Efficacy of PUB's Biomanipulation and Other Measures to Control Midge Fly Population at Pandan Reservoir

8 Mr Leong Mun Wai asked the Minister for Sustainability and the Environment whether an update can be provided on the efficacy of PUB's biomanipulation and other measures to control the midge fly population at Pandan Reservoir.

Ms Grace Fu Hai Yien: The Public Utilities Board (PUB) has implemented a suite of measures to control midges at Pandan Reservoir. These include removing midge eggs along embankments and floating structures, applying biological larvicide within the reservoir, releasing insectivorous fishes into the reservoir and fogging around the reservoir dyke and surrounding vegetation.

The intensity of these measures is continuously adjusted based on PUB's monitoring of eggs, larvae and the adult midge population. These mitigation measures have proven to be effective in keeping the midge population low in Pandan Reservoir, with no major midge outbreaks occurring since 2019.