The Hydrologic Cycle

Water covers 70 percent of earth’s surface area, in which less than 2 percent is ground water that provides 30 percent of human daily fresh water (Olien, 2005; Wiltz 2011). Water is one of the essential necessities needed by all living organisms to survive. Absence of water kills. It is one of the most unique and mysterious elements on earth that is renewable if it is managed abstinently. Hydrologic cycle, describes the way in which water moves around the earth in an endless circle from the ocean to our atmosphere. According to Das (n.d.), the conversion process of water from liquid or solid phase into the vapor phase is known as hydrologic cycle. Hydrology involves not only the movement of water, but also its geomorphic, geochemical and biological processes (Dunne & Leopold, 1978). Yong, Mulligan, and Fukue (2007) mentioned that there is a total of five crucial steps in the hydrologic cycle namely condensation, precipitation, infiltration, runoff and evapotranspiration (refer to Figure 1 in Appendix 1).

Hydrologic cycle begins with condensation phase. Water vapor is the gaseous form of water presents in the surrounding atmosphere. This water vapor tends to condense and becomes suspended in the form of tiny droplets. Water molecules combine with dust, smoke and other tiny particles in the air forming cloud droplets. They then increase in size and develop into clouds which can be retained in the sky. Cooling of warm, moist air is the main reason for condensation of water vapors. According to Chhatwal et al. (1989), there are three main factors of cloud formation. The most important cause for condensation is due to the masses of warm and moist air that move into areas of cold air. The second mechanism is mainly caused by lower densi...

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...ogic cycle. Retrieved from http://www.nasa.gov/audience/forstudents/5-8/features/Observatorium_Feat_5-8.html.

Olien, R. (2005). The water cycle. Mankato, MN: Capstone Press.

Rosenberg, M. (n.d.). The hydrologic cycle. Retrieved from http://geography.about.com/od/physicalgeography/a/hydrologiccycle.htm.

Sneed, J. D. (n.d.). Precipitation types. Retrieved from http://inside.mines.edu/fs_home/jsneed/courses/LISS.380-83/LISS.380/syllabus/week.1/session.1/climate/precipitation/types/index.shtml.

United States Geological Survey (n.d.). The water cycle. Retrieved from http://water.usgs.gov/edu/watercyclegwstorage.html.

Wiltz, J. (2011). Importance of rain water. Retrieved from http://www.livestrong.com/article/179964-importance-of-rain-water/.

Yong, R. N., Mulligan, C. N., & Fukue, M. (2007). Geoenvironmental sustainability. Boca Raton, FL: Taylor & Francis Group, LLC.