The branch of science which studies the distribution of water as well as its quality and movement is known as hydrology. It is also involved in the collection and analysis of data for solving water related problems like natural disasters and wastewater treatment. Some of the different areas studied within this field are water cycle, environmental watershed sustainability and water resources. There are various sub-disciplines within hydrology such as groundwater hydrology, marine hydrology, chemical hydrology, isotope hydrology and hydrogeology. This discipline finds application in a variety of areas like in determining the water balance of a region, providing drinking water and designing bridges. The book aims to shed light on some of the unexplored aspects of hydrology. It presents this complex subject in the most comprehensible and easy to understand language. This textbook will serve as a reference to a broad spectrum of readers.