Attachment 1
Attachment 1
Table 1: Pollution Treatment Priorities
Development Type
Litter
(Gross
Coarse
Sediment
Nutrients
Fine
Sediment
Hydrocarbons
Motor Spirit, Oil
Pollutants) & Grease
Residential
Developments such as multi-unit developments where common property is involved.
Residential subdivision
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.
Table 2: Pollution Retention Criteria
Pollutant
Gross Pollutants
Coarse Sediment
Fine Sediment
Nutrients
Hydrocarbons, motor oils, oil & grease
Description
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.
Table 3: Qualitative Operational Objectives for New Development
Pollutant/Issue
Runoff Volumes and Flow Rates
Stormwater Quality
Management Objective
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.
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.
Amenity 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)
