Hydrological Cycle

The hydrological cycle also know as the water cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapor, and ice at various places in the water cycle. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go, in and out of the atmosphere.

The hydrologic cycle involves the exchange of heat energy, which leads to temperature changes. The main energy is the sun, which drives the water cycle, heats water in oceans, seas, and surface. The sun will emit sunshine that carries the heat energy to heat the oceans and surface of the earth. Heating on oceans cause Water evaporates as water vapor into the air or Ice and snow can sublimate directly into water vapor. And heating on surface cause Evapotranspiration is water transpired from plants and evaporated from the soil. Rising air currents take the vapor up into the    atmosphere which caused the drop in temperature accord lifting condensation level, the cold temperature reaches the dew point temperature of the water vapor causes it to form into clouds. Air currents move clouds around the globe, when the heavy clouds containing water vapor so that water vapor will fall as precipitation to the surface of the earth.

The precipitation can falls as rain or some precipitation falls as snow or hail, and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpack’s can thaw and melt, and the melted water flows over land as snowmelt. Most water falls back into the oceans or onto land as rain, where the water flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, with stream flow moving water towards the oceans. Runoff and groundwater are stored as freshwater in lakes. Not all runoff flows into rivers, much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes aquifers, which store freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into surface water bodies (and the ocean) as groundwater discharge. Some groundwater finds openings in the land surface and comes out as freshwater springs. Over time, the water returns to the ocean, where our water cycle started. While the sun still emits sun shines the hydrological cycle will go on continuously until the main energy source (sun) runs out.

The water cycle figures significantly in the maintenance of life and ecosystems on Earth. Even as water in each reservoir plays an important role, the water cycle brings added significance to the presence of water on our planet. By transferring water from one reservoir to another, the water cycle purifies water, replenishes the land with freshwater, and transports minerals to different parts of the globe. So, hydrological cycle is so important and useful for continuity of human life.

By*Maulana Syarif Al-Khafie Satrya