A WA parliamentary question seeks data on dam storage levels, rainfall, and runoff, particularly investigating the impact of a bushfire on Mundaring Dam's catchment. The answer confirms increased runoff due to the fire.

AnsweredQoN 478Legislative Council
Asked
17 August 2005
Portfolio
Water Resources

QuestionView source ↗

(1) What are the current storage levels in the following major dams as of 10 August 2005: Mundaring, Canning, Serpentine and Wungong? (2) What are the total rainfall recordings to 10 August 2005 over the catchment areas? (3) Has there been an increase in the run-off from the Mundaring catchment area into the Mundaring Dam this year in comparison with the Canning, Serpentine and Wungong catchment areas? (4) If so, has this been as a result of the bushfire earlier this year in the Mundaring catchment area, resulting in forest floor reduction? Hon KIM CHANCE

AnswerView source ↗

On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(2) What are the total rainfall recordings to 10 August 2005 over the catchment areas? (3) Has there been an increase in the run-off from the Mundaring catchment area into the Mundaring Dam this year in comparison with the Canning, Serpentine and Wungong catchment areas? (4) If so, has this been as a result of the bushfire earlier this year in the Mundaring catchment area, resulting in forest floor reduction? Hon KIM CHANCE replied: On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(3) Has there been an increase in the run-off from the Mundaring catchment area into the Mundaring Dam this year in comparison with the Canning, Serpentine and Wungong catchment areas? (4) If so, has this been as a result of the bushfire earlier this year in the Mundaring catchment area, resulting in forest floor reduction? Hon KIM CHANCE replied: On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(4) If so, has this been as a result of the bushfire earlier this year in the Mundaring catchment area, resulting in forest floor reduction? Hon KIM CHANCE replied: On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
Hon KIM CHANCE replied: On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
On behalf of the minister representing the Minister Assisting the Minister for Water Resources, I thank the member for some notice of this question. (1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(1) Mundaring Weir, 29 251 megalitres; Canning Dam, 32 641 megalitres; Serpentine Main Dam, 28 758 megalitres; and Wungong Dam, 20 326 megalitres. (2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(2) The water year starts in May. The following are units in millilitres for the 2005-06 water year: South Dandalup Dam, 651; North Dandalup Dam, 622; Serpentine Main Dam, 597; Serpentine PH Dam, 651; Wungong Dam, 631; Canning Dam, 594; Victoria Dam, 539; Mundaring Dam, 559; and Stirling Dam, 461. (3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(3) Yes, as a percentage of average stream flow. Mundaring has already received 70 per cent of its average. This compares with an average of between 31 and 34 per cent for the run-off in the Canning, Serpentine and Wungong catchment areas. (4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.
(4) Yes. A reduction in forest vegetation and litter and temporary changes to the physical and chemical properties of the soil after bushfires results in increased run-off.

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