Secchi Disk monitoring files

If you want an electronic copy of the monitoring manual or data sheet these can be accessed from the files below:

Secchi Disk manualFOGSV_2017v4_780KB



Secchi Disk Monitoring videos

We now have a promotional film and detailed instructional video on Youtube. You can access these films here:



Facebook page

We now have a Facebook page specifically for the Secchi Disk project for volunteers and supporters to share photos, tips and video from their monitoring activities.








Interesting trends

Volunteers have been recording Secchi Depths around the Gulf for over 2 years and some interesting readings have emerged.

Secchi Depths around the Gulf have ranged from a very low 70cm at Henley Beach up to 730cm at Port Noarlunga where waters are generally less turbid.

It is suggested by some that a Secchi Depth of 1.2 or less is unsafe for swimming. In the two years of data collection, 8 readings have fallen below that level at sites around the Gulf.

As yet there is not enough data to say whether there are any trends, but many sites seem to be showing an increase in turbidity rather than a decline. Although there is not enough data to say this with confidence. An example of readings is shown from Brighton.



The more data we can collect, the more rigorous it will be and the more information we can provide to decision makers and the community.


Measuring water quality – the Secchi Project

The Secchi disk used to measure water clarity.

People who observe our coastal waters regularly can’t help but notice when they are dirty.

In most cases it is possible to make a good guess as to why. Near Adelaide, stormwater is a likely culprit, and we have become accustomed to seeing murky water after rainy and windy conditions. Other causes may include dredging operations, runoff from building sites or agricultural land, waste spills etc.

The Adelaide Coastal Waters Study highlighted the importance of clean water for a healthy marine environment, particularly in relation to seagrasses, which play such a pivotal role in the gulf.

The Secchi disk disappears from view quickly in turbid water

The Friends of Gulf St Vincent, in collaboration with the Adelaide and Mount Lofty NRM Board, have a project up and running to monitor water quality using Secchi discs. The Secchi disc is a relatively simple and inexpensive way to measure water clarity – the black and white disc is lowered into the water until it is no longer visible. This distance is the Secchi depth.

The rule of thumb is that if you can’t see your feet when you are standing in chest-deep water it is not safe to go swimming.

Similar projects have been run elsewhere – in locations where local pollution of lakes and bays was causing concern, and the benefits are that people become involved in regular observation of changes in the water quality, the data provides a baseline and record of trends, and we all learn more about the sources and impacts of pollution.

In Gulf St Vincent the Secchi depth is usually between 2 and 10 metres, but in other parts of the world measurements of 40 – 80 metres have been recorded!

The waters extending from Outer Harbour to Port Stanvac are particularly at risk from turbidity (muddy waters), but we also need to monitor coastal waters at all jetties around the gulf, so that we can identify marine areas that may be affected by turbidity now, and those which may be at risk in the future.

The project has been running since April 2012, and we are getting data for the Adelaide metropolitan jetties, but we would also really like to sign up some Secchi volunteers for the Yorke Peninsula side of the gulf.

The FoGSV will provide a Secchi kit and training to volunteers for this important monitoring program of Gulf coastal waters. The goal is to get one or more people collecting data (taking measurements and then submitting it via the Secchi Project website) from their local jetties or boats. Volunteers need to have safe access to a relatively deep measuring location. Secchi readings should ideally be taken regularly (once a week would be great) but all data collected will be useful!

If you are interested in participating in this project, or if you know of someone who might be, please contact Mel Rees at

 Continuing on with our chat with Featured speaker Sarah-Jo Lobwein and the work she does in regards to single use plastics #swapforthesea 2. Plastics - what can’t you avoid or still struggle with finding an alternative? . “Dried Dog food that’s not overly expensive (but recently found a brand that is meant to be home compostable packaging but will have to see if it passes my dog’s taste test!), potato and corn crisps (there seems to be alternative to all other snack packaging except for these) and CDs – I have always loved the joy of purchasing a new music CD and most come in plastic hard or paperboard plastic covered. Those three all have alternatives, but they are my naughty weaknesses. . The main struggle for me, as a someone who is gluten AND lactose intolerant AND travels to remote places, is sometimes I have to eat a lot of rice or just accept the plastic until I find a way to get the venue or place to change. Usually I take my own packaging with me and then bring it home to recycle, for example when I am home my bread comes in paper or reusable bags, but travelling I will take with me gluten free bread in plastic sealed bags.” . Plastic Free July example of a ready to go reusable kit you can have waiting by the door as you head out. . . . . . . . . #waronwaste #waste #saynotoplastics #refuse #recycle #reuse #repurpose #upcycle #protectourgulf #saveouroceans #gogreen #nature #conservation #climateaction #marinedebris #beachcleanup #bethechange #adelaide #fogsv #friendsofgulfstvincent
 Continuing on with our chat with Featured speaker Sarah-Jo Lobwein and the work she does in regards to single use plastics #swapforthesea . 1. Plastics - what have become your favourite swap items? . “There are technological advancements and inventions, (or rediscoveries of what society used before we became addicted to plastic), all the time that amaze me – straws made out of wheat for example, and consumable soft bio plastic packaging of pasta made out of algae that we can just throw into boiling water etc. . But my favourites are the every day items – reusable, take your own or compostable straws, cutlery, takeaway containers, coffee cups, water bottles, shopping bags, paper bin bags and produce bags because they are so easy and accessible –humans were using them before plastic was invented or became prolific. The ones that reduce waste in general such reusable or not using an item at all is the best solution (such as not using a straw), and then compostable such as paper or bamboo. . Personally I can’t believe how empty my bins are once I phased out most plastics – I use the paper sandwich/ mushroom veggie bags or paper retail shopping bags for my bin and wash out the bin if it gets dirty (and there are businesses now that can come clean your bins!) - there is always an alternative.” . . . . . . . . #waronwaste #waste #saynotoplastics #refuse #recycle #reuse #repurpose #upcycle #protectourgulf #saveouroceans #gogreen #nature #conservation #climateaction #marinedebris #beachcleanup #bethechange #adelaide #fogsv #friendsofgulfstvincent

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