our Groundwater Resources

Transcription

1 Protecting our Groundwater Resources by Dr Richard Evans Principal Hydrogeologist Sinclair Knight Merz

2 Significance ifi of Groundwater in Australia Availability: 25,000,000 ML/ year Use: 6,000,000 ML/ year 60,000 bores used 20,000 bore constructed per year 500 cities and towns use groundwater

3 Groundwater Entitlement t for 2004/2005 Total Entitlement for 04/05 Groundwater (GL) New South Wales 2,658 Victoria Queensland Western Australia South Australia Tasmania Northern Territory Australian Capital Territory TOTAL , ,000 * Excludes many Regions either not licenced or no licenced volume.

4 Bottled Water Use > Total Australian bottled water use = 600 ML/yr (90% Groundwater > Total Australian Groundwater use in 04/05 = 6,000,000 ML/yr Hence bottled water represents about 0.01% of total groundwater use but Quality is the key

5 Characteristics ti of Groundwater Pollution > Not easily detectable > Complicated & expensive to monitor; and > Once it occurs it is expensive to clean-up, if clean-up is actually possible

6 Point Source Contamination ti > Contamination is localised > It may be centred on one or more identifiable structures or facilities

7 Examples of Point Source Contamination ti > Leaking underground storage tanks (UST s) > Chemical spills & accidents > Leaking gpp pipelines > Poorly designed & sited landfills > Improperly lined waste water ponds etc

8 Hopkins Point Warrnambool, milking shed waste discharged to a depression in the limestone terrain. The aquifer is used for the farm shed water supply, (1987, AShugg photo).

9 Oil, hydrocarbons and drummed waste disposal in a quarry in the porous fractured basalt aquifer, St Albans Road Sydenham (1973, A. Shugg photo).

10 Waste disposal into a deep lead mine shaft a short distance from the Chiltern town water supply bores, North Eastern Victoria, (1984, A. Shugg photo).

11 Diffuse Source Contaminants t > Broad scale phenomena; > Cannot be ascribed to a single source; > Can be due to a widespread land use practice or; > Can be due to a widespread collection of point sources.

12 Examples of Diffuse Source Contamination ti > Pesticide contamination due to agricultural use > Nitrate contamination due to agricultural use of nitrogenous fertilisers & grazing activities > Nitrate and pathogen contamination due to large numbers of septic tanks

13 Groundwater Pollution Incidents 1. Walkerton, Ontario, Canada (2000) Walkerton is a small town located in Ontario, Canada The following hazards were found in the water supply (sourced from Groundwater) E. coli 0157:H7 & Campylobacter jejuni. 7 people died from the water contamination incident and ca 2,300 were confirmed ill. Water was supplied by the local water utility. The hazard source was identified as cow manure being washed into the well following unseasonably large rains. No monitoring was in place and therefore, turbidity and lack of chlorine (from a failing chlorinator) were not picked up in time. Total cost of the hazardous event was ca $AUD180 million.

14 Groundwater Pollution Incidents 2. Alamosa, Colorado, US (March/April 2008) Alamosa, a southern Colorado town with about 8,500 residents, gets its water from a deep well system. Water sourced from the aquifer is not chlorinated. An outbreak of salmonellosis from Alamosa s water supply led to approximately 400 cases of illness and up to 16 people being hospitalised. Salmonella, Giardia and Cryptosporidium were found in the town s water supply. The contamination ti of the water supply is still unknown.

15 Groundwater Pollution Incidents 3. Tinamba, Eastern Victoria Hepatitis A outbreak, people affected. Traced to beer from local hotel. Hotel was supplied from a bore servicing the hotel, too close to a septic tank. 4. Worldwide thousands of examples By far the biggest problem is arsenic poisoning currently affecting 100 million people, mostly in Bangladesh and India, from using Groundwater.

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17 Partners in Groundwater Protection ti The Consultative Approach Community Manager & regulators Industry & land owners

18 What Does Groundwater Protection ti Mean? > Managing activities by using a variety of methods to ensure acceptable land use practices. > Avoid undue or unacceptable pollution of Groundwater

19 Tools for Managing Land Uses > Statutory control > Community / industry participation and education > Market approaches

20 Statutory t t Control > Control as part of the development approval process > Involves assessing the potential threat and applying ppy conditions to developments > Easier to apply and understand for point sources but now being accepted for diffuse sources.

21 Community/Industry Participation & Education > Regulators cannot practically control all potentially ti adverse land uses. > Partnerships with community and industry are essential for protection of water values Participation Education

22 Market Mechanisms > Penalties or incentives to influence users to minimise i i pollution. > Less taxes on Groundwater friendly products, eg rapidly degradable pesticides. > Financial bonds for rehabilitation of sites to avoid pollution occurring or for clean-up if pollution happens.

23 Defining Groundwater Protection Areas > Numerous approaches: o o o Total groundwater catchment Groundwater travel times Fixed distance > Wellhead protection zones (WHPZs) > Delineation methods include: o o o Fixed radius Hydrogeological lmapping Analytic methods Technical Components

24 Wellhead Protection Principles

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26 Wellhead Protection ti Area divided into 4 zones, each representing a different area of risk and priority > Zones are based on empirical and scientific criteria based on distances and groundwater flow systems Zone 1 (Inner protection zone) Any pollution that can travel to the borehole within 50 days from any point within the zone is classified as being inside zone 1. This zone also has a minimum 50 metre protection radius around the borehole. Zone 2 (Outer protection The outer zone covers pollution that takes up to 400 days to travel to the zone) borehole, or 25% of the total catchment area whichever area is the biggest. Zone 3 (Total catchment) The total catchment is the total area needed to support removal of water from the borehole, and to support any discharge from the borehole. Zone of special interest (Sometimes a fourth zone is defined) Usually where local conditions mean that industrial sites and other polluters could affect the groundwater source even though they are outside the normal catchment area.

27 Wellhead Protection or Source Water Protection Planning Six steps: > form a local team > define and map the protection area > identify and inventory potential sources of contamination > manage potential sources of contamination (through planning process) > provide for public education and participation > monitoring, evaluation and review

28 What Will happen If We Don t Try To Protect Groundwater Resources?

29 There Will be No Safe and Useable Groundwater Resources For Future Generations