fertilising or perhaps lining with a geotextile fabric or something similar.

Design Criteria

D7.32 THE LOCATION OF SHAKEDOWN AREAS AND ACCESS STABILISATION

1. Access to construction sites shall be limited to a maximum of two locations. Number of Accesses

2. Access locations and shakedown areas shall require Council approval. Location Approval

3. Shakedown areas or access stabilisation shall comprise a bed of aggregate on filter cloth or a metal bar cattle grid located at any point where traffic enters or leaves a construction site. Stabilised accesses reduce or eliminate tracking of sediments onto public rights of way or streets. Should such tracking occur the contaminants must be swept off the roadway each day or before rain. Clean off draw bars etc after dumping and before starting journey.

Types

4. If a shaker grid is used, this should be so placed as to ensure the vehicles when crossing the grid have sufficient speed to “shake the mud” or other contaminants such as gravel from the vehicle. It must not be placed where the vehicle is slowing to enter a roadway. Cattle grids shall be a minimum length of 7 metres.

Cattle Grid

5. A stabilised access comprises a vehicular pathway suitably constructed to facilitate the collection of any site debris in order to prevent such material leaving the site. Stabilised accesses are generally used on small sites. The entrance shall be at least 15 metres long with a minimum width of 3 metres for a one-way entrance and 6 metres for a two-way entrance.

Stabilised Access



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6. Surface water flowing to the street entrance/exit must be piped under the access, or a berm constructed to direct surface flow away from the exit.

Flow Control

D7.33 WIND EROSION/DUST CONTROL

1. Research has demonstrated average dust emission rates of over 2½ tonnes per hectare per month at urban construction sites. This erosion rate is unacceptable.

Erosion Rate

2. Various measures are available to minimise such emissions, including:-

a. limiting the area of lands exposed, maximum 2 ha, to erosive forces through phasing works/progressive revegetation and/or provision of a protective ground cover and/or keeping the ground surface damp (not wet) and/or by using onsite water from detention basins where available.

b. on building sites, installing a barrier fence on the windward side – effective to a distance of 15 times its height, assuming an acceptable soil flux of 5 grams per metre per second. See Figure D7-12.

c. control techniques may include the use of water sprays, application of dust suppressants, surface stabilisation or covering of exposed surfaces.

Treatments

3. Dust control techniques must be employed on site at all times including outside normal working hours.

4. All permanent roads and trafficable areas must be sealed or hard surfaced to minimise dust generation.

5. Unless an exemption from Council is obtained, all sites where over 1500 m² are to be disturbed must be provided with a barrier fence wind break [Ref 1] 6.3.6(b)(iii).

Fig. D7 – 12 Effect of distance from windbreak on soil loss, wind blowing at less than 90º to the windbreak



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D7.34 REQUIREMENTS FOR BUILDING SITES

1. In addition to D7.23.1 and Council Code No.18 (Erosion and Sediment Control ), DCP 41 (Building Construction and Site Management.), Council Policy No. E1/1 (Erosion and Sediment Control Policy) the following shall apply.

2. The clearing of vegetation and preparation of building pads is to be undertaken in the last stages of the development when the majority of the site has been effectively revegetated.

Site Clearing

3. When the development calls for the construction of a number of buildings, the sediment trap/s and other appropriate sediment controls shall remain operational.

Development Control

4. Cross/catch drains shall be installed on long or steep unpaved driveways, disposing run-off to stable areas.

Driveway Control

5. Where a majority of the lot is disturbed the following controls or measures shall be undertaken:

a. Silt fences, located around the downstream sides of the lot.

b. Sediment traps/barriers to be provided to all on-site and adjacent stormwater inlets.

c. Only one site access to be provided. This may require treatment to prevent soil being tracked from the site.

d. All subsurface drainage for roofing must be in place prior to the installation of the roof and gutter so downpipes can be immediately connected.

Lot Control

6. When roof structures and piped or artificial stormwater systems are in place, discharge water is to be managed in a manner that reduces erosion. Roof water drainage systems must be functional and discharge to the stormwater system before roof runoff begins. The stormwater system must prevent sediment from being eroded from the site and deposited downstream.

D7.35 EXTERNAL SITE REQUIREMENTS

1. Sediment control devices or stabilising works shall be provided outside construction sites where necessary or as directed by the Superintendent.

Necessary Controls

2. Where increased stormwater run-off is likely to or is found to accelerate erosion of any downstream watercourse, the necessary remedial work shall be provided concurrently with other sediment and erosion requirements.

Accelerate Erosion

3. Where sediment is likely to be transported from the site, all immediate downstream drainage inlets shall have appropriate controls installed.

Downstream Controls

4. If such works require entry onto private property, written permission shall be obtained prior to the entry and commencement of such works.

Written Permission

5. All disturbed areas on private property to be reinstated to original condition and to the satisfaction of the owner.

Reinstated



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D7.36 DEFINITIONS

Term Description

Average Recurrence Interval (ARI) Is the average time between storm events of a given value. Eg: a 1 in 2 year ARI storm event.[5]

Aquifer An underground water-bearing geological formation.[5]

Base Flows Underlying flow rate that cannot be directly attributed to storm events and is present during some or all dry periods.[5]

Best Management Practice (BMP) Structural and non structural measures used to reduce the impact of development on the urban water cycle. [6]

Bioretention System A grassed or landscaped swale or basin promoting infiltration into the underlying medium.[6]

BOD Biological Oxygen Demand [7]

Buffer zone The zone contiguous with a sensitive area that is required for the well being of the sensitive area.[7]

Catchment Area The contributing area of land which drains to a single point of interest.[7]

COD Chemical Oxygen Demand [7]

Constructed Wetland A man made artificial water body containing aquatic plants and designed to mimic the ecological and physical tratment processes of natural wetlands.



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Detention Basin Detention basins are structures designed to retard the flow of minor and major storm events and to provide controlled outlet of stormwater flows. They are provided with low level and high level outlets and are designed for a series of peak flow events through the use of hydrographs. The low level outlet is designed to release flow at a predetermined rate for minor storm events and the high level outlet is designed as an overflow for major storms.[8]

DO Dissolved Oxygen [7]

Easement A right of one owner of land over the lands of another.[7]

Ecological Sustainable Development (ESD) "Development that improves the total quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends."

Environmental Values The actual or potential function carried out by the water body (eg: suitable for recreational use).

Ephemeral Creek A periodically wet and dry watercourse.

Event Mean Concentration EMC The total mass of a pollutant constituent divided by the volume of surface runoff.[7]

Filtration A series of processes that physically removes particles from water.[7]

First Flush The Delivery of a disproportional large load of pollutants during the early part of storms due to the rapid suspension of accumulated settled particles.[7]

Freeboard The distance required between a calculated or known water level to a specified location on a structure.

Floodway "A carriageway across a shallow depression subject to flooding, specially constructed to resist the effects of submergence. [1]"

Gross Pollutant Trap(GPT) A structure designed to trap gross pollutants ( trash litter & vegetation > 5mm) for certain design storm events.

Groundwater water saturating the voids in rocks; water in the zone of saturation in the earths crust eg: in aquifers.[5]

High Risk Development Any development in a waterway corridor; and/or Multiple dwellings or commercial developments with an impermeable surface area in excess of 2500 m²; and/or Subdivision where at least 6 lots are involved: and/or Industrial activities that are not impact assessable and at least 1000m² in uncovered storage/working space; and/or uncovered car parks with at least 100 spaces.

Infiltration System "A system which uses permeable material to infiltrate water into the soil. Infiltration trench, Infiltration wells, Infiltration basins & onsite.

Intensity Frequency Duration (IFD) A three-way relationship that defines that statistical distribution of rainfalls expected to occur at a particular location.

Interallotment Drainage A drainage system design to carry stormwater runoff from impervious surfaces that do not drain to a street frontage, usually located along the rear boundary of a property. Primarily used where the natural slope drains to the rear of property.

Life Cycle Cost "The total cost incurred to construct, operate, maintain and replace an asset over a given time frame.[6]"

Low Risk Development "Development subject to Council approval but specified as ""low risk development"“. Water quality impacts shall be minimised by identifying and adopting best practice techniques."

Macrophyte zone That portion of a constructed wetland that contains macrophyte plants (eg: reeds, rushes)"

Mean Annual Runoff The average annual runoff from a catchment [5]

MUSIC The Model for Urban Stormwater Improvement Conceptualisation software developed by CRC for Catchment Hydrology to model urban stormwater management schemes.

Natural Channel Design The design of hydraulic conveyance structures, which maintain the engineered and environmental values of a waterway.

Natural Water Course "A river, creek or stream in which water flows either permanently, intermittenly or occasionally in a natural channel, or in a natural channel artifically improved, or in an artificial channel that has changed the course of the water course.[7]"

Residence Time The average length of time the water stays in the wetland.[5]



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Retention Basin Basins designed similarly to detention basins.The difference is in their operation in that the outlet for low flow is not provided but the high level overflow is retained. Wet retention basins are used in situations where significant reductions in pollution concentrations are required. This is achieved by maintaining a constant pool of water within the basin and carrying out some form of treatment process.[8]

Riparian "Concerning the banks of a stream, lake or canal.[7]"

River "A major watercourse with a large catchment, usually a wide flat channel bed, a high natural sediment flow and a near constant base flow. In arid and semi-arid areas rivers can run dry. [4]"

Runoff Coefficient The ratio of how much water is likely to runoff a site against how much rain falls in any particular storm event [10]

Sediment Basins "Permanent or semi permanent structures, which are used to trap sediment from disturbed or developed areas, they are used as part of an overall designed system."

Sedimentation The process in which setteable solids are removed from the water column by gravity.

Short Circuiting "term used to describe a pond or wetland where water entering moves quickly to the outlet without interacting with the treatment structures (eg: Ephemeral zone, wetland zone)"

Stochastic A random process that can be described using certain statisitical patterns.[5]

Stormwater Surface water run-off following a rain event (including piped flows)

Stormwater Management Plan (SMP) "A plan that evaluates options for the management of stormwater quantity, quality and ecological values within a predetermined catchment. [9]"

Surcharge The increased water level in a storage beyond the designed operating level eg; storage of a reservoir above the level of the spillway.

Surcharge Path The direct escape path for water.

Total Catchment Management "The coordinated and sustainable use and management of land, water, vegetation and other natural resources on a water catchment basis so as to balance resource utilisation and conservation.[5]"

TP Total Phosphorus - a measure of organic and inorganic phosphorus in particulate soluble forms.[5]

Trunk Drainage Those drainage systems having catchment areas greater than 15 Hectares or runoff in excess of 3m³/s during a 20% ARI event (Urban Drainage Design Manual Sutherland Shire Council ).

TSS Total Suspended Solids - a measure of filterable matter in a water sample.[5]

Turbidity "Measure of the clarity of water using a colorimetric scale, generally relating to suspended material in water.[5]"

RUSLE Revised Universal Soil Loss Equation

Water Sensitive Urban Design (WUSD) "A design principle which encourages the integration of principles such as detention of stormwater, the use of vegetation for filtering purposes, water efficient landscaping, protection of water related environmental, recreational and cultural values."

Water Table The surface of a body of ground water at which the pressure is atmospheric.[5]

Water Quality Indicator "an indicator for an environmental value measured in a quantitative way Eg. mg/L, pH . The water quality indicator is compared to the water quality guidelines to determine if the environmental value is being achieved.[9]"

Water Quality Objectives measurable goals for the quality of receiving waters to ensure the Environmental Values are upheld.[9]

Source of definitions

"[1] Australian Standards (1972), Terms Used in Road Engineering. Australian Standard AS 1348-1972, Sydney."

"[2] Houghton, P.D. & Charman, P.E.V. (1986) Glossary of terms used in Soil Conservation. Soil Conservation Service of NSW."

"[3] Macquarie Library, (1981) The Macquarie Dictionary. Macquarie Library Pty Ltd, Sydney."



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"[4] National Steering Committee for the development of fish and flow friendly causeway, culvert and wetland inlet structures."

[5] The Constructed Wetlands Manual DLWC 1998

[6] Water Sensitive Urban Design - A stormwater management perspective -CRC Industry report 02/10 2002

[7] RTA Road Design Guide Section 7 stormwater Management and Drainage Design

[8] Practical design of stormwater retention basins. IPWEA June 2002

[9] Guideline on identifying & applying water qualtiy objectives in Brisbane City (V1)

"[10] Managing Urban Stormwater, Soils & Construction 1998



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APPENDIX A

TABLE D7A – 1 MUSIC DEFAULT PARAMETERS ( Example Only-not for Design use )

Total Suspended Solids (Log10 mg/L)

Total Phosphorus (Log10 mg/L)

Total Nitrogen (Log10 mg/L)

Land Use Parameter Base Flow

Storm Flow

Base Flow

Storm Flow

Base Flow

Storm Flow

Mean 0.99 2.18 -0.95 -0.47 0.19 0.26 Urban Residential

Std Deviation 0.38 0.39 0.34 0.30 0.19 0.23 Mean 0.82 2.17 -0.66 -0.40 0.35 0.37 Commercial Std Deviation 0.40 0.39 0.49 0.35 0.30 0.33 Mean 0.78 1.96 -1.15 -0.56 0.12 0.28 Industrial Std deviation 0.44 0.44 0.44 0.37 0.19 0.33 Mean 0.54 2.36 -1.52 -0.52 -0.52 0.36

Rural Residential Std Deviation 0.24 0.51 0.41 0.27 0.42 0.25

Existing MUSIC defaults (after Duncan, 1999)

Urban Mean Std Deviation

1.10 0.17

2.20 0.32

-0.82 0.19

-0.45 0.25

0.32 0.12

0.42 0.19

Agriculture Mean Std Deviation

1.40 0.13

2.30 0.31

-0.88 0.13

-0.27 0.30

0.07 0.13

0.59 0.26

Forest Mean Std Deviation

0.90 0.13

1.90 0.20

-1.50 0.13

-1.10 0.22

-0.14 0.13

-0.07 0.24

TABLE D7A – 2 WETLAND ZONES , TYPICAL SPECIES AND FUNCTIONAL PROCESS (Somerset et al 1996) EPHEMERAL SWAMP Typical Ecological Characteristics Dominant species: eg. Eucalyptus, Melaleuca, Casurina, Juncus ; Vegetation: 2m woodland overstorey, low-high density openclosed canopy, ~0.5m low-high density grassland-rushland groundcover Typical Physical Characteristics Surface area : volume ratio: high (when inundated); Water depth: ~0.1-0.2m; Natural water regime: ephemeral (mostly dry, occasional irregular inundation cycle) Potential Treatment Processes and Mechanisms Solids removal: sedimentation and filtration (particularly of fine particles); Mineralisation: microbial growth, enhanced by wetting and drying; Nutrient uptake and transformation: microbial and macrophyte growth; Nutrient storage: sediment adsorption SHALLOW MARSH Typical Ecological Characteristics Dominant species: eg. Baumea articulata (Jointed Twig rush) ; Vegetation: 0.3-0.7m, low-medium density open canopy, typically supports epiphytic algae on submerged culms Typical Physical Characteristics Surface area : volume ratio: high; Water depth: ~0.1-0.2m; Natural water regime: ephemeral (regular seasonal dry cycle) Potential Treatment Processes and Mechanisms Aeration: surface exchange and epiphytic photosynthesis; Solids removal: filtration (surface adhesion); Mineralisation: microbial growth, enhanced by wetting and drying; Nutrient uptake and transformation: microbial, epiphyte and macrophyte growth; Nutrient storage: sediment adsorption MARSH



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Dominant species: eg. Baumea sp. Bolboschoenus sp ; Vegetation: 0.5-1.5m high, high density closed canopy, Typical Ecological Characteristics

high litter production Typical Physical Characteristics Surface area : volume ratio :medium-high; Water depth: ~0.3m; Natural water regime: ephemeral (occasional-regular dry cycle) Potential Treatment Processes and Mechanisms Solids removal: sedimentation and filtration; Mineralisation: microbial growth; Nutrient uptake and transformation: microbial and macrophyte growth; Nutrient storage: sediment adsorption and litter accumulation

DEEP MARSH Typical Ecological Characteristics Dominant species: eg. Eleocharis sphacelata (Tall spike rush) ; Vegetation: 1-2m, medium-dense semi-closed canopy, supporting some epiphytic algae, moderate litter production Typical Physical Characteristics Surface area : volume ratio: medium; Water depth: ~0.4-0.6m; Natural water regime: permanent (occasional irregular dry cycle) Potential Treatment Processes and Mechanisms Solids removal: sedimentation and filtration; Mineralisation: microbial growth; Nutrient uptake and transformation: microbial, epiphyte and macrophyte growth; Nutrient storage: sediment adsorption and litter accumulation

OPEN WATER Typical Ecological Characteristics Dominant species: algae (or submerged macrophytes in low nutrient conditions) ; Vegetation: phytoplankton growth resulting in secondary solids production, (macrophyte growth inhibiting mixing and removing solids by sedimentation and filtration) Typical Physical Characteristics Surface area : volume ratio: low; Water depth: 1m; Natural water regime: permanent, generally well mixed but may stratify during still conditions, particularly in the warmer months Potential Treatment Processes and Mechanisms Solids removal: sedimentation (and filtration); Aeration: wind mixing, algal photosynthesis; Sterilisation: UV exposure; Nutrient uptake and transformation: phytoplankton and submerged macrophyte growth; Nutrient storage: sediment adsorption and accumulation

WETLAND VEGETATION SELECTION LIST - Sandy Soils

WETLAND ZONE BOTANICAL NAME / COMMON NAME

Submerged Marsh 0.4 – 0.9 m below normal top water level . Recommended plant density 2 plants / m²

Potamageton crispus Curly Pondweed Potamageton ochreatus Blunt Pondweed Potamageton pectinatus Fennel Pondweed

Deep Marsh 0.2 – 0.4 m below normal top water level The recommended plant density is 4 plants / m²(planted in bands perpendicular to flow).

Baumea articulata Jointed Twig-rush Eleocharis sphacelata Tall Spike-rush Potamageton pectinatus Fennel Pondweed Schoenoplectus tabernaemontani River Club-rush Triglochin procerum Water Ribbons

Shallow Marsh

0 – 0.20 m below normal top water level The recommended plant density 4 plants / m² (planted in bands perpendicular to flow).

Baumea arthrophylla Fine Twig-rush Baumea articulata Jointed Twig-rush



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WETLAND VEGETATION SELECTION LIST - Sandy Soils Bolboschoenus caldwelli Marsh Club-rush Eleocharis acuta Common Spike-sedge Ranunculus inundalus Buttercup Myriphyllum capul Medusa Cat Tail Myriphyllum verrucosum Red water milfoil Myriphyllum varriifolium milfoil Schoenoplectus validus River Club-rush Villarsia reniformis Running Marsh-flower

Ephemeral Marsh

Above normal water level, temporally inundated during high flows plant density is 6 plants / m².

Carex appressa Tall Sedge Carex gaudichaudiana Fen Sedge Centella asiatica Centella Pennywort Cyperus lucidius Leafy Flat-sedge Eleocharis acuta Common Spike-sedge Juncus amabilis Hollow Rush Philydium lanuginosum Frogsmouth

Ephemeral Wetland Above normal water level, temporally inundated during high flows

Carex appressa Tall Sedge Centella asiatica Centella Pennywort Juncus pallidus Pale Rush Melaleuca ericifolia Swamp Paperbark Persicaria decipens Slender Knotweed lanuginosum Frogsmouth Juncus usitatuss Tussock Rush

Wetland Margin plant density is 6 plants / m².

Baumea arthrophylla Fine Twig-rush Carex appressa Tall Sedge Carex fasicularis Tassell Sedge Eleocharis acuta Common Spike-sedge Isolepis inundata Swamp Club-rush Juncus pallidus Pale Rush Juncus usitatuss Tussock Rush lanuginosum Frogsmouth Isolepis nodosus Club-rush Leptospermum junipernum Tea - Tree

WETLAND VEGETATION SELECTION LIST – Saline Soils (2000 to 10000 ppm)



Ruppia maritime Sea Tassel Ruppia megacarpa Sea Tassel Potamageton pectinatus Fennel Pondweed


Baumea articulata Jointed Twig-rush Phragmites australis Common Reed Potamageton pectinatus Fennel Pondweed Schoenoplectus tabernaemontani River Club-rush Triglochin procerum Water Ribbons

0 – 0.20 m below normal top water level



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WETLAND VEGETATION SELECTION LIST – Saline Soils (2000 to 10000 ppm) Shallow Marsh The recommended plant density 4 plants / m²

(planted in bands perpendicular to flow).

Baumea arthrophylla Fine Twig-rush Baumea articulata Jointed Twig-rush Bolboschoenus caldwelli Marsh Club-rush Eleocharis acuta Common Spike-sedge Myriphyllum verrucosum Red water milfoil Myriphyllum salsugineum Lake milfoil Schoenoplectus pungens Sharp Club-rush

Ephemeral Marsh


Juncus flavidus Yellow Rush Juncus krausii Sea Rush Poa labillardierei Common Tussock-grass Samolus repens Creeping Brookweed Triglochin striatum Streaked Arrow-grass Lobelia alata Angled Lobelia Ranunculus inundalus Buttercup


Juncus flavidus Rush Juncus kraussii Sea Rush Melaleuca ericifolia Swamp Paperbark Melaleuca quinquenervia Broad leaved Paperbark Triglochin striatum Streaked Arrow-grass


Baumea arthrophylla Fine Twig-rush Baumea juncea Bare Twig-rush Carex fasicularis Tassell Sedge Juncus subsecundus Finger Rush Juncus flavidus Yellow Rush Juncus kraussii Sea Rush Leptospermum junipernum Tea - Tree Lobelia alata Angled Lobelia Ranunculus lappaceus Common Buttercup Triglochin striatum Streaked Arrow-grass Isolepis nedosus Knobbly Club Rush

WETLAND VEGETATION SELECTION LIST - Salurian Soils



Potamageton crispus Curly Pondweed Potamageton ochreatus Blunt Pondweed Vallisneria americana Eel - grass


Eleocharis sphacelata Tall Spike-rush Potamageton ochreatus Blunt Pondweed Schoenoplectus tabernaemontani River Club-rush Triglochin procerum Water Ribbons Ottelia ovalifolia Swamp Lily Vallisneria americana Eel - grass

Shallow Marsh

0 – 0.20 m below normal top water level The recommended plant density 4 plants / m² (planted in bands perpendicular to flow).



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WETLAND VEGETATION SELECTION LIST - Salurian Soils

Alisma plantago-aquatica Water Plantain Baumea articulata Jointed Twig-rush Bolboschoenus caldwelli Marsh Club-rush Cyperus gunnii Flecked Flat-sedge Eleocharis acuta Common Spike-sedge Myriphyllum crispatum Upright milfoil Myriphyllum varriifolium Variable milfoil Ranunculus inundatus River Buttercup Schoenoplectus validus River Club-rush

Ephemeral Marsh


Carex appressa Tall Sedge Carex gaudichaudiana Fen Sedge Philydiva lanuginosum Frogsmouth Cyperus lucidius Leafy Flat-sedge Eleocharis acuta Common Spike-sedge Melaleuca ericafolia Swamp Paperbark Melaleuca quinquenervia Broad leaved Paperbark Persicaria decipens Slender Knotweed Poa labillardierei Common Tussock-grass Persicaria praetermissa Spotted Knotweed Gratiola peruviana Brooklime


Carex appressa Tall Sedge Carex fasicularis Tassell Sedge Juncus amabilis Hollow Rush Melaleuca ericifolia Swamp Paperbark Melaleuca quinquenervia Broad leaved Paperbark Persicaria decipens Slender Knotweed Persicaria praetermissa Spotted Knotweed Philydrum lanuginosum Frogsmouth Gratiola peruviana Brooklime


Calistemon salignus Pink –tipped Bottlebrush Carex appressa Tall Sedge Carex fasicularis Tassell Sedge Carex gaudichaudiana Fen Sedge Cyperus lucidius Leafy Flat-sedge Eleocharis acuta Common Spike-sedge Isolepis inundata Swamp Club-rush Juncus usitatuss Tussock Rush Juncus vaginatus Rush lanuginosum Frogsmouth Melaleuca ericifolia Swamp Paperbark Melaleuca quinquenervia Broad leaved Paperbark



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TABLE D7A - 3 TOTAL WATERCYCLE MANAGEMENT PLAN REQUIREMENTS

TYPE & SCALE OF DEVELOPMENT

Development >100 Lots or 8 Ha.

(Whichever is Lesser)

STAGE OF PROJECT Pre – DA : Preliminary (P) sketch/concept acceptable unless noted otherwise. DA Submission : Draft (D) sketch/concept acceptable unless noted otherwise. Construction Certificate : Final (F) detail in accordance with relevant Council Specification unless noted otherwise. Pr

e- D

A DA

Sub

miss

ion

Cons

tructi

on

Certif

icate

Site conditions – topography, soils, groundwater, vegetation, and habitat connectivity.

Catchment context and land capability. Estimates of all water flows –

o potable water supply requirements, o wastewater ( black and grey water components ), o roofwater volumes.

Site and receiving water quality :- o Water quality of the receiving waters o Pre development modelled pollutant loads o Post development modelled pollutant loads. o A management plan identifying treatment measures,

using a treatment train approach to meet water quality objectives. .

Site hydrology :- o Pre development hydrology ;- runoff volumes, frequency,

and peaks. o Post development hydrology :- runoff volumes,

frequency, and peaks. o Stormwater volumes for pre and post development

scenario o A management plan which identifies measure to reduce

hydrological changes. Strategies for improving

o water efficiency and rainwater, stormwater, grey-water, reclaimed wastewater, and reuse opportunities in accordance with Council policy/strategy

o protecting water quality, o flood protection, o aquatic ecosystem protection or enhancement in

degraded areas, o habitat connectivity protection or enhancement in

degraded areas. Integrated water infrastructure systems. Proposed layout and street design measures to protect landform, natural

water features and environment as per Chapter 4 of ARQ. Proposed trunk drainage measures to protect natural water feature and

environment . Proposed landscape features to protect natural water features and

environment as per Chapter 4 of ARQ. Provision of water tanks, detention, infiltration, SQID/s and other

stormwater infrastructure. Maintenance Operation Plan requirements for infrastructure and

stormwater treatment devices. Maintenance requirements for landscaping and rehabilitation. Monitoring requirements (stream health, vegetation, water quality,

rehabilitation works and systems).

P P

N/A N/A N/A

N/A N/A N/A N/A

N/A

N/A

N/A N/A

P

P P P

P

P P

P N/A

N/A

N/A

N/A N/A

P P

P P P

P P P P

P

P

P P

P

P P P

P

P P

P

P

P

P

N/A P

F F

F F F

F F F F

F

F

F F

F

F F F

F

F F

F

F

F

F

N/A F



Page 45

TABLE D7A - 4 STORMWATER MANAGEMENT PLAN REQUIREMENTS - SMP TYPE & SCALE OF DEVELOPMENT

High Risk Development >6 Lots and/or

2500m²

Low Risk Single dwellings &

Duplexes < 6 Lots or < 2500m²


e- D

A

DA S

ubmi

ssion

Cons

tructi

on

Certif

icate

Pre-

DA

DA S

ubmi

ssion

Cons

tructi

on

Certif

icate

Details of the development showing :- The boundary of the development. The north point. The location of services. The footprint of the development. The footprint of impermeable paved areas. The location of fences The total hardstand area of the site i.e the total area of roof area, garage area,

concreted area and impervious area ( footpaths, driveways, pool paved area). A schematic showing the location and direction of flow of all “ sustainable water”

elements (including: rainwater tank, infiltration, and detention system) and, if applicable, the location of on site septic tank and disposal areas.

P P

N/A P

N/A P

N/A

P

F F F F F F F

F

F F F F F F F

F

P P

N/A P

N/A P

N/A

P

F F F F F F F

F

F F F F F F F

F

Where rainwater tanks are proposed to be installed :- The location of the rainwater connection, Size, height and type of storage. Overflow and connection to stormwater / other systems. Depth and details if to be constructed underground. Details of pump. Details of first flush system Details of connections to internal and external plumbing. Details of backflow prevention.

Details of connection to mains if rainwater is to be internally plumbed

N/A N/A N/A N/A N/A N/A N/A N/A N/A


F F F F F F F F F


P P P P P P P P P

F F F F F F F F F

Where infiltration and detention systems are proposed to be installed. Soil permeability. Size of system.

Overflow and connection to stormwater / other systems

N/A N/A N/A

P P P

F F F

N/A N/A N/A

P P P

F F F

Where OSD systems are proposed to be installed. Size of system ( volume ) Flow rate.

Overflow and connection to stormwater / other systems.

N/A N/A N/A

P P P

F F F

N/A N/A N/A

P P P

F F F

HYDROLOGY Pre development hydrology ;- runoff volumes, frequency, and peaks. Post development hydrology :- runoff volumes, frequency, and peaks. Management measures to reduce impacts.

P P P

F F P

F F

N/A

P P P

F F F

F F F

WATER QUALITY Pre development water quality of receiving waters. Pre development pollutant loads (modelled ). Post development pollutant loads ( modelled ). Management plan to address water quality.

N/A N/A N/A N/A

P P P P

F F F F

N/A N/A N/A N/A

P P P P

F F F F

Where the reinstatement of riparian vegetation is proposed :- A landscape plan detailing the location and type of species. Staging plan for works.

A maintenance and monitoring program for the first year of regeneration.

P P P

D D D

F F F

P P P

D D D

F F F

If cut and fill is undertaken the site a plan must be submitted to council which shows :- Existing topography, Existing overland drainage direction ( upstream and downstream ). Location of upstream and downstream neighbouring landholders. Proposed volumes and location of cut and fill. The proposed source of the fill. Proposed revised levels and topography of the site. The overland drainage direction following cut and/or fill ( upstream and

downstream, ). Description of any new overland flow on neighbouring properties.

P P P P P P P

P

F F F D D F F

F

F F F F F F F

F

P P P P P P P

P

F F F D D F F

F

F F F F F F F

F SQID PLAN How the chosen treatment devices relates to the treatment train and the rationale

for SQID selection as described in section D7.13 That the SQID/s chosen address target pollutants as listed in Tables D7A - 6 That the SQID/s chosen meets the water quality objectives as listed in Section

D7.11 The catchment area that the SQID is treating and the optimum treatment area for

P

N/A

N/A

D

D

D

F

F

F

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A



Page 46

TYPE & SCALE OF DEVELOPMENT

High Risk Development >6 Lots and/or

2500m²

Low Risk Single dwellings &

Duplexes < 6 Lots or < 2500m²


e- D

A

DA S

ubmi

ssion

Cons

tructi

on

Certif

icate

Pre-

DA

DA S

ubmi

ssion

Cons

tructi

on

Certif

icate

the device chosen. The Hydraulic regime of the SQID and the Hydraulic regime of the site, including

influence by tidal factors ( if applicable ). The target pollutants to be removed by the SQID and how it relates to the

treatment train for the development. An operations and maintenance plan detailing maintenance costs.

N/A

N/A

P

N/A

D

D

D

D

F

F

F

F

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

SQID Maintenance and Operation Manual for the maintenance of Stormwater Quality Improvement Devices must be prepared in accordance with Councils Maintenance Operation Procedures Manual and contain: Worksafe procedures (Workplace Health and Safety) for the safe operation and

maintenance of the SQID. Supplier contact for parts, services and / or technical advice. The mechanism required to clean the device ( eg manual removal, backhoe,

inductor truck ) etc. Any consumables required for the maintenance of the device. Maintenance and Inspection forms (REFER TO COUNCIL STD FORMS) which

clearly identify the data collection requirements. A specified maintenance frequency Eg either in terms of maintenance on a

specific events basis, a periodic basis, or based on certain levels of material trapped within the device. NOTE The statement “ Maintain as required “ is not acceptable.

Dewatering and waste disposal procedures. This includes the names and locations of licensed operators able to take the waste. Any and all regulated, hazardous or other waste licensing requirements, which must be followed in the transportation and disposal of the liquid and dry waste components.

Access points for vehicles / machinery as required. An estimate of costs for maintenance incorporating the likely frequency of

cleanout, type of cleanout, the costs for transport, vehicle hire ( eg Inductor truck if any ), disposal and consumables and replacement costs.

A schematic of the SQID, its connections to the drainage system, and description of operations.

Electrical diagrams for any and all electronic components. Inspection and monitoring frequency including the type of monitoring and data

collection required to assess the performance of the system. Supplier contact for parts, services and / or technical advice. The type of material likely to be caught in the device ( eg liquid or solid ). A replacement cost for the asset. Stakeholder notification requirements when undertaking maintenance.

N/A

N/A N/A

N/A N/A

N/A

N/A

N/A N/A

N/A

N/A N/A

N/A N/A N/A N/A

P

N/A P

P N/A

P

P

P P

P

N/A P

N/A P P

N/A

F

F F

F F

F

F

F F

F

F F

F F F F

N/A

N/A N/A

N/A N/A

N/A

N/A

N/A N/A

N/A

N/A N/A

N/A N/A N/A N/A

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A

N/A

N/A N/A

N/A N/A

N/A

N/A

N/A N/A

N/A

N/A N/A

N/A N/A N/A N/A



Page 47

TABLE D7A - 5 EROSION AND SEDIMENT CONTROL PLAN REQUIREMENTS – ESCP SCALE & TYPE OF DEVELOPMENT

High Risk

Development >6 Lots and/or

2500m²

Low Risk

Single dwellings & Duplexes < 6

Lots or < 2500m² STAGE OF DEVELOPMENT Pre – DA : Preliminary (P) sketch/concept acceptable unless noted otherwise. DA Submission : Draft (D) sketch/concept acceptable unless noted otherwise. Construction Certificate : Final (F) detail in accordance with relevant Council Specification unless noted otherwise. Pr

e-DA

DA –

Subm

ission

Cons

tructi

on C

ertifi

cate

Pre –

DA

DA –

Subm

ission

Cons

tructi

on C

ertifi

cate

a. Plans of external and internal catchments N/A P F P F F 1. Site layout to include • Plans showing existing site topography, water courses,

contours • Final contours with cut and fill locations identified. • Property boundaries and lot lines. • General staging of works. • Staging of works including site clearing & topsoil stripping. • Location of site works, facilities and access. • Location of parking areas, roadways & tracks. • Location of site storage & stockpile areas. • Utility plans. • Erosion risk mapping – identification of low, medium, high and

extreme erosion risk areas. • Topographic site limitations which may include:- excessive

slope gradients; unstable hazardous terrain; flood inundation areas; rock outcrops; active coastal dune systems; land subject to wave attack; existing erosion; water bodies; drainage problem areas; areas of potential mass movement.

P

P P P

N/A N/A N/A N/A N/A N/A

N/A

F

F F F F

N/A N/A N/A N/A P

F

F

F F F F F F F F F

F

P

P P P

N/A N/A N/A N/A N/A N/A

N/A

F

F F F F

N/A N/A N/A N/A P

F

F

F F F F F F F F F

F

2. Vegetation layout • General location, nature and condition of existing vegetation. • Identification of buffer width requirements adjacent to

watercourses. • Location plan of protected trees and bushland, non

disturbance areas, buffer zones, disturbance control fencing and limits of clearing.

• Revegetation landscape plan (including staging).

P

N/A

N/A

N/A

F F

F

N/A

F F

F

F

P

N/A

N/A

N/A

F F

F

N/A

F F

F

F 3. Soil properties • Location and limitations of major soil types on site. • Identification of all known areas of dispersive soils (more than

10% being dispersive). • The R and K factors for the RUSLE and Soil Loss Classes

(delineated where more than one occurs). • Soil hydrologic group [ “Managing Urban Stormwater, Soils

and construction” NSW Dept of Housing 1998 Appendix F]. • Soil texture group Type C, F or D

N/A N/A

N/A

N/A

N/A

F

N/A

N/A

N/A

N/A

F F

F

F

F

N/A N/A

N/A

N/A

N/A

F

N/A

N/A

N/A

N/A

F F

F

F

F 4. Drainage • Plans of both temporary and permanent drainage, including

design/capacities of major drains. • identification of all proposed temporary and final overland flow

paths. • any proposed diversions of overland flow paths or

N/A

N/A

N/A

P

P

N/A

F

F

F

N/A

N/A

N/A

P

P

N/A

F

F

F



Page 48

SCALE & TYPE OF DEVELOPMENT

High Risk

Development >6 Lots and/or

2500m²

Low Risk

Single dwellings & Duplexes < 6

Lots or < 2500m² STAGE OF DEVELOPMENT Pre – DA : Preliminary (P) sketch/concept acceptable unless noted otherwise. DA Submission : Draft (D) sketch/concept acceptable unless noted otherwise. Construction Certificate : Final (F) detail in accordance with relevant Council Specification unless noted otherwise. Pr

e-DA

DA –

Subm

ission

Cons

tructi

on C

ertifi

cate

Pre –

DA

DA –

Subm

ission

Cons

tructi

on C

ertifi

cate

watercourses from the site. • Lawful point of discharge, easements/land required for lawful

discharge.

N/A

P

F

N/A

P

F

5. Erosion and sediment control proposal including • Site specific text overview and design philosophy of erosion

and sediment control proposal • Location (on plans), type and function of drainage, erosion and

sediment control measures (the location plans must include areas external to the site where these areas impact or are impacted upon by the drainage or ESCP of the subject site).

• Areas proposed for clearing (maximum of 2ha. Per stage ) • Calculation of Sediment pond sizes during construction. • Timetable, integration/sequencing of ESCP with staging of

works • RUSLE calculations to evaluate current annual soil loss and

likely annual soil losses from the proposed development incorporating the proposed ESCP

• Water quality monitoring program with water quality objectives, parameters to be monitored, locations and monitoring frequency.

• Proposed response to failure of system and non-compliance with discharge quality standards.

• Reporting procedures. • Procedures for amending the ESCP

N/A

N/A

N/A N/A N/A

N/A

N/A

N/A

N/A N/A

P

P

F N/A F

P

N/A

P

P P

F

F

F F F

F

F

F

F F

N/A

N/A

N/A N/A N/A

N/A

N/A

N/A

N/A N/A

P

P

F N/A F

N/A

N/A

P

P P

F

F

F F F

F

F

F

F F

g. Acid soil management plan. N/A P F N/A P F h. Details of receiving waters including quality characteristics. N/A F F N/A F F i. Assessment of effects of construction phase of development on receiving waters.

N/A F F N/A F F

j. Details of proposed water quality monitoring program. N/A P F N/A P F k. If the development proposal is for a subdivision containing “master lots” ie. Large lots to be further subdivided under a future DA, then the ESCP must be prepared containing details of erosion and sediment controls for each “ master lot”, independent of the ESCP for any other lots.

N/A F F N/A F F


TABLE D7A – 6 POLLUTANT REDUCTION EFFICIENCIES ( Brisbane City Council Design Guidelines for Stormwater Quality Improvement Devices Final Draft – 4 November 1999)

Management Device Litter CoarseSednt Suspended

Solids Nutrients (N & P) Oxygen

Demanding Substances

Hydrocarbons Pathogens Heavy Metals

Source Controls

Street Sweeping H – M M - - L - - L

Rubbish Bins H – M - - - L - - -

Education L L L L L L L LPrimary Treatments Small Scale Litter Baskets L – M L - - L - - -

Grates & Entrance Screens L - - - - - -

Side Entry Pit Traps L – M L - - L - - -

Baffle Pits L L – M L L L - - L

Catch Pits L L – M L L L - - L

Oil & Grit Separators L L – M L L L L – M L L

Nets H - - - - - - -

Medium Scale Devices Litter & Trash Racks M L - - L - - -

Downwardly inclined screens H - - - - - - -

Floating Litter Booms L – M - - - - - - -

In Ground GPT H – VH H L L L – M L - L In Line Separators M L – M - - - - - -

Large Scale Devices

Open Gross Pollutant Traps M – H H L L L L L L

Sediment Traps L H L L L L L L

Secondary Treatments Filter Strips M H M L – M L L M L

Grass Swales L – M M – H M L – M L L M M

Sand Filters - M – H M – H M M M M MInfiltration Trench / Basin - M – H M M M M M M – H Porous Pavement - H M – H M M M H M – H Extended Detention Basins - M – H L – M L L L M L

Tertiary Treatments Water Quality Ponds M – VH H L – M L – M L L L L – M

Constructed Wetlands M - VH H M M L M M H

Legend: - = Neglible benefit L = 10 – 30 % Pollutant reduction efficiency M = 30-50% Pollutant reduction efficiency H = 50 – 75 % Pollution reduction efficiency VH = 75-100% Pollution reduction efficiency

D07-Stormwater Management- Hastings 2003 Rev 1.doc February 2004 (Copyright ) Page 49

STORMWATER MANAGEMENT Contract No. TABLE D7A – 7 Brisbane City Council design guidelines for Stormwater Quality Improvement Devices Final Draft – 4 November 1999

Device / Practice Maximum Flow Rate (L/S) for Design Event (Q 3 month) Target

Pollutants Size

Criteria 30 50 70 100 150 200 250 300 350 400 450 500 600 700 800 1000 1250 1500 1750 2000 2500 3000 4000

In Ground GPT Humes Humeguard in

line Gpt Model No CONTACT CSR HUMES FOR SIZING INFORMATION

Ecosol RSF 4000 Flow L/S 300ø 450 600ø 750ø 900ø 1050ø 1200ø 1350 1500ø 1800ø Ecosol RSF 6000 Flow L/S 450ø 600ø 750ø 900ø 1050ø 1200ø 1350 1500ø 1800ø Rocla Cleansall Inlet ø CL375 CL600 CL900 CL1350 CL1800 Rocla Downstream

Defender Flow L/S DD1200 DD1800 DD2400 DD3000

Baramy Inlet ø 300 – 1300 øCDS CDS unit

Litter, Sediments

Flow L/s F0908 P1512 P1516 P2018 P2028 P3024 * Combinations Oil and Grit Separators Humes Humeceptor Model No STC2 to STC27 CONTACT CSR HUMES FOR SIZING INFORMATION Ecosol RSF 5000 Flow L/s 300ø 450 600ø 750ø 900ø 1050ø 1200ø 1350 1500ø 1800ø CDS CDS unit

Hydrocarbons Sediments

Flow L/s F0908 P1512 P2018 * SIZED ON FLOW, CAPACITY AND/OR MAINTENANCE COSTS Grease Traps Everhard Grease Traps Hydrocarbons Cap L 250-10000 L Traps Open GPT

Baramy Direct Flow Inlet Dia. 300 – 1500 øBaramy Channel

Litter, sediment Litter Treatable Flow = 40% of Channel Depth

End of Pipe Litter Nets Stormwater Systems

Pratten Trap PT 2000

Litter Inlet Dia PT 2000

Net Tech Interceptor Inlet Dia ALL Litter Baskets Ecosol RSF Series Litter, Sediment Unit Dia. 300ø 450ø 600ø Ingal Litter, Sediment Side Entry Trap Ecosol RSF 100 & GSP Litter, Sediment Pit Size Gully Pits and pavement grated inlets Sediment Trap Hydro Storm King Sediment Unit Size m 3.0 ø x 2.57 3.66 ø x 3 5.0 ø x 3.59 6.0 ø x 4.13 Hydro Overflow Sediment Unit Dia. 1.4 ø 2.6 ø 3.4 ø 4.1 ø Sized to suit flow Swales & Filter Strips Grass Swales, Filter Strips, Bioretention Systems

Nutrients, Sediments, Metals, Litter

Hydraulic residence time Refer to ARQ for design considerations

Notes: Devices cannot be selected on the basis of size alone. All relevant design criteria must be taken into account when selecting a device. Other relevant criteria include: Pollutant characteristics, maintenance, hydraulic head, pipe gradient, tidal influence, health, safety, aesthetics.


Page 50


Figure D7-10 Hastings and Camden Haven River Catchments water quality regions


Page 51


Table D7A – 8 Environmental Values Hastings and Camden Haven Regions


Page 52


Coastal Region Monthly Rainfall Distribution(Bureau of Meterology Port Macquarie 1960 to 2003)

154.0 159.5

195.6

177.8

147.3 151.1

72.5

63.0

57.9

103.2 12

1.7

122.3

357

259

437

400

269

313

182

155

130

298

199

243

91 94 103

93

79 79

37 32 29

58 67 69

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

450.0

500.0Ja

n

Feb

Mar

Apr

May

Jun Jul

Aug

Sep

Oct

Nov

Dec

Month

Rai

nfal

l (m

m)

AverageAverage MaxAverage Min

Average Annual Rainfall 1526mmAverage Annual Maximum 2062Average Annual Minimum 1172mm

Fig D7A - 11 Coastal Region Monthly Rainfall Distribution


Page 53


Lower Inland Monthly Rainfall Distribution(Bureau of Meterology Site 060124 Wauchope 1960 to 2002)

143 15

8 175

138

115

106

49 48 44

95

111 114

328

318

433

392

258

255

140

167

118

336

200

235

80102

9172

60 53

25 24 22

5063 63

0

50

100

150

200

250

300

350

400

450

500Ja

n

Feb

Mar

Apr

May

Jun Jul

Aug

Sep

Oct

Nov

Dec

Month

Rai

nfal

l (m

m)

AverageAverage MaximumAverage Minimum

Average annual Rainfall 1297mm Average Annual Maximum 1814mmAverage Annual Minimum 974mm

Fig D7A - 12 Lower Inland Region Monthly Rainfall Distribution


Page 54


Upper Inland Monthly Rainfall Distribution(Bureau of Meterology Site 060121 1982 to 2002 )

140

157

128

96

78

47 47

31

40

63

105 11

0

245

187

159

89

146

86

161

189

83

97

69

53 48

24 23

16 21

33

64 61

92

303 301

151

0

50

100

150

200

250

300

350

Jan

Feb

Mar

Apr

May

Jun Jul

Aug

Sep

Oct

Nov

Dec

Month

Rain

fall (

mm

)

AverageMaximumMinimum

Average Annual Rainfall - 1040 mmAverage Annual Maximum - 1225 mmAverage Annual Minimum - 837mm

Fig D7A - 13 Upper Inland Region Monthly Rainfall Distribution


Page 55


Regional Rainfall Distribution

2062

1225

1526

1297

10401172

974837

1814

0

500

1000

1500

2000

2500

Coastal Region Lower Inland Upper Inland

Region

Rai

nfal

l Ave

rage

s (m

m)

Average Annual Max

Avaerage Annual

Avaerage Annual Min.

Fig. D7A – 14 Regional Rainfall Distribution Hastings LGA Table D7A – 9 Landuse and Pollutant Concentrations LANDUSE Suspended

Solids mg/L Total

Phosphorus mg/L

Total Nitrogen

mg/L

Ph mg/L

Total Oil & Grease mg/L

Forest 140 0.1 1.5 6.65 0Rural Allotments 200 0.4 3.5 6.65 8 Woodland 100 0.75 0.85 6.65 0Open space & Parks 200 0.5 3 6.65 0 Agriculture 300 1 6 6.65 0Schools & Churches 300 0.5 3.5 6.8 9 Low Density Residential 220 0.6 4.5 6.8 8 High Density Residential 250 0.7 4 6.8 8 Rural Roads 150 0.3 3 6.9 17 Commercial 250 0.5 3 6.7 17Urban Roads 400 0.6 3 6.9 17 Roofs 70 0.13 3 5.6 9Industrial 300 0.5 3 7.1 9


Page 56


D07-Stormwater Management- Hastings 2003 Rev 1.doc February 2004 (Copyright ) Page 1

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