Topic > The hydrological cycle - 985

Water covers 70% of the Earth's surface, of which less than 2% is groundwater which provides 30% of human daily freshwater (Olien, 2005; Wiltz 2011 ). Water is one of the essential goods that all living organisms need to survive. The absence of water kills. It is one of the most unique and mysterious elements on earth that is renewable if managed abstinently. Hydrological cycle, describes how water moves around the earth in an infinite circle from the ocean to our atmosphere. According to Das (n.d.), the process of converting water from the liquid or solid phase to the vapor phase is known as the 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 are a total of five crucial steps in the hydrological cycle: condensation, precipitation, infiltration, runoff, and evapotranspiration (refer to Figure 1 in Appendix 1). The hydrological cycle begins with the condensation phase. Water vapor is the gaseous form of water present in the surrounding atmosphere. This water vapor tends to condense and remains suspended in the form of tiny droplets. Water molecules combine with dust, smoke and other tiny particles in the air to form cloud droplets. They then increase in size and develop into clouds that can be held in the sky. Cooling of warm, moist air is the main reason for condensation of water vapor. According to Chhatwal et al. (1989), there are three main factors that determine cloud formation. The most important cause of condensation is due to masses of warm, moist air moving towards areas of cold air. The second mechanism is mainly caused by the lower density... half the paper... logical loop. 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 hydrological cycle. Retrieved from http://geography.about.com/od/physicalgeography/a/idrologiccycle.htm.Sneed, J.D. (n.d.). Types of precipitation. 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 rainwater. Retrieved from http://www.livestrong.com/article/179964-importance-of-rain-water/.Yong, R.N., Mulligan, C.N., & Fukue, M. (2007). Geo-environmental sustainability. Boca Raton, Florida: Taylor & Francis Group, LLC.