How Safe is the Water in San Leandro Creek?

Cal State researchers find high levels of fecal bacteria in upper reaches of the creek, while an EBMUD biologist says much of the creek may be irreparably damaged.

San Leandro Creek has suffered the same fate as many urban creeks in the last century — with the onslaught of development and its natural channels manipulated, it began to function ecologically much differently than in the past. 

Today, the most pristine portion of the creek is in its upper reaches, near the unincorporated community of Canyon, which is nestled between Oakland and Moraga. There the creek channels are natural and experience a limited urban influence.

But when researchers from CSU East Bay sampled water from that area last year, they found evidence of fecal pollution that sometimes exceeded state guidelines.

The creek, a protected watershed, flows from the eastern slope of the hills near Oakland's Huckleberry Botanic Regional Preserve. It runs southeast through Canyon before joining Upper San Leandro Reservoir and then Lake Chabot, two bodies of water owned by the East Bay Municipal Utility District (EBMUD).

It then flows west through San Leandro and on into San Leandro Bay at Arrowhead Marsh, just north of Oakland International Airport.

The study on the health of upper San Leandro Creek was conducted by CSU East Bay biologist Dr. Stephanie Molloy and graduate student Kathy Seiber.

Between October 2009 and May 2010 they sampled water 10 times, five during rain conditions and five when there had been no precipitation for at least 24 hours. Bacteria indicating the presence of fecal matter were found in all samples. The bacteria levels were higher after rain events, and highest overall upstream of Canyon.

For the sampling events last September and October, the team found levels of E. coli and Enterococcus, both bacteria that live in human intestines, exceeded maximum guidelines for recreational fresh water established by the California Department of Public Health. 

The findings could be due to environmental runoff from less forested land cover, the researchers postulate. Other studies have shown that fecal indicator bacteria levels in creeks and streams are affected by land use, with urban and agricultural areas having higher numbers than forested land, Molloy said.

A genetic marker for ruminant fecal bacteria was not detected in any samples. (Ruminants include cattle, goats, sheep and deer, among other animals.)

The researchers also suspect the pollution is partly caused by runoff from septic systems near Canyon, Molloy said, although they couldn't prove their hypothesis because they weren't allowed to test that water, she said.

Bert Mulchaey, an EBMUD fisheries and wildlife biologist who works extensively in the creek watershed near Canyon, said that although he hadn't read the study, he also suspected septic systems could be the source of the contamination. The water district has in the past found similar issues with fecal pollution in the area, he said.

EBMUD’s master plan, adopted in 1996, says of the watersheds near San Pablo and Upper San Leandro reservoirs: “Runoff samples have extremely high amounts of fecal bacteria, as is typical of developed watersheds.”

Mulchaey participated in a forum last month on the health of San Leandro Creek sponsored by Friends of San Leandro Creek. About 20 residents and high school students attended the meeting, held Feb. 19 at the .

At the forum, Mulchaey said biologists with the agency test water quality in the watershed primarily by conducting fish and bug sampling. Though fish species are struggling in other, more urban areas along the creek, they are actually thriving in its upper regions, Mulchaey said. That includes native species like rainbow trout. 

“But it’s definitely an issue of public health,” he said of the study showing high fecal bacteria in the creek.

Friends of San Leandro Creek also tests water quality monthly at a site near Lake Chabot. Laurey Hemenway, watershed awareness coordinator for the group, said she tests pH, oxygen and nitrate levels, temperature, depth and turbidity (how clear the water is). 

Hemenway said the results usually show acceptable water quality, although there have been exceptions,  as in February when she tested the water and found the pH and dissolved oxygen levels were abnormally high.

According to Mulchaey, the area from the Chabot dam to I-580 is pretty much the only viable habitat for fish species in lower San Leandro Creek, and that may be because the water in the lake itself does not come from local sources.

About 90 percent of the water in the agency's reservoirs, including Lake Chabot, is piped in from the Mokelumne River, which is fed pure water from melted snow in the Sierra Nevada mountains.

"San Leandro Creek obviously has significant problems with pollution. Most Bay Area creeks are in the same boat," Mulchaey said."Most of the damage was done a long time ago."

Biologists with EBMUD are focusing their energy on areas of local creeks that are more natural, which have a greater chance of reestablishing native ecosystems.

But while Mulchaey said the situation looked bleak for the creek as a whole, if government and the public do their part to manage its health, "hopefully we can improve the  habitat and range of these fish species."

In the early 1990s, the Oakland Museum of California published a report on East Bay creeks. Included is a written guide to a tour of San Leandro Creek.

Wayne Gregori March 18, 2011 at 02:34 PM
Great story Jennifer. I've been curious about San Leandro creek for some time and I thoroughly enjoyed reading it and following your research. There's talk about taking down damns throughout the state to restore water ways... do you know how important Chabot Lake is as a source of drinking water?
Fran March 18, 2011 at 05:02 PM
If, in fact the septic systems are not the cause, it would be helpful if they suggested what some other causes of the contamination may be.
ken March 18, 2011 at 08:10 PM
Live in the Bay Area my entire life 60+ years and have never heard of "Canyon"
Jennifer Courtney March 19, 2011 at 03:21 AM
Neither had I until about a year ago, when my dad wanted to take me through "the old country roads we used to drive on all the time back in the day" in the Chevy Nova he had just got. Except it was dark and very foggy and I pretty much feared for my life. But we passed a post office and I googled it and that's how I found out we were in the small alternative community of Canyon. http://sanfrancisco.cbslocal.com/2011/02/11/eye-on-the-bay-road-to-nowhere-canyon-21411/
Brian Coyle March 19, 2011 at 08:10 AM
Only environmental research studies that show negative impacts tend to be published. I point this out because the graduate student's research in the creek was presented to the Canyon community as completely inconclusive, yet when presented to a conference the significance was huge. The Canyon Elementary School board found this surprising, because the graduate student's supervisor Stephanie Molloy claimed she wanted to test community water systems to show they weren't the source of contamination. It was only by accident we found the student's project posted at a conference, where the tone was different. She said the community contamination was definite, despite results that were ambiguous, with no community samples. Arguably, the academic system pushes researchers to say they've uncovered something major, viewed as more interesting and citable. If the graduate student didn't find human contamination, she wasn't going to get attention. Originally Canyon supported the research, which we were told would have results shared with us. That hasn't happened; instead we find it in the media. Molloy told us the real excitement behind the study was testing a new genetic technology, whose output was still uncertain. It's bad enough being a guinea pig for new tech toys, but now her reports exaggerate findings at out expense. Perhaps this is a bit unethical, no?
Jennifer Courtney March 19, 2011 at 07:58 PM
Hi Brian, thank you for commenting here. The study admits that results are inconclusive insofar as the researchers were not given access to Canyon's wastewater system to test samples. Can you tell me more about that?
Jennifer Courtney March 19, 2011 at 08:17 PM
Hi Wayne, glad you enjoyed it. Interesting that people are beginning to discuss removing dams from waterways. It's true that dams have a really significant impact on the ecosystems they are constructed in, including those built along San Leandro Creek for water storage and flood control. As for Chabot Lake, it is preserved as an emergency back-up water supply, though back in the late 1800s it was constructed as a primary source of water for residents in the area. I don't know when that changed and when it was taken over by EBMUD, though I do know it was first opened up to limited recreation in the 1960s. Maybe I'll look into it some more sometime!
Brian Coyle March 19, 2011 at 11:17 PM
Dr. Malloy told us the genetic marker tests, which are new and still being calibrated in this area of research, identified biomaterial that could have been ruminant, vegetative, or human. She wanted to test Canyon systems to determine if they had similar markers or not, under the presumption that they would not -- and if not, it would not support a conclusion of human impact. The system she requested testing was the school's. The school board met several times to review this, and we were inclined to support the project, despite the grad student not showing up to our meetings as requested. However prior to our vote on the issue, someone turned up a conference poster about the research, which claimed it had already shown that human waste had caused the genetic markers the student found. It's tone was alarmist. We immediately contacted Dr. Malloy, who denied that the conference report was inflammatory, rather than address its statements. We then declined to authorize her testing. Now that the report is public, apparently Malloy and the student claim the biomaterial was human and only their inability to test our system makes it inconclusive. Since were are the humans nearby, the implicit conclusion is that its our waste. CONTINUED BELOW
Brian Coyle March 19, 2011 at 11:18 PM
CONTINUED FROM ABOVE Canyon has probably the most restricted, monitored septic systems in the East Bay. For three decades we've had a moratorium on building expansion and septic enlargement. EBMUD tests the runoff, streams, and local water systems of concern regularly. The community works closely with them. Unlike suburban communities, we live in ecologically authentic surroundings. All water is from wells. But the real problem with Malloy's student's research is that to get attention, it needs to be alarmist. I doubt Patch would report on it, if the research conclusions were that the stream was either unimpacted or the results were inconclusive. This drives researchers to exaggerate facts. I don't know the solution to this problem, except that had she involved the community honestly and more thoroughly, she might have found a story equally compelling, if different.
Stephen Carbonaro May 26, 2011 at 11:34 PM
Did EBMUD mention the fact that in July of 1993 it dumped thousands of gallons of PCB contaminated water into Dunsmuir Creek, a tributary of San Leandro Creek? As I understand it, PCBs were found more than a mile downstream of whare the two creeks meet. Millions were spent on remediation, but how effective it was, I could not say. That's where sampling should be done.
Thomas Clarke May 28, 2011 at 12:07 AM
Gary, it is wonderful that you would post these links. I looked at all of them and the key element appears to me to be the actual testing for PCB's in Zone 12. None of the links are specific to testing in that area, that I could locate. If I missed the test results and findings to see if the EBMUD deposited PCB's from 1993 are cleared and cleaned from Zone 12, please indicate where those are. The call outs for the downstream area, which is zone 12 are clearly not addressed so far. It would be good to finally get a public agency subject to actually reveal the truth. Transparency, especially in light of the fact that EBMUD wants more money from us, is not actually rendered here. As others have pointed out, it is not likely that EBMUD or its apologists are likely to render the truth.
Gayle October 13, 2011 at 03:19 PM
A belated comment to this thread - While cleaning up the creek last fall with Friends of San Leandro Creek, we discovered many deposits of human waste on the creek bed near Root Park. When the creek bed is dry, unfortunately, it becomes a toilet. The pools of water were very still and looked stagnant. I netted a dozen small goldfish, which I quarantined and later relocated to my pond, but I also netted a steelhead trout, which I had to leave. Rains arrived about a month later and all that waste would have flowed out to the Bay. Michael Gregory is now President of Friends of San Leandro Creek and his goal is to restore flow to SL Creek throughout the year.


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