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Why do watersheds matter?
A newscaster might announce that a particular creek is flooding. Do you know where that flooded creek is? Do you live near it? Do you drive over it or near it on your way to work, school or activities? Knowing your watershed can protect your family!

Or you might hear that there’s a pollution problem in a particular creek. You could be helping—or hurting—that creek depending on what you do in your yard, driveway or home. 
  • When it rains, watersheds are nature’s way of draining excess storm water.
  • Watersheds supply drinking water.
  • They provide places of natural beauty and for recreation.
  • Each watershed has different pollution problems and flooding concerns.
Torrence Creek and development around it.   In a watershed, what happens on land affects the creeks. And what    
  happens in the creeks can affect the land.

  Pollution and flooding are common ways that land and water affect
  each other in a watershed.

  The types of pollution and amount of pollution in a creek are usually
  influenced by the land around it.

Flooding  is often worse in watersheds with more development and less open space. If excess rainwater cannot soak into the soil, it goes down storm drains and is piped to creeks. Those creeks can spill over their banks, causing flooding on land that’s otherwise dry.

The best way to reduce pollution levels and flood risks is to understand the natural characteristics and manmade development patterns of each watershed

Some local watersheds flow directly to drinking water sources. They are called water supply watersheds and often need additional protection to keep the water clean. Some local watersheds have unique plants and animals including endangered species. To improve water quality and to protect aquatic and wildlife, a management plan is often needed for the entire watershed. See which local watersheds have master plans or water quality recovery plans. 

Making a difference


You can help protect and restore your watershed.

Storm Drain Marking

Volunteer Water Monitoring 

Adopt-a-Stream

Big Sweep cleanup of creeks and lakes

Report water pollution

Prevent pollution at your home, yard or business


Maintain buffers along streams and shorelines

See mapped floodplains in each local watershed