Rainfall and other forms of Precipitation

In addition to controlling gully erosion, check dams also serve to slow the movement of water, allowing increased percolation into the soil. Just above a check dam is a good place to put in a percolation structure. Silt that builds up behind the dam creates good farmland, which can be planted after the rains while it retains moisture. The following series of pictures show one farmer’s success with building a percolation tank just upstream of a series of check-dams.

This presentation by Arghyam deals with filters used in a rainwater harvesting system as also in other sources to remove suspended pollutants from rainwater collected. In a rainwater harvesting system, the water comes in contact with several surfaces, such as the roof or gutters. Water sources too are contaminated by various minerals and chemicals. These affect the colour, odour, taste and composition of water.Its flow becomes possibly mixed with leaves or dust.

This document describes the drought situation in India over the years, the earlier perspective at drought management and the gradual change in perspective at managing droughts that evolved over the years.

Climate Change is a significant change in temperature, wind patterns and precipitation that occurs over a long period of time. Some of these changes occur in cycles over decades, hundreds, thousands and millions of years; some could be random occurrences.

Agriculture is a vital sector in India with about 60% of the population engaged in agricultural vocations and contributing to about 30% of the GDP. It consumes about 80% of water used in the country and 76% of the net irrigated area in the country is from ground water sources.

The heat evaporates the moisture in the soil rapidly leading to widespread drought conditions. The changes in ocean temperatures are modifying the ocean currents, thus creating erratic and extreme weather conditions - creating more intense and frequent storms and cyclones; thus creating cycles of floods and drought.

Global warming induces an increase in global precipitation through the augmentation of evaporation. According to the IPCC, rainfall patterns are likely to be modified with some regions becoming more arid and others experiencing more rainfall.

As observed by the United Nations Environment Program (GRID-Arendal) ice and snow are major components of the climate system. That is why human induced climate change can be first observed in Polar Regions where most of Earth's snow and ice are concentrated. In these areas global warming induces the progressive melting of ice and snow.

Altered frequencies and intensities of extreme weather, together with sea level rise, are expected to have mostly adverse effects on natural and human systems.

The earth is currently warming rapidly. And this warming is bringing about massive changes. Our glaciers are melting rapidly. The artic ice-shelf is breaking apart into pieces and threatens to modify the salinity of the oceans.