HYDROLOGYLET US GET STARTED

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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)

HYDROGICAL CYCLE

Precipitation and evaporationIn 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.

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

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MAJOR RESERVOIRS OF WATER

[does not add to 100% due to rounding, numbers differ slightly depending on study used]

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].

THE LAKE ARAL DISASTER

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