DIT:Planning Reform Submissions From: Sent: Friday, 18 December 2020 6:15 PM To: DIT:Planning Reform Submissions Subject: Water Sensitive SA submission - Code Phase 3 I 4 November 2020 amendment Attachments: WSSA_Planning and Design Code Revision _submission FINAL_Letter and Submission_ 18Dec20.pdf - ■ Dear Mr Lennon Please find attached the submission from W ater Sensitive SA in response to the consultation on the Code (Phase 3) amendment 4 November 2020. Regards Me llissa Mellissa Bradley ager Water Sensitive SA · 142 --e~s1 1vesa.com LIVFRBLE - WRTER WRTER SENSITIVE ■■ SENSITIVE SR COMMUNITIES. 1 ■■ WRTER ■■ SENSITIVE SR 18 December 2020 Mr Michael Lennon Planning Commission [email protected] Dear Mr Lennon Planning and Design Code – Phase 3 submission, 4 November 2020 amendments Water Sensitive SA is pleased to submit this response to the Planning and Design Code- Phase 3. Water Sensitive SA has devoted considerable resources over the past three years to understand the changing urban form, the associated implications for communities and the environment and to develop suitable solutions at a range of scales to meet the strategic targets of the 30 Year Plan for Greater Adelaide. The focus of this submission is on the urban greening and stormwater management aspects of the Code. The recent amendments to the deemed-to-satisfy stormwater policy for small-scale development (Part 3 – Stormwater Management Overlay) will improve peak flow management performance of small-scale developments, which is an important step forward. This improvement did however come at the expense of the other performance criteria for water conservation and stormwater quality water quality management. We appreciate this is a balance act and offer in this submission the outcomes of modelling that attempts to find optimal lot scale solutions for stormwater management for your consideration. Attached is our detailed submission comprising: ▪ Policy and guideline recommendations ▪ Appendix A –Evidence base for recommendations We would welcome the opportunity to work with DPTI to assist in any refinement of policy and guidelines that support the Code. Water Sensitive SA can offer assistance with the development of design guidelines for built form typologies and allotment scale solutions. If you require any clarification of the comments raised as part of this submission, please contact the Program Manager, Mellissa Bradley at [email protected] or 0431 828 980. Yours sincerely Keith Downard Chair, Water Sensitive SA Steering Committee LIV ERB LE WRTER SENSITIVE COMMUNITIES. WATER SENSITIVE SA – Comment on Code amendments 4 November 2020 Submission to the Planning Commission on the Planning and Development Code – Phase 3 (the Code) November 2020 Revision OVERVIEW Urban infill provides governments and communities with the opportunity to regenerate our suburbs. Without suitable amendments to the Code and associated guideline development, there is a risk that poor quality infill will continue to degrade our suburbs. This submission provides the quantitative evidence of the water performance of differing rainwater harvesting, tank size and use options, site coverage and urban greening at the lot and scale, to inform the stormwater management and canopy cover policies within the Planning and Design Code Phase 3 November 2020 Update. Combined rainwater harvesting and reuse via retention and stormwater detention is provided in the policy as the means of meeting the performance objectives for small-scale development in the deemed-to-satisfy solutions in Part 3 – Stormwater Management Overlay. Incentives are provided to increase overall site permeability via discounting of minimum tank sizes, which is strongly supported as a means of demonstrating the importance of reduced site coverage. To ensure small-scale infill gives back to the local area and does not distract from streetscape amenity, modest changes to housing footprint (site coverage and layout) and design are required to accommodate greater dwelling density while retaining green space and permeability of outdoor spaces, and support greening, thereby contributing to stormwater management objectives. The deemed-to-satisfy criteria target absolute minimum standards and are expected to fall short of community expectations and state level targets for urban greening and stormwater management. Recommendation 1 - All allotments < 200m2 shall include a detention component as per the findings of BDO EconSearch (2020a) OPTIONS ANALYSIS: Costs and Benefits of Stormwater Management Options for Minor Infill Development in the Planning and Design Code. A Report to the Attorney-General’s Department, September 2020 and an analysis using the Water Sensitive SA Insite Water tool analysis. The inclusion of the detention component for all small-scale infill is needed, not just for those sites of 200m2 or greater, to sustain an acceptable level of service of local flood protection for the minor drainage system. This is consistent with the outcomes of the: ▪ BDO EconSearch report: BDO EconSearch (2020a) OPTIONS ANALYSIS: Costs and Benefits of Stormwater Management Options for Minor Infill Development in the Planning and Design Code. A Report to the Attorney-General’s Department, September 2020 (BDO EconSearch Options Analysis Stormwater Report) and ▪ Water Sensitive SA InSite Water Analysis (Refer to Appendix A Evidence for policy recommendations for more information that clearly states the cumulative impacts of infill development on peak flows are substantial and that onsite detention is a cost-effective method to manage these impacts. Suggested amendments to the Code (Phase 3) – Part 3 Stormwater Management Overlay are provided in red in Table 1. WATER SENSITIVE SA- Comment on Code amendments 4 November 2020 Table 1 Alternative deemed-to-satisfy solution to replace Code Phase 3 Part C - Stormwater Management Overlay PO 1.1 DTS/DPF 1.1 Residential development is Residential development comprising detached, semi-detached or row designed to capture and re- dwellings, or less than 5 group dwell ings or dwellings w ithin a residential use stormw ater to: flat building: 1. maximise 1. includes rainwater tank storage: conservation of 1. connected to at least 80% of the roof area w ater resources 2. connected to either all toilets, laundry cold water outlets 2. manage peak or hot water service for sites less than 200m2 stormw ater runoff flows and volume to 3. connected to ~ all toilets and either the laundry cold ensure the carrying water outlets or hot water service for sites of 200m2 or capacities of greater downstream 4. with a minimum total capacity in accordance w ith Table 1 systems are not overloaded 5. where detention is required, includes a 20-25 mm diameter slow release orifice at the bottom of the 3. manage stormwater runoff quality. detention component of the tank 2. incorporates dwelling roof area comprising at least 80% of the site's impervious area Table 1: Ra inwater Tank Site size Minimum Minimum detention volume 2 (m ) retention (Litres) volume (Litres) <200 2000 NM,1000 200-400 2000 Site perviousness <30%: 1000 Site perviousness =30%: N/ A >401 4000 Site perviousness <35%: 1000 Site perviousness =35%: N/ A Recommendation 2 - Prior to the release of the Code (Phase 3), develop a guideline to support better choices for deemed-to-satisfy solutions for stormwater management for small-scale development Appendix A.1 provides an analysis of the performance of a range of allotment sizes, tank sizes and connected uses. Key take-home messages to be drawn from this work are: • The deemed-to-satisfy solution for allotments < 200m2 should be amended to be l000L retention + 1,000L detention storage, instead of 2,000L retention only. Page I 2 WATER SENSITIVE SA – Comment on Code amendments 4 November 2020 ▪ For a combined 1000 L detention and 1000 L retention tank the ranking in order of decreasing performance across all criteria is hot water service, laundry, all toilets, and a single toilet. ▪ One toilet alone provides minimal benefit due to the high efficiencies of modern toilets and associated limited rainwater use (draw down on the tank). Recommendation 3 – DO NOT delete the rainwater tank requirements from the National Construction Code The rainwater tank requirements within the National Construction Code (SA Amendment) (NCC) need to be retained, with minor amendments, if the deemed-to-satisfy pathway proposed in Part 3 of the Code has any chance of effective implementation. The recommended minor amendments to the NCC with respect to rainwater tanks is that the NCC should be silent on the size of the rainwater tank and the type of rainwater use connections (e.g. toilet, laundry cold tap or hot water service. Rather, it should define how the connections should be made. The Code (Phase 3) should specify the tank size and rainwater use connections. Recommendation 4 – Require compliance certificate prior to occupation for stormwater management that is inspected and deemed-to-satisfy the Code Further to Recommendation 3, the certificate of occupancy must include the installation of the rainwater (combined detention and retention) tank and connection to approved uses. The absence of this requirement both: ▪ undermines the entire Stormwater Management Policy in Part 3 Overlays, and ▪ brings into question why the Attorney-General’s Department would invest in the BDO EconSearch Options Analysis Stormwater Report to determine the most cost-effective solutions for stormwater management at the city scale,