Natural water resources are facing extreme stress, especially in dry areas, due to growing water demand and changing climate/rainfall patterns. This is true for both the surface (rivers, storage reservoirs behind dams, etc.) and sub-surface (aquifers) sources of water.
With an increasing population and industrialization level, the water demand is ever increasing, leading to higher withdrawal rates from existing water resources and exploitation of new ones. It is very common in dry areas to supplement surface water supplies with groundwater wells. This situation is a perfect example of excess harvest and low recharge that leads to a drop in the groundwater table and reduced reservoir levels.
These problems are exacerbated by climate change, which leads to higher temperatures resulting in increased evaporation from surface sources. Hot weather also leads to an increased demand on water for various applications. Additionally, hot weather is also conducive to the growth of flies, mosquitoes and pathogens and faster organic reactions, thus causing contamination in natural sources if wastewater is disposed of without appropriate treatment. Higher temperatures and increased water exploitation from surface sources will leave less water for the recharging of aquifers, which would already be stressed by over-exploitation to meet higher demands.
Thus climate change will ultimately stress our water resources. Already in some countries the minimum flow conditions are not being met in most of the rivers and the water table is rapidly falling.
As the world grows bigger so does the demand for goods like water grow. Although water is a renewable source only 1% of the worlds water is drinkable/ accessible. Also with the increased amount of pollution temperatures has risen as well as the amount of acid rain. Acid rain is the cause of at least 75% of acidic lakes, ponds, and etc and this causes water to become undrinkable and thus un-useable to the growing population especially dry areas.
The growing demand for water affects areas that are natural resources of water for it drains them of the water that they have. Living organisms that live within those waters are having their homes taken away from them as a result. In dry areas, most likely the water would come from the ground. If that is so, then plants that rely on that water source would slowly die out. The decrease in the number of plants affects organisms that rely on the plants as a food source, further affecting the food chain and web.
Climate change (global warming) has affected dry areas in that it has caused less rainfall. Less rainfall affects the growing demand for water in that it increases it, since there is less water available for people to drink. It also affects living organisms as well, as said before. Lack of water causes them to die out.