On-site wastewater management (GD06) Community of Practice: - - PowerPoint PPT Presentation

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On-site wastewater management (GD06) Community of Practice: - - PowerPoint PPT Presentation

Nov 15, 2023 777 likes •1.2k views

On-site wastewater management (GD06) Community of Practice: feedback and next steps Auckland Council Engineering & Technical Services and Heathy Waters Agenda Morning tea available prior to meeting 9:00am 9:30am Introduction and

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On-site wastewater management (GD06)

Community of Practice: feedback and next steps

Auckland Council Engineering & Technical Services and Heathy Waters

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Agenda

Morning tea available prior to meeting 9:00am – 9:30am Introduction and welcome 9:30am –9:45am Details of on-site management in Auckland:

  • Development of document
  • Significant differences
  • Next steps/timeframes
  • Unitary Plan Change
  • By-law update
  • Region-wide wastewater compliance monitoring

programme 9:45am – 10:45am Break out session: 10:45am – 11:30am Regroup and summary: 11:30am – 12:00pm

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First things first…

Introduction GD 06 Overview Next steps Feedback

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Acknowledgements

The team of authors & contributors

Justine Bennet, Graham Boyle, Patricia Burford, Zhou Chen, Andrew Dakers, Simonne Elliot, Peter Gearing, Ian Gunn, Jack Feltam, Grant Fleming, Robyn Floyd, Kristina Healy, Anthony Kirk, Terry Long, Alan Moore, Sandy Ormiston, Noel Roberts, Ross Roberts, Gretel Silyn Roberts, Robyn Simcock, Karamjeet Singh Siani, Anna Tyrrell, Branko Veljanovski, Nick Walmsley, Dylan Walton, Robert Watson, John Whitmore, Sam Wiess, the Land Treatment Collective and WaterNZ

Our mana whenua representatives

Ngāti Manuhiri, Fiona McKenzie, Ngāti Maru, Geoff Cook, Ngāi Tai ki Tāmaki, Jeff Lee, Ngāti Tamaoho, Hero Potini & Lucille Rutherfurd, Ngāti te Ata Waiohua, Berenize Peita, Ngāti Wai, Dane Karapu, Ngāti Whātua Ōrākei, Moana Waa, Te Ahiwaru Waiohua, Kowhai Olsen, Te Ākitai Waiohua, Adrian Pettit, Te Kawerau a Maki, Scott Lomas, Te Rūnanga o Ngāti Whātua, Tame Te Rangi, Te Uri o Hau, Tina Latimer

All our Community of Practice participants All those who will provide us valuable feedback in the coming months

Introduction GD 06 Overview Next steps Feedback

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Auckland Design Manual

Introduction GD 06 Overview Next steps Feedback

Send us your feedback Access the document

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Document structure

  • Section A – Introduction
  • Section B – Site and subsurface evaluation
  • Section C – Design flow volume
  • Section D – Wastewater treatment units
  • Section E – Design of land application systems
  • Section F – Construction, commissioning and maintenance
  • Section G – Risk management

Introduction GD 06 Overview Next steps Feedback

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Introduction GD 06 Overview Next steps Feedback

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Summary of key changes

Item GD06 change Site and soil evaluation A revised chapter: both theory and technical guidance. Importance of functional soils, guidance on sample collection, testing, and analysis. Soil classification Seven soil categories changed to six: to align with those of AS/NZS 1547:2012 Slopes and setbacks Methods for managing wastewater on slopes and limits for steep slopes. Adjusted setback distances for different types of infrastructure and receiving environments. Design loading rates Revised design loading rates for different soil categories. Construction and

  • peration and

maintenance Details of how on-site wastewater systems should be constructed and how they should be operated and maintained. Risk management New chapter: hazard identification and risk management with examples

Introduction GD 06 Overview Next steps Feedback

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Site and subsurface evaluation

  • How do we assess soils?
  • How do we standardise our

assessments?

  • Bore logs
  • Categorisation based on:
  • Texture
  • Structure
  • Clay content
  • Indicative permeability

Introduction GD 06 Overview Next steps Feedback

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GD06 soil categories

Soil category Soil texture [Note 1] Soil structure [Note 2] Typical clay content Indicative permeability (Ksat) (m/d) [Note 3] 1 Gravel, coarse/medium sand Granular, structureless or weakly structured <5% >3.0 2 Loamy sand, sandy loam Weakly structured 5 – 10% >3.0 Massive 10 – 20% 1.4 – 3.0 3 Fine sandy loam, loam, silt loam High/moderate structured 10 – 20% 1.5 – 3.0 Weakly structured or massive 10 – 25% 0.5 – 1.5 4 Sandy clay loam, fine sandy clay, clay loam, silty clay loam High/moderate structure 20 – 30% 0.5 – 1.5 Weakly structured 20 – 30% 0.12 – 0.5 Massive 25 – 35% 0.06 – 0.12 5 Sandy clay, light clay, silty clay Strongly structured 35 – 45% 0.12 – 0.5 Moderately structured 35 – 40% 0.06 – 0.12 Weakly structured or massive 40 – 50% < 0.06 6 Clays (including swelling and grey) and hard pan Strongly structured 40 – 55% 0.06 – 0.5 Moderately structured >50% < 0.06 Weakly structured or massive >50% < 0.06

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Soil classification – refer to page 3

  • TP58 has seven categories
  • AS/NZS Standards has six

categories

  • GD06 aims to realign with the

six soil categories used nationally

Introduction GD 06 Overview Next steps Feedback

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Soil categories – refer to page 4

(Prepared by A Dakers)

TP58

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Slopes – refer to page 5

Introduction GD 06 Overview Next steps Feedback Land application system Slope gradient limitations* Notes Surface irrigation (spray, drip and low-pressure effluent distribution irrigation) <5.7° (10%)

  • Due to risks of effluent run-off during wet weather.
  • Assumes little disturbance occurs during construction.
  • This is limited by natural infiltration rate and even distribution.

Subsurface drip irrigation (i.e. pressure compensating drip irrigation) <16.7° (30%)

  • All irrigation lines should be installed along the land contours.
  • If this is not possible, and if the lines have non-leak emitters, then

lines may run through contour lines in accordance with the manufacturer’s specifications.

  • A copy of the specifications should be included with the system

design for approval. Subsurface low-pressure effluent distribution or low- pressure pipe <8.5° (15%)

  • Shallow and narrow trenches for low pressure effluent distribution
  • r low-pressure pipe systems must be constructed along the

contour. Evapotranspiration beds <5.7° (10%)

  • High soil disturbance and erosion issues may arise during

construction on steeper slopes. Trenches and beds, including discharge control trenches and beds <8.5° (15%)

  • Construction becomes difficult and costly when slopes are high.
  • High soil disturbance and erosion issues may arise during

construction on steeper slopes. Mounds <8.5° (15%)

  • High soil disturbance and erosion issues may arise during

construction on steeper slopes.

Table 17 in GD06

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Setbacks – refer to pages 6 - 9

  • Adjustments for slopes

to ensure steeper slopes have more conservative setbacks

  • Adjusted to six soil

categories

  • Includes surface waters

(with maximum slopes of 18°)

Introduction GD 06 Overview Next steps Feedback

Table 19 of GD06

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Reserve areas – refer to page 10

Introduction GD 06 Overview Next steps Feedback Land application method Minimum reserve area allocation Subsurface drip irrigation (pressure compensating) (Where non-conservative design flow based on less than 145 L/p/d) 33% - 100% (67% - 100%) Surface drip irrigation (pressure compensating) (Where non-conservative design flow based on less than 145 L/p/d) 50% - 100% (80% - 100%) Shallow trenches (with primary treated effluent) 100% Standard/deep trenches (with primary treated effluent) 100% Evapotranspiration seepage beds 100% Shallow trenches (with secondary treated effluent) 50% - 100% Mound systems 100%

Table 20: Reserve application area requirements

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Design loading rates – refer pages 10-12

Introduction GD 06 Overview Next steps Feedback

  • Changes made to align with

AS/NZS and Auckland soils

  • Ranges removed where possible

(e.g. discrete values as minimums)

  • Very similar to TP58 for majority
  • f soil types (3-5)
  • Reduced loading for soil category

1 (sands)

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Construction, operation & maintenance

  • Installation
  • Protecting soils
  • Documentation (certification, management plans, product

certification)

  • Commissioning
  • Operation:
  • Education for homeowners
  • “Do”s and “Don’t”s
  • Maintenance:
  • Sludge/scum removal at 50%
  • Need for a maintenance contract
  • Mechanisms for monitoring compliance

Introduction GD 06 Overview Next steps Feedback

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Risk management

  • System has to operate as

designed

  • Protect public health
  • Protect receiving environment

Introduction GD 06 Overview Next steps Feedback

Likelihood

5 Risk = Likelihood x consequence 4 Low risk 3 Moderate risk 2 High risk 1 1 2 3 4 5

Consequence

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Regulatory context

  • TP58 held much of the

regulatory context for the Air, Land and Water Plan for Auckland Regional Council

  • GD06 has removed this

regulatory context; this will need to be transposed into the Auckland Unitary Plan.

Introduction GD 06 Overview Next steps Feedback

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Introduction GD 06 Overview Next steps Feedback

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Next steps

  • Deadline for feedback – October 12th
  • Major feedback by mid-September please!
  • Document finalised and uploaded onto Auckland Design Manual
  • Adopted through a Plan Change within 18 months.

2018 GD06 draft published Final released 2019 Deadline for feedback: Oct 13 Adopted into AUP through Plan Change Jan Jun Fully replaces TP58 Dec Jan Jun Dec

Introduction GD 06 Overview Next steps Feedback

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Other parallel workstreams

Unitary Plan Change

  • Chapter E5 revision
  • Content from TP58 transposed into AUP

Bylaw update

  • Proposal to revoke four legacy bylaws
  • Feedback up to August 31st

Region-wide wastewater compliance monitoring programme

  • Compliance programme being rolled out

Introduction GD 06 Overview Next steps Feedback

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Introduction GD 06 Overview Next steps Feedback

Unitary Plan revision of Chapter E5

Sorcha Peren - Plans and Places

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Unitary Plan change

Current status

  • Chapter E5 refers to TP58
  • TP58 holds a lot of

regulatory content Proposed change

  • Cross-reference GD06

instead of TP58

  • Regulatory content from

TP58 transposed into AUP

Introduction GD 06 Overview Next steps Feedback

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Introduction GD 06 Overview Next steps Feedback

Legacy bylaws

Maclean Grindell – Social Policy

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Review of legacy on-site wastewater bylaws

Findings

  • The bylaws do not provide additional regulation to

the unitary plan

  • The unitary plan has stronger enforcement powers

than the legacy bylaws

  • Although pollution is still occurring, the bylaws are

not needed to address this issue

Recommendation: revoke the legacy on- site wastewater bylaws and rely on the unitary plan Consultation Open Until August 31st

Introduction GD 06 Overview Next steps Feedback

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Introduction GD 06 Overview Next steps Feedback

Roll out of On-site Wastewater Compliance Monitoring Programme

Water Quality Targeted Rate Janet Kidd – Healthy Waters

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What

  • Poor water quality from onsite

wastewater systems issue across the region.

  • Very little oversight of these devices –

majority permitted activities / existing use.

  • Proposed regional compliance

monitoring - request owners for inspection and maintenance records

  • Part of Water Quality Targeted Rate
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When

Requires numerous tasks to develop “infrastructure:”

  • Regional onsite wastewater database
  • Communications and education
  • Industry group liaison?

Rolled out in stages – existing schemes / high risk areas first, then remainder of region. Provisionally take 2-3 years for whole region

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Feedback Sought

Standardised inspection and maintenance checklists

  • Appendix J of GD06
  • Online version

Definition of Suitably Qualified and Experience Personnel

  • Years experience
  • Professional accreditations / registrations – Plumbers and Drainlayers, Liquid and

hazardous Waste Operators, others Sharing of existing information for regional database Interest in setting up regional industry forum or work with national forums

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Introduction GD 06 Overview Next steps Feedback

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Feedback sessions

Introduction GD 06 Overview Next steps Feedback

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Facilitated feedback sessions 15 minutes each – choose three

Table Facilitator Subject matter expertise Table 1 Gretel Technical detail Table 2 Janet Operation & Maintenance Table 3 Alan Consents Table 4 Sorcha & Maclean Auckland Unitary Plan changes

Introduction GD 06 Overview Next steps Feedback

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Questions for your session (15 min each):

What do you like?

  • Is it easy to use?
  • Clear?

What don’t you like?

  • Errors?
  • Unclear?
  • Policy versus science?

Try to be specific – the more details the better

Introduction GD 06 Overview Next steps Feedback

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Stop watch

Introduction GD 06 Overview Next steps Feedback

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Education & Training

Introduction GD 06 Overview Next steps Feedback

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What technical information would you like training

in?

How would you like to receive training?

  • Full/half day of training?
  • Additional tools?
  • Available on the internet as learning modules?

Try to be specific – the more details the better

Questions for your session

Introduction GD 06 Overview Next steps Feedback

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Wrap up

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And lastly…