Why do we have a filtration system? What happened to Clear Water Lagoon?

In late 2013, a significant blue-green algae bloom caused Clear Water Lagoon’s natural filtration process to fail. This resulted in the water in the lagoon being unsuitable for Mount Isa Water Board to supply to Mount Isa City Council for use by the Mount Isa community without subsequent filtration. As there was no likelihood that the algae bloom could be resolved within a suitable timeframe, the Mount Isa Water Board urgently sourced a filtration system as an interim measure to ensure the continued supply of clean water to Mount Isa City Council. The blue-green algae bloom in Clear Water Lagoon grow to be potentially the largest ever recorded in a Queensland water supply system. Levels of blue-green algae have risen to never before seen levels of more than 6 million cells per millilitre in March 2015 — 10,000 cells per millilitre is considered normal and acceptable. While investigations are currently being undertaken into the future of Clear Water Lagoon, the Mount Isa Water Board now considers a filtration system essential to future operations. Recent events have demonstrated that Clear Water Lagoon can no longer be relied on to the extent it has been in the past and will not be able to meet the process assurance requirements of modern drinking water standards. A permanent water filtration facility has now been established to assure Mount Isa's drinking water quality.