SHaring The Secret Part 1Read Now
Remember January 22, 2022?
Today was one of those dates I’ll remember for life. The Bureau had been talking up a big rain so last night I rushed home from the beach. Katherine and I had just completed an 18-kilometre addition to our feral proof Mallee Refuge fence at Secret Rocks, between Kimba and Whyalla. The tiny bandicoots reintroduced in July were raising their second cohort of twin joeys. Last week we caught an endangered sandhill dunnart and thrilled at the return of a pair of malleefowl. One cat or fox squeezing under where water had rushed, or worse still sauntering in if the fence had been knocked down, could quickly finish them all off.
Pelting rain on our iron roof snapped me awake at 4:10. The energy was contagious. I jumped into my bathers, donned a headtorch and ran outside. Through the torchlit rain curtain I could see water, the most precious asset in the bush, gushing out the top of our house tank. Between lightning strikes I scooped leaves and silt from the filter basket and was rewarded by the hollow sound of a tank rapidly filling. There was already 65mm in the gauge.
As soon as the feeble daylight had breached the cloud ceiling, I went out exploring. To my surprise a 40m wide creek was flowing across our driveway in a series of rapids. We’d lived here for 12 years and never even suspected this was a creek, only 500 metres from our house.
I was intrigued. Did this flow just get absorbed by the sandplain or did it end in a swamp? Boosted by tributaries from ‘Beer Rock’ and other local outcrops, the creek became wider rather than disappearing into the sand as I had suspected. Fortunately, the flow had spread and filtered through our new fence without any damage. Wherever I cleared debris from the netting, a gush of dammed back muddy water surged on downstream.
Relieved that ‘Surprise Creek’ hadn’t knocked the fence down I continued to follow it, paying more attention to the bush. The birds were also excited by the unexpected torrent. Rainbow bee-eaters, that had been surprisingly scarce this summer, noisily snapped up flying insects. Budgies and masked woodswallows, the most excitable of desert birds, wheelied around in noisy flocks. Spending my 20’s and 30’s in the desert at Roxby I always loved it when these desert nomads paid a visit. They had found the creek before me.
All the way from the house the creek had been flowing through mallee burnt in our big fires two summers ago. But now the creek demarked the boundary of unburnt scrub. Further along the creek marked the edge of a 2km long control burnt I lit nine years ago. I’d been intrigued by bushfire patterns since my first brief contract after Uni mapping fire scars in National Parks. Fire edges could often be explained by wind changes, and sometimes changes in vegetation. Previous floods of Surprise Creek had washed fallen combustible leaves from a wide strip of mallee, way more effectively than a dozen rake hoes or even the fancy new backpack leaf blowers we used to slow down our 2019 fire.
The trilling rattle of burrowing Neobatrachus frogs indicated I was approaching the terminal swamp, where a dune blocked Surprise Creek. I’d studied these turbocharged frogs at Roxby. When water from big rains percolated down to their cocoon of shed skin, the frogs scramble up through the mud, eat their old skin and embark on a few days of frenetic action. Females rapidly develop their clutch of eggs as they seek out the best calling male in the deepest pond. Lucky males, and sometimes some cheeky interlopers, grasp the slippery females with special glove-like nuptial pads and fertilise their string of eggs. The race continues as the tadpoles hatch and grow faster than any other tadpole in the world so they can metamorphose and bury themselves before their pond dries out. Seventeen days was the record in shallow hot ponds but taddies in deep cooler ponds could take over 9 months.
What about Secret Rocks fence?
If Surprise Creek had flowed so vigorously, I worried what damage had been caused to our fence where it crossed known drains. Secret Rocks, the iconic granite outcrop where Edward John Eyre was introduced to a reliable water source in 1840, was my main concern. That was where the bandicoots were, and I knew of three places where smaller rains had run water off the rock and through the fence.
I jogged through the mud back home, through another brief but intense storm. The deluge, or maybe the flooding of the trench where our internet connection runs, had shut down the internet - no BOM weather radar or even Facebook updates from neighbours.
I strapped a long-handled spade to my pushbike and headed off to check the 25km perimeter fence. Within 10 minutes of boggy riding my back tyre was flat. Worried about the bandicoots I ditched the bike and headed off on foot with my spade. Amazingly, the first drain I reached near Secret Rocks had not even flowed to the fence, the same with the second. This highest risk part of our fence seemed to have been spared the heaviest rain.
Trilling frogs that have been sought by local kids for generations were already amplexing in the rockholes. I counted 8 in one, 14 in another. My phone beeped with messages and I quickly learned that some mates near Kimba had received 220mm, others over 300mm, of rain - nearly three times what I had emptied from my rain gauge at home. Apparently there was more on the way.
With another 16km of fence to check I slipped back down the rock, taking the opportunity to slide down a mossy waterfall and past some rare acacias from the Botanic Gardens we planted last year. It had not rained for a few hours by now and the humidity was stifling, my bathers now wetter from sweat than rain. A couple of hours later I came across a lake straddling our new fence, flooding dense mallee on both sides and ruling out driving around this section of fence for weeks. This was the fifth site I found breeding frogs. Not having had a drink all day, I knelt down and sucked up eucalyptus-flavoured water, very different from the familiar rainwater flavour of rockholes or claypans.
Ironically, as soon as I’d had a drink I heard a distant roar, like the Perth-bound jets that flew over before COVID. But there were no planes in the sky, only a black cloud eerily bruised with green and purple. The birds that had been noisily feeding on flying ants and termites went quiet. From ahead a waterfall approached, roaring until it reached me. Suddenly the tracks along both sides of the fence turned to rushing torrents, racing toward the lake I had just drunk from. Then the lightning started. I’d been cracked by lightning before and didn’t fancy repeating the experience walking underneath the floppy overhang of a 2-metre netting metal fence.
As I jogged for home I noticed one of my cat-killing Felixers in danger of being flooded. I’d not even considered the likelihood of flooding when I chose this spot where I had seen feral cat tracks. I wasn’t the first to misread floods. The old Roxby Downs Homestead was nestled amongst the gums and tea trees of Chances Swamp, an ideal location until it was flooded to the top of the door several times, including in 1989 and 2007 when I was there. I wondered how many inappropriately located silobags, sheds or houses on the EP were also inundated or threatened by these unprecedented floodwaters.
Home came into sight as the dark afternoon faded into twilight. None of the fence was down, at least until the last deluge, which was testament to savvy fence alignment designed to avoid dunes, rocks and known drainage lines. Our workmate Cat Lynch was also relieved as my responded to all her worried messages. Centuries-old sandalwoods and pines near our house that survived the 2018-19 drought were already rejoicing, their roots probably drenched for the first time in decades.
Another 36mm in the gauge brought our total to 110mm for the day. Pikey on the radio announced his rainfall tally had smashed generational daily records just down the Cowell Road. Footsore on my couch, I giggled. Would Pikey and Rachel change the name of their farm from ‘Winter Springs’ to ‘Summer Torrent’? This unusual almost stationary tropical low had delivered a rain for the ages.
The thunder and pelting rain had stopped for now but there was something eerily quiet about the calm after the storm. Then it dawned. There were no giant rain moths bashing into our widows like flat tennis balls. I hadn’t noticed any of their tell-tale cases where they typically emerged from the ground after a big rain. Why were the dragonflies already here but the rain moths hadn’t made an appearance?
From studying the aftermath of floods in deserts I expected a series of plagues to follow a big rain like this; flies, grasshoppers, caterpillars, stink beetles, moths, mice and maybe even nomadic kites and owls. I was intrigued to learn how the mallee would respond. When would the rain moths or the lumbering bright orange jewel beetles emerge? How many of our new swamps would last long enough for tadpoles to metamorphose? I set myself a challenge of documenting the changes for a year, a year when we hoped to reintroduce more rare animals and threatened plants to this special drenched place.
3/2/2022 11:46:28 am
John, great read (no pun) thanks for putting fingers to keyboard. Look forward to the next installments. Regards.
4/2/2022 07:36:07 am
A great account John. Look forward to reading more.
John L Read
4/2/2022 01:25:42 pm
Thanks Ross and Piers
13/2/2022 01:11:53 pm
John L Read
27/2/2022 01:41:24 pm
About 70mm of rain is usually required to entice trilling frogs to the surface but once they are up they only require 10mm over three days to keep them active at night. At Roxby, where these frogs have been studied in detail, they typically require over 100mm to breed, maybe twice a decade. Even the great rains we had in the Kimba district in January were insufficient to allow successful breeding in most ponds. All four of the natural swamps and even some of the rockholes at Secret Rocks are already dry and the tadpoles died before they could metamorphose, although that 10mm we had last week enabled some little guys to leave the rockholes and hopefully bury in the wet sand..
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John L. Read, PhD, author-ecologist
Wakefield Press, Dear Grandpa, Why? Reflections From Kokoda to Hiroshima