25-Influence of growing environmental pollution on the natural hydrologic cycle.

Abstract

This paper describes the influence of environmental pollution on the components of the hydrologic cycle. Water pollution in the form of dissolved solids (organic or inorganic) and oils decrease the rate of evaporation from the hydrosphere into the atmosphere. Widespread destruction of forests by man-made activities reduces the magnitude of transpiration into the hydrologic cycle. The urban heat island creates thermally induced upward motions that act to diminish the atmospheric stability. Air pollutants introduced into the atmosphere through industrial, energy production, and transportation processes, have a strong attraction for water vapour which condenses and freezes on them forming ice crystals which in turn form clouds. If sufficient moisture is there, cloud droplets grow in size and eventually fall as precipitation. However, increased particle concentration due to high atmospheric pollution will result in a large number of cloud droplets of smaller size, which do not coalesce as readily as bigger cloud droplets and by this the intensity of precipitation may be hindered. Increased industrial, urban construction and excessive dumping of solid and liquid wastes in the soil modify the surface properties and causes changes in rates of runoff and infiltration.