What controls apply to work in a drinking water catchment?

Work in a drinking water catchment is controlled so that soil, fuel, chemicals and cut vegetation stay out of the water. The land drains to a supply people drink. A fuel leak or a washed-out slope that would be a minor clean-up on a suburban site is a much bigger problem here.

What a catchment is

A catchment is all the land that drains into a dam or river. Rain that falls on a work area there runs downhill into a creek and on towards the storage, and there is no stormwater system to catch it along the way.

The bush protects the water. Plants slow the runoff and their roots hold the soil, so anything that strips that cover has an effect well beyond the work area.

Access

Parts of a catchment are closed to the public, and contractors go in only with the authority's approval. Crews stick to the agreed gates and tracks. Everyone on the job is briefed on the conditions before their first day, including anyone who only comes in for a single delivery.

The work area is marked on the ground, so an operator knows exactly where the job stops. On a slope, one wrong turn with a machine does a lot of damage.

Soil and sediment

One heavy storm can move a lot of bare soil. The plan is to disturb as little ground as possible, keep vehicles on existing tracks and put sediment controls downhill of anything that has been left exposed.

Disturbed ground is covered or replanted as the job goes, so it never sits waiting for rain. The wider set of site controls is described in environmental controls on a construction site.

Fuel and chemicals

A small fuel spill near a creek is a serious event in a catchment. Machines are checked for leaks before they go in, refuelling happens well away from drains and waterways, and spill kits stay within reach of the crew for the whole shift. Herbicide is cleared with the authority before it comes on site.

Vegetation work

Asset protection work cuts back fuel around roads and structures so a bushfire has less to burn near them. In a catchment, it has to be done without leaving bare ground behind. Cut material stays out of the gullies, where the next rain would carry it off.

How these zones are set up and maintained is covered in what an asset protection zone is.

Monument's catchment work

Monument delivered catchment vegetation and asset protection works for the Sydney Water Catchment Authority in 2014, including at Avon Dam. Those works sit alongside its Crown land ground maintenance and asset protection zone works for the NSW Office of Strategic Lands, and both are described in who does grounds maintenance and asset protection on NSW Crown land. Monument's environmental management is certified to ISO 14001.

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