EBMUD: Moldy Water Problem
Video of Channel 2 Story on 5/24/10 - Rob Roth Reporting
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Answers from EBMUD Representative Debra Skeaton
You asked several good questions. I will respond to them in the
order that they appear in your letter.
ALGAE BLOOM
I can appreciate your skepticism regarding the reported algae bloom in San Pablo
Reservoir. Although algae can grow in San Pablo Reservoir or any other body
of water at any time, an algae bloom represents a rapid growth or large concentration
of algae. These blooms occur whenever ideal conditions exist to support them.
There have been a few warm days in the East Bay within the past month; and the
seasonal rainfall produced runoff with the right nutrients. These conditions
supported aggressive growth of blue-green algae, a species known to cause taste/odor
problems. Since San Pablo Reservoir is open to the public, you are welcome to
visit so that you can verify this year’s occurrence. A similar bloom occurred
in June 2009.
COMMUNITIES THAT RECEIVE WATER FROM SOBRANTE WATER TREATMENT PLANT
When it is in service, Sobrante WTP takes water from San Pablo Reservoir and
supplies Crockett, Rodeo, Hercules, Pinole, El Sobrante, and portions of Richmond
and San Pablo. This is why only certain communities are affected by the change
in water quality. The Sobrante plant is used during high demand periods - usually
in Summer. It was also the water supplier for a larger region when we seismically
upgraded the Claremont tunnel several years ago.
CHEMICALS AND PROCESSES USED TO CORRECT THE TASTE AND ODOR PROBLEM
EBMUD took two steps to correct the taste/odor problem:
EBMUD is using ozone, a form of oxygen, to correct the taste and odor issues
that customers are experiencing. The ozone system was online and in operation
when Sobrante went into service on Thursday, 5/20/10. When we became aware of
a taste and odor issue, plant operators increased the ozone dosage.
We also changed the intake elevation in San Pablo Reservoir. In other words
we started taking deeper water to move away form the influence of the algae
blooms on the surface.
These two changes had a positive effect on water quality at the water treatment
plant. Depending on consumption, customers could expect to notice a difference
within the next few days as the improved water reaches different portions of
our distribution system.
WHY DID EBMUD SWITCH FROM SNOWMELT?
EBMUD places Sobrante in service every Spring to supply customers from San Pablo
Reservoir during the high-demand spring and summer months. Normally it is removed
from service in the fall because the Orinda Treatment Plant is large enough
to handle winter use. This year we placed Sobrante in service later in the season
since customer demand was low. Unfortunately, it happened to coincide with a
bloom
The San Pablo Reservoir is used to store water that comes from the Sierra as
well as local runoff.
Although I wanted to ensure that I responded to your questions, we have taken
the Sobrante Treatment Plant out of service until we can resolve the problem.
We can do this because the weather has reduced demand.
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At 12:18 PM 5/24/2010, you wrote:
As discussed, EBMUD increased the ozone dosage at the water treatment
plant in response to the calls we received from customers. In addition,
we changed the intake point on the tower in San Pablo Reservoir so that
water comes in from a different elevation. Based on taste and odor
tests today at the plant, these changes resulted in improved taste and
odor in the water that you will receive. You should notice these
changes during the current week, depending on the time it takes that
water to reach your area. Please call or write if you require further
assistance.
Debra Skeaton
Water Distribution Supervisor
East Bay Municipal Utility District
P. O. Box 24055
Oakland, CA 94623
(510) 287-1071 Office
(510) 715-9049 Cellular
(510) 287-1155 Fax
dskeaton@ebmud.com