What is water resource sustainability?

The majority of the earth's surface is composed of water. The water which is available for use by the living beings on earth comes from various water resources. Water resources are the naturally occurring water bodies that are intended to be used by the living beings on earth for drinking and other uses. Water resources provide 3% as freshwater, 97% as saltwater, two-thirds of which are frozen as glaciers and ices. The remaining water which generally doesn't remain frozen are the water resources found underground, precisely known as groundwater. The majority of these water sources act as non-convention sources of power generation, like in hydropower stations.

Some of the freshwater resources include surface water, water from river basins, groundwater, under river flow water, and frozen water. Wastewater is largely an industry-treated form of freshwater.

There possess a threat in the depletion of natural water resources due to water pollution, climate change, water scarcity, deforestation, lack of precipitation, and human activities. According to the reports, major depletion of groundwater is in the progressive stage in Asia, North America, and South America. Proper water resource management is crucial to ensure the nation is supplied with ample water to meet various needs like drinking, agricultural purposes, irrigation, and other commercial uses.

The rising issues of water scarcity and freshwater use are indicated in planetary boundaries, out of the nine planetary boundaries. This concept was first introduced by Johan Rockstrom in 2009. Planetary boundary signifies earth's environmental boundaries which define a safe operating zone for human life.

Natural sources of water

Here, in this section some of the natural sources of freshwater, which form the basic source of water used by plants and animals.

Surface water

Surface water is the water found in river basins, lakes, wetlands, and other water-related ponds and natural springs. This water is mainly used for drinking water purposes. The surface water is replenished by precipitation and lost by phenomena like evaporation, and evapotranspiration. As the availability of surface water largely dependents on the rate of precipitation, other factors like the storage capacity of lakes, ponds, river basins, soil permeability, and runoff characteristics also strongly affect surface water availability. Human activities have a strong impact on the quality of surface water.

Under river flow

Under river flow is characterized by subterranean river flow. It is a water body, which flows either wholly or partially under the surface of the earth. The river bed does not represent the earth's surface and are both of them are not interlinked. The under river flow can be a natural water source flowing through caves and get disappeared through sinkholes. The pathway of such water systems can be traced by following the water footprints.

Groundwater

These are the water sources that flow with aquifers under the water table. The groundwater is usually found between the pores and spaces between the rocks and other materials found beneath the earth's surface. The water from the groundwater makes its way out onto the surface of the earth through groundwater discharges majorly used for water supply. The input to groundwater is the pores present on the soil, through which water gets absorbed and refills the groundwater storage. Groundwater is pretty much similar to surface water, the only difference is the amount of water volume it can handle. Like surface water, groundwater is also important to mankind for water use and water supply. The water quality of groundwater is improved water treatment facilities.

Frozen water

Ice and glaciers are frozen water. There are schemes and techniques developed over time to make use of frozen water. Frozen water can be a potential source of freshwater, and also free of micro-organisms.
An increase in global warming is responsible for ice and glaciers on verge of melting. One of the major reasons for this threat is the increasing percentage of carbon dioxide. carbon dioxide gas has the highest value of global warming potential (GWP) than any other gas.

Water resources management techniques

In this section, some of the majorly used procedures of water resources management are outlined.

Rain water harvesting

Rainwater harvesting is the process of collecting rainwater rather than allowing it to pass off and get accumulated in the groundwater storage. Cleaver decision-making and construction plan allow maximizing the storage capacity of rainwater.
Rainwater harvesting is an intelligent way of water management that requires building roofs like structures that store rainwater and direct the water to storage tanks, and cisterns. It is a decentralized storage system that forms the primary source of water used for household and industrial purposes.

Groundwater recharge

The groundwater recharge technique is another water management technique that enhances the groundwater storage capacity. Rain, snow melting, and surface water recharge groundwater. Due to certain circumstances and human activities, the groundwater lacks adequate recharge.
Groundwater is thus recharged artificially by building dams, infiltration basins, trenches, and injection wells.

Drip irrigation

The main idea of water irrigation is to direct the water and nutrients directly to the roots of the crops and plants rater then make the water available to the plant through the ground surface. It is a eutrophication technique that minimizes the loss of water through evaporation to a large extent. Drip irrigation is a kind of micro-irrigation process. The process makes use of long pipes with added small holes and small tubular branches that go deep into the soil.

Sewage water treatment

Sewage water treatment is the process of removing pollutants like household and industrial wastes from water. This water management method uses many chemical and biological treatment procedures like catalyzing, salinization, etc. The processes first make the water treatable and further passed to the water treatment plant for purification. It improves the water quality and makes the water drinkable.

Water stress, a major problem world wide

The term water stress refers to water scarcity. Water scarcity is associated with a particular area if the water use is more than the water supply. About 70% of the freshwater is used for irrigation and agriculture, the left out is divided between industrial use and household use. Various factors decide the water stress level of an area these factors include water use, industrial use, level of water pollution, climatic factors, rainfall frequency, amount of irrigation, groundwater recharge, etc. According to 2019 reports, Qatar, Lebanon, Israel, and Iran are among the most water-stressed nations.

Context and Applications

This topic is taught in various undergraduate and postgraduate degree courses like-

• Bachelors of Technology (Civil engineering, Environmental engineering, Geotechnical engineering, Soil engineering, Mechanical engineering)
• Masters of Technology (Civil engineering, Environmental engineering, Geotechnical engineering, Soil engineering, Mechanical engineering)
• Masters in Science in Water management

Practice Problems

Q 1. How can the paths of the water be traced in an under river flow water resource?

1. By following the water footprints
2. By detecting groundwater storage
3. Water fragmentation
4. Detecting water flow pattern in river basins

Answer: Option a

Explanation: The paths of water for an under river flow can be traced by following the water footprints.

Q 2. What is the other term for under river flow?

1. Basin-wide
2. Savenije
3. Subterranean flow
4. Trade offs

Answer: Option c

Explanation: The other term for under river flow is subterranean flow.

Q 3. Which of the following facility is constructed for groundwater recharge?

1. Dams
2. Infiltration basins
3. Trenches
4. All of these

Answer: Option d

Explanation: To recharge groundwater, several constructions are undertaken like dams, infiltration basins, trenches, etc.

Q 4. Which of the following is intelligent water resources management?

1. Rainwater harvesting
2. Drip irrigation
3. Groundwater recharging
4. Sewage water treatment

Answer: Option a

Explanation: Out of other methods of water resources management, rainwater harvesting is an intelligent way of water resources management. It is majorly used for drinking water purposes.

Q5) What is the abbreviation for GWP?

1. Groundwater purification
2. Global warming potential
3. Global water potential
4. None of these

Answer: Option b

Explanation: The abbreviation for GWP is global warming potential.