Wednesday, March 08, 2006

Violating the Integrity of the Parkway?

This story from Sunday’s Bee gives us a clear example of the perceptive dissonance between the public using the Parkway, and the public agencies responsible for it.

A central aspect of the Parkway are the trees, and about 300 of them, including many heritage oaks, are threatened with removal to maintain the flood control conveyance aspect of the river, (its ability to funnel water released from Folsom Dam to create more space in Folsom Lake for American River Watershed run-off) by building a larger levee.

This is directly related to our contention, that to protect the “integrity of the Parkway” we must consider building a major new dam on the American River to allow for a much higher level of surface water storage to allow for reliance on dams for flood control rather than levees.

It is also important to keep in mind that the present reason we are able to consider building a dam to protect the integrity of the Parkway, one of the most important urban parks in the country, is because the Parkway is also in the center of the most flood-prone city in the nation, and the larger benefit to the surrounding city makes our proposal part of the ongoing community discussion about flood control.

In the future, as we discuss removing a dam (which we support) to restore the important natural area, Hetch Hetchy Valley; the thought of building one to preserve another will not seem remote.

Here is an excerpt.

Tempting Fate: Trees vs. levee
Century-old oaks stymie flood wall
By Matt Weiser -- Bee Staff Writer Published 2:15 am PST Sunday, March 5, 2006


Sacramento's Mayhew levee could be a poster child for the challenges that often surround simple urban flood-control projects.

The Mayhew levee is located on the American River's south bank, in unincorporated Rosemont, across the river from Rio Americano High School. It is the lowest levee on the American River, and, therefore, would seem a high priority for Sacramento flood protection.

But a project to raise the levee by 3 feet has crawled through the approval process since it was authorized by Congress in 1999.

The new levee would stretch 4,300 feet long and, if federal design standards are applied, up to 90 feet wide. Such a levee would take out nearly 300 mature trees along the American River Parkway - a federally designated Wild and Scenic River corridor and beloved public park.

The threatened trees include three heritage oaks that are more than 100 years old.

"We're pushing them on the design to do something that's innovative," said Jim Morgan, secretary of the neighborhood group, the Butterfield-Riviera East Community Association. "We're trying to improve the flood protection, and at the same time we're trying to minimize damage to the parkway."

In a worst-case storm scenario, when federal officials would be forced to open all the spillway gates at Folsom Dam to save it from washing out during torrential upstream runoff, the Mayhew levee is the only American River levee that is too short to contain the flows.

If dam operators had to push the American River to an emergency flow of 160,000 cubic feet per second, water could overflow the Mayhew levee and flood about 300 homes. The rushing water would run across Folsom Boulevard, eventually inundating the city of Sacramento.

The flood could cut off key evacuation routes for many Sacramento residents trying to flee the unthinkable.