Factors affecting water supply

Freshwater is found around the globe, in rivers, lakes and underground. However, there are several factors that affect how much freshwater is available for use - the water supply. Some of the factors are natural. These include climate, rocks and landforms, and natural events such as earthquakes, droughts, or floods. Climate plays a major role.

Temperature, the amount of rainfall and the amount of sunlight, all affect how much water, water sources can hold and how fast the sources refill. In areas where there is little rainfall, or where it’s hot and water evaporates quickly, there is not much water available. And where it’s colder, and it rains or snows more often, water is more abundant. When rain falls in an area, types of rock and landforms there affect what happens to that rainwater. Some types of soil and solid rock let the water seep through.

Some don’t. Because of this, water collects in different places, above ground and underground. This makes freshwater more, or less, easy to access. Earthquakes might cause new cracks in the ground and underground, through which water can seep. As a result, the level of groundwater often drops after an earthquake.

This makes it more difficult to draw water from wells. When there is suddenly very little or no rain at all, for a long period of time - during a drought, there is also less water available. Since water above ground or underground is not refilled, the water level starts to drop, and water can become scarce. When there is heavy rainfall though, or a lot of snow and ice thawing at once, water levels can rise suddenly and rivers overflow. This is called a flood.

A flood can damage pipes and other elements of infrastructure which deliver water to buildings. Many factors that affect water supply negatively are caused by human activity. The amount of water on Earth doesn't change, but the number of people is growing. And we use water for more and more purposes too. Industry, farming, and even transportation require more and more water from surface and groundwater sources.

If we extract water faster than it is refilled, water levels drop, and this might lead to water shortage. Imagine there are two towns by a small river, one upstream, close to the mountains where it rains a lot, and one downstream closer to the sea where the climate is very hot. There is normally enough water in the river to supply both towns. But if the town upstream by the mountain starts drawing a lot of water for farms, factories and private use, the water level in the river will drop. The little water left evaporates, and the river dries up before it even reaches the other town.

People there by the sea are left without a source of freshwater. This, in turn, probably leads to a conflict between the two towns. Another factor that affects water supply is pollution. Chemicals used in production plants or in farming might leach into the water sources and contaminate them. Such water is no longer safe for drinking or to use for many other things.

Although many places have the technology to purify water, it’s not available everywhere. Clean freshwater is essential to our lives. We need to make sure that there is enough water for everyone. We can only achieve this if we use our water resources in a responsible and sustainable way.