H - Revised Integrated Water Management Plan by Cardno (inc MUSIC file) (13.09.19)

3 Design Guide
WSUD Strataflow tree pit systems can be configured in a number of ways depending on specific site opportunities and
constraints. The fundamental elements of a WSUD tree pit system include the following;
  • Sufficient structural soil volume to facilitate tree growth and root expansion
  • Available impervious catchment for passive watering
  • Inlet for stormwater supply to tree
  • Suitable tree species
  • Treatment element for management of solids and pollutants in stormwater
  • Drainage layer and stormwater outlet connection (as required)
A design procedure has been prepared to assist specifiers and designers with the integration of WSUD features into
Strataflow Tree pit systems. The procedure is presented as a flowchart which describes the general steps involved in the
design process.



3.1 Design Procedure for Strataflow™ systems

  Step 1                                                                          Step 2
  Preliminary Analysis/                                                           Determine Configuration
  Feasibility                                                                        • Refer to:

     • Preliminary Layout                                                             1. List of Strataflow WSUD configurations
                                                                                         (section 3.2)
     • Identify Catchments
                                                                                      2. Decision tree (Appendix A)
     • Initial modeling accordint to objectives
                                                                                      3. Standard drawings (Appendix B), to determine
     • Water Quality/Detention/Infiltration Tree health
                                                                                         the most ideal configurations for the site
     • Services and constraings assessment
     • Assess site conditions




  Step 3                                                                          Step 4
  Prepare Functional                                                              Civil and Landscape Design
  Layout Plans                                                                       • Design appropriate edge treatments and
                                                                                       safety measures
     • Develop a functional layout based on the selected
       standard configuration                                                        • Design stormwater inlet and outlet arrangement

     • The results of the preliminary analysis should                                • Design pre-treatment and necessary filtration
       inform the functional design                                                    elements

     • Create a project specific functional design                                   • Final selection of appropriate tree and plant
       drawing using WSUD standard drawings and                                        species
       specifications                                                                • Specification of appropriate soil / media fill


* The objectives will determine the sizing method and will be influenced by the configuration adopted. A number of Tools are provided to size for
detention, infiltration and plant health. The water balance will also aid with tree selection. MUSIC is typically used to size for water quality.



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