❓ Hon. Moore questions the underutilisation of groundwater capacity, referencing previous answers and public statements. Hon. Stephens explains limitations due to infrastructure, seasonal demand, and environmental considerations.
AnsweredQoN 1301Legislative Council
QuestionView source ↗
GROUND WATER, EXCESS CAPACITY
I refer the minister to public statements by the Chief Executive Officer of the Water Corporation suggesting that the excess capacity of ground water supplies cannot be utilised fully as bores cannot run around the clock. I also remind the minister of his answer to question on notice 453, which shows that artesian bores are running at 75 per cent capacity, three out of seven well fields are running at around 90 per cent capacity and four well fields are running at around 50 per cent capacity. Is there any technical reason that those four well fields cannot also be utilised at closer to 90 per cent capacity like the other well fields? Hon TOM STEPHENS
I refer the minister to public statements by the Chief Executive Officer of the Water Corporation suggesting that the excess capacity of ground water supplies cannot be utilised fully as bores cannot run around the clock. I also remind the minister of his answer to question on notice 453, which shows that artesian bores are running at 75 per cent capacity, three out of seven well fields are running at around 90 per cent capacity and four well fields are running at around 50 per cent capacity. Is there any technical reason that those four well fields cannot also be utilised at closer to 90 per cent capacity like the other well fields? Hon TOM STEPHENS
AnswerView source ↗
Yes. This volume of ground water could not be collected and distributed within the constraints of the existing trunk network. The technical capacity to abstract water from the Water Corporation’s ground water schemes is in the order of 240 gigalitres a year. Within this capacity are provisions for supplying peak demands during the summer period, allowances for maintenance activities and recognition that some bores into the superficial aquifers cannot be operated during times of drought, for environmental reasons. For those reasons, the technical capacity of ground water schemes to abstract water will always exceed annual production capacity. The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
Hon TOM STEPHENS replied: Yes. This volume of ground water could not be collected and distributed within the constraints of the existing trunk network. The technical capacity to abstract water from the Water Corporation’s ground water schemes is in the order of 240 gigalitres a year. Within this capacity are provisions for supplying peak demands during the summer period, allowances for maintenance activities and recognition that some bores into the superficial aquifers cannot be operated during times of drought, for environmental reasons. For those reasons, the technical capacity of ground water schemes to abstract water will always exceed annual production capacity. The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
Yes. This volume of ground water could not be collected and distributed within the constraints of the existing trunk network. The technical capacity to abstract water from the Water Corporation’s ground water schemes is in the order of 240 gigalitres a year. Within this capacity are provisions for supplying peak demands during the summer period, allowances for maintenance activities and recognition that some bores into the superficial aquifers cannot be operated during times of drought, for environmental reasons. For those reasons, the technical capacity of ground water schemes to abstract water will always exceed annual production capacity. The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
Hon TOM STEPHENS replied: Yes. This volume of ground water could not be collected and distributed within the constraints of the existing trunk network. The technical capacity to abstract water from the Water Corporation’s ground water schemes is in the order of 240 gigalitres a year. Within this capacity are provisions for supplying peak demands during the summer period, allowances for maintenance activities and recognition that some bores into the superficial aquifers cannot be operated during times of drought, for environmental reasons. For those reasons, the technical capacity of ground water schemes to abstract water will always exceed annual production capacity. The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
Yes. This volume of ground water could not be collected and distributed within the constraints of the existing trunk network. The technical capacity to abstract water from the Water Corporation’s ground water schemes is in the order of 240 gigalitres a year. Within this capacity are provisions for supplying peak demands during the summer period, allowances for maintenance activities and recognition that some bores into the superficial aquifers cannot be operated during times of drought, for environmental reasons. For those reasons, the technical capacity of ground water schemes to abstract water will always exceed annual production capacity. The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
The design of the transfer and distribution system for Perth is based on assumptions for annual and peak production from individual ground water systems. This is matched with the seasonal variation in customer demand, which changes by a factor of three from winter to summer. Although production of 240 gigalitres from ground water assets is technically possible, this volume of water could not be collected and distributed within the constraints of the distribution network and seasonal variations in customer demand. If access to ground water were not encumbered by its effect on the environment, around 185 gigalitres, or 77 per cent of technical capacity to abstract water, could be produced, treated and distributed by the existing system and supplied to customers. This represents the technical capacity of the integrated scheme to distribute and utilise ground water.
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