How A Waterfall Is Formed
A waterfall is formed when the river bed changes from a layer of hard bedrock to a layer of soft bedrock.
Over a long period of time erosion to the river bed occurs due to 2 main factors:
a.) The water passing over it.
b.) Other objects such as small rocks and sand flowing with the course of the water.
The soft rock erodes at a faster rate than the hard rock. So, where the layer of hard rock meets the layer of soft rock, a step is formed. The layer of soft rock continues to be eroded at a faster rate by the course of the river and the added force of the water falling over the step.
This erosion eventually forms a waterfall.
Hopkins Falls Formation
The river bed in this part of the river is made of volcanic rock, which is hard rock. This volcanic rock likely overlayed a section of softer rock around this area where the Hopkins Falls have formed.
The Hopkins Falls waterfall is 90 meters wide and 11 meters high, making it one of the widest waterfalls in Australia.
Types Of Waterfalls
There are several types of waterfalls, which are determined by the way they decend, the main types are:
· Plunge: Water descends vertically, losing contact with the bedrock surface, appearing as a sheet.
· Punchbowl: Water flow is narrow at the ledge and descends into a wider pool.
· Horsetail: Starts from a narrow stream and fans out a little. Descending water maintains some contact with bedrock.
· Cataract: A large, powerful waterfall.
· Block: The waterfall is wider than it is tall. Water flow maintains the same width as it decends. It maintains contact with the bedrock.
· Cascade: Water descends a series of rock steps.
· Multi-step: A series of waterfalls one after another of roughly the same size each with its own sunken plunge pool.
· Segmented: Distinctly separate flows of water form as it descends, usually separated by large rocks.
· Fan: Water spreads out as it descends while remaining in contact with bedrock.
How To Log This Earthcache
You will need to answer the following questions:
1. How wide and high are the Hopkins Falls.
2. What type of rock forms the river bed around the falls.
3. How would you describe the rock found in and around the falls – colour, size, shape etc.
4. What type of waterfall would you say the Hopkins Falls is?
5. Why do you say it is that type?
Feel free to log this cache as found at any time. However, you must send your answers through to me either by messenger or email via the Geocaching website. If I haven’t received the answers 1 week after it has been logged as a find, the log will be deleted.
The answers must be correct for this to be a find. If any of your answers are incorrect, I will let you know and give you a chance resubmit your answers. I'll probably give you a strong hint for the correct answer to make it easier.
Enjoy your visit to the Hopkins Falls and make sure you follow the path to the lower level to get a different vantage point of the falls.