3. Sampling and identification regime

Pathogen species and strains need to be identified to a resolution that permits 1) identification of sources/potential sources and 2) adequate protection of public health.

3.1 Current sampling regime

The Regional Board has historically focused on swimming beaches along the middle and lower reaches of the Russian River. Other programs, conducted by the CCWI, SCWA, and Russian River-keeper monitor bacteria in tributary waterways and watersheds. The Regional Board has used this sampling program to monitor compliance with the Basin Plan and not to directly measure recreational exposure or forensically identify sources of contamination.

In virtually all cases, the sampled medium was the water column. In exceptional cases, including one special study for this report, other media have been studied.

Sample collection has been through grab sampling using sterilized 100 ml bacteria bottles. Samples are stored on ice for up to 4 hours, until delivery to the laboratory for analysis. Prior to 2002, concentrations of total and fecal coliform bacteria were determined using the multiple tube fermentation method; from 2002 onward, total coliform and E. coli concentrations were determined using the Colilert © Quanti-Tray method. In 2006, Enterococcus concentrations were also determined using a similar method – Enterolert ©.

3.2 Sampling Intensity

Sampling and identification of fecal coliform bacteria (including E. coli) have occurred irregularly over the last decade (Figure 5) and unevenly over the watershed (Figure 4). Temporally, sampling has been throughout the year, with the most focus on summer sampling along the Russian River and wet season sampling in tributaries near urban areas.