❓ A WA parliamentary question highlights concerns about water quantity, quality, and cost for horticultural producers in the northern corridor due to the declining Gnangara mound watertable. The response acknowledges the issue but defers providing detailed chemical analysis.
AnsweredQoN 1092Legislative Council
QuestionView source ↗
The horticultural producers in the northern corridor are experiencing a critical shortage in the quantity and quality of water. At the same time, the cost of pumping water has increased appreciably due to the lowering of the watertable in the Gnangara mound. This is not in line with the projected level 16 to 17 years ago when water usage licensing was enforced on horticultural producers. A maximum two-metre drop in the watertable was predicted, although the drop has been around the six to nine-metre level. (1) What was the level of the watertable at the Gnangara mound when compulsory water licensing was introduced, and what is the current level? (2) What was the chemical analysis of the water at the time of compulsory licensing and what is it now? In particular, what are the levels of the following: nitrate, phosphate, borate, chloride, sulphate, iron trioxide, aluminium trioxide, heavy metals such as mercury, cadmium, copper and zinc, and toxic chemicals such as arsenic? Hon KIM CHANCE
AnswerView source ↗
I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(1) What was the level of the watertable at the Gnangara mound when compulsory water licensing was introduced, and what is the current level? (2) What was the chemical analysis of the water at the time of compulsory licensing and what is it now? In particular, what are the levels of the following: nitrate, phosphate, borate, chloride, sulphate, iron trioxide, aluminium trioxide, heavy metals such as mercury, cadmium, copper and zinc, and toxic chemicals such as arsenic? Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(2) What was the chemical analysis of the water at the time of compulsory licensing and what is it now? In particular, what are the levels of the following: nitrate, phosphate, borate, chloride, sulphate, iron trioxide, aluminium trioxide, heavy metals such as mercury, cadmium, copper and zinc, and toxic chemicals such as arsenic? Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(1) What was the level of the watertable at the Gnangara mound when compulsory water licensing was introduced, and what is the current level? (2) What was the chemical analysis of the water at the time of compulsory licensing and what is it now? In particular, what are the levels of the following: nitrate, phosphate, borate, chloride, sulphate, iron trioxide, aluminium trioxide, heavy metals such as mercury, cadmium, copper and zinc, and toxic chemicals such as arsenic? Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(2) What was the chemical analysis of the water at the time of compulsory licensing and what is it now? In particular, what are the levels of the following: nitrate, phosphate, borate, chloride, sulphate, iron trioxide, aluminium trioxide, heavy metals such as mercury, cadmium, copper and zinc, and toxic chemicals such as arsenic? Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
Hon KIM CHANCE replied: I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
I thank the member for the question. (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that the Gnangara mound is a complex ground water system comprising several aquifers with natural and human-induced variations in characteristics throughout. Since licensing was introduced in the Wanneroo area in 1982, the general decrease in ground water level in the northern corridor is in the order of two metres. This is primarily the result of an extended low rainfall sequence, with additional impacts from pumping for private and public supply, and changes in land use. The mound responds to long sequences of above and below average rainfall years. Ground water levels are believed to have increased substantially between 1914 and 1968. The lack of wet years since the 1969 drought has resulted in a sustained reduction in levels which can be attributed to climate, not to land and water use patterns. (2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
(2) As it will take the Water and Rivers Commission some time to provide the information on the analytical data of the chemicals in the water, the Minister for the Environment and Heritage has requested that this part of the question be placed on notice.
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