Rainwater harvesting is a way of capturing and storing water during rainy periods for use in times when there is little to no rain available. In certain regions of the world, rainwater harvesting can be the difference between having a plentiful crop and dried up vines. There are several objectives behind rainwater harvesting.
Increase Available Water During Dry Season
Many ecosystems have wet and dry seasons. Because the dry seasons can consist of weeks or months of little to no rain, it is important to capture during the rainy season and have it available for use during the dry season. Rainwater harvesting enables you to store rain when it is prevalent to be used when there is no rain.
Reduce Flooding and Erosion
By capturing and storing large amounts of rainwater in reservoirs, it is possible to reduce the amount of runoff and limit the impact on the land of large rainfalls. By capturing rainwater you are basically reducing the amount of water that is flowing across the land, which reduces flooding chances and the impact of erosion.
Prevent Overuse of Aquifers
As cities and towns grow the need for water increases. Many municipalities rely upon aquifers deep below the ground for this water supply. The problem is it takes a long time to replenish an aquifer if it is quickly drained. By harvesting rainwater for later use, the demand on aquifers is reduced, which enables them to remain full.
Pumping water up from underground aquifers can be a fairly expensive operation. It is estimated that for every one meter rise in water level, there is a reduction of 0.4 KWH of electricity usage. So by having water closer to the surface, or at the surface in reservoirs, less electricity is needed to pump it so less money is spent.