Building & construction
Stormwater pollution prevention
Activities undertaken in the building and construction industry have the potential for significant stormwater pollution and impacts to receiving waters. The stormwater drainage network is separate from the sewage system. It drains from the gutters and pipe network into our natural water bodies (creeks, rivers, groundwater, wetlands and the sea). If not managed appropriately, stormwater generally flows with pollutants, including those from building and construction activities, untreated into natural water bodies.
As with all stormwater pollution, it is this cumulative impact that causes significant environmental degradation.
Construction activities disturb soil. Once disturbed it is easily eroded and moved off the site into the stormwater drains, becoming a major source of sediment pollution in waterways, and ultimately the sea.
Studies have shown that sediment from an area under building and construction development, may be 5-20 times greater than sediment pollution in an already developed area (Landcom NSW Blue book pp 6–2).
While the principle pollutant is sediment, there are many other pollutants that may also be generated on building sites and activities such as concreting, plastering and painting which must be managed to prevent impacts to our waterways and oceans.
The Environment Protection (Water Quality) Policy 2015 specifies that a number of pollutants cannot be discharged to the stormwater system or onto land where they may enter stormwater. By law you are obliged to ensure these pollutants do not reach the stormwater system from your site. Those pollutants most relevant to the building and construction industry include:
- brick, bitumen or concrete cutting wastewater
- building washwater
- washdown water from cleaning vehicles or equipment
- high pressure water blasting waste
- building construction or demolition waste
- concrete waste
- roof cleaning waste
- paint and paint scrapings, painting washwater, paint stripping waste, stain or varnish
- plaster, plaster waste and plaster wastewater
- solvents, stain or varnish
- soil, clay, gravel or sand
- rubbish, hard waste.
To fulfil the obligations of the Water Quality Policy and ensure these pollutants do not move off site, it is strongly recommended that all building or construction sites undertake erosion, sediment and drainage control management practices.
The Code of practice for the building and construction industry requires that a soil erosion drainage management plan (SEDMP) must be prepared:
- where there is a high risk of sediment pollution to adjoining lands or receiving waters; or
- if the total area to be disturbed, or left disturbed, at any one time exceeds 0.5 ha.
This code is linked to the Water Quality Policy and designed to assist in the compliance with the general environmental duty. The requirements outlined in the code are enforceable by the issuing of an EPO under section 93 of the Environment Protection Act 1993. Failure to comply with an order is a breach of the Act and constitutes a criminal offence.
Erosion is the detachment of soil particles through the action of water or wind at a rate greater than the soil forming process. The soil is transported by water (or wind) and deposited in a process known as sedimentation. During the building and construction process there is a very high risk of sediment moving off site through these processes and sediment pollution in stormwater is a major cause of environmental degradation in receiving waters.
Erosion and sediment control are considered essential on any building or construction site. There are two distinct practices:
- erosion controls aimed at preventing soil erosion in the first instance
- sediment controls aimed at capturing the soil particles once disturbed through soil erosion.
By minimising soil erosion in the first instance it can reduce the need for sediment controls. It is usually far more cost effective to reduce erosion than use sediment controls.
Environmental management of dewatering during construction activities
Dewatering is the process of removal of any water that accumulates in earthwork excavations or below ground structures, as a result of, for example:
- intersecting aquifers
- seepage of soil water/groundwater
- storm events or rainfall (including surface water runoff).
The water removed during dewatering activities is classified as wastewater.
Underground waters may be contaminated by a wide range of pollutants. Dewatering these contaminated waters and then discharging them to surface waters, such as inland and marine waters or a stormwater system, may result in environmental harm. Any responsible party must ensure that dewatering wastewater must not be discharged directly or indirectly to surface waters including the stormwater system, inland or marine waters, and are required to consider all reasonable and practicable alternatives to environmental discharge.
Failure to anticipate dewatering requirements and subsequent intersection of groundwater during excavation can lead to costly construction delays, while approvals for dewatering are sought. This highlights the need for dewatering to be considered during the design stage. Proponents should be aware that dewatering wastewater that is highly contaminated and unsuitable to be discharged to surface waters can have costly disposal options, for example liquid waste facility or SA Water trade waste.
The primary focus of the Guideline for environmental management of dewatering during construction activities is to identify the risks associated with contaminated groundwater or dewatering wastewater that may be released to surface waters.
This guideline relates specifically to construction sites where earthworks will intersect groundwater or other non-groundwater related temporary dewatering activities and highlights the intersection of dewatering with earthworks drainage which is a licensed activity under Schedule 1 of the Environment Protection Act 1993.
This document should be read in conjunction with the Guideline for construction environmental management plans (CEMP) which describes how activities undertaken during the construction phase of development will be managed to avoid or mitigate negative environmental impacts and how those environmental management requirements will be implemented.
Effective planning for dewatering activities can inform site design and decrease costs associated with dewatering. This document aims to clarify the current regulatory requirements that already exist for proponents, site owners, developers and their professional consultants and contractors through the planning system or in general as part of their general environment duty under the Environment Protection Act 1993 and Environment Protection (Water Quality) Policy 2015.
Principles of erosion and sediment control
Adapted from Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia) 2008.
1. Ensure erosion, sediment and other pollutant control is considered in the planning phase of the development
By incorporating erosion and sediment in the planning phase it will identify high-risk construction activities and areas of the site. This allows for appropriate management and timing when these high-risk activities are undertaken to minimise the risk. Consider the physical constraints of the site and plan erosion and sediment control before construction activities begin.
2. Develop a soil erosion drainage management plan (SEDMP) based on the soil conditions, likely weather and construction conditions
An SEDMP must be considered a dynamic plan that adapts to varying site conditions and the construction activities being undertaken at a given point in time. It must include responsibilities, inspection, review and assessment, and modified should controls prove to be ineffective.
Review the SEDMP according to the changing site conditions and update it accordingly. Remember it is a dynamic plan that needs to adapt.
3. Minimise soil erosion
- Avoiding soil disturbance. All activities should be timed and staged to minimise the time and extent where soil is exposed to water and wind.
- Controlling water movement into and around the site. Reasonable and practical measures must be taken to ensure that all runoff upstream of the site is diverted around the site. This ensures only the water falling on the site requires management. Within the site water should be diverted around areas where soil has been disturbed and flow velocities minimised.
- Stabilising all disturbed areas as quickly as possible.
4. Use sediment capture controls and retain soil and other pollutants on the site
These controls must be appropriate to the soil and weather conditions. However sediment controls should never be the sole means of minimise pollution and secondary to minimising erosion.
5. Inspect and maintain all controls regularly
This is essential to ensuring they maintain the functional design and refers to both erosion and sediment controls.
There are a number of resources available to building and construction managers outlining erosion control and sediment control techniques. It should be emphasised that no two sites are the same and the techniques used on any site may vary to those used at another location.
- EPA 2010, Handbook for pollution avoidance on building sites, 2nd edition.
- KESAB Clean Site®, How to do it right.
- International Erosion Control Association (Australasia) 2008, Best Practice Erosion and Sediment Control.
- Catchments & Creeks 2012, Erosion and Sediment Control A Field Guide for Construction Managers Version 5.
- Catchments & Creeks 2013, Erosion and Sediment Control A Field Guide for Builders Version 3.
- Catchments & Creeks 2012, Principles of Construction Site Erosion and Sediment Control Version 1.
- Landcom 2004, Managing Urban Stormwater: Soils and Construction Volume 1, 4th edition (the Blue Book).
Your legal obligations
The EPA is responsible for the control of stormwater pollution through the Environment Protection Act 1993 (The Act). It provides the regulatory framework to protect the South Australian environment and is supported through a suite of subordinate legislation and regulatory tools including the Environment Protection (Water Quality) Policy 2015 (the Water Quality Policy).
The Act places a general obligation on you to take all reasonable and practicable measures to minimise environmental harm caused by pollution and promotes ecologically sustainable development.
The Water Quality Policy is second-level legislation and offers more specific protection for the state’s waters. It prohibits the pollution of the stormwater system and our natural waters. The policy has general obligations which every person, business and industry must comply with as well as specific obligations for particular activities.
Clauses 10 and 11 of the Water Quality Policy states that a person must not discharge pollutants listed in Schedules 2 and 3 of the Policy into any waters. Furthermore, those pollutants known as Class 1 and listed in Schedule 2 must not be deposited onto land where they are likely to enter waters.
The definition of waters includes the stormwater system. This means that listed pollutants cannot be placed in the stormwater system or on land where they may enter the stormwater system.
Failure to comply with these obligations may result in a $300 fine, an Environment Protection Order or a prosecution.
The Stormwater Pollution Prevention Codes of Practice look more specifically at preventing stormwater pollutions and are linked to the Water Quality Policy and are enforceable by the issuing of an Environment Protection order under the Environment Protection Act 1993.
Schedule 2 – Class 1 Pollutants [clause 10 Environment Protection (Water Quality) Policy 2015]
The following must not be placed on land where they may enter water, including the stormwater system:
- Agricultural chemicals
- Biosolids and wastewater treatment sludge
- Brick, bitumen or concrete cutting wastewater
- Building washwater
- Carpet or upholstery cleaning waste
- Chemicals designed for human or animal therapeutic use
- Chemicals listed in Schedule A of the National strategy for the management of scheduled wastes 1992, prepared by ANZECC, as in force from time to time
- Cleaning agents
- Concrete waste
- Condensate from compressors
- Construction and demolition waste (whether or not inert)
- Detergents and their byproducts
- Domestic waste (being waste produced in the course of a domestic activity)
- Engine coolant
- Food or beverage waste
- Fuel dispensing area washwater
- Hard waste (eg vehicles, tyres, batteries, metal parts, piping, electronic equipment and municipal solid waste)
- Hazardous waste
- Human waste
- High pressure water blasting waste
- Liquid waste
- Medical waste
- Motor vehicle servicing or repairs waste
- Oil, grease or lubricants
- Paint and paint scrapings
- Painting washwater
- Paint stripping waste
- Petroleum products
- Photographic chemicals
- Plaster, plaster waste and plaster wastewater
- Pool backwash water
- Pool chemicals
- Putrescible waste (eg food scraps and dead animals that are putrid or likely to become putrid)
- Quarantine waste (waste that is subject to quarantine under the Quarantine Act 1908 of the Commonwealth)
- Radioactive waste (being waste, the management or disposal of which is regulated under the Radiation Protection and Control Act 1982 or a law of the Commonwealth)
- Roof cleaning waste
- Rubbish and litter (eg bottles, cans, cartons, cigarette butts, food scraps, packaging and paper, glass or plastic items or materials)
- Stain or varnish
- Steam cleaning waste
- Street cleaning waste
- Timber preservatives
- Trade waste
- Washdown water from cleaning animals or animal enclosures
- Washdown water from cleaning vehicles, plant or equipment
- Washdown water from commercial or industrial premises or wharves
- Waste from grease traps.
Schedule 3 – Class 2 pollutants [clause 11 Environment Protection (Water Quality) Policy 2015]
The following must not be placed in water including the stormwater system:
- Air-conditioning or cooling system wastewater
- Animal faeces
- Green waste (eg lawn clippings, leaves and prunings)
- Soil, clay, gravel or sand.