Recent news releases from the Bay Delta Conservation Plan (Tunnel Plan) paint quite a rosy picture for California: The proposed tunnels to take water from the Sacramento River near Hood under the Delta to Clifton Court Forebay in the south and are said to provide a $5 billion net benefit and a reliable water supply for the state. However, the calculations used to create this benefit are so skewed they border on fraud.

The BDCP is being sold as a Habitat Conservation Plan, despite its goal being to install twin 40-foot diameter tunnels 150 feet below the Delta.

As an HCP, only biological impacts must be considered. The biological impacts are being mitigated by an experimental use of 50,000 acres (11 percent) of Delta farmland being taken out of production, via eminent domain, for wildlife restoration.

The plan grossly underestimates the impact on the recreation and farming economy of the five Delta counties. During the 10-year construction period, use of the 1,000 miles of waterway would be significantly impacted, bankrupting marinas and plummeting property values in communities like Discovery Bay.

Taking fresh water out upstream, instead of having it flow through the Delta, will allow increased saltwater intrusion and sterilize fertile Delta farmland.

A major component of the cost-benefit analysis is the reduction of earthquake risk.

The BDCP assumes there are three thrust faults under the Delta, although there has been no evidence of activity for the last million years. The closest active faults are at least 35 miles away. The plan has used a 2 percent probability per year of a catastrophic failure of Delta levees causing a one year loss of water to the state. The 50-year plan, therefore, assumes that without the tunnels, the state will lose its water supply for one full year.

This is ludicrous. I am not aware of one levee failure caused by an earthquake, including the 1906 San Francisco earthquake. We have had several levee failures over the years during high water levels, the latest being lower Jones Tract in 2004.

That levee failure resulted in about 2 feet of water on Jones Island before the levee was plugged, without impacting California's water supply.

Even if there were to be a catastrophic quake, dropping San Francisco into the Pacific, what the plan doesn't consider is rupture of its tunnels 150 feet underground, nor failure of San Luis Reservoir and the California Aqueduct over the Grapevine.

The BDCP has a published benefit-cost ratio of 1.35 to 1.4. That is, the expected benefits exceed costs by up to 40 percent. One needs only to look at the Bay Bridge project to realize that a major plan that is only 10 percent designed will have cost growth, and it only takes cost growth of 35-40 percent to make the plan economically unfeasible.

It's interesting that the through-Delta alternative in the plan has a benefit-cost ratio of 1.9, much better than the tunnels, but still not viable for a private company.

Dr. Jeff Michael, from the University of the Pacific, has computed that the cost of the BDCP actually exceeds the benefits by a factor of 2.5, using data provided by the BDCP.

We are being conned by the BDCP.

A new BDCP "fact sheet" addresses an "armored" through-Delta levee system that would be expensive and "dirty" because of the air pollution from truck convoys. But they don't mention the BDCP creates giant "muck" ponds lined with impermeable barriers to prevent the foaming agents and polymers the tunnels would require from getting into the water table.

In summary, fortifying the existing levee system to continue to transport water to Clifton Court Forebay, with a permeable levee fish barrier is an order of magnitude more cost effective than the BDCP tunnels, and ensures fresh water adequate for farming and recreation in the Delta.

Increased water needs should be addressed through conservation, desalination, reoperation and conjunctive use.

Michael McCleery is a resident of Discovery Bay.