A waterfall is a place where water flows over a vertical drop in the course of a stream or river. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Waterfalls are commonly formed in the upper course of the river. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it. The rate of retreat for a waterfall can be as high as one and half meters per year.
Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning that undercutting due to splashback will occur here to form a shallow cave-like formation known as a rock shelter under and behind the waterfall. Eventually, the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they collide with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool or gorge.
Streams become wider and shallower just above waterfalls due to flowing over the rock shelf, and there is usually a deep area just below the waterfall because of the kinetic energy of the water hitting the bottom. Waterfalls normally form in a rocky area due to erosion. After a long period of being fully formed, the water falling off the ledge will retreat, causing a horizontal pit parallel to the waterfall wall. Eventually, as the pit grows deeper, the waterfall collapses to be replaced by a steeply sloping stretch of river bed. In addition to gradual processes such as erosion, earth movement caused by earthquakes or landslides or volcanoes can cause a differential in land heights which interfere with the natural course of a water flow, and result in waterfalls.
A river sometimes flows over a large step in the rocks that may have been formed by a fault line. Waterfalls can occur along the edge of a glacial trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls inYosemite Valley are examples of this phenomenon, which is referred to as a hanging valley. Another reason hanging valleys may form is where two rivers join and one is flowing faster than the other. Waterfalls can be grouped into ten broad classes based on the average volume of water present on the fall (which depends on both the waterfall's average flow and its height) using a logarithmic scale. Class 10 waterfalls include Niagara Falls,Paulo Afonso Falls and Khone Falls.
Classes of other well-known waterfalls include Victoria Falls and Kaieteur Falls (Class 9); Rhine Falls and Gullfoss (Class 8); Angel Falls and Dettifoss(Class 7); Yosemite Falls, Lower Yellowstone Falls and Umphang Thee Lor Sue Waterfall (Class 6); Sutherland Falls (Class 5).
THE FALLS:
The Cascades Trail is a short, beautiful river walk following the Notch Brook in North Adams from the end of Marion Avenue to a popular cascading waterfall. A hidden in-town gem, this trail is minutes away from downtown areas of North Adams and Williamstown and short enough to attempt on a whim for those of you who may be seeking to squeeze a nice hike into a limited amount of time.The entire hike takes about an hour and a half, and is flat enough for even the most inexperienced hikers to enjoy a taste of nature. Just after that short section, you will traverse a moderately steep but very short side hill for your first glimpse of the falls. Mt. Greylock State Reservation is not the only park in northwestern Massachusetts known to embrace waterfalls. The Cascade, or Notch Brook Cascade, as it has also long-been known, lies in a small town park in North Adams. The Cascade is partially hidden in a near completely-enclosed gorge with towering walls, and the only way to get a full look at the falls is to hike into the gorge. The reward is a sometimes powerful, sometimes gentle 45-foot horsetail, depending on the water conditions. The Cascade is highly seasonal and is also affected by a dam upstream, which is not visible. The months of April to June should present you with the best of what the falls are capable of.
More information can be found at: http://www.worldwaterfalldatabase.com/waterfall/Cascade-The-7370/
LET'S LEARN SOMETHING!!!: Mount Greylock and the neighboring Taconic Mountains are comprised predominately of Ordovician phyllite, a metamorphic rock, overlain on younger layers of metamorphized sedimentary rock, especially marble. Mount Greylock is the product of thrust faulting, a tectonic process by which older rock is thrust up and above younger rock during periods of intense mountain building. The younger, underlying marble bedrock layers have been quarried in the lower foothills of the mountain in nearby Adams and North Adams, Massachusetts. During the Pleistocene, 18,000 years ago, Mount Greylock and the surrounding region were covered by the Laurentide ice sheet up to 1-kilometer (0.62 mi) in thickness. Glaciation rounded and wore down the mountain, carving out U-shaped valleys and leaving glacial erratics such as the Balanced Rock in Laneborough on the west side of Greylock.[13] The Hopper, a cirque, also located on the west side of Greylock, is the southernmost such glacial feature in New England. TO COMPLETE THIS CACHE: PLEASE BE CAREFUL AND RESPECT THE TERRAIN RATING AND NATURE. THERE IS NO NEED TO CROSS THE RIVER OR THE FALLS AT ANY POINT ESPECIALLY NEAR THE TOP. IF YOU APPROACH THE FALLS ALONG THE TRAIL ON THE WEST SIDE OF THE RIVER, YOU'LL ALREADY BE ON THE CORRECT SIDE. THERE WILL BE GPS BOUNCE, BUT USE DISCRETION AT THE TOP.
1. Based on the information learned above related to the evolution of rock formations and types that are indigenous to the region, describe the types of rock found at the coordinates. What are the the sizes or color characteristics?
2. Do you see evidence of bedrock quarried along the trail and near the falls based on the Pleistocene 18,000 years ago? How so and describe what you see?
3. Please take elevation recordings at the posted coordinates. As you meander along the trail, there is a trail along the west side of the river that works its way up towards the top of the falls. From the coordinates, or best I could average, you will have a nice view of where the falls start. Please be careful here and respect the terrain ratings as the path up the hill can be slippery and drops off.
4. Describe the flow of water at the time you were there. This will change depending on the season.
5. (Optional) Take a photo at the posted coordinates.
Email me answers to questions 1 and 2 from the email link within my profile or the new messenger function. All other photos of your journey are great although not required.