This article from today’s Bee continues the taboo against discussing a new dam to control floods in the American River Parkway, instead focusing on large releases, which further degrade the Parkway. The throwaway acknowledgement of the proposed raising of Folsom Dam, (a troubling concept on its face) to increase reservoir capacity won’t do much at all to reduce the large releases that degrade the Parkway.
Maintaining a taboo about public discussion of all of the options to control flooding, whether on the Parkway, or in residential and business areas, is a grave disservice and does little to help the public discussion.
Here is an excerpt from the article:
“Folsom Dam modifications were originally deemed necessary after huge storms in 1986 showed that the eight existing river outlet gates in the main dam were not sufficiently large to release enough water quickly when massive runoff was expected to hit the reservoir.
“The original plan called for enlarging those eight gates and adding two new ones.
“In 1999, Congress authorized a budget of $215 million for the project. But in June 2005, construction firms interested in the job submitted bids as high as $650 million.
“The risk of working on an existing dam – and compromising its limited release capacity during construction – was considered a key factor in the high bids.
“The new approach calls for an auxiliary spillway to be built just south of the existing main dam. This new spillway would include new river outlet gates that could be opened ahead of a storm, like existing gates in the main dam, to empty the reservoir quickly.
“The new gates would be built below the reservoir’s maximum water level, but not as deep as the existing gates. This means it is likely they can be built faster, without limiting the dam’s current release capacity and without exposing the contractor or the public to as much risk.
“Meanwhile, early research shows the project is likely to achieve the same goal as the original project: giving Sacramento 140-year flood protection by 2013. The city currently has protection from a 100-year flood or a flood with a 1-percent chance of occurring in any given year.
“A related project to increase reservoir capacity by raising Folsom Dam’s height, estimated to cost $250 million, would give Sacramento 200-year flood protection.
“The dam raise was originally targeted for completion in 2021. But improved cooperation between the bureau and the corps, better integration of the two projects and simpler construction methods means this ultimate goal could be reached sooner, Matsui said.”