4.1.1. Surface Water Resources

There are four major sources of surface water. These are rivers, lakes, ponds, and tanks. In the country, there are about 10,360 rivers and their tributaries longer than 1.6 km each. The mean annual flow in all the river basins in India is estimated to be 1,869 cubic km.

Surface water resources in India are derived from four main sources: rivers, lakes, ponds, and tanks. The country has approximately 10,360 rivers that are longer than 1.6 kilometers. The total annual flow of all these rivers combined is estimated to be 1,869 cubic kilometers. This means that these rivers are a significant source of water availability for various uses, including agriculture, drinking, and industry.

Think of rivers as large highways for water, where the flow represents the traffic. Just as highways need maintenance to support vehicles, rivers need management to ensure they can sustainably provide water to communities.

However, due to topographical, hydrological and other constraints, only about 690 cubic km (32 per cent) of the available surface water can be utilised.

Despite having a substantial amount of surface water, practical use is limited. Only about 32% of the total surface water available can be effectively utilized due to various challenges such as geography (the layout of the land), hydrology (water movement), and infrastructural limitations. This highlights the importance of strategic planning in water resource management.

Imagine having a giant tank of water in your backyard, but due to leaks and rusty pipes, you can only collect a small amount. This scenario is similar to how India can only utilize a fraction of its available surface water.

Water flow in a river depends on the size of its catchment area or river basin and rainfall within its catchment area.

The amount of water that flows in a river greatly depends on two main factors: the size of its catchment area (the land area that drains water into the river) and the amount of rainfall that it receives. A larger catchment area can collect more water, while sufficient rainfall is critical for replenishing river flows. Therefore, understanding rainfall patterns is crucial for managing surface water resources effectively.

Think of a sponge that soaks up water. A larger sponge (catchment area) holds more water, but if you don't pour enough water on it (rain), it will not fill up. Similarly, rivers will only flow well if their catchment areas receive enough rain.

The availability of freshwater varies over space and time. The tensions and disputes on sharing and control of this scarce resource are becoming contested issues among communities, regions, and states.

Freshwater is not evenly available across India; it varies significantly by region and season. This uneven distribution often leads to conflicts over water rights and access, as different communities and states compete for this limited resource. These tensions highlight the necessity for fair and efficient water management policies.

Imagine a classroom where one student has all the candy and the others get none. This can lead to disputes and arguments. Similarly, when water is scarce, conflicts emerge between regions and communities over access.

The assessment, efficient use and conservation of water, therefore, become necessary to ensure development.

To ensure that water resources are available for future generations and to support continued development, efficient water management practices must be implemented. This includes assessing water resources, using them wisely, and conserving what we have. Measures such as watershed management, rainwater harvesting, and pollution control are vital.

Consider how you might save money for a future purchase. Just like saving allows you to budget for what you want later, conserving water helps ensure there is enough for everyone in the future.

--