2. 2
WHAT IS HYDROLOGY ?
Hydrology is the study of the movement, distribution, and quality of water
throughout the Earth, including the hydrologic cycle, water resources and
environmental watershed sustainability. A practitioner of hydrology is a hydrologist,
working within the fields of either earth or environmental science, physical
geography, geology or civil and environmental engineering.
Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology,
drainage basin management and water quality, where water plays the central role.
Oceanography and meteorology are not included because water is only one of
many important aspects.
Hydrological research can inform environmental engineering, policy and planning.
Water covers 70% of
the Earth's surface
(from Wikipedia)
4. Precipitation and evaporation
In some considerations, hydrology is thought of as
starting at the land-atmosphere boundary and so it is
important to have adequate knowledge of both
precipitation and evaporation. Precipitation can be
measured in various ways: disdrometer for precipitation
characteristics at a fine time scale; radar for cloud
properties, rain rate estimation, hail and snow
detection; Rain gauge for routine accurate
measurements of rain and snowfall; satellite – rainy
area identification, rain rate estimation, land-cover/land-
use, soil moisture.
5.
6. HYDROLOGY | themes | groundwater & soil water
“Water beneath the land
surface that fully
saturates the pores in
the ground is called
groundwater”
“Water stored in the
unsaturated zone above
the water table is called
soil water”
Topics
• Aquifers
• Darcy’s Law
• Soil moisture
• Capillary rise &
evaporation
• Infiltration &
percolation
7. 7
MAJOR RESERVOIRS OF WATER
[does not add to 100% due to rounding, numbers differ slightly depending on study used]
8. Floods cause extensive damage: “during 1991-1995,
flood related damage totaled more than US$200 billion
(not inflation adjusted) globally, representing close to
40% of all economic damage attributed to natural
disasters in the period -- (Pielke Jr. and Downton,
2000, citing IFRCRCS, 1997). In the United States,
annual flood damage runs in the billions of dollars
(Pielke Jr. and Downton, 2000). Improved prediction of
floods could reduce these costs substantially, in
addition to reducing flood-induced loss of life.
FLOODS
Damage survey in St. Genevieve, Missouri,
during the 1993 Midwest floods [courtesy of FEMA].
