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"Everyday Engineering"

"Everyday Engineering" was a technical column posted regularly on the VACETS forum. The author of the following articles is Dr. Binh Anson. For more publications produced by other VACETS  members, please visit the VACETS Member Publications page or Technical Columns page.

The VACETS Technical Column is contributed by various members , especially those of the VACETS Technical Affairs Committe. Articles are posted regulary on vacets@peak.org forum. Please send questions, comments and suggestions to vacets-ta@vacets.org

Perth, Tha'ng 10, 1994.

A Brief Note On protection Of Public Water Supply Sources (*)

Binh Anson (Perth, Australia)

All countries have experienced serious water supply contamination problems. In the USA cleaning up groundwater is a major industry and work still outstanding is estimated to cost 250 billion US dollars. The US Environmental Protection Agency has found that pesticide contamination of 10% of public water supply wells has occurred. In the UK, an outbreak of water borne cryptosporidium infected 470 people in 1990. In the same year, 5.3 million people were supplied with water contaminated with nitrate at levels above drinking water health limits.

In Western Australia, contamination is also a problem. Many of our sources are contaminated with salt which has been accumulated in the soil profile for many years. Many of the water resources that remain fresh are now under the threat of contamination from land development.

Any substances on or in soils that can be dissolved or carried by water will contaminate the water. Unfortunately, most thing we do place the water at risk. Fertilisers, fuels, solvents, domestic and industrial waste, heavy metals and pesticides, are some of the widely used substances that can make water unsafe to drink.

All activities on land may cause a degree of contamination. Activities with a high risk of contamination, or for which pollution control will be expensive, should be directed to areas where they will not cause signifivant damage to the water source. Activities such as residential development and agriculture, that are a source of diffuse contamination and will cause slow degradation, should be excluded from areas where we wish to preserve a higher water quality.

Integrated land and water resource planning is the essential first step in limiting development to activities that can be undertaken in a way that prevents contamination. Public planning exercises, such as the preparation of land use and water management strategy in a groundwater catchment area, are an excellent way to delineate and protect water source areas. However these plans are not mandatory and ad-hoc development projects over groundwater recharge areas can undo the planning effort unless the strategies are incorporated into town planning schemes.

The next step in protecting water sources is the development of catchment (**) land management programmes that incorporate catchment protection requirements. These programmes should meet the needs of all interested parties. A catchment land management programme should address matters that influence water quality: such as fuel storage, waste disposal, waste water treatment, clearing, vegetative buffer zones and the use of substances that can contaminate water including pesticides and fertilisers.

By-laws are used to limit the use of certain substances and to control the way in which contaminating activity is undertaken. The by-laws are the last line of defence against contamination. They can "fine tune" good planning to reduce the risk of contamination but they cannot fix bad land planning decisions.

Technology sometimes allows us to clean up contaminated water. Even sewage can be made safe to drink. Many countries around the world rely on water sources that are polluted and must be treated to produce water with safe levels of contaminants. We are fortunate in that we still have uncontaminated sources. The cost of our water is lower and the safety is higher.

In summary, the following steps are required for effective public drinking water source protection:

1. Develop a land use and water protection strategy. 2. Declare the water source protection areas. 3. Incorporate the strategy into land planning scheme. 4. Develop effective and appropriate water quality protection by-laws. 5. Enforce the schemes, plans, and by-laws.

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Notes:

(*) Excerpt from a draft report on By-laws and Catchment Protection, being finalised for the Water Authority of Western Australia.

(**) In the Australian (and UK) context, "catchment" has the same meaning as "watershed" used in the US.

oOo

Binh Anson, BE, ME, Ph.D. - Ky~ Su+ Tru+o+?ng, Quy Hoa.ch Qua?n Ly' Lu+u Vu+.c, Thu?y Cu.c Ta^y U'c.


Binh Anson, Ph.D.
anson@saigon.com

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Copyright © 1994 - 1997 by VACETS and Binh Anson

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