The San Gabriel River Watershed includes 1,236 miles of streams stretching from the San Gabriel Mountains to the Pacific Ocean and supports a population of more than 2.3 million people. Protection and management that ensures the sustainability of this unique resource requires an understanding of the watershed's overall health and the human and natural stressors that affect its condition. The San Gabriel River Regional Monitoring Program (SGRRMP) was developed as a collaborative effort to assess the health of San Gabriel River Watershed . The motivation for this program came from the Los Angeles Regional Water Quality Control Board (Los Angeles Water Board or LARWQCB) using a unique permit condition for the Los Angeles County Sanitation Districts (LACSD) that initiated a monitoring program designed to increase awareness of issues at the watershed scale.

Since 2005, the SGRRMP has performed rigorous, scientific monitoring at sites distributed throughout the watershed including the mountainous upper watershed, the highly urbanized lower watershed and the concrete-lined mainstem channel.

By providing a framework for monitoring at the watershed scale and working with stakeholders to establish a question-based monitoring approach, the SGRRMP aims to provide regional information specifically designed to answer the five key management questions:

1. What is the condition of streams in the watershed?
2. Are conditions at areas of unique interest getting better or worse?
3. Are receiving waters near discharges meeting water quality objectives?
4. Is it safe to swim?
5. Are locally caught fish safe to eat?

A specific monitoring design was established for each of these questions that included a set of parameters to be measured and an analysis approach to help managers answer these questions.

The SGRRMP has successfully shown that by striving to answer these essential management questions, regional context is provided to local monitoring and management programs, while also improving monitoring efficiencies.