It’s usual for both Mabel Talbot and Lake Jualbup to dry out each summer; these are natural occurrences because both lakes are dependent on rainfall to fill up.
The City will not be pumping water artificially into the lakes as they are natural systems (unlike Subiaco Common which is a manmade lake) and we do not have the groundwater allocation available to be able to fill them up (see here for more).
As the lakes dry out, algae and avian botulism may become an increasing concern but the City is working hard to mitigate the risk of these occurring including:
Adding beneficial anaerobic bacteria to both lakes that outcompetes the botulism strain. This bacterium lays dormant in dry lake beds, so will work even if the lake dries out.
Adding Coptrol (a copper algaecide) to our lakes to mitigate algal outbreaks.
Installing new solar aerators at Mabel and Jualbup that work in very shallow water.
Improving water quality and biodiversity with upcoming mass native plantings.
Residents may see some deceased fish at the lakes throughout the dry, hot summer and/or see staff scooping them out; these are invasive carp and koi fish which are detrimental to native fish and wildlife, negatively impact water quality, destroy and uproot native plants and can introduce or spread diseases.
While it may be distressing to see, the City has proactively been removing these fish (see here) to help improve the health of these lakes and native wildlife.
Our natural lakes are also home to turtles which are well equipped to deal with the drying of wetlands through aestivation (they dig into the mud and wait it out).
Turtles have been known to survive a year and a half in aestivation and, as it is already February, they will be able to safely aestivate until the winter rains refill the lake.
Drying wetlands can be dangerous to birds as they may become stuck in the mud. If you see a bird trapped or injured at Mabel or Jualbup, please call WA Seabird Rescue on 6102 8464 in the first instance.
The City relies on the experts at WA Seabird Rescue to help save local birdlife; they recently saved an ibis that was trapped in the mud at Mabel Talbot after giving it CPR (mouth to beak!) and the team have advised that its doing well in their care.
If you have any further questions about this natural occurrence, please contact the City on 9237 9222.
