Source: Baden Myers
The latest report from the Goyder Institute for Water Research (Goyder Institute), Implementing water sensitive urban design in stormwater management plans, provides the foundation to enable a jump step in South Australia’s capability to deliver water sensitive urban design (WSUD). The report offers guidance on stormwater quality and quantity modelling for SA conditions, and evidence of the need for planning policy that ensures the design of new development is consistent with the objectives and strategies contained within council stormwater management plans (SMPs).
As an urban water management industry we now need to digest the recommendations of this report and work collaboratively to bring about the changes in policy and practice necessary to advance the mainstream adoption of WSUD, to deliver the type of communities we all want to live in.
The report addresses some of the significant barriers to the adoption of WSUD techniques via:
- a review of existing stormwater management plans in SA, and in particular evaluating how WSUD approaches had been considered and applied
- an evaluation of the implications of antecedent conditions on the performance of WSUD storage devices
- an assessment of the MUSIC software model for planning and designing WSUD approaches in the SA context
- an analysis of how frequent flows should be considered in planning stormwater management approaches in SA.
Stormwater management plans and MUSIC guidelines
The Goyder Institute reviewed the approaches used to assess water quality treatment measures with nine SMPs approved by the Stormwater Management Authority at the time of the report, and found in some cases the underlying assumptions used in modelling WSUD performance were not clearly documented. This reinforces the need for the development of SA guidelines for adoption of the model for urban stormwater improvement conceptualisation (MUSIC) software tool, a priority within the Water Sensitive SA business plan.
This guideline is now one step closer with the support of the Goyder Institute’s work, which makes recommendations regarding appropriate climate data, soil parameters, run-off pollution generation data and routing parameters for SA. Stormwater design engineers are encouraged to join an industry discussion on the calibration of MUSIC.
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Planning policy
The need for stormwater runoff quality and quantity performance measures to be reflected in council development plans, as the basis for development assessments, has been a topic of hot discussion amongst local government and consulting stormwater engineers in SA for more than 10 years. The Goyder Institute’s research review of the stormwater management plan in SA found that eight of the nine SMPs reviewed provide recommendations with respect to improved planning policy to facilitate WSUD objectives.
Antecedent conditions
The antecedent conditions of a catchment describe the relative wetness or dryness of a catchment prior to a design storm, which can greatly influence the rate of stormwater runoff. The Goyder Institute findings on the effect of antecedent conditions on the performance of WSUD elements will be critical as the stormwater industry moves towards continuous model techniques in line with the 2016 update of Australian rainfall and runoff. The recommendations will be a key consideration in the development of the Water Sensitive SA Online stormwater assessment tool for small-scale developments.
Other recommended reading includes the Goyder Institute’s Pathways for implementation of water sensitive urban design policy in South Australia.
References
Myers B, Cook S, Pezzaniti D, Kemp D, Newland P (2016) Implementing water sensitive urban design in stormwater management plans. Goyder Institute for Water Research Technical Report Series No. 16/7, Adelaide, South Australia.
Cook S, Myers B, Newland P, Pezzaniti D, Kemp D (2015) Pathways for Implementation of Water Sensitive Urban Design Policy in South Australia. Goyder Institute for Water Research Technical Report Series No. 15/51, Adelaide, South Australia.