Earland Falls
The Routeburn track leads against the mountain bluffs and emerges at the foot of Earland Falls. These falls resemble the Sutherland in that they come from a little lake, which was named after Mr K. C. Roberts, who first observed it from the summit of Mount Crosscut in the Upper Hollyford.
The waterfall is quite tall with 174m, and especially remarkable after heavy rain. Spray fills the air and its performance on a rain-filled day is spectacular and will be compensation for a soaking hike. If the creek fed by the falls is flooded, you can use the side-track using the bridge otherwise the track passes under the falls.
Waterfalls
A waterfall is a river or other body of water's steep fall over a rocky ledge into a plunge pool below. Waterfalls are also called cascades. The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls. Waterfalls themselves also contribute to erosion. Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.
A fall line is the imaginary line along which parallel rivers plunge as they flow from uplands to lowlands. Many waterfalls in an area help geologists and hydrologists determine a region's fall line and underlying rock structure.
As a stream flows, it carries sediment. The sediment can be microscopic silt, pebbles, or even boulders. Sediment can erode stream beds made of soft rock, such as sandstone or limestone. Eventually, the stream's channel cuts so deep into the stream bed that only a harder rock, such as granite, remains. Waterfalls develop as these granite formations form cliffs and ledges.
A stream's velocity increases as it nears a waterfall, increasing the amount of erosion taking place. The movement of water at the top of a waterfall can erode rocks to be very flat and smooth. Rushing water and sediment topple over the waterfall, eroding the plunge pool at the base. The crashing flow of the water may also create powerful whirlpools that erode the rock of the plunge pool beneath them.
The resulting erosion at the base of a waterfall can be very dramatic, and cause the waterfall to "recede." The area behind the waterfall is worn away, creating a hollow, cave-like structure called a "rock shelter." Eventually, the rocky ledge (called the outcropping) may tumble down, sending boulders into the streambed and plunge pool below. This causes the waterfall to "recede" many meters upstream. The waterfall erosion process starts again, breaking down the boulders of the former outcropping.
Erosion is just one process that can form waterfalls. A waterfall may form across a fault, or crack in the Earth’s surface. An earthquake, landslide, glacier, or volcano may also disrupt streambeds and help create waterfalls.
Types of Waterfalls
- Block waterfall: descends from a wide stream
- Cascade is a waterfall that descends over a series of rock steps
- Cataract is a powerful, even dangerous, waterfall
- Chute is a waterfall in which the stream passage is very narrow, forcing water through at unusually high pressure
- Fan waterfalls are named for their shape. Water spreads out horizontally as it descends
- Horsetail waterfalls maintain contact with the hard rock that underlies them
- Multi-step waterfalls are a series of connected waterfalls, each with their own plunge pool
- Plunge waterfalls, unlike horsetail falls, lose contact with the hard rock
- Punchbowl waterfalls are characterized by wide pools at their base
- Segmented waterfalls separate as distinct streams. Huge outcroppings of hard rock separate the streams
Earthcache Tasks
Please make your way to GZ were you will find a large bolder which will help answer the following questions:
- Describe the type of waterfall this waterfall would be classified as and justify your answer.
- Explain and estimate where the widest part of the falls is?
- Take a close look at the huge rocks at the pool. Describe the texture and appearance of this rock. Classify the type of rock.
- (Optional): Take a photo of yourself, your GPS or just the waterfall and add it to your log.
Please log your find at the same time as your email me your answers. However, if your answers are incomplete or wrong you will be asked to provide more details. If this is not provided the log will be deleted.
Source: http://www.nationalgeographic.org/encyclopedia/waterfall/