Umpherstone Sinkhole in Mt Gambier in South Australia

Sinkholes with Gardens: The Limestone Coast

The temperature on the dashboard reads 40°C Degrees (104°F). Thankfully it is not accompanied by the suffocating nature of humidity. This is a dry heat, the kind that warms all the way to the bone. It feels good. I love the feel of dry heat.

Dry heat is also deceptive. It steals hydration from the body without even sweating. It drains energy quietly like an oil leak from an engine. If left unattended it can leave us sitting by the side of the road unable to move forward. The heat here is not to be taken lightly. I measure my water intake just to make sure I’m taking in at least 3 liters a day, sometimes more.

No Air Conditioning

For multiple reasons, we have decided not to install an air conditioner in Lil’ Beaut. The decision was not made lightly and many Australian travelers were consulted. Some said we were crazy, but that is already established. Others gave us tales of their treks across the continent without AC and confirmed that they would do it again and prefer it that way. Our decision is open-ended. Right now we are going to do without, but if it becomes miserable then we will install one. So far, even with the heatwaves, it is just fine.

Neither of us really care for air conditioning. If we install a good one it would not be able to run off the current solar we have. It would leave us with the two choices. One way to power the air conditioning would be to pay for a powered campsite each night ranging from $20 – $50. We have no desire to stay in paid campgrounds. We love the privacy of off-grid camping. Our other option would be to purchase a generator that we would have to lug around in the already full boot. The noise of generators is annoying, both to us and other campers if there are any nearby.  I’d rather use the small USB fan hooked up to the solar and listen to the Kookaburra laugh as the sun sets each night.  

Sunset in a free campground. Lil' Beaut is parked one sand dune away from the ocean located in South Australia
Lil’ Beaut in the sunset at a free camp spot. It is just one sand dune away from the ocean and is quiet and secluded.

Planning out the hot days

During the heatwaves, we find ways to cool down. Sometimes that results in us hanging out in a library. Other times we wade into the ocean and float there a while as we talk or watch the crabs beneath the surface of the crystal clear waters as they adopt a defensive stance upon our approach. Sometimes the crabs hide by burying themselves in the sand within a fraction of a second. 

It has been my goal to spend two days a week writing while we are here in Australia. A library is a great place to spend those days even if the libraries aren’t so quiet here in Australia. Kids run back and forth screeching, or the loud conversation of the librarian with a patron can be overheard. Sometimes it’s the group of eight women who just came in and sat around the central table enjoying a raucous afternoon of scrabble. But the climate is controlled, the seats are comfortable, the power source and Wi-Fi are free. If it gets too loud I just put on my headset and listen to music as I work.

Nights so far have grown cool enough to often need our blanket. Since our home is a bus we choose to park near the ocean on the hottest nights. The cool breeze and the calming sound of the waves lapping the shore make for pleasant evenings and a good night’s sleep. Only one night while inland exploring the Barossa valley beyond Adelaide did we need to keep the fan running all night. 

Summer is still heating up, but we plan to spend February, which is generally the hottest month, in the Margaret River area. Margaret River is usually cooler than the rest of the contingent continent. The area has multiple options for swimming at the beach or in the river.

Wallabies looking at us on the path to hells hole, one of the remote sinkholes in South Australia
Wallabies looking at us on the path to hell’s hole, one of the remote sinkholes in South Australia’s Mt Gambier area

Garden in a hole

So on this very hot day, we decided to go see a hole in the ground.  If you are from Pennsylvania you might have just imagined the Archbald pothole state park. No this was a bigger hole, big enough for a large picnic for a family reunion. It is carved into the limestone by nature and made into a beautiful garden by humans.

We amused ourselves with the thought of driving across this long hot road to see a hole in the ground and wondered if it was just a tourist trap put up by the town of Mt Gambier.

Pulling into the parking lot we immediately let down all our solar covers for the windows of Lil’ Beaut. We climbed out to go see the Umpherston Sinkhole.

Palm trees in Umpherstone Sinkhole in Mt. Gambier South Australia
Palm trees in Umpherstone Sinkhole in Mt. Gambier South Australia

After walking through the beautiful little park with shrubbery for archways and flowers lining the green patches of lawn we reached the hole. Before us the ground opened we were standing on the edge of the large sinkhole and I smiled with excitement.  

A stairway hidden behind long hanging vines gave us access down into the sinkhole. As we descended the air cooled down and a small pleasant breeze stirred around us. Roses decorated the sunken garden that spread out across the floor of the sinkhole. Water dripped from pools descending down the far side of the hole. A picnic table sat in the shade under a limestone overhang and a grassy area with park benches beckoned us to relax. It was enchanting. This was just the start of our exploration of the Limestone Coast.

View of the Umpherston sinkhole from the picnic area under the limestone overhang
View of the Umpherston sinkhole from the picnic area under the limestone overhang

Town of Mt Gambier

The area is rife with sinkholes and geological wonders created by volcanic activity, water, and limestone. Together they make this area worthy of a sightseeing trip.  In the middle of town, there is another sinkhole right next to the library. We chose to spend these hot days split between the library and climbing down into holes in the ground.

Right next to the library, on the other side of the sinkhole, an art center offers a free video about the volcanic past that created some of the unique landmarks in this area.  

Aboriginal Origin Story

The video begins with the Aboriginal version of this area’s history. According to those who originally lived in this land, Craitbul and his family made cooking fires that eventually exploded. When the mountains shrieked and blew smoke they moved on. This happened multiple times until eventually, they found a place where their cooking fires no longer exploded. Here in Australia, the story is not discounted, nor is it mocked. The video simply continues with alternate views of scientists today.  It is a beautiful combination that gives voice even to stories many discount as a myth.  

Face of an Aboriginal man carved into stone
The face of an Aboriginal man carved into stone

Maybe today we know that a cooking fire did not cause the maars in this area, but they probably did experience the explosions and at the time that was the only explanation that they knew. I find the stories give insight into how they may have reacted to the natural phenomena. It’s nice to be in a place that doesn’t mock and gives voice to alternate views. 

Observers are treated as adults that should be astute enough to decide what they will believe.  They are not treated as stupid people who are only capable of hearing one version. It is when we begin to mock the belief of others that we cease to learn. For even from what seems like a far fetched story one can deduce what it may have been like to those who lived during the time that volcanoes were active here.

The town itself is beautiful and peaceful and the people very friendly. It is just one of those places that make you want to stay awhile.

Blue Waters

Within the city limits of Mt Gambier lies another rare phenomenon. A large lake of vibrant turquoise rest at the bottom of a maar. A maar is basically a hole left in the ground after ultra heated lava and cool water meet underground. The water boils creating an explosion. The ejected matter created the rim around this lake and groundwater is now filtered by the surrounding limestone. The ultra-pure water is 70 meters deep. Each November the lake turns bright blue for the summer and is a mesmerizing sight.

Blue Lake of Mt. Gambier in South Australia
Blue Lake of Mt. Gambier

Sinkholes and frigid water

A few kilometers out of Mt Gambier is Little Blue Lake. Unlike the maar of the Big Blue Lake, Little Blue Lake is a water-filled sinkhole. They look similar but the first was created by an explosion, the second by the collapse of a limestone cave. Little Blue Lake also used to turn a vibrant blue each summer but in recent years it has remained green year-round. 

Little Blue Lake is a round hole in the ground, the cliff edges descend 47 meters (154 ft) straight down to the surface of the water. These cliff edges continue to descend far below the water’s surface the shallowest point being 25 meters (82ft) deep and extending up to 36 meters (118 ft).

Locals jump off the cliff edges to the frigid water below to cool off on a hot afternoon. The water temperature remains 12°C (54°F) year-round.  One side of the sinkhole has been artificially cut away to create an angle for swimmers to be able to climb back out to the hot plain above.

Expert divers only

The region is littered with pure white limestone “dirt” roads, sinkholes, caves, maars, and other geological wonders.

White limestone roads along the Limestone Coast in South Australia
White limestone roads along the Limestone Coast in South Australia

Wandering down white limestone roads we sought out a few of the remote sinkholes with interesting histories or features.  Beside one dusty lonely road, we parked by a sign for Goulden’s Waterhole. This sinkhole was similar in structure to the Little Blue lake but with a much smaller circumference.  There was a warning sign stating that cave diving certification was required to enter the water. We looked at the small hole and placid surface letting our imagination run wild with what one might find below it.

Divers only sinkhole outside Mt. Gambier in South Australia
Goulden’s Waterhole, Divers only sinkhole

Deceptive Waters

The next hole we stopped at appeared to be dry from our view at the top. We climbed down to the bottom of the hole via a small staircase. Along the edges of the circle, the cliff edge fell away leaving small openings on two opposite walls for a cave entrance. 

Descending down into the Fossil cave sinkhole. Small cave openings are under the limestone overhang.
Descending down into the Fossil cave sinkhole. Small cave openings are under the limestone overhang.

We tentatively stepped near the edge and peered in. The water inside each cave was so clear and its surface so still that it was almost invisible. Light from above seeped in creating a perfect reflection of the cave ceiling onto the water. The reflection was so flawless we could not distinguish what was actual reflection versus the floor of the cave as seen through the absolutely clear water.  It appeared to be shallow all the way in. But we knew our sight was deceiving us.  

Deceptive Water in the cave opening of the fossil cave sinkhole
Deceptive water in the cave opening of the fossil cave sinkhole

Above the edge of the sinkhole at the entrance of the stairway stood a sign “Only expert cave divers allowed.”  There were unseen dangers right in front of us. Not being able to perceive the danger with our eyes gave the waters an allure of deception, a danger that caused a respectful fear of what lay within these caves. Truth is sometimes beyond what we can perceive with our eyes.

Sometimes finding the blue door requires a perception gained only by listening.

“Let the wise listen and add to their learning, and let the discerning get guidance for understanding proverbs and parables, the sayings and riddles of the wise” – King Solomon

5 thoughts on “Sinkholes with Gardens: The Limestone Coast”

  1. Beautiful scenery. Description is so good that I can picture exactly what it looks like. Keep writing. The blogs are so enjoyable.

  2. Mount Gambier is a great little place. You write so beautifully. We don’t have air conditioning in our camper and we go to Darwin each year. A fan usually is all that’s needed.

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