Water always runs downhill due to the pull of gravity. This is what creates a watershed. A watershed, or “catchment area,” is the region defined by this flow of water from higher elevations to lower. The water collects in underground aquifers and in surface streams that flow into rivers, lakes, and eventually oceans. The good quality and correct quantity of this water are essential to a healthy environment.

Most of the water comes from precipitation. In order for the land to absorb rainwater and replenish aquifers, the soil must be kept loose and rich in organic material. Plants such as trees, grass and other ground cover take a vital role in this process. Their roots break up the soil, and the leaves they shed provide important organic matter.

Wetlands are an essential part of the watershed. Here the water does not rush downhill the way it does in a stream. It moves very slowly and gradually filters through the soil and around the roots of plants to replenish aquifers. This process of filtration purifies the water, removing harmful chemicals, particulate matter and bacteria.

Watersheds provide drinking water, irrigation for farmland, support for ecosystems, water transportation, recreation and aesthetic beauty.

When the natural ground cover is removed and replaced with concrete or asphalt, this filtration system is seriously compromised. Properly managing watersheds is vital to our communities and the region as a whole.

Did you know?
Watersheds provide us with many vital services every day – at no cost! This is sometimes referred to as green infrastructure or natural capital.  Some of the services watersheds provide include:

  • Recharge our water supply and help with droughts by collecting rainwater which flows underground into our aquifers – supplying residents and communities as well as agriculture and businesses with their water needs.
  • Slow down water to prevent flooding and control erosion that can harm our fresh and ocean water bodies.
  • Serve as recreational and educational places for communities and schools
  • Protect public health by providing clean water and air as well as absorbing climate-damaging greenhouse gases
  • Provide support to important wildlife and ecological functions

WP Glossary Term Usage