Catchment Plan targets creek protection in Ku-ring-gai

Integrated water cycle management catchment study for the 521 Ha Avondale Creek.

Ku-ring-gai Council engaged Storm to prepare an integrated water cycle management catchment study for the 521 Ha Avondale Creek.  Avondale Creek is a tributary of the Lane Cove River which flows into Sydney Harbour.  The aims of the study were to:

  • Prepare a catchment water cycle model
  • Identify options for retrofitting streetscapes with Water Sensitive Urban Design (WSUD)
  • Model the impact of the options against environmental outcomes

Council is seeking to undertake a more strategic and sophisticated approach to identifying IWCM projects, and so they engaged Storm.  A major focus is to more clearly define the impact of urban development on stream flow and consequent environmental effects.

Storm undertook an assessment of the main stream and tributaries of Avondale Creek in order to determine its condition, especially in relation to erosion.   Various IWCM/sustainable water management (SWM) scenarios were modelled in the catchment and compared to the existing conditions.  Some of the key findings and principles that influence the derivation of a strategy are summarised as follows:

  • Erosion hotspots need to be addressed by remedial works.  The most severe erosion of is assigned priority.
  • The presence of a dam on the creek means that water quality impacts in two subcatchments are effectively managed.  Therefore water quality works in close proximity to the dam are assigned low priority.
  • There is little scope to expand stormwater harvesting as an option to reduce flows in the creek.
  • On-Site Detention and On-Site Retention are proposed at the lot and street scales to alleviate localised flooding and to reducing creek flows.
  • Out of 13 sites investigated for WSUD, only two were progressed to concept design based on feasibility assessment.