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Fed May Strip Trees from CA Levees05-06-10 | News

Fed May Strip Trees from CA Levees

The federal government is pressing forward with a policy that could require trees to be stripped from California levees, eliminating what shade and wildlife habitat remain along the state's rivers.

The Army Corps of Engineers believes trees cause floods. After Hurricane Katrina in New Orleans, the Army Corps began imposing its national levee maintenance rules on all U.S. flood management agencies. The move prompted a backlash in California, and federal officials offered a conciliatory response.

An interim agreement appears likely to shield the state?EUR??,,????'?????<

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Levee experts and environmentalists alike said they are disappointed the federal government has shown little flexibility, despite earlier assurances. California long has operated under a different policy than the rest of the nation, with Army Corps consent. The allowance for mature trees reflected the unique history of flood protection in the state, which left levees as virtually the only remaining riverside wildlife habitat.

In 2007, the Army Corps commander, Lt. Gen. Robert Van Antwerp, stood on a levee in Sacramento?EUR??,,????'?????< But the result, a so-called ?EUR??,,????'?????<

Army Corps officials say the variance lives up to Van Antwerp?EUR??,,????'?????<

Pete Rabbon, director of the Army Corps National Flood Risk Management Program, said the policy itself does not require that any trees be cut down. It does, however, establish criteria for maintaining levees, and those criteria require the levees to have nothing other than grass on them, unless a variance is obtained.

The reality, critics charge, is that California levees now run afoul of the standards set by the Army Corps, and compliance requires cutting trees. If a region fails to comply, it could lose federal aid in the event of a flood, and may lose eligibility for federal flood insurance. Local agencies can apply for a variance, but the corps will grant it only for the lower two-thirds of a levee?EUR??,,????'?????<

In a 64-page analysis accompanying its letter, the state agencies estimate removing trees from California?EUR??,,????'?????<

The Army Corps believes trees cause floods, mainly in two ways: by ripping out whole sections of a levee should they fall over in a storm, or by creating a path for water to seep through a levee via their roots.

But there is little proof of this, especially in California, where storm conditions differ from those in the hurricane-plagued South. In fact, research suggests trees strengthen levees by binding the soil together.

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Rabbon said the corps is doing more research but stands behind its policy. ?EUR??,,????'?????<

The corps requires detailed surveys of levees before it will consider a variance.The Sacramento Area Flood Control Agency is believed to be the first to seek a variance in California, related to repairs on 30 miles of levees in the city?EUR??,,????'?????<

Actually removing trees, if necessary, would cost much more. Once a tree is cut down, the roots have to come out. Otherwise, the dying roots could create a path for water to seep through the levee as they decay. Then the levee must be rebuilt where the roots were.

California currently operates under a 2009 agreement with the Army Corps that allows simple pruning to ensure access to levees for inspection. The corps has agreed to honor this deal until 2012, when the Central Valley Flood Protection Board will submit a comprehensive regional flood protection plan. If the Army Corps does not accept the 2012 plan, tree removals could be required.

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