Tables 28 and 29 detail common surface water, groundwater and storage issues, their probable causes and possible corrective action that could be undertaken to control issues.
Table 28. Troubleshooting poor surface water quality
| Probable causes | Preventive measures | Checking preventive measures | Corrective action | |
|---|---|---|---|---|
| What to check | Signs that action is needed | |||
| Observation: Poor surface water quality Possible hazards: Reduced water quality |
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| Flooding leading to rapid changes in water quality | Diverters Water storage Additional pre-treatments | Turbidity Organic matter/colour | Severe weather event Increased turbidity and organic matter | Monitor raw water. Ability to shut off intake if raw water beyond acceptable limits. Appropriate treatment to deal with raw water. |
| Absence of characterisation of the raw water source | Monitor source water regularly | Water quality criteria | Level regularly exceed water quality criteria | Conduct catchment risk assessment and/or establish a monitoring programme. |
| Upstream discharge with potential to cause microbial contamination | Monitor source water | E. coli levels Nitrogen Nitrate Phosphorus | Increase in nutrients levels or E. coli | Ensure appropriate treatment and that a robust disinfection system is in place with appropriate monitors and alarms on key equipment. |
| Stormwater overflow upstream with potential to cause microbial contamination | Diverters Water storage Additional pre-treatments | Turbidity Organic matter/colour E. coli levels Nitrogen Nitrate Phosphorus | Severe weather event Increase in nutrients levels or E. coli | Ensure appropriate treatment and that a robust disinfection system is in place with appropriate monitors and alarms on key equipment. Monitor raw water to identify times of higher risk. |
| On-site systems /or septic tanks upstream with potential to cause microbial contamination | Extract water at a point that is unlikely to be contaminated Additional pre-treatments | E. coli levels Nitrogen Nitrate Phosphorus | Increase in nutrients levels or E. coli | Ensure appropriate treatment and that a robust disinfection system is in place with appropriate monitors and alarms on key equipment. |
| Microbial contamination from agriculture or wildlife | Extract water at a point that is unlikely to be contaminated Additional pre-treatments | E. coli levels Nitrogen Nitrate Phosphorus | Increase in nutrients levels or E. coli | Source water management. Ensure appropriate treatment and that a robust disinfection system is in place with appropriate monitors and alarms on key equipment. |
| Intake not secured against livestock access causing microbial contamination | Extract water at a point that is unlikely to be contaminated Additional pre-treatments | E. coli levels Nitrogen Nitrate Phosphorus | Increase in nutrients levels or E. coli | Install and maintain fencing in the vicinity of the intake. |
| Direct surface water intake causing variability in water quality | Ensure effective monitoring of intake water. Redesign intake if required. | Turbidity Organic matter/colour Algae/chlorophyll a E. coli levels Nitrogen Nitrate Phosphorus | Variation in water characteristics | Change intake point to minimise variability in raw water. Provide bankside storage. |
| Lake or dam source intake point vulnerable to variation due to streams, stratification, algal blooms or increased turbidity | Monitor raw water | Turbidity Organic matter/colour Algae/chlorophyll a E. coli levels Nitrogen Nitrate Phosphorus | Increase in nutrients levels or E. coli | Change water intake point to minimise variability in raw water. |
| Sediment build up causing contamination | Regular programme to inspect the intake | Turbidity before pre-treatment | Increase in turbidity or colour | Clean as appropriate. |
Table 29. Troubleshooting poor groundwater quality
| Probable causes | Preventive measures | Checking preventive measures | Corrective action | |
|---|---|---|---|---|
| What to check | Signs that action is needed | |||
| Observation: Poor groundwater quality Possible hazards: Reduced water quality |
||||
| Geology – surface water ingress associated with a raw water source | Monitoring Additional pre-treatment | Turbidity Colour | Increase in turbidity or colour | Appropriate pre-treatment to deal with source water. Consider closing intake, or switching to other sources, if raw water quality deteriorates. |
| Bore casing incomplete or borehole unsealed causing intrusion of surface water or other contamination | Monitoring Additional pre-treatment | Turbidity Colour | Increase in turbidity or colour | Secure and maintain the bore head to prevent contamination. |
| Borehole not lined causing ingress of surface water | Follow Australian standards when constructing bore | Turbidity Colour | Increase in turbidity or colour | Line borehole to sufficient depth to prevent ingress. |
| Borehole or spring source influenced by surface water, e.g. shallow borehole or well | Monitoring Additional pre-treatment | Turbidity Colour | Increase in turbidity or colour | Ensure appropriate treatment and robust disinfection system in place with appropriate monitors and alarms on key equipment. Use another source if adequate treatment not in place. |
| Well head not secured against livestock access causing microbial contamination | Monitoring Follow Australian standards when constructing bore | E. coli levels Dissolved nutrients – nitrogen and phosphorus | Increase in nutrients levels or E. coli | Protect bore head with appropriate cover. |
| Observation: Poor storage water quality Possible hazards: Reduced water quality |
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| Susceptible to flooding or contamination | Consider flood defences. Liaise with catchment stakeholders to minimise the risk of contamination | Turbidity Colour | Increase in turbidity or colour | Raw water contamination monitoring programme. |
| Wildlife access to raw water tank causing contamination | Erect fencing or cover to prevent wildlife access | Turbidity Colour Nitrate | Increase in turbidity or colour Nitrate from manure | Erect fencing or cover to prevent wildlife access. |
| Sludge build up in raw water tank causing contamination | Erect fencing or cover to prevent wildlife access | Turbidity Colour | Increase in turbidity or colour | Erect fencing or cover to prevent wildlife access. |
| Leaking impounding reservoir causing ingress of contamination | Regular inspection and maintenance programme | Turbidity Colour | Increase in turbidity or colour | Regular inspection and maintenance programme. |
