Brentwood Press - Index

Brentwood Press - BrentwoodPress_08.22.08 - Index

12A | brentwoodpress.com commUnItY august 22, 2008
Concerns surface over marsh project
TL Cakes
Cake Specialists
by Dave Roberts
staff Writer
A plan to convert the old Emerson dairy
and nearby properties into a tidal marsh might
become a vital step in saving endangered Delta
fish and would provide a large waterfront park,
but it also has the potential to increase salinity,
carbon and toxic mercury in local drinking
water.
That was the mixed news in a report to the
Oakley City Council last week by Patty Quickert,
who is heading up the Dutch Slough Restoration
Project for the California Department
of Water Resources (DWR).
Council members are looking forward to
the 65-acre park with trails along the Delta, ball
fields, boat launching and other recreation. But
they are concerned about the potential mercury
toxicity that could result from breaching
the levee and flooding much of the 1,166-acre
property south of Dutch Slough between Big
Break and Jersey Island Road.
“As you all probably know, there’s a great
deal of mercury in the Delta system,” Quickert
told the council on Aug. 12. “It washed downstream
during the Gold Rush. And it comes
from the mines in the area that are leeching it
to the system.
“Most of that mercury is elemental mercury
– it’s fairly inert. Mercury is mostly harmful
to people when you breathe the gas, like
when you break a fluorescent tube. That’s mercury
vapor, and it’s really harmful. Most of the
mercury that’s in the sediments of the Delta is
not harmful in the state that it’s in.
www.Delta-comm.org
DeltaCommunity@yahoo.com
“However, when you have a tidal marsh
project, an area that is under water, the mercury
in the sediments can react with bacteria and it
can form methyl mercury, which can be toxic.
That’s when you hear these warnings about eating
fish – it’s because the fish contains mercury,
and when you eat the fish the mercury stays in
your body and can be potentially toxic.
“The Dutch Slough area has actually one
of the lowest levels of mercury in the Delta
area. We don’t know how the tidal marsh will
affect the methylation and the potential toxicity
of the mercury. Tidal marshes do export
methyl mercury.
“But in some cases they are also known
to decrease the amount of mercury. Because
not only do bacteria create the methyl mercury
but other bacteria can break it down back
into mercury. This is something that we will be
monitoring very closely to see how much mercury
is being exported from the site.”
Councilman Brad Nix said that after the
council approved the Dutch Slough project
several years ago, scientists expressed concerns
“about how serious the mercury problem was
with this type of restoration. We’ve been sort of
waiting for somebody to come back to us and
tell us that the problem has been solved here
and a consensus reached. Are the … scientists
now on board saying it’s OK and it’s safe?”
Quickert responded, “The most recent
research shows that tidal marshes are not a primary
producer of methyl mercury. Some tidal
marshes actually reduce the amount of mercury.
There are studies being done to try to figure
out what aspects of the different areas make it
TICKETS AVAILABLE AT OUR EVENT SPONSORS
• Brentwood Community Center • Brentwood Chamber of Commerce
• Health Hut • Weathervane Western Wear • Brentwood Press
• Delta Community Service, Inc. • SpeeDee Oil Change & Tune Up
have less mercury or more mercury. But none
of the tidal marshes have produced toxic levels
of methyl mercury. They do produce some but
not nearly as much as flood plains do.”
Nix replied, “Well, some poison may not
be good.”
“It’s definitely a very difficult problem,”
acknowledged Quickert. “We at the Department
of Water Resources are being told from
many different directions that we need to do
these tidal marsh projects because the pumps
are having impacts to Delta smelt and other
species and we need to improve the ecosystem.
Tidal marsh restoration is kind of the best hope
for ecosystem improvement.
“But you’re right: the mercury is an issue.
It’s like so many things in life. It’s like you get
one thing and have to give up something else.”
There are three separate parcels – once
belonging to the Emerson, Gilbert and Burroughs
families – that will be converted to
marshland one at a time.
Councilwoman Carol Rios asked Quickert,
“As you’re doing the project and find there
is a problem with methyl mercury, how would
you correct it? Once you breach, there’s no going
back? If you found it really is a problem,
how would you deal with that?
“We will do a phased approach,” replied
Quickert. “If we breach one parcel and there’s a
problem, we would probably do something different
with the other parcels. But you’re right:
once it’s breached, you can’t do a whole lot.”
Nix is also concerned about saltier water
pouring into the Delta when the levee is
breached, “which would, of course, impact our
water intake.”
Quickert responded, “Right, because
you’re opening up a whole new volume that
will essentially, to use a really crass term, suck
water from the Bay, because that’s the larger
volume of water. I’ve worked with an engineer
at DWR that has done a lot of this kind
of modeling. What his modeling has shown is
that at this location, it should not have an appreciable
increase in salinity.
“We have studies that show the numbers. It
actually decreases the salinity at some tidal stations.
It increases it like a hundredth of a part per
thousand. So it’s negligible. So we are not expecting
that to be an appreciable effect, but it’s one of
the things we will be monitoring.”
There will also be an increase in carbon in
the water when the nutrients in the marsh break
down. “That will be an issue that we will monitor
prior to doing the restoration and after the
restoration is done to manage the amount of
carbon that’s going in the water,” said Quickert.
An environmental impact report scheduled
to be released in the next month or two will
provide more detail on the potential impacts of
the project and the mitigation measures that
could be taken to minimize those impacts.
In order to create an appropriate land
level for the marsh, about a half-million cubic
yards of dirt that have been irrigated with secondary
effluent from the Ironhouse Sanitary
District will be hauled across Marsh Creek to
the Dutch Slough project area.
The Burroughs parcel on the east will
probably be converted last to marshland, if at
all, because a levee would need to be built along
Jersey Island Road to prevent flooding of the
road and the planned developments to the east.
DWR currently does not have the several million
dollars it will take to build that levee.