Simplifying and Reducing the Maintenance of WSUD Elements

Fairfield City Council commissioned consultants, EDAW, to liaise with Council staff and review four significant riparian and WSUD projects to:

• Revisit each project’s WSUD objectives,
• Better understand ongoing maintenance issues, and
• Inform how WSUD elements can be designed to reduce maintenance burdens.

The projects reviewed were sites in parks with the following “WSUD Elements”: stormwater treatment ponds, wetlands, rehabilitated streams and a raingarden. The maintenance issues identified include:

• Inadequate plant establishment (so sites becoming a source of weed propagules).
• Soil erosion due to inadequate flow protection - insufficient plant density, rock protection or exposed subsoils due to earthworks).
• Access issues for mowers and trimmers: boggy edges, steep slopes, complicated layout of trees, fences, walls and bollards. Requires hand maintenance which, if left undone (as it’s more expensive), contributes to weed invasion.
• Undefined edges between areas that require different maintenance practices. Eg where mowers stop and hand weeding begins. Eg. Bushland adjacent to mown areas.
• Insufficient plant densities (resulting in vegetation that is not self-sustaining).
• Empty spaces in public parks invited litter, rubbish dumping and vandalism.

The review team identified the following design and maintenance responses:

• Consider soil properties to prevent erosion and stabilizing landform.
• Group features with similar maintenance requirements together.
• Provide clearly defined and maintainable boundaries between areas with different maintenance requirements (eg. With mulch, vegetation types, hard edges).
• Take a bush reconstruction/regeneration approach – choose low maintenance vegetation and
  Eliminate difficult to maintain areas through dense infill planting with appropriate species.

The report gives some excellent landscape design concept drawings that illustrate these principles in practice.