The surface water is the water on the surface of the earth. This includes the streams, rivers, lakes, bays and so on. It is one of the many forms of water on earth such as groundwater, which is water located beneath the surface of the earth. Water undergoes a hydrologic cycle. It moves on, above, and under the surface of the earth from one phase to another through different ecological processes such as precipitation, evaporation, transpiration, condensation, percolation, runoff, subsurface flow, etc. For instance, transpiration from plant metabolism turns liquid water to vapor. Surface runoff, which is the flow of water over the earth's surface, is essential in the hydrologic cycle in a way that it replenishes water reservoirs such as lakes and streams. Thus, it is important that water pollution is prevented since the pollutants carried through are also being moved via surface runoff. Apart from runoff, naturally-flowing water forms such as rivers tend to fill other water reservoirs such as seas and oceans. Water pollution is capable of disrupting the ecological balance in the ecosystem and affect the living organisms thriving on these habitats.