What is a Valley?
A valley is a type of landform which usually features as lowland between two higher landforms (which may be mountains or hills). Usually, valleys contain a stream or river flowing along the valley floor. Significant proportions of valleys are connected to other valleys downstream, which ultimately lead down to the coast. Most sides of large valleys in low-lying areas are usually gently sloping with an average slope of just a few degrees. However, in mountainous regions, valleys are typically deep and narrow and the sides have slopes of 35° or more.
All valleys are separated from adjacent valleys by a ridge called a drainage divide. The rain falling on opposite sides of drainage divides flow in opposite directions toward the bottoms of the adjacent valleys. This area bounded by a drainage divide is called a drainage basin, or, in the United States, a watershed, and it represents all of the land area drained by a valley.
The longest and broadest valley in the world is the Mississippi River Valley, which crosses the United States from north to south. Most times, the Mississippi River winds down the center of this valley and is joined at intervals by other major rivers flowing in their own valleys, such as the Missouri, Ohio, and Tennessee rivers.
Also, the deepest valley in the world is a section of the Indus River Valley in Kashmir. It passes through the western end of the Himalayas, the difference in height between the valley bottom and the top of the drainage divide is about 7000 m (about 23,000 ft).
The valleys are totally enclosed by higher terrain, and rivers or streams within them may terminate in a lake. Some examples of valleys that are wholly surrounded by higher ground and do not open to the ocean include Death Valley in California and the Jordan River Valley in the Middle East.
In some instances, valleys have side valleys, which are formed by tributaries to streams and rivers and feed the main stem. If the main channel is carved deeper than the tributary, as commonly occurs during glaciations, the side valleys are left hanging. Whereas, waterfalls often cascade from the outlet of the upper valley into the drainage below.
Some hollows, like those in Appalachia, are small valleys nestled between mountains or hills.
Most times, steep-sided valleys are often found in Young Mountain ranges where the land is still being lifted to create mountains. These steep-sided valleys occur because the uplift tends to increase the channel slope, which in turn causes the river to cut more rapidly into its bed.
For example, the Indus River maintains its course across the western end of the rapidly uplifting Himalayas by eroding its bed at a rate of up to 1 cm/year (up to 0.4 in/year). In most of the world, however, uplift is slow or absent. Thus slopes of most valley floors are low, the erosive power of most rivers is modest, and valley-side slopes tend to be relatively gentle. Valleys are very important landforms which have been known for several ages. They are of historical and economic importance.
Various Examples of Valleys
The following are some great examples of valleys:
- The Lauterbrunnen valley in Switzerland (situated in the Alps between gigantic rock faces and mountain peaks.
- Waipi’o Valley in Hawaii
- Khumbu valley in Nepal
- The valley of Geysers in Russia
- Douro Valley in Portugal
- Kaghan valley in Pakistan
- Jordan River valley in the Middle East
- Death Valley in California
- Napa Valley in California
- Porsmork valley in Iceland
- Hanza valley in Pakistan
- Verde Valley in Arizona
15+ Spectacular Facts About Valleys
Below are some spectacular facts about valleys:
Fact 1: The depth of a valley relative to the surrounding higher landforms is dependent on the degree of steepness of the mountains or hills. Water flows faster on steep mountains, which in turn leads to the formation of deeper valleys. In some cases, the valley formed as a steep canyon.
Fact 2: Interestingly, glaciers (huge sheets of ice) make larger valleys. The glaciers move slowly down a mountain and follow an existing valley (one created by a river). The glacier rounds out the valley in such a way that the resulting valley eventually has a U-shape of a V-shape.
Fact 3: Because of their location, valleys are usually protected from fierce winds and storms.
Fact 4: The Kali Gandaki River in Nepal is the world’s deepest valley. The valley lies between two 8,000-meter Himalayan peaks known as Dhaulagiri and Annapurna. The term ‘Himalayas’ refers to one of Earth’s most active tectonic uplifts, and this valley illustrates the rapid down-cutting that occurs in areas with a rapid uplift.
Fact 5: Most known valley in the world is the Grand Canyon of the Colorado River in Arizona. The Grand Canyon is 1 mile deep and 180 meters (590 feet) to 30 kilometers (19 miles) wide. The valley was formed when the Colorado River incised into a tall upward of sedimentary rocks.
Fact 6: When valley river waters wind closer to the sea, they follow the natural curves in the land by stripping sediment from outside bends and depositing it in the inside bends. The process of down-cutting, rock, and dirt dredged from the middle of the channel, leads to deep, slender chasms such as the Black Canyon in Colorado’s Gunnison National Park.
Fact 7: An important term related to ‘valley’ is ‘vale’. The term is used to describe a valley which has a running river.
Fact 8: Ever heard about the ‘dell’? The term is used to refer to a wooded valley. Dells have a small shape with a secluded feature. In Scotland, the word ‘glen’ is often used when referring to dell and the word ‘strath’ in Scotland is used when referring to a valley which has a running river and flat shape.
Fact 9: Small valleys are often seen on a mountain cover. The valley is formed due to the erosion of geology found in the southern and central Appalachian Mountains. The word ‘hollow’ is used when referring to a valley bordered by ridges or mountains.
Fact 10: Structural valleys are valleys formed during the rise of highlands or even drop faults. While erosional valleys are formed due to the presence of erosion. Some geographical features included as valleys include gullies, ravines, canyons, gorges, kloofs, and chines.
Fact 11: Valleys located in the Napf region of Switzerland include The Black Canyon of North America and upper Inn valleys of Australia. The valleys are some examples of broad V-shaped valleys.
Fact 12: River valleys have been of great importance since the ancient period. River valleys such as the Yellow River, Nile, Ganges, Indus, and Tigris-Euphrates originated the first human society.
Fact 13: Rivers on valleys are useful as a source of food and fresh water for people.
Fact 14: Tectonic activity may form rift valleys. A notable example is the Albertine Rift.
Fact 15: Valleys may not be formed from rivers or glaciers in some cases. Most times, valleys result from regions where two plates are not in complete touch with one another.
Fact 16: In some cases, valleys are created from rushing rivers or streams over several thousands of years.
Fact 17: A major characteristic of valleys is that they are totally enclosed by a higher terrain and rivers or streams which may terminate in a lake.
- Summerfield, Michael A. “Valley.” Microsoft® Encarta® 2009 [DVD]. Redmond, WA: Microsoft Corporation, 2008.
- 25 Most beautiful valleys in the world. By Sameen (2015, April, 18). Retrieved from: https://www.list25.com/25-of-the-most-beautiful-valleys-in-the-world/2/