Page 1215 - Week 04 - Friday, 23 April 2021

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The EIS will need to address all impacts relating to Commonwealth matters of national environmental significance and ACT protected matters. For each impact identified, the EIS will need to detail any proposed avoidance, mitigation and as a last resort, offset measures.

Environment—water quality

Mr Rattenbury (in reply to a supplementary question by Ms Lawder on Tuesday, 30 March 2021):

The mesocosms in Lake Tuggeranong were used over the summers of 2018-19 and 2019-20 to conduct experiments into 1) a potential treatment—‘Phoslock’—for locking phosphorus in the lakebed so it does not pollute the overlying water column and 2) agents to diminish algal concentrations, clearing blue-green algal blooms once they arise.

This work has been completed with the findings that Phoslock combined with hydrogen peroxide (as an algicide) show good potential as treatments for algal blooms in Lake Tuggeranong. However, these agents will only be effective once the amounts of pollution coming from the catchment are reduced to manageable levels.

The mesocosms were left in the lake for possible experiments in the summer of 2020-21, however, it was decided to refocus research work on investigating the sources of pollution in the Tuggeranong catchment.

Blue-green algal concentrations have been too high since that decision was made for divers to remove the mesocosms. The blooms should soon dissipate as temperatures drop this autumn, and the mesocosms will then be removed.

Research into Phoslock and algal control agents will resume once the predominant sources of phosphorus pollution, which are coming from the catchment, have begun to be mitigated.

Energy—solar

Mr Barr (in reply to a supplementary question by Ms Lee on Tuesday, 30 March 2021):

The Sustainable Household Scheme ($150 million zero interest loan scheme) has been designed to support households and not-for-profit organisations to purchase a range of products in recognition of their different individual energy needs. These include swapping out gas appliances, household batteries and electric vehicles.

It is difficult to make a precise assessment of how the scheme will affect the level of electricity exported by rooftop solar photovoltaic (PV) as each of the eligible products have different implications for the electricity grid. Some products will export energy, others will draw energy, and some will do both.


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