The water cycle or the hydrologic cycle is one of the greatest natural processes . It has two significant effects:

1-Effects on climate

The water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate.

2-Effects on biogeochemical cycling

While the water cycle is itself a biogeochemical cycle,[21] flow of water over and beneath the Earth is a key component of the cycling of other biogeochemicals. Runoff is responsible for almost all of the transport f eroded sediment and phosphorus[22] from land to waterbodies.

There are many articles which discusses the human impact on water cycle. here is the effects based on NASA website:

Large-scale human manipulation of water has significantly altered global patterns of streamflow. Resulting changes in sea level, ocean salinity, and in biophysical properties of the land surface could ultimately generate climate feedbacks.

According to a study by Vivien Gornitz (GISS/Columbia), Cynthia Rosenzweig (GISS), and Dan Hillel (University of Massachusetts), human regulation of river flow and vegetation clearing has reduced river runoff by around 324 km3 per year, representing nearly 1% of the total annual streamflow (41,022 km3/yr) and around 10% of the yearly volume of fresh water used by people (3240 km3/yr).

http://www.sciencelearn.org.nz/Contexts/H2O-On-the-Go/Science-Ideas-and-Concepts/Humans-and-the-water-cycle

http://www.giss.nasa.gov/research/briefs/gornitz_02/

The water cycle also known as the hydrologic cycle describes the continuous movement of water on, above and below the surface of the Earth. The total mass of water on Earth remains fairly constant but moves into different reservoirs of ice, fresh water, saline water and atmospheric water. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, etc. such as evaporation, rain, and snow.

A comprehensive detail of water cycle is given here. The image is from USGS (http://water.usgs.gov/edu/watercycle.html)

http://water.usgs.gov/edu/watercycle.html

Dear Saleem,

Is it a poetic question?

The water cycle or the hydrologic cycle is one of the greatest natural processes and indispensable for maintaining life. Unfortunately, the water (a common) became also a product for some corporations and governments and try to commercialize it. Another trouble is that most of industrial and agricultural producers think they have right to pollute surface and ground waters as well as seas and oceans.

The water cycle or the hydrologic cycle is one of the greatest natural processes . It has two significant effects:

1-Effects on climate

The water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate.

2-Effects on biogeochemical cycling

While the water cycle is itself a biogeochemical cycle,[21] flow of water over and beneath the Earth is a key component of the cycling of other biogeochemicals. Runoff is responsible for almost all of the transport f eroded sediment and phosphorus[22] from land to waterbodies.

There are many articles which discusses the human impact on water cycle. here is the effects based on NASA website:

Large-scale human manipulation of water has significantly altered global patterns of streamflow. Resulting changes in sea level, ocean salinity, and in biophysical properties of the land surface could ultimately generate climate feedbacks.

According to a study by Vivien Gornitz (GISS/Columbia), Cynthia Rosenzweig (GISS), and Dan Hillel (University of Massachusetts), human regulation of river flow and vegetation clearing has reduced river runoff by around 324 km3 per year, representing nearly 1% of the total annual streamflow (41,022 km3/yr) and around 10% of the yearly volume of fresh water used by people (3240 km3/yr).

http://www.sciencelearn.org.nz/Contexts/H2O-On-the-Go/Science-Ideas-and-Concepts/Humans-and-the-water-cycle

http://www.giss.nasa.gov/research/briefs/gornitz_02/

The hydrological cycle controls the ecological function of any aquatic system. The ecological characteristic of the Iraqi marshes are controlled by the hydrological cycles of the Tigris and Euphrates Rivers. its starts when the spring freshwater pulse that originated mainly from snow melt in the Turkish and Syrian Montanans enters Iraq. As a consequence, the water level and discharge of the Two Rivers increase and they load the marshes with huge amount of fresh water. In addition, the spring freshwater supply comes with an increase in water velocity and an improvement in water quality. This time of the year is the most important time for the aquatic habitat’s annual life cycle. The spring increase in flow and quality of water increases dissolved oxygen levels. Also, the large volume of water dilutes the salinity and flushes debris from the previous cycle out of the marshes system. Also the suspended component (mainly silt), enriches the marshes with organic matter and nutrients.The effect of the spring pulse gradually fades giving way to dry summer season.

Dear Saleem ,

I think , hydrological cycle is a truth that the importance is clear. So it is important to recognize the cycle and it appears that there is complete relatively recognition.

Thanks for all Bhatti.

The role of the hydrological cycle is broadly divided into two.

1. physical role such as the maintenance of balance between surfac and ground water.

transfer of water on the land , landscape evolution etc.

the second role is bilogical e.g. water supply to the living world,maintenance of the ecosystem etc.