Silt fences – Silt fences are useful for small, disturbed areas or sloping areas.  For steep slopes, use more than one silt fence and decrease the spacing between fences as slope increases.

Earthbunds – Constructed across slopes and near the edges of the site, earthbunds control and detain runoff, allowing sediment to settle out. The bund can be constructed from clay or topsoil from the site.  Channels formed by bunds can also be used to divert clean water away from disturbed areas.

Stabilised entranceway – The stabilised entranceway should be the first works to occur on site, as soil transferred to the roadway by vehicles will be washed into stormwater systems. All vehicles should use it for site entry and exit. An entranceway constructed from a generous spread of metal aggregate will be sufficient on small sites. A wheel wash may be needed for larger sites. Wooden planks can offer protection to footpath, grass berm and kerb, and reduce reinstatement costs. Keep all traffic off grass berms, and stabilise disturbed berms immediately - during winter significant volumes of sediment can wash off them.

Clean water diversion – Separation of clean and dirty water will greatly reduce the effort needed to prevent sediment runoff. Divert all upstream runoff away from the site with a bund or diversion channel. Channels will need to be stabilised when gradients exceed 2%. During construction, roof runoff may be diverted to the kerb by connecting a non-perforated pipe to the downpipe outlet.

Strawbales – Strawbales can impound sediment-laden water at points of discharge, but will only be successful if installed correctly. They need to be trenched into the ground and securely staked together, with bale strings positioned on the sides.

Stabilising disturbed ground – After soil is disturbed, stabilise as soon as possible with straw or hay mulch or hardfill. Where appropriate grass should be sown as soon as works are completed.

On site works – Concrete washings, water blasting, equipment washing, concrete and tile cutting - these works can all pollute waterways unless care is taken. These products cause problems as they can be highly alkaline, or can contain oxides, heavy metals (copper drill lubricants) or petroleum products.

• If washing fines, make sure the wash water is confined, filtered (for instance, across grass or through silt fence or haybales), or diverted to a soak area. If discharge is necessary, do so to the sanitary sewer, not the stormwater system.

• Don’t wash vehicles and equipment on site unless there is a designated wash out area where wash water soaks into the ground, or is treated before discharging from the site.

• Settle drill slurry (see Directional Drilling, below).

• When waterblasting, contain dirty waste runoff. Chemical additives must not be discharged to stormwater drains. Carefully filter out paint flakes and dirt using filter cloth, bunds or similar before discharge to stormwater drains.

Trenching/stockpiles – Material from trenching and excavation should be stockpiled away from low points, runoff channels or kerbs. Ideally, stockpiles should be covered immediately or stabilised with mulch or vegetation. Any runoff from stockpiles needs to be directed to suitable sediment control measures such as silt fences, earthbunds or properly installed haybales.

Garden tanks – The inclusion of a garden tank to collect roof rainwater can reduce the amount of stormwater runoff from the site in the short and long term. During construction it may reduce the volume of clean water runoff from the site and provide on-site water for construction activities. Long-term, it can provide free non-potable water for the property owner.

Cesspit protection – Filter cloth across cesspits may be used on a temporary basis as a last resort to capture sediment. However this is not an effective control measure, as filters block up rapidly and are difficult to install and maintain. Sediment is better managed on the site, using measures described in this guideline. When temporarily using cesspit protection, the filter cloth must fully cover the cesspit grate and inlet at the back.

Pumping water from the site – Untreated water from trenches or waterlogged areas on the site must never be pumped directly to the kerb or cesspit. If water needs to be removed from the site, wait for suspended sediment to settle out. Never pump from the bottom of the trench or impoundment area – filter the pumped water across a grassed area or into a sediment control device before discharging to a cesspit or waterway.

In short, unless it is clean, don’t discharge to a cesspit or waterway.