Event: NOT ENOUGH SOURCE WATER AVAILABLE FOR ABSTRACTION Hazards: Germs and chemicals that get into the water because of low system pressure; hazards associated with poor hygiene. Level of risk: High P1.4.1.1 Start water Water Drop in system Prepare new conservation demand. pressure. resource Drought. measures as soon consent Source usage Customer as water shortage application. rate. complaints becomes likely. about low Find new System Plan the pressure. sources. pressure. development and Increase use of the storage source, and the capacity. need to identify and Partially close develop new valves through sources, based on the network to flow records of the equalise spring. pressures. P1.4.1.2 Negotiate new Water Drop in system Find new resource consents. demand. pressure. sources. Resource consent Source usage Customer Increase limitations. rate. complaints storage about low capacity. System pressure. pressure. Event: CONTAMINATION GETS INTO THE SPRING BOX Possible hazards: Germs and chemicals. Level of risk: High P1.4.2.1 Install upstream Raw water: Non-compliance Review cut-off drains to turbidity, with DWSNZ: Heavy rain minimise suspended 2000 particularly options. leading to high contamination from solids, turbidity, and levels of Review run-off. E. coli counts. turbidity and alternative quality. organic Ensure spring box is Increased filter source matter. covered, and backwash options. constructed so that frequency (if water cannot enter filtering). through manholes. Difficulty in achieving free available chlorine residual in treated water (if chlorinating). Spring box not covered. P1.4.2.2 Fence off Increase abstraction area, chlorine Observed or and undertake residual in known regular inspection treated water. contamination and repair. in area of spring. Event: CONTAMINATION OF THE AQUIFER (the source) Possible hazards: Germs and chemical determinands appropriate to contamination sources. Level of risk: High
Event: NOT ENOUGH SOURCE WATER AVAILABLE FOR ABSTRACTION Hazards: Germs and chemicals that get into the water because of low system pressure; hazards associated with poor hygiene. Level of risk: High P1.4.1.1 Drought. Start water conservation measures as soon as water shortage becomes likely. Plan the development and use of the source, and the need to identify and develop new sources, based on flow records of the spring. Water demand. Source usage rate. System pressure. Drop in system pressure. Customer complaints about low pressure. Prepare new resource consent application. Find new sources. Increase storage capacity. Partially close valves through the network to equalise pressures. P1.4.1.2 Resource consent limitations. Negotiate new resource consents. Water demand. Source usage rate. System pressure. Drop in system pressure. Customer complaints about low pressure. Find new sources. Increase storage capacity. Event: CONTAMINATION GETS INTO THE SPRING BOX Possible hazards: Germs and chemicals. Level of risk: High P1.4.2.1 Heavy rain leading to high levels of turbidity and organic matter. Install upstream cut-off drains to minimise contamination from run-off. Ensure spring box is covered, and constructed so that water cannot enter through manholes. Raw water: turbidity, suspended solids, quality. Non-compliance with DWSNZ: 2000 particularly turbidity, and E. coli counts. Increased filter backwash frequency (if filtering). Difficulty in achieving free available chlorine residual in treated water (if chlorinating). Spring box not covered. Review options. Review alternative source options. P1.4.2.2 Observed or known contamination in area of spring. Fence off abstraction area, and undertake regular inspection and repair. Increase chlorine residual in treated water. Event: CONTAMINATION OF THE AQUIFER (the source) Possible hazards: Germs and chemical determinands appropriate to contamination sources. Level of risk: High
treatment-springs-feb14-v2.docx