Mount Diablo Creek Volunteer Monitoring Report, Spring 2006
By Lisa Anich, Friends of Mount Diablo Creek

Our volunteer water quality monitoring program is off to a great start thanks to volunteers Dianne Malucelli, Lois and Roger Willhite, and Dlorah Whitmire.

We have tested the creek at six locations for coliform bacteria, temperature, pH, conductivity and dissolved oxygen. The summary of results is attached as a Word document.

Coliform Bacteria

Measured levels of coliform bacteria were low. That's what we would expect for the high flow season. The e. coli bacteria counts ranged from <10 for Mitchell Creek within the State Park to 260 for Mount Diablo Creek at Port Chicago Highway.  For comparison, California's criteria for contact recreation (swimming, etc) is 200 and the standard for non-contact recreation is 2000. We tested the creek weekly between February 23 and March 23, 2006.

Other Water Quality Indicators

The conventional water quality parameters (temperature, pH, conductivity and dissolved oxygen) indicate that the creek is generally healthy.

It is surprising that Donner Creek has the highest pH values of any of our sampling sites. We have not pinned down the cause yet. It doesn't seem to be soils and geology: the soils of Donner Creek watershed are slightly acidic (low pH), and many of Mount Diablo's springs are known to be acidic. We would not expect the upper Donner Creek watershed to have much impact from human activities. We've measured pH values from 8.35 to 8.4 in March, April and May at Donner Creek near the boundary of Mount Diablo State Park. Most aquatic organisms do best in water with pH between 6.5 to 8.5. At pH levels beyond this range (lower or higher) aquatic organisms will be stressed.

Want to Help? More Sampling Dates to Come:

Conventional parameters are tested monthly. Upcoming dates are on Saturday mornings, June 17, July 15, August 12.  We'll be testing the creek for E. coli concentrations during low-flow conditions in July and August.

If you are willing to help with our volunteer creek monitoring efforts please contact Lisa Anich at (925) 689-2642 or glanich@california.com.