❓ A WA parliamentary question on notice addresses the Water Corporation's handling of sewage overflows following a major storm and power outage in Perth, inquiring about impacted pumping stations, overflow management, and future planning.
AnsweredQoN 2182Legislative Council
QuestionView source ↗
I refer to the recent storm and subsequent power outages in Perth on Monday 22 March 2010, and I ask the following -
(1) Which Water Corporation sewerage pumping stations were without power after the storm?
(2) What length of time was each pumping station without power?
(3) What is the overflow tank capacity of each pumping station?
(4) In each instance where did overflows from each pumping station get directed?
(5) What were the approximate volumes of overflow for each pumping station without power?
(6) Who is responsible for public health and environmental health impacts from sewage overflows in each instance?
(7) Who is responsible for physical quarantining, clean-up, and disinfection in each overflow instance?
(8) How much sewage is managed by Water Corporation each year in the Perth metropolitan area?
(9) What are the projected volumes of sewage that will need to be managed over the next ten, twenty and thirty years?
(10) What overflow capacity capital expenditure is being projected over the next ten, twenty and thirty years in the Water Corporation Water Forever planning document?
(1) Which Water Corporation sewerage pumping stations were without power after the storm?
(2) What length of time was each pumping station without power?
(3) What is the overflow tank capacity of each pumping station?
(4) In each instance where did overflows from each pumping station get directed?
(5) What were the approximate volumes of overflow for each pumping station without power?
(6) Who is responsible for public health and environmental health impacts from sewage overflows in each instance?
(7) Who is responsible for physical quarantining, clean-up, and disinfection in each overflow instance?
(8) How much sewage is managed by Water Corporation each year in the Perth metropolitan area?
(9) What are the projected volumes of sewage that will need to be managed over the next ten, twenty and thirty years?
(10) What overflow capacity capital expenditure is being projected over the next ten, twenty and thirty years in the Water Corporation Water Forever planning document?
AnswerView source ↗
Answered
18 May 2010
Responded by
Parliamentary Secretary representing the Minister for Water
Response time
49 days
1) The Water Corporation has 687 wastewater pumping stations in the metropolitan area, of these, 180 lost power, as a result of the storm event. Please [see tabled paper no] which details which stations lost power.
2) The duration that each station was without power ranged from only a few minutes to over 36 hours, with the average duration being over 13 hours. Please [see tabled paper no]. Which details the duration of the power outage at each pumping station.
3) The emergency overflow capacity varies from station to station, but they are generally designed to accommodate between three and six hours of average peak inflow. Please [see tabled paper no] which details the emergency storage capacity at each pumping station.
4) Due to the extreme nature of the event and the resultant prolonged power outages at a significant number of pumping stations, wastewater overflows to the environment were inevitable. The wastewater system is designed to overflow in a controlled fashion with health protection the prime objective when a major incident occurs, such as an extended power failure. This requires the redirection of overflows to natural drainage and rivers to minimise the environmental impact and protect low lying houses and buildings.
5) As part of the Water Corporation's contingency plans for a power outage event, the major pumping stations in environmentally vulnerable areas have emergency storage capacity and standby generators, and as a result, none of the major stations adjacent to the Swan River overflowed. The Corporation's other pumping stations, without standby generators, have between three and six hours emergency storage but on this occasion, many stations were without mains power for much longer periods than that. As a result, approximately 43 million litres overflowed from the Corporation's pumping stations to the environment.
6) The Department of Health and the Department of Environment and Conservation are responsible for managing any health and environmental impacts respectively.
7) The Water Corporation takes direction from the Department of Health and is generally responsible for quarantining, the clean-up and disinfection for any overflow where there is potential for the public to come into primary contact with wastewater.
8) In 2009 - 127.50 Gigalitres.
9) Projected annual volume of sewage in the Perth metropolitan area without additional water efficiency savings are:
2020 153 gigalitres
2030 181 gigalitres
2040 203 gigalitres
10) Between July 2003 and June 2010, the Water Corporation will have spent $65.5 million on wastewater overflow risk management. This expenditure on retrofitting the overflow capacity to existing assets has achieved a significant reduction in the risk of overflows. While the Water Corporation maintains a ten-year preliminary capital program, the capital budget is for four years. Subject to annual reviews, a further $25 million is included in the capital budget to June 2015. In addition, all new assets are being built with an overflow capacity. This overflow capacity is not separately costed.
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2) The duration that each station was without power ranged from only a few minutes to over 36 hours, with the average duration being over 13 hours. Please [see tabled paper no]. Which details the duration of the power outage at each pumping station.
3) The emergency overflow capacity varies from station to station, but they are generally designed to accommodate between three and six hours of average peak inflow. Please [see tabled paper no] which details the emergency storage capacity at each pumping station.
4) Due to the extreme nature of the event and the resultant prolonged power outages at a significant number of pumping stations, wastewater overflows to the environment were inevitable. The wastewater system is designed to overflow in a controlled fashion with health protection the prime objective when a major incident occurs, such as an extended power failure. This requires the redirection of overflows to natural drainage and rivers to minimise the environmental impact and protect low lying houses and buildings.
5) As part of the Water Corporation's contingency plans for a power outage event, the major pumping stations in environmentally vulnerable areas have emergency storage capacity and standby generators, and as a result, none of the major stations adjacent to the Swan River overflowed. The Corporation's other pumping stations, without standby generators, have between three and six hours emergency storage but on this occasion, many stations were without mains power for much longer periods than that. As a result, approximately 43 million litres overflowed from the Corporation's pumping stations to the environment.
6) The Department of Health and the Department of Environment and Conservation are responsible for managing any health and environmental impacts respectively.
7) The Water Corporation takes direction from the Department of Health and is generally responsible for quarantining, the clean-up and disinfection for any overflow where there is potential for the public to come into primary contact with wastewater.
8) In 2009 - 127.50 Gigalitres.
9) Projected annual volume of sewage in the Perth metropolitan area without additional water efficiency savings are:
2020 153 gigalitres
2030 181 gigalitres
2040 203 gigalitres
10) Between July 2003 and June 2010, the Water Corporation will have spent $65.5 million on wastewater overflow risk management. This expenditure on retrofitting the overflow capacity to existing assets has achieved a significant reduction in the risk of overflows. While the Water Corporation maintains a ten-year preliminary capital program, the capital budget is for four years. Subject to annual reviews, a further $25 million is included in the capital budget to June 2015. In addition, all new assets are being built with an overflow capacity. This overflow capacity is not separately costed.
Notice: This document is created or edited using unregistered or evaluation copy of rtLib valid for testing or development purposes only. To use it for productive or any other purposes please register it. You may purchase the license on
http://www.rtlib.com
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