Deforestation leads to reduced rainfall because it leads to reduction in natural recycling of moisture from the soils. This recycling takes place through vegetation and returns back in the form of rainfall.
According to studies, when forests are replaced by pastures, water recycle gets affected which leads to reduction in humidity in atmosphere which has an impact on the precipitation.
Deforestation also means that the level of carbon dioxide in the atmosphere increases giving rise to global warming. Increase in global warming has adverse effects on natural water cycle.
Deforestation also leads to floods. This is because the water holding capacity of the soil is dependent on the number of trees. As the number of tresses reduces, the soil structure changes and the soil the particles that are held firmly gets disturbed. When there is heavy rainfall, the rain water does not seep down into the ground and is not absorbed by the tress. Hence, it leads to flooding.