Intrusion into the Water Cycle:
Water management is one of the leading concerns of man today. The natural water cycle has not been able to compensate for the effects of human actions on water resources. The amount of water that is fit for human consumption has decreased over the years and its quality has deteriorated. To a large extent this is due to increased population, higher demands of water for personal use, agriculture and industry.
Foremost in the list of detrimental effects of human activity is deforestation, that is the indiscriminate cutting of trees and the ultimate depletion of the vegetation cover. Extensive use of paper, and of wood for construction and fuel is responsible for this. Deforestation, not only reduces the humidity in the atmosphere but also leads to a chain of other undesirable effects, for instance, the vegetation that helps to hold the soil together, when reduced considerably, is not able to hold the top soil in place. This eventually results in washing away of fertile, top soil during rainfall or by blowing winds, thus exposing harder infertile rocks. Not much water seeps down the hard soil, and the underground water reservoirs are not ~roperly replenished. The loosely bound soil is carried along by water running on its surface, and is ultimately deposited in river beds and dams, thus choking them.
The other human activities that disrupt the water cycle are: concentration of population in big industrial towns; lack of proper sanitary facilities, and disposal of wastes. Domestic and industrial wastes are often rcleased intb the water streams, sometimes adversc ,effecting lire in the water. The antidote of deforestation is afforestation, i.e., plantation of new trees. For this, it is very important to know what kind of plant would be suited for a particular condition if no attention is paid to this aspect, we may further increase the damage to our envircnent. Eucalyptus is one example in this regard. It is one of the economically important and fast growing trees. It was planted as a soil binder and wind breaker in places where there was need of water conservation. The choice of Eucalyptus proved disastrous as this plant is notorious for its high rate of water intake from the soil and subsequent loss to the atmosphere. Many people also call this plant an "ecological monster", as it drains the water table and prevents all other plants from growing underneath. It also makes cultivation on neighbouring lands impossible.