Erosional Landforms (Running water)| Class 11 Geography Notes

Erosional landforms created by running water are the result of water moving across the land, carving out valleys, shaping mountains, and creating a variety of other structures through processes of erosion and deposition. These landforms show us the path water takes as it travels over and through the earth.

This article will give you a detailed guide on Erosional landforms by running water, including their formation and the unique landscapes they create.

Erosional Landforms (Running water)| Class 11 Geography Notes

Erosional Landforms of Running Water

Erosional landforms created by running water are shapes on the earth’s surface made over time by the flow of rivers and streams. This happens because the moving water picks up and carries away bits of soil and rock.

As the water travels, it wears down the land and can carve deep valleys, create steep cliffs, and form winding river channels. These changes show how powerful water can be in shaping our planet.

One of the most well-known examples of this is the Grand Canyon in the United States. It was formed by the Colorado River cutting through rock for millions of years. Small streams and rivers also create erosional landforms.

 Some of the erosional landforms formed by running water above the surface of the earth are :

1. Valleys
2. Potholes and Plunge Pools
3. Incised or Entrenched Meanders
4. River Terraces

Valleys

Valleys are among the most common erosional landforms created by running water. They start as small and narrow rills, which gradually develop into long and wide gullies. Over time, these gullies deepen, widen, and lengthen, eventually forming valleys. There are different types of valleys, such as:

• Gorges: Deep valleys with very steep to straight sides, often found in hard rock areas.
• Canyons: Similar to gorges but wider at the top than at the bottom, canyons are characterized by steep step-like side slopes.

Potholes and Plunge Pools

Potholes are circular depressions formed by the erosion of rock fragments carried by running water. These depressions grow as pebbles and boulders are collected and rotated by the flowing water.

Plunge pools are large, deep potholes formed at the base of waterfalls due to the impact of falling water and the rotation of boulders. They contribute to the deepening of valleys. They’re like nature’s swimming pools, but they can be really deep and dangerous.

Incised or Entrenched Meanders

These are deep and wide meanders cut into hard rocks, typically found where a river rapidly cuts into its bed without significantly eroding its banks. Streams flowing over gentle slopes tend to develop sinuous or meandering courses, especially over floodplains and delta plains where gradients are very gentle.

• Entrenched meanders are deep loops in a river that cuts into the ground.
• They form when a river erodes downwards faster than it erodes sideways.
• This can happen when the land lifts up or the river’s water gets lower.
• The river keeps its twisty path but flows in a deep valley.
• These meanders look like winding canyons from above.
• They’re different from regular meanders, which are more about the river spreading out on a flat area.
• There are many plants and animals that depend on the river’s unique habitat.

River Terraces

River terraces are flat surfaces that mark old valley floors or floodplain levels. They result from the vertical erosion by a stream into its own floodplain, creating terraces that can be paired (at the same elevation on either side of the river) or unpaired (at different elevations or only on one side).

• River terraces are like steps along a river.
• They form when a river cuts down into its own floodplain.
• Older terraces are higher up, younger ones are closer to the river.
• They show where the river used to flow at different times.
• Rivers carve terraces during periods of changing water volume or land height.
• People use terraces for farming and building because they’re flat and fertile.
• We can tell how old a terrace is by looking at the soils and rocks on it.

Difference between Erosional and Depositional Landforms

Erosional and depositional landforms are created by natural processes involving the movement of earth materials by agents like water, ice, wind, and gravity. Here are some of the key differences between Erosional and Depositional Landforms tabulated below :

Erosional vs. Depositional Landforms (Running Water)
Feature	Erosional Landforms	Depositional Landforms
Formation Process	Formed by the removal or wearing away of earth materials by natural forces.	Formed by the accumulation or deposition of earth materials carried by water, wind, ice, or gravity.
Examples	Canyons, valleys, gorges, mesas, mountain peaks, sea cliffs.	Deltas, beaches, sand dunes, alluvial fans, moraines.
Agents	Water (rivers, waves), ice (glaciers), wind, and gravity (mass wasting).	Water (rivers, lakes, seas), wind, ice (glaciers), gravity (sedimentation).
Characteristics	Often rugged, steep, and characterized by features showing evidence of removal of material.	Generally flat, gentle sloping areas, characterized by features showing evidence of deposited material.
Materials Involved	Involves the movement and erosion of rock and soil.	Involves the transportation and accumulation of sediments.
Landform Features	Cliffs, arches, valleys, and channels are common erosional features.	Flood plains, deltas, sand bars, and beaches are common depositional features.
Impact on Landscape	Erosional landforms often expose underlying geology, leading to a varied and dramatic landscape.	Depositional landforms tend to fill in valleys and other low-lying areas, smoothing out the landscape.
Process Duration	Erosion processes can be rapid or occur over millions of years, depending on the material and erosional agent.	Deposition can occur quickly during events like floods, or gradually over thousands to millions of years.

Conclusion

Erosional landforms created by running water are key features of the Earth’s surface. They include valleys, canyons, gorges, etc. They have been shaped over millions of years. These formations show us the power of water to erode and reshape landscapes. These erosional processes contribute to the Earth’s geological diversity. They show us the balance between erosion and the creation of new geological features.

Read More

• Evolution of Landforms
• Major Landforms on Earth
• Coastal Landforms
• Coastal Erosion

FAQs on Erosional Landforms (Running Water)

What are erosional landforms created by running water?

Erosional landforms created by running water include features such as canyons, valleys, gorges, and river cliffs. These formations result from the continuous movement of water eroding the earth’s surface over time.

How does a river create a valley?

A river creates a valley by eroding the land along its course. Over millions of years, the water’s persistent flow wears away the rock and soil, deepening and widening the riverbed into a valley.

What is a canyon, and how is it formed?

A canyon is a deep, narrow valley with steep sides, often formed by the erosion caused by a river cutting through rock. The process is accelerated in areas where the river has a steep gradient.

Can running water form gorges?

Yes, running water can form gorges, which are similar to canyons but narrower and with steeper sides. Gorges are formed by the rapid erosion of rock by a river or stream, especially in areas where the water flow is strong and concentrated.

What is the difference between a valley and a gorge?

The main difference between a valley and a gorge is their size and the steepness of their sides. Valleys are broader and have gentler slopes, while gorges are narrower with more abrupt and steeper sides.

How do rivers create cliffs?

Rivers create cliffs through the process of undercutting, where the water erodes the base of a slope or hillside, eventually causing the upper portions to collapse and form a steep, vertical face.

What role do waterfalls play in the formation of erosional landforms?

Waterfalls contribute to the formation of erosional landforms by eroding the rock at the base of the falls through the force of the falling water. This process can create plunge pools and, over time, lead to the retreat of the waterfall, further shaping the landscape.