How bad is pollution in Port Phillip Bay?
I wonder why Melburnians are not more concerned about the impact of sewage spills in Port Phillip Bay? Because every day I read posts parroting advice from the EPA regarding poor water quality. That advice is … don’t swim! But that’s hardly the point. Surely we should be shouting at those responsible for protecting the bay’s health … these are the same organisations advising we don’t swim (Melbourne Water, the EPA etc).
Victoria’s chief environmental scientist Professor Taylor has told reporters that:
“After 30 years of monitoring, and more than 3,000 reports provided, we’re seeing water quality in the bay maintaining a high standard, something we will continue to focus on for the next 30 years and beyond.”
But the data show differently (see below).
Port Phillip Bay Recent Water Quality
Port Phillip Bay’s water quality is rapidly worsening. This 2,000 km2 inland sea is connected to the ocean by a narrow passage. Therefore, during high rainfall events, the pouring of partially treated sewage into a system, means it stays inside the bay for between 234-390 days.
There’s no point in blaming this on the weather though. We know climate change is making storms more intense and localised and that means building better infrastructure.
Secchi disc readings at Hobsons Bay (from the Victorian EPA), which measures light attenuation, show how underwater visibility has reduced from 4m to 2.5m in less than 10 years. When the reading is lower, it means less light reaching seagrass and other vegetation, which makes ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More sensitive to collapse.
Secchi disk data are really accurate and they capture the whole impact of all pollutants. There’s little need to focus on specific issues like bacteria and nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More, when you know the water is getting dirtier.
The impact of dirtier water
Dirtier water means less light reaching the seafloor. This collapses whole food chains that provide everything we depend on. It also inhibits the system’s ability to withstand further increases in pollution. Fixing this is a case of reversing the trend. But this means valuing community needs more. At the moment, decisions are being made that benefit polluters, further erode ecosystems and failure to address key threats.
We’ve known about these for 20 years.
Developed in 2001, the first Port Phillip Bay Environmental Management Plan (EMP) has been an important guide for managing the bay. The EMP specified a set of environmental objectives to manage two priority risks to the bay: nutrients (see Water quality) and marine pests – State of the Bays
What should we expect to happen?
Every year, millions of dollars are being spent on pier redevelopment, fishing infrastructure, beach replenishment, channel dredging and coastal defence. So, why shouldn’t we expect some of our money to be spent on better sewage management? Is it too much to ask for clean water?
Fortunately, there are massive changes underway to give the community more of a voice in how we look after our bay. This includes addressing the impact of sewage spills in Port Phillip Bay. The EPA, Parks Victoria, the Victorian Fishing Authority and others, are now required to make the sustainable use of our bay a priority.
Here is a video explaining more.
