My understanding was that Upper Stranger Pond (Isabella Lake) is being pumped out into Tuggeranong Pond (the bit above the weir between Isabella Pond and Lake Tuggeranong)
Their common name is needle bug. Water scorpions are in the sub-family Nepinae. There are 4 genera in the sub-family Ranatrinae. They are good fliers and readily colonise temporary ponds and are attracted to light at night.
I think there is some confusion over the ponds names on different maps. Isabella Pond (on the north side of Isabella Drive) is being drained into Lake Tuggeranong. Upper Stranger (on the south side of Isabella Drive) is being drained into Stranger Pond.
No confusion with pond names. Upper Stranger Pond is better known as Isabella Lake. The way I read the information both Isabella Pond and Isabella Lake are being drained into Tuggeranong Pond. The placement of the pump (Northwestern end of Isabella Lake) is closer to Tuggeranong Pond. See under FAQ of: http://www.economicdevelopment.act.gov.au/have-your-say/community_engagement/current_activities/isabella-pond-and-waterway-improvement-work