Type of wetland
Constructed – Urbanised
Description of the wetland management issue
- The waterbody has a natural groundwater connection due to the low groundwater table.
- The lake is not supplied with any further groundwater via a bore system.
- There are four storm water inlets connected to the waterbody, which provide annual stormwater from residential areas and parks runoff.
- The waterbody has no aerators or active mixing.
- Ongoing water quality monitoring reports that the water is consistently high in nutrients.
- Name of treatment: Phoslock
- Quantity used: 2,367 kg
- Method of application: Mobile shore-based application equipment.
- Is there any known scientific research supporting its effectiveness? Yes. Proposal for Phoslock treatment of Lyndhurst Place Lake Mandurah, Report, Phoslock Environmental Technologies.
Date(s) of treatment
27/05/2019 one-off application
Outcome of treatment
- Visual observations: Water column seems clearer.
- Have water parameters specific to the treatment claims been measured before and after application? Yes. “Lyndhurst Place Lake Quarterly Health Check Report, EcoAdvise, August 2019″ (available upon request).
- Water testing was carried out on the 12/06/2019 after the first major winter rainfall event. Further regular quarterly testing was carried out on the 8/08/2019.
- Phoslock treatment reduced the TP concentration in the water considerably, by 91% after two weeks and by 75 % after three months. Also, Phoslock treatment has helped to drop the EC or TDS levels in water and show a 50% reduction in Biochemical Oxygen Demand (BOD) levels after 3 months. Reduction in BOD could be helpul in maintaining DO levels in water, which is good for this lake as there is no active aeration system installed.
- Although the TP level dropped post Phoslock treatment, TN and TP levels remained high enough for the lake to be considered eutrophic
Contact Officer: Tanith McCaw and Dale Robinson
Email: [email protected] and [email protected]