Guide to Hydrological Practices  

Hydrology is the science that deals with the occurrence
and distribution of the waters of the Earth in
time and space, both above and below the land
surface, including their chemical, biological and
physical properties, and their interaction with the
physical environment (WMO/UNESCO, 1992). It
provides an understanding of various phases of
water as it passes from the atmosphere to the Earth
and returns to the atmosphere. As such, it forms the
basis for water resources assessment and management
and the solution of practical problems relating
to fl oods and droughts, erosion and sediment transport
and water pollution. Increasing stress on the
available water resources in the search for improved
economic well-being and concerns for the pollution
of surface water and groundwater have
highlighted the central role of hydrology in all
water and environment initiatives.