Landscape drainage

Positioning
Best practice guidance for the placement and arrangement of embellishments
Site setout
Orientation
- Sub-surface drainage is recommended to be installed under turf/garden areas to disperse water to more appropriate areas.
- Install sub-surface drainage under playground sand/bark safety surfacing to disperse water out of the surfacing area, to prevent water-logging.
- Field inlets and overflow gullies are recommended to be located in open grassed areas, garden beds and hard surface areas at low points.
- Open flow channel swales are recommended to be located along the lower boundary of a site, gently sloping towards stormwater outlet.
- Swales are designed for filtration of stormwater, to maximise surface infiltration and to reduce runoff.
- Swales require hardy and drought tolerant planting.
- Slopes for swales are to be suitable for ride on deck mowers (1:6 preferred, 1:4 max).
- Trees are not to be planted in direct flow paths.
- Swales are designed to direct overland flows away from embellishments such as play spaces, seats, pathways and shelters.
- Swales may be designed to catch and direct flows off paths/trails/roads.
- Culvert with a pedestrian overpass is recommended to allow vehicle and pedestrian access over a swale drain where required.
- Trench drains are recommended to be located in hard surface areas to prevent water ponding at pavement low points.
- Maintenance access should be provided near low points such as areas of deposition.
Safety
Crime Prevention through Environmental Design (CPTED) principles apply.
Clearances
Table 5: Positioning guidance offsets
Embellishment | Distance from | Minimum distance | Reason |
Barrier/fence/handrail | culvert end/headwall | no offset required (attach barrier to headwalls) | barrier is installed on or near to headwall for public safety. |
Pedestrian path | any other object | 500 mm | required Austroads safe design offset and AS 1428 ‘at grade’ requirement. |
retention/detention basin/lake/waterway | depends on projected tides and/or flood model levels | public safety – rapid rise in water level may create a hazard for pedestrians. | |
Rock lined drain | any other object | 2.5 m | deck mower clearance (where possible) Avoid creating small difficult to mow areas. |
turf | width of planted buffer depends on plant species | safety measure to prevent loose rock becoming a projectile. |
This component is currently in development