San Gabriel River Regional Monitoring Program

Key Questions

Question 1: What is the condition of streams in the water?

Parameters measured to assess the condition of streams in the watershed include water chemistry, biological condition, physical , riparian zone condition, and toxicity testing. These parameters combines multiple lines of evidence to provide stream condition information on a watershed wide basis. In addition, it is hoped that by measuring water chemistry and streambed physical habitat we might begin to learn what habitat status favors good biological condition over poor biological condition.

This sampling program has been conducted annually in the summer months from 2005 to present, with 90 sites sampled over that time period.

Question 2: Are conditions at unique sites changing over time?

This question is focused on assessing if conditions have changed over time at locations the workgroup deemed to be of unique interest. These locations included eight stream confluence sites on major tributaries to the San Gabriel River; three sites in the San Gabriel River Estuary; five bacteria sentinel sites in the lower watershed; and, four riparian and wetland locations in the lower watershed. These sites were revisited each year since 2006 to assess trends in water quality, biotic, and riparian zone condition. To learn more about this program go to any of the Annual Assessment Reports under Publications and Presentations, Chapter 2, on this website.

Question 3: Are receiving waters downstream of discharges meeting regulatory requirements?

This question was answered using routine NPDES monitoring data collected downstream of five Los Angeles County Sanitation Districts (LACSD) waste treatment facilities (POTWs). This question assesses the potential impacts from these point source discharges into the San Gabriel River and its tributaries. To accomplish this, 2015 NPDES receiving water data was evaluated against regulatory thresholds for E. coli, ammonia, dissolved metals, and trihalomethanes. To learn more about this program go to any of the Annual Assessment Reports under Publications and Presentations, Chapter 3, on this website.

Question 4: Is it safe to swim?

The parameter measured to assess swimming safety includes a fecal indicator bacteria (FIB) called E. coli. The presence of E. coli in a water body indicates fecal contamination may have occurred, especially as the concentrations increase above State of California recreational standards (AB411).
The SGRRMP has measured E. coli at up to nine recreational swim sites located in the upper watershed, five times per month, from May to September each year since 2008.

Question 5: Is it safe to eat fish?

Parameters measured to assess fish consumption safety include tissue concentrations of mercury, arsenic, selenium, DDTs, PCBs dissected from sportfish located at popular swim sites. The concentrations of these constituents are compared to State of California consumption thresholds to determine if they are safe to eat.
Since 2008 fish have been collected from 6 fishing sites and analyses have been performed on 13 species.