Granite Falls
Located alongside the Glacier Campground Road leading to a view of the Valdez Glacier Lake just outside of Valdez.Valdez Glacier earth cache is nearby, and truly worth taking the time to stop off and see. They are impressive, and you will be glad you stopped. It provides some great photographic opportunities.
When driving into Valdez, you pass through Keystone Canyon. It is a place of spectacular waterfalls, magnificent geology and fascinating history. Keystone Canyon at miles 14 through 17 on the Richardson Highway you will find a roadside turnout – Scenic View Area – Bridal Veil Falls, and Horsetail Falls.
You can raft or kayak the Lowe River. You can also climb the magnificent, steep-sided, rock walls. During the winter the canyon is a popular place for ice climbing. The Valdez Goat Trail is a great place to hike. It is located at mile 13.5 in Keystone Canyon, and begins at the Bridal Veil Falls turnout.
The geological story of the surrounding mountains in the Valdez area starts about 20,000 years ago. The Earth's climate cooled and the last of the great Pleistocene ice age glaciers advanced down from the Chugach Mountains. Glaciers formed in the streambeds of the coastal plateau and carved deep valleys and beautiful waterfalls in the path. When the glaciers receded about 12,000 years ago, they had scoured the Earth's crust down to the granite roots of the Chugach range and scoured out deep fjords (glacially carved valleys filled with sea water) creating Prince William Sound and the rugged, glacially sculpted Chugach Mountains. Prince William Sound, nestled in the coastal arc of Alaska's Chugach Mountain Range, has over 20 glaciers terminating at sea level; numerous others cling to precipitous mountainsides. These glaciers form because warm, low pressure systems sweeping in off the Pacific Ocean in the winter encounter the high mountains, rise, cool and deposit their excess moisture as snow. More snow falls in the long winter than melts during the short summer. In fact, in the higher elevations of the Chugach Mountains it is not uncommon for snow to fall twelve months of the year. The thick, accumulating snow layers compress into ice which gradually flows down to the sea carving out the granite rock canyons and forming new waterfalls.
From 1910 to 1916, copper and gold mining flourished in the Valdez area. There were attempts to build a railroad through the canyon and into the copper country. Rival railroad corporations fought a gun battle in the canyon to secure a right-of-way-north of Valdez. A tunnel, which was built at the time, can still be seen as you drive through the canyon.
Waterfalls
A waterfall is usually a geological formation resulting from water, often in the form of a stream, flowing over an erosion-resistant rock formation that forms a sudden break in elevation or nick point.
Some waterfalls form in mountain environments where the erosive water force is high and stream courses may be subject to sudden and catastrophic change. In such cases, the waterfall may not be the end product of many years of water action over a region, but rather the result of relatively sudden geological processes such as landslides, faults or volcanic action.
Typically, a river flows over a large step in the rocks which may have been formed by a fault line. Over a period of years, the edges of this shelf will gradually break away and the waterfall will steadily retreat upstream, creating a gorge of recession. Often, the rock stratum just below the more resistant shelf will be of a softer type, meaning undercutting, due to splash back, will occur here to form a shallow cave-like formation known as a rock shelter or plunge pool 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.
Streams become wider shallow just above waterfalls due to flowing over the rock shelf, and there is usually a deep pool just below the waterfall because of the kinetic energy of the water hitting the bottom.
Waterfalls can occur along the edge of glacial trough, whereby a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon. The rivers are flowing from hanging valleys.
Types of Waterfalls
Block:Water descends from a relatively wide stream or river.
Cascade: Water descends a series of rock steps.
Cataract: A large waterfall.
Fan: Water spreads horizontally as it descends while remaining in contact with bedrock.
Horsetail: Descending water maintains some contact with bedrock.
Plunge: Water descends vertically, losing contact with the bedrock surface.
Punchbowl: Water descends in a constricted form, and then spreads out in a wider pool.
Segmented: Distinctly separate flows of water form as it descends.
Tiered: Water drops in a series of distinct steps or falls.
Multi-Step: A series of waterfalls one after another of roughly the same size each with its own sunken plunge
pool.
To log this earth cache you must post a picture of you with your GPS with the falls in the background (optional) and Email me the answers to the following questions...
1) Approximately how high are the falls?
2) Approximately how wide are the falls?
3) What type of Waterfall?
4) What type of rock is the Waterfall formed out of?