STORM Report or

WSUD (Water Sensitive Urban Design) Report

This report outlines the Water Sensitive Urban Design Response to achieve the objectives of Clause for Stormwater Management (WSUD) Policy of your local council Planning Scheme. The following site plan shows the location of the catchment areas. The following table shows the proposed calculated Raingarden size and the Rainwater tank capacity in from of its catchment area.


This report calculates the required treatment measures size/capacity for compliance with the Clause. Architect and/or other relevant consultants will be responsible for implementing the treatment measures and showing the required information on the application drawings to be submitted to the Council.

STORM Calculator

Anyone can use the STORM calculator to design small residential or commercial developments, ensuring they achieve the stormwater treatment objectives required by state and local government planning provisions.

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The following STORM rating report outlines how this application achieves the objectives of Storm water Management (Water Sensitive Urban Design) Policy of your council Planning Scheme. The achieved STORM rating should be minimum 100 to satisfies the benchmark 100 scores required.

The above rating demonstrates that the client has met the best practice stormwater quality for the proposed development using the WSUD measures described in the STORM report, and that if constructed in harmony with WSUD measures outlined in the WSUD report.

Note: For the development to achieve the STORM score listed, it must be constructed according to the town planning drawings as well as the following specifications. The type, location and any necessary design details need to be shown on the planning drawings and submitted to the Responsible Authority to be endorsed. If consultants/engineers preparing the plans have any questions relating to the WSUD measures in this report, they should contact Energy Compliance Team for further clarification.

Site management program

The builder and/or project manager will be responsible for providing a site management plan including stormwater management before and during construction. This may be incorporated within a broader Construction Management Plan.

Site maintenance program

Rainwater tanks

The project’s hydraulic/services engineers will be responsible for the design of the Rainwater tanks and rainwater reticulation, shall inform the building facility manager and/or owners corporation in writing, of the required maintenance tasks to keep the system operational. This includes:

  • Regular inspections of the tank(s), pump(s), reticulation system and toilets to ensure that the system is operating for toilet flushing as designed.
  • Periodic cleaning and major maintenance of the tank(s), pump(s) and reticulation system to ensure the long term viability of the system.
  • The building facility manager and/or owner’s corporation shall include on their building maintenance schedule the required maintenance tasks specified by the hydraulic/services engineers at the required intervals.

Appendix A provides a checklist for the future operational and maintenance arrangements for Rainwater tanks.

Raingardens

The project’s hydraulic/civil engineers will be responsible for the design of the Raingardens and the connection inlets and outlets to and from the Raingarden and shall inform the building facility manager and/or owners corporation in writing, of the required maintenance tasks to keep the system operational including:

  • Watering the Raingarden if it does not rain for a long period until plants have established compliance with local water restrictions,
  • Regular inspections of the Raingarden, level of gravel mulch covering the Raingarden, blockages in the overflow pipe, sediments in the downpipes, weeds and plant erosion in the Raingarden itself,
  • Distribution of the water flow into the Raingarden to limit erosion from heavy rainfall,
  • Ongoing protection from pedestrian and vehicular access,
  • Owner’s Corporation (OC) bylaws to prohibit the removal of all soil and plants within Raingarden, and an obligation on residents to report any maintenance concerns to the OC.

The building facility manager and/or owners corporation shall include on their building maintenance schedule the required maintenance tasks specified by the hydraulic/services engineers at the required intervals. Appendix B provides a checklist for the maintenance arrangements for Raingardens.

Raingarden mistakes to avoid

A raingarden doesn’t need to be 1m high!

The ponding depth of 100mm or 300mm options in STORM report refer to the depth above the top of gravel mulch and below the grated cap. The following diagram of a raingarden has 100mm from the top of gravel mulch to the grated cap overflow drain.



Infiltration System

Stormwater infiltration system (infiltration sand) directs Stormwater to infiltrate the soil in the vicinity of the system.

The effectiveness of this system depends on the surrounding soil and state of groundwater. This system is very effective if the surrounding soil is sandy with deep groundwater. This is due to the fact that:

  • Sandy soils have very high permeability and thus, prevents surface run-off.
  • These soils are natural filters. As water passes through sandy soil, the pollutants inside the water stream are filtered out.
  • Deep groundwater ensures that stormwater has a long path of travel. This enhances the filtration process, effectiveness of pollutant removal and eliminates the risk of contamination.

Infiltration systems must allow for pretreatment of stormwater to prevent clogging of soil and to protect groundwater quality. Australian Runoff Quality Guidelines (2003) provides guidelines and procedures for sizing infiltration systems.

To design an infiltration system, following must be noted:

  • Not all areas are suited for the installation of infiltration systems. Soils with hydraulic conductivities lower than 0.00001 m/s (36 mm/hr) are not suited for infiltration systems. Not only the required infiltration area becomes unfeasible, but also low conductive soils increase the risk of clogging, mostly due to algal growth.
  • The area where the runoff originates is important for the effective operation of the system in the long run.
  • Type of catchments and pollutants are important
  • Position of infiltration system in a stormwater treatment train is crucial for pretreatment of stormwater and to prevent the risk of clogging. Infiltration system must be positioned as the final element to discharge the treated water into the surrounding soil and groundwater.
  • Regular maintenance is necessary for these systems to work effectively over time

What are the differences between Raingardens and Infiltration Systems?

Raingardens and infiltration systems are both used for the treatment of stormwater. They both use soil and water settlement to remove pollutants from the runoff water. However, there are several differences between these systems:

  • Design: Infiltration systems are often more complex systems than raingardens. An infiltration system requires a primary storage or basin for the settlement of pollutants and then the stormwater is conveyed to the infiltration sand. Raingardens are more shallow and require plants for the absorption of rainwater.
  • Application: Raingardens are suitable for any soil type and location. However, infiltration sands are only applicable in places where the groundwater is not shallow or not of a high value consumption. Also, soil must be tested before the installation of an infiltration system. Infiltration systems are effective only if the available soil at the site has a high hydraulic conductivity.
  • Maintenance: Raingardens require regular maintenance since they rely mostly on plants to remove pollutants and to control runoff. However, infiltration systems require periodic maintenance and are more effective in controlling stormwater runoff.

Porous pavements

Porous pavement can be created with traditional masonry tiles that have a porous jointing material between the tiles. The jointing material is often loose and not robust like typical grouting material – but it plays an important role in allowing the water to move through to the ground below.

A sample maintenance checklist or porous pavements is provided in figure below. Click to enlarge.


Reference information

Further information regarding the recommendations contained within this report may be found within the following documents, including examples of the design details of WSUD drainage features that may need to be specified by the landscape architect or civil engineer.

Feel free to contact our team if any further information or clarification is required.

Assessor Qualifications

The WSUD modelling has been undertaken by Dr Kevin Kivi. Amir has 9 years’ experience in NCC energy compliance modelling. In the following a summary of Amir’s qualifications are presented:

EDUCATION

  • 2015-2016: Certificate 4 in Building and Construction
  • 2015-2016: Certificate 4 in NatHERS (6-star building energy assessment)
  • 2011- 2015: PhD in energy systems, Infrastructural Engineering Department,University of Melbourne, Australia.
  • 2007- 2010: M.Sc. in Civil Engineering, Sharif University of Technology, Tehran, Iran.
  • 2003- 2007: B.Sc. in Civil Engineering, IKIU, Iran.

ROLE

  • Responsible for energy modelling and STORM modelling at GeoHeat Australia Pty Ltd; a Melbourne based sustainability consultancy specialized in environment-friendly energy solutions.

SOFTWARE USED

  • Energy Modelling: TRNSYS, TRNBuild, FirstRate5, Carrier HAP, LEAD, LBNL WINDOW, TRNSHEL
  • Other: STORM, NREL System Advisor Model, AutoCAD, Revit