A daily compilation for DWR personnel of significant news articles and comment
August 29, 2007
1. Top Items
Due to technical difficulties here at DWR, it was reported by some of our subscribers that they received only certain sections of yesterday’s California Water News, and some subscribers reported not receiving any emails at all. Instead of resending yesterday’s Water News to everyone, we have included the articles collected yesterday with today’s Water News. Thanks for your understanding.
DWR Water News Editors
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Scientists: Trees help, not hinder, levee safety; U.S. Army Corps of Engineers hears challenges to its removal policy at Sacramento hearing - Sacramento
High Tech Measures To Fix California
8/28/07 - Top Item
$1.43 billion tally to fix
Scientists: Trees help, not hinder, levee safety; U.S. Army Corps of Engineers hears challenges to its removal policy at Sacramento
Sacramento
By Matt Weiser, staff writer
Though federal officials on Tuesday faced a deluge of evidence that trees do not threaten levees, they continued to tout their own policy that could require every mature tree to be cut down on
At a symposium on the issue in
The backdrop to Tuesday's meeting were the 32
The corps, which is preparing a new national levee maintenance policy, currently says no vegetation larger than 2 inches in diameter should grow on a levee. But that standard has not been applied in
The issue affects levee managers nationwide, but it is especially critical in
"By and large ... trees have a positive or beneficial influence on the safety of levees," Donald Gray, a geotechnical engineering professor at the
The findings were included in a 1991 paper he co-wrote based on a study sponsored by the corps. "This report was vetted by all the corps districts before its publication," Gray said.
However, David Pezza, engineering and construction chief of the corps' civil works branch, said officials did not consider the study in their maintenance polices because "it didn't match what they saw in the field."
"We do a lot of research in support of our civil works program. But in that particular case, we did not find that science was relevant to what we were doing," Pezza said. "Vegetation is very hazardous to infrastructure when it's not done in an integrated way."
Much of the corps' policy is based on a Federal Emergency Management Agency document called "FEMA 534 Technical Manual for Dam Owners," which explains threats to earthen dams from trees and other vegetation.
"When trees grow, they tend to corkscrew their way into an embankment and that tends to loosen the soil," said Bill Bouley of the U.S. Bureau of Reclamation, co-author of the FEMA document. "Tree roots do not stabilize soil mass. On the contrary, tree root penetration loosens the soil."
Other scientists at Tuesday's symposium contradicted that.
Douglas Shields, a hydraulic engineer at a U.S. Department of Agriculture lab in
"You see a major increase in factor of safety as we move from a minimal root area ratio to a higher level," he said. "We concluded that maintenance standards should favor shrubs and woody trees."
This year, he and several colleagues used a computer model to show that trees also offer more erosion protection than a uniform carpet of grass, the levee cover favored by the corps.
More than 500 people from as far away as
UC Davis horticulture professor Alison Berry said this could destabilize levees by causing a large and disparate root mass to decay in unison. Levee erosion also might increase.
Dirk Van Vuren, a UC Davis professor of wildlife biology, said removing trees could create better conditions for animals that are most troublesome for levee managers: burrowing rodents.
Gophers, ground squirrels and voles are the most prolific burrowing mammals on area levees, Van Vuren said. But they actually prefer open landscapes to easily detect predators. So a tree-clearing program on levees, he said, is likely to improve their habitat and cause their numbers to grow.
Joe O'Connor, who lives along the
O'Connor fought to preserve three heritage oak trees during design of a new levee in his Butterfield-Riviera East neighborhood.
He lost that battle last year to the corps, which insisted on a standard levee design that required the trees to be cut down.
"Safety is No. 1, always," O'Connor said. But, he said, "There's no need to damage the parkway if it's not going to produce a beneficial effect." #
http://www.sacbee.com/101/story/349565.html
High Tech Measures To Fix California
KGO-TV ABC Channel 7 (Bay Area) – 8/28/07
By Laura Anthony
Aug. 28, 2007 (KGO) - This week marks the two year anniversary of Hurricane Katrina and the disastrous levee breaks that destroyed much of
It's a threat that looms large in
Emergency repairs aside, the levees that protect
"Every time you live behind a levee, you're vulnerable. And there's always a risk behind a levee," said Meegan Nagy of the U.S. Army Corps of Engineers,
According to the California Department of Water Resources, more than 1.8 million people now living in the
"With every house that's added, there's an increase in risk," said Nagy.
The risk is more prominent if the levee is in disrepair. A new pilot study by the U.S. Army Corps of Engineers, on a one and a half mile stretch of a levee along the
The same test will be applied to hundreds of other levees. Starting next week, a torpedo-like electromagnetic device, suspended from a helicopter, will begin surveying 350 miles of urban levees in the
"It's a means of looking into the foundation of levees, and through levees to evaluate the properties of the soils or geologic features below levees," said Mike Inamine, CA Dept. of Water Resources. "Certainly, it will [reveal weak spots]."
In the meantime, levee experts are now meeting in
The concern is by removing vegetation from levees, it would eliminate a habitat for some endangered species, making the fragile structure more attractive to burrowing animals like squirrels and gophers.
"I think we need more information and I think simple blanket approaches - remove all vegetation from all levees - is not the way to go," said Dr. Dirk Van Vuren, U.C. Davis Researcher.
Whatever methods eventually used to reinforce
http://abclocal.go.com/kgo/story?section=local&id=5614052
8/28/07 - Top Item
$1.43 billion tally to fix
By Julia Prodis Sulek, staff writer
For years, local environmentalists have been dreaming that the old dikes and salt ponds, hay fields and abandoned airfields jutting into the
Now, one conservation group leading the charge is putting a price tag on that dream - $1.43 billion.
A new report released today by Save The Bay also suggests residents in the nine counties that ring the bay are willing to help pay the cost for what's being called one of the most ambitious wetlands restoration projects west of the Mississippi.
"These nine counties each have a small slice of shoreline," said David Lewis, executive director of Save The Bay, whose group is calling for the creation of a special regional taxing district to raise money and manage the projects. "So having some agency that can be regional in scope seems to make more sense."
Reaction from environmental groups and people connected to the restoration projects was predictably enthusiastic about a plan to double tidal wetlands from
The $1.43 billion would be spent on 36,176 acres around the bay that have already been acquired for restoration, including 13,000 acres of
"If you spread it out over 50 years and everybody paid a share, it would be less than $4 per year per person," Lewis said. "It's a big number, but we think it's an achievable amount over 50 years."
A 2006 poll conducted by EMC Research, on behalf of Save The Bay, found 83 percent of residents polled said they would be willing to pay $10 per year in taxes or fees to restore the bay's wetlands.
Regional priorities
The report calls for a special district, much like the East Bay Regional Park District, to set wetland restoration priorities and seek funding from local, state and federal sources. The district should have a governing body that may include representatives from key state, regional or local agencies.
Establishing a special district with the ability to collect taxes would require state legislation or a public vote.
Restoring the wetlands would help rebound the populations of the endangered salt marsh harvest mouse and
"In the
Restoring the wetlands, and creating a special district to help do it, is an idea supported by the Bay Area Council, a collection of 275 chief executives of the area's largest employers.
"It seems trite to say, but a clean environment is one of the most important features you can have in an innovation economy," said John Grubb, the council's spokesman. "We're all in a talent battle. The opportunities that nature provides is one of the draws here - and the reason costs are so high - but you get what you pay for."
Feinstein said in a statement Monday that she welcomes "any mechanism to develop local funding for wetlands restoration."
"I do my level best to get funding for wetlands restoration every year, and I will continue to do so," she said. "But there is only so much federal funding. Wetlands restoration is very costly, and additional federal dollars are very difficult because you have to take it from other projects."
The vanishing bay
Today, the bay has shrunk by one-third of its original size, with only 5 percent of the bay's original wetlands remaining. The destruction of the
Over the past century, private companies turned tens of thousands of acres of marsh along the
"Now, we're reclaiming it for the bay," Lewis said.
Numerous wetlands restorations already are under way, paid for by a combination of sources, including state resource bonds paid by taxpayers for projects across the state.
While shaving down levees to let the tide come and go isn't expensive in itself, protecting developed areas on the shore-side of the levees is costly, Lewis said. A steady funding source is needed, he said. #
http://www.mercurynews.com/news/ci_6738099
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