Development Type Litter (Gross Pollutants) Coarse Sediment Nutrients Fine Sediment Hydrocarbons Motor Spirit, Oil & Grease
Residential Developments such as multi-unit developments where common property is involved. Residential sub division Commercial, Shopping Centres, and Retail Outlets 1 1 1 4 4 4 5 5 5 2 2 2 3 3 3 Industrial Industrial/ Commercial subdivision Fast Food, Drive-in & Take-Away Restaurants Carparks, Service Stations and Wash Bays 3 3 2 3 4 4 3 4 5 5 5 5 1 1 4 2 2 2 1 1
Note: For developments on sites less than 5 ha – The pollution treatment method(s) selected must treat the first three priority pollutants cited. For developments on sites greater than 5 ha - The pollution treatment method(s) selected must treat all the pollutants cited with emphasis on the first three priority pollutants.
Gross Pollutants Coarse Sediment Fine Sediment Nutrients Hydrocarbons, motor oils, oil & grease
Trash litter and vegetation larger than 5mm Contaminant particles between 0.1mm and 5 mm Contaminant particles 0.1mm or less Total phosphorus and total nitrogen
Retention Criteria for Development Sites
90% of the total annual load 80% of the total annual load 50% of the total annual load 45% of the total annual load for each nutrient Whichever is greater: 1. 90% of the total annual load; or 2. Total discharge from site of Total Petroleum Hydrocarbons (TPH) <10 mg/L at all times.
Runoff Volumes and Flow Rates Stormwater Quality
Impervious areas are not to be directly connected to the stormwater drainage system unless uncontrolled property runoff needs to be constrained. Reuse of stormwater for non-potable purposes maximised. Vegetated flow paths, or similar, are to be used to connect impervious areas to the stormwater system. Use of stormwater infiltration ‘at source’ where soil types allow. Riparian Vegetation and Aquatic Habitat Flow Protect and maintain (i.e. no demonstrated adverse impact on natural wetlands, watercourses and riparian corridors.) All natural (or modified) drainage channels within the site that possess either: 1. Base flow 2. Defined bed and/or banks 3. Locally occurring native riparian vegetation are to be protected and maintained. ‘Natural’ channel designs should be adopted in lieu of floodways in areas where there is no natural (or unmodified) channel. Natural flow paths, discharge points and runoff volumes from the site should not be altered. Amenity The frequency of bank-full flows should not increase as a result of development. Generally, no increase in the 2 year and 100 year ARI peak flows. Multiple uses of stormwater facilities to the degree compatible with other management objectives. Natural Bushland No demonstrated adverse impact from stormwater discharges into urban bushland area.
(Adapted from: Water Sensitive Urban Design – Technical Guidelines for Western Sydney, 2004)