Last month while away on work I was lucky enough to tick off a couple of bucket list dives. I had always wanted to try freshwater diving and was able to experience what is arguably the best Australia has to offer down on South Australia’s Limestone Coast. The two sites were Ewens Ponds and Kilsby Sinkhole.
Both dive sites are a short fifteen minute or so drive out of Mount Gambier, which itself is nestled close to the Victorian border; equidistant from both Melbourne and Adelaide at about five hours from either state capital. Mount Gambier sits at the base of an active albeit dormant volcano. The city is both architecturally and geologically beautiful with the latter providing the unique conditions that make the regions freshwater diving so infamous.
The Limestone Coast region takes its name from the vast deposits of limestone that formed millions of years ago on what was once the ocean floor. As the land began to take rise from the water, the porous rock formed extensively in the region and in some places is up to 300 meters thick. As groundwater has moved through the very soluble limestone, vast caves and passages formed below the earth’s surface. When the overarching roofs of these caves eventually collapsed, the spectacular sinkholes or cenotes that exist in the region today were finally revealed.
Ewens Ponds
Ewens Ponds was the first of two such freshwater sinkhole dives. The ponds consists of three limestone cenotes interconnected by shallow channels. Each pond is basin shaped and approximately ten meters deep, with a spring close to the centre that provides the inflow of crystal clear water. The first thing that struck me aside from the icy water was the visibility; 80-100 meters such that you could easily see from one side of the pond to another.
The ponds are home to an array of aquatic fauna such as crayfish that will be out in numbers on an overcast day, as well as the endangered golden pygmy perch. The source of water for Ewans Ponds are quite easily identifiable springs close to the centre and bottom of each pond. The comparatively bright white of the limestone gives away its location and is an easy swim to the bottom. If you look carefully you can see water bubbling through the sandy crack in the pond floor like a witches cauldron.
The scenery within the ponds is made spectacular by the abundance of plant life that thrives in the sun soaked ecosystem. Beneath the surface a vibrant garden exists in stark contrast to the dry grass and bush land that surrounds Ewans. This contrast is best observed in one of the two interconnecting waterways where the depth is in some parts only half a meter deep. Here in the shallow steady current is where the plant life really flourishes and the galaxias and pygmy perch seek refuge. In the shallow waterway between the ponds you can relax and allow the current to slowly push you into the next sinkhole.
Ewans Ponds is ideal for both snorkelers and scuba divers given its size and depth. From entering the water in the first pond to exiting in the third, the dive takes approximately 30 to 40 minutes. Take your time and appreciating what is on offer. Local guides suggest that the best time of year to dive at Ewens is winter, and with the water temperature fairly constant at around 15 degrees Celsius year round, a wetsuit is a must. Facilities are limited to one drop toilet located adjacent to the small car park so have your morning coffee before you arrive at the ponds. There are no bins on site so be prepared to cart out all that you brought in.
The site is popular and can get busy during the day with tour groups operating alongside self-guided tourists. Bookings are essential to dive at this site and can be made through the Parks SA website. The ponds are open to bookings all year round with the exception of 1 September to 30 November when the site is closed. Worth noting is that dive slots are limited to one hour, with a maximum of two dives per day. Dive groups require a minimum of two and maximum of six people. There are also guided tours for snorkelers and scuba divers and these can be booked online through local operators; they cover all the site entry fees etc. Park rangers frequent the area and are known to hand out fines for non-compliance; it is the responsibility of visitors to understand the rules and requirements of visiting, such that the fragile ecosystem can be maintained for others to appreciate.
Kilsby Sinkhole
Kilsby is located on private property on what has been a sheep farm owned by the Kilsby family for the past four generations. The sinkhole has a colourful past and has only recently been developed into a site made accessible to the public. In the 1970’s Kilsby Sinkhole was used by the government for the purpose of weapons research and development of sonobouys used to find submarines and surface ships. For diving, use of the site was limited to cavers and annual police diver training. In recent years the owners made the sinkhole accessible to certified divers and snorkeling tours alike.
Typical of sinkholes in the area, the limestone roof to what was an underground cave eventually dissolved, weakened and collapsed. What remains appears to be an enormous water filled hole in the rolling green grass hills that surround. Access to the water surface is via a ramp, stairs and ladder that descend steeply down through a narrow carved out limestone passage. If you take your time on the way down, you can see embedded shells other small marine life that formed with the rock millions of years ago! Once down on the floating pontoon, looking up reveals another perspective on the size of this cenote. Some of the overarching limestone still remains of what once used to be the roof.
Once below the surface the drama of the afternoon sun becomes apparent. Beams of light cut through the sinkhole ceiling and water and onto the walls – this is what Kilsby is most well known for. The dive went as deep as about 20 meters which is plenty to see some of the historic remnants of the government testing, the beautiful light display as well as a few animal bones left behind after a some misadventure. With the exception of one introduced turtle, Kilsby contains an apparent lack of wildlife. As such the 30 minute dive for me was predominantly about being still and taking in my surroundings; appreciating the quiet and lack of distraction in order to take in the geological marvel I was floating in.
Once out of the water, dried off and warm, its worthwhile heading across to the gift shop inside what looks like a big shed. As well as sheep farming and sinkhole tours, the Kilsby family has also started distilling their own series of gin! Made with water from the very same aquifer that feeds into the sinkhole, this has got to beat any t-shirt or stubby cooler as far as souvenirs go.
Overall
While South Australia’s freshwater diving is a little more remote than other Australian dive sites, it has been one of the most unique experiences and well worth the effort. The Limestone Coast has other well known fresh water diving such as Piccaninnie Ponds and Little Blue Lake. Definitely worth checking out if you have the time. Mount Gambier itself has plenty of other things to see and do beyond diving. Blue Lake, a crater lake in the top of a dormant volcano, is another local icon and changes to a vibrant blue in the warmer months. Engelbrecht Cave under the city can be accessed via guided tours and give a spectacular insight into what exists below the city and region. Umpherston Sinkhole became another one of the regions icons when in 1886, its then owner James Umpherston turned the site into a beautiful garden. If you are looking for a more interactive experience then take a short trip up the highway toward Adelaide and stop in Coonawarra to sample some of the country’s best wine!
