One day last week I was prompted to look up the location and characteristics of two watery places using Google Earth and Maps. Looking for one was prompted by a rather tragic news report from a recreation area just south of Sydney, NSW. Since the article referred to witnesses claiming the two men appeared to be struggling against a strong current, before disappearing, I assumed this swimming area must be near the ocean. However, when I looked up “Bent’s Basin” on Google, it showed a fairly small lake– almost a natural pond
– without any noticeable river flowing through it that might have created a current! Sure, the Nepean River, certainly has a good flow, but it doesn’t seem to make much of an impression on this “basin”. The basin is quite near the escarpment so maybe the Nepean River hasn’t accumulated much flow at this stage- it looks like just a measly trickle of a creek. In fact the basin is a result of long past geological events that have created a conical hole (vertically, like an icecream cone) with the water surface being about 209 metres maximum by 114m minimum and the deepest part of the cone is 23m. The figures in the article I consulted said that the inflow rate of the river is less than 157 megalitres for 86% of the year and I’m not sure if this is sufficient to create a current when spread over 24 hours of the day. Maybe someone can comment and let me know!? Anyway, photos of the pond certainly don’t show swirls or eddies, as though a current is disturbing the water. You are probably wondering WTF I’m so interested- well it just seemed odd to me that two strong young men could drown in this peaceful looking pool, under the watchful gaze of other adults. Perhaps they were all drunk? The pool itself intrigues me- why is there a large pond with huge depth placed right where it is? How could it have formed to be deep rather than broad and shallow if it’s all in sandstone? Was there a glacier nearby that melted into that hole long ago? The description of Bents Basin as a “scour pool” makes me think it is attributed to scouring our by gravel in a high speed flow- but the river today doesn’t seem to conform to this. I guess we’re talking geological time and what we see now bears little resemblance to the area before the pool formed. I am destined to remain in the dark about this, I suppose!
The other body of water that I found myself intrigued by was something named “The Swatch of No Ground”, in the Bay of Bengal offshore from the delta of the Brahmaputra River. It just struck me as a crazy name for something, especially since (as it says)- there is no ground or island- just part of the bay! I only came across it accidentally on Google Earth while I was following some of the fault lines on the map after the recent earthquake off Indonesia’s south coast. I was looking at the proximity of the earthquake’s epicentre to the freshly erupting Merapi volcano and speculating about the connections between displacements of the earth’s crust. [I do wonder about the strangest things, LOL!] Since two of my friends in my Masters course on Indigenous Health were from nearby Aceh and one from the North Coast of Java, I was also looking at how the earthquake might have affected their homes. It was also informative to view the surface map around the Merapi volcano because it showed a huge network of tracks and small farms, almost to the summit! I had no idea that the nearby towns affected were so F..ing close to the source of all the lava and ash!
Anyway, it’s bedtime and I’ll have to finish this tomorrow morning!