Water Quality

Human population growth and development throughout San Diego County has led to significant habitat loss and a reduction in watershed ecosystem services. As water flows through our neighborhoods, it picks up pollution from yards (fertilizers and pesticides), streets (oil and grease), and walkways (trash and pet poop), and carries the pollutants throughout the watershed.

Today’s polluted water no longer encounters the cleaning services that wetlands used to provide. Over the past 200 years, nearly 85% of Southern California’s wetlands have been destroyed. With fewer wetlands, the job for those that remain is bigger and more challenging. Too much pollution and trash can overwhelm wetlands’ cleansing abilities and destroy their usefulness. This disrupts the lives of the plants and animals living there, and ultimately affects the health of habitats throughout the watershed.

Ecosystem health is crucial to ecosystem services. Scientists and technicians use different tests to measure a watershed’s health, just like doctors use different tests to measure your health. One way to determine the health of a watershed is to monitor the water quality.

Almost everything we do affects water quality. When the physical, chemical and biological components of water are altered, it causes the watershed to become unhealthy. There are a number of different measureable characteristics of water that can give us clues to a watershed’s health including ambient measurements (temperature, pH and dissolved oxygen) and pollutants (nitrate and phosphate). As you visit the different sites included in this program, you will observe and record these measurements to determine water quality and overall health of the San Dieguito Watershed.

Since everyone lives in a watershed, everyone affects the quality of the water. We all have a responsibility to protect our limited freshwater resources and the ecosystem services they provide. By caring for and protecting our watershed, we’re helping care for the ocean as well. It’s critical that we keep the water in our watersheds flowing clean and healthy.