Water Divide: Flows and Patterns

A water divide, also known as a drainage divide or hydrological divide, is a line or ridge that separates two drainage basins, or regions of land that are drained by different river systems. A water divide marks the highest point from which water flows in two different directions, and it determines which rivers will carry water away from a given area of land.

The pattern of flow made by water is influenced by a number of factors, including the slope of the land, the permeability of the soil, and the presence of any physical barriers such as mountains or valleys. In general, water will flow downhill and follow the path of least resistance until it reaches a river or other body of water.

Drainage Patterns

Forms of Water Divide

1. Continental divides: These are large-scale water divides that separate rivers that flow into opposite sides of a continent.
2. Ridge divides: These are water divides that occur along ridges or hills that separate two drainage basins.
3. Valley divides: These are water divides that occur along valleys or low-lying areas that separate two drainage basins.
4. Stream divides: These are water divides that occur along streams or rivers that separate two drainage basins.

Understanding the pattern of water flow and the location of water divides is important for many fields, including hydrology, environmental management, and land use planning. By identifying water divides, scientists and planners can better understand the flow of water across a landscape, and make informed decisions about how to manage water resources and prevent environmental degradation.

Drainage Patterns and Flow of Water

The patterns of drainage in a given area are influenced by various physical factors such as topography, geology, and climate. The six main types of drainage patterns are: 

Dendritic pattern

This pattern is characterized by a network of tributaries that converge to form the main channel, much like the branches of a tree. This pattern is often found in areas with a gentle slope and uniform rock type, where water can easily flow in multiple directions. An example of a dendritic drainage pattern is the Mississippi River basin in the United States.

Trellis pattern

This pattern is characterized by parallel sub-parallel tributaries that join the main channel at approximately right angles. This pattern is often found in areas with alternating hard and soft rock layers, where the hard layers restrict the flow of water and cause it to converge in narrow channels. An example of a trellis drainage pattern is the Brahmaputra River in Asia.

Radial pattern

This pattern is characterized by streams that originate from a central point and radiate outward, much like the spokes of a wheel. This pattern is often found in areas with a central peak or dome-shaped uplift, where water flows in all directions from the high point. An example of a radial drainage pattern is the Deccan Plateau in India.

Centripetal pattern

This pattern is characterized by streams that converge towards a central point, much like the inward flow of a whirlpool. This pattern is often found in areas with a central low-lying depression, where water flows inward towards the lowest point. An example of a centripetal drainage pattern is the Great Basin in the western United States. 

Annular Pattern

This type of drainage pattern is formed in areas of relatively flat terrain with a central upland that has resistant rock layers. Streams flow away from the central upland in a circular pattern. An example of this type of drainage pattern is seen in the Deccan Plateau in India.

Deranged Pattern

This type of drainage pattern forms in areas of highly irregular topography, such as areas of glacial erosion or areas of tectonic activity. Streams in this type of drainage pattern are often disconnected and not well-defined. An example of this type of drainage pattern is seen in the Kashmir Valley in India.

The flow of water in drainage systems can also be influenced by the type of flow, including laminar flow, turbulence, and supercritical flow. Laminar flow occurs when water flows in a smooth, uniform manner, without any turbulence or mixing. Turbulent flow occurs when water is disrupted by turbulence, such as when it flows over a rough surface or through a narrow channel. Supercritical flow occurs when the flow rate of water exceeds the capacity of the channel, resulting in a mixture of water and air.

In addition to understanding the drainage pattern, geologists and water resource managers must also consider the flow of water, as different types of flow can have different impacts on the environment. “For example, the laminar flow may cause sediment to settle out of the water column, while turbulent flow can cause erosion and sediment transport.“ Understanding the flow of water can help inform decisions about water resource management, land use planning, and the design of infrastructure such as dams and levees.

Importance of Water Divide

The water divide in India plays a critical role in determining the flow and distribution of water resources in the country, which is crucial for the country’s economic and agricultural growth.

In India, the Himalayan mountain range acts as the main water divide, separating the Indus-Ganges Basin in the north from the Brahmaputra Basin in the northeast. The water divide also affects the flow of major rivers such as the Ganges, the Brahmaputra, and the Indus, and the availability of water resources for different regions.

The water divide is also important for the management and conservation of water resources. For example, the government of India has built several large dam projects on the rivers that flow through the country to store water for agricultural, industrial, and domestic purposes. These dams play a crucial role in managing the flow of water and ensuring water security for different regions.

The importance of the water divide lies in its impact on the country’s water resources and the role it plays in the management and conservation of these resources. Understanding the water divide and its effects is crucial for sustainable development and economic growth in India.

Example of Water Divide

Here are some examples of water divides 

1. The Himalayas: As mentioned earlier, the Himalayas are a major water divide that separates the Indus-Ganges Basin from the Brahmaputra Basin.
2. The Western Ghats: The Western Ghats, which run parallel to the west coast of India, act as a water divide between the Deccan Plateau and the coastal regions of India.
3. The Eastern Ghats: The Eastern Ghats, which run parallel to the east coast of India, form a water divide between the Deccan Plateau and the coastal regions of India.
4. The Vindhya and Satpura Ranges: This mountain ranges in central India form a water divide between the Narmada Basin in the west and the Godavari Basin in the east.
5. The Aravalli Range: The Aravalli Range in Rajasthan acts as a water divide between the Thar Desert in the west and the Indo-Gangetic Plains in the east.

FAQs on Water Divide

Question 1: Define water divide. 

Answer:

A water divide, also known as a drainage divide or hydrological divide, is a line or ridge that separates two drainage basins, or regions of land that are drained by different river systems. A water divide marks the highest point from which water flows in two different directions, and it determines which rivers will carry water away from a given area of land.

Question 2: List the various drainage patterns. 

Answer:

Radial patterns, Trellis patterns, Dendritic patterns, Centripetal pattern, Annular Pattern, Deranged Pattern:

Question 3: What are the different types of water divide? 

Answer:

1. Continental divides
2. Ridge divides 
3. Valley divides 
4. Stream divides