1. Hydrosphere
The hydrosphere (from Greek ὕδωρ -
hudōr, "water"[1]
and σφαῖρα - sphaira,
"sphere"[2]
) in physical geographydescribes
the combined mass of water found on,
under, and over the surface of a planet.
Water cycle
The water cycle, also known as
the hydrologic cycle or the H2O cycle,
describes the continuous movement of
water on, above and below the surface of
the Earth. The mass water on Earth
remains fairly constant over time but the
partitioning of the water into the major
reservoirs of ice, fresh water, saline water
and atmospheric water is variable
depending on a wide range of climatic
variables. The water moves from one
reservoir to another, such as from river
toocean, or from the ocean to the
atmosphere, by the physical processes
of evaporation, condensation, precipitation
,infiltration, runoff, and subsurface flow. In
so doing, the water goes through different
phases: liquid, solid (ice), and gas (vapor).
Surface runoff
Surface runoff is the water flow that
occurs when the soil is infiltrated to full
capacity and excess water from rain,
meltwater, or other sources flows over the
land. This is a major component of the
water cycle, and the primary agent in
water erosion.[1][2]
Surface water
Surface water is water on the surface of
the planet such as in a stream, river, lake,
wetland, or ocean. It can be contrasted
with groundwater and atmospheric water.
Non-saline surface water is replenished by
precipitation and by recruitment from
ground-water. It is lost through
evaporation, seepage into the ground
where it becomes ground-water, used by
plants for transpiration, abstracted by
mankind for agriculture, living, industry
etc. or discharged to the sea where it
becomes saline.
Groundwater
Groundwater is the water located
beneath the earth's surface in soil pore
spaces and in the fractures of rock
formations. A unit of rock or an
unconsolidated deposit is called an aquifer
when it can yield a usable quantity of
water. The depth at which soil pore spaces
or fractures and voids in rock become
completely saturated with water is called
the water table. Groundwater is recharged
from, and eventually flows to, the surface
naturally; natural discharge often occurs at
springs and seeps, and can form oases or
wetlands. Groundwater is also often
withdrawn for agricultural, municipal and
industrial use by constructing and
operating extraction wells. The study of the
distribution and movement of
groundwater is hydrogeology, also called
groundwater hydrology.
Water table
The water table is the surface where the
water pressure head is equal to the
atmospheric pressure (where gauge
pressure = 0). It may be conveniently
visualized as the "surface" of the subsurface
materials that are saturated with
groundwater in a given vicinity. However,
saturated conditions may extend above
the water table as surface tension holds
water in some pores below atmospheric
pressure.[1]
Individual points on the water
table are typically measured as the

2. elevation that the water rises to in a well
screened in the shallow groundwater.
Aquifer
An aquifer is an underground layer of
water-bearing permeable rock or
unconsolidated materials (gravel, sand, or
silt) from which groundwater can be
extracted using a water well. The study of
water flow in aquifers and the
characterization of aquifers is called
hydrogeology. Related terms include
aquitard, which is a bed of low
permeability along an aquifer,[1]
and
aquiclude (or aquifuge), which is a solid,
impermeable area underlying or overlying
an aquifer. If the impermeable area
overlies the aquifer pressure could cause it
to become a confined aquifer.
Plankton
Plankton (singular plankter) are any
organisms that live in the water column
and are incapable of swimming against a
current.[1]
They provide a crucial source of
food to many large aquatic organisms, such
as fish and whales.
Bioremediation
Bioremediation is a waste management
technique that involves the use of
organisms to remove or neutralize
pollutants from a contaminated site.[1]
Technologies can be generally classified as
in situ or ex situ. In situ bioremediation
involves treating the contaminated
material at the site, while ex siti involves
the removal of the contaminated material
to be treated elsewhere.
Upwelling
Upwelling is an oceanographic
phenomenon that involves wind-driven
motion of dense, cooler, and usually
nutrient-rich water towards the ocean
surface, replacing the warmer, usually
nutrient-depleted surface water. The
nutrient-rich upwelled water stimulates the
growth and reproduction of primary
producers such as phytoplankton.
Floodplain
A floodplain or flood plain is an area of
land adjacent to a stream or river that
stretches from the banks of its channel to
the base of the enclosing valley walls and
experiences flooding during periods of high
discharge.
Relative humidity
Relative humidity is the ratio of the
partial pressure of water vapor in an air-
water mixture to the saturated vapor
pressure of water at a prescribed
temperature. The relative humidity of air
depends on temperature and the pressure
of the system of interest.
Reference: wikipedia