Jawaharlal Nehru Technological University Hyderabad B.Tech III GROUND WATER DEVELOPMENT AND MANAGEMENT Previous Question Paper (November/December - 2020 - R16)

The groundwater hydrological cycle, or hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. It is a closed system driven primarily by solar energy and gravity.

The cycle begins with evaporation, where solar radiation heats water from oceans, lakes, and rivers, converting it into water vapor. This vapor rises into the atmosphere, cools, and undergoes condensation to form clouds. Through precipitation, water returns to the Earth's surface as rain, snow, or hail.

Upon reaching the ground, water follows several paths:

1. Infiltration: Water penetrates the soil surface and moves downward through the unsaturated zone (vadose zone).
2. Percolation: Water continues to move deeper through soil pores and rock fractures until it reaches the saturated zone, where all voids are filled with water, forming an aquifer.
3. Groundwater Flow: Due to gravity and hydraulic gradients, groundwater moves slowly through the subsurface toward discharge areas like springs, rivers, or oceans.
4. Surface Runoff: Water that does not infiltrate flows over the land surface into streams and rivers, eventually returning to larger water bodies.
5. Transpiration: Plants absorb groundwater through their roots and release water vapor back into the atmosphere through their leaves.

The cycle is completed as water is again evaporated, maintaining the balance of Earth's water resources. In a neat sketch, one would illustrate the ocean as the primary source, clouds representing condensation, precipitation falling over mountainous and flat terrain, surface runoff feeding rivers, and a cross-section of the subsurface showing the water table, the zone of aeration, and the zone of saturation, with arrows indicating the continuous movement of water between these reservoirs.