September 3, 2018
Why is the water clarity in Jervis Bay so incredible?
Have you been amazed by the incredible photos of crystal clear water, shades of green, blue water clear as can be and our beautiful white sandy beaches splashed across our social media lately?!
It is even more spectacular when seen for yourself, but you will have to come out on a cruise with us for that! (even we can barely believe it!)
The water clarity in Jervis Bay is influenced by several key factors;
Seagrass meadows, mangroves, river systems, ocean flushes.
Jervis Bay is home to the largest and most pristine populations of endangered seagrass known as Posidonia australis. Seagrasses absorb heavy metals and filter sediments and here in Jervis Bay sediments dating back as far as 1 300- 3000 years ago have been captured and recorded. (You can read more about seagrasses specifically in our recent blog post.)
Often when the bay is calm and clear like at the moment even when the sea floor is 10 metres below you can make out the individual blades of seagrass- it is pretty incredible!!!
When you are next in Husky, take a walk through the board walk at the Jervis Bay Maritime Museum. There you can experience the lungs of Jervis Bay. The mangroves are able to capture sediments and stabilise banks here in Currambene Creek and also in other places around the Bay- eg. Hare Bay. Mangroves reduce the turbidity of the estuary and in turn the water that exits the creek into the Bay, right where we moor our vessels.
River systems, rainfall and runoff.
Jervis Bay only has one main river that flows into the Bay, (Currambene Creek) and has a relatively small and local catchment. Meaning the water that enters the Bay has only started flowing from the hinterland of Jervis Bay between Huskisson and Falls Creek, there is a lack of industrial presence and a small agricultural region. So heavy metals entering our marine park is relatively small- especially compared to other rivers around the world- eg. Sydney Harbour! When it does rain often the creek turns a muddy brown- but we are in drought at the time of writing with very little runoff entering the bay.
Being a bay, we are protected from large powerful ocean swells and often currents- this is why cruising here is so perfect! However, we are influenced by the joining of warm water from the East Australian Current and cooler water from the Bass Strait, combined with periodic upwelling of cold nutrient – rich waters from the continental shelf. These waters meet and flow clockwise around the bay flushing Jervis Bay out every 24 days or so.
All these factors contribute to the health of our beautiful bay and the incredible water quality. We feel it is important to educate people who visit Jervis Bay for its impressive natural features, so we can all appreciate it and care for it in the future.
We are lucky enough to be home to Australia’s largest population of resident bottlenose dolphins, we attribute this to the incredible water quality!