Sacramento’s River Threat Roils Debate Over Dams : Disaster: A levee break could leave the state Capitol under 20 feet of water. Residents are divided over the best way to block a flood.

SACRAMENTO —  Developers and environmentalists are digging in along the American River near Sacramento for yet another “High Noon” in California’s endless water squabbles.

This time it isn’t the usual North-South row, with Northern Californians fighting transfer of water to the thirsty South.

It’s Northerners against Northerners in the Sacramento area. They all agree that Sacramento lives under the danger of a devastating flood. They all agree something must be done. What they don’t agree on is what to do.

Lined up on one side are people who think the solution is to build a smaller version of long-stalled Auburn Dam on the American River about 30 miles northeast of Sacramento.

Opposing them are environmentalists to whom dams--especially Auburn Dam--are anathema. They argue that Sacramento could be defended by fixing up the levees along its rivers and keeping less water behind the Folsom Dam, with its capacity of 1 million acre-feet, on the American River 22 miles east of the city. That would leave more space in the Folsom Dam to store water during big storms.

As a last resort, leaders of environmental lobbies, such as Friends of the River and the influential Planning and Conservation League, might accept a so-called “dry dam,” one that could hold back water temporarily in flood emergencies and then be quickly drained when the rain stopped.

However, they really don’t want the dry dam. They add that they will fight to the finish against any dam that could be modified later to store water or generate electricity because it would mean flooding the American River Canyon.

“We might take the dry dam as a last resort, but I don’t think they have really explored the possibilities of doing other things,” said Jennifer Jennings, spokeswoman for the Planning and Conservation League. “If it’s a dry dam, we want it hedged in with guarantees from Congress that it could never be turned into anything else.”

Veteran engineers from the state Department of Water Resources shrug at Jennings’ argument. “Why spend all that money on a dam you can only use for one thing? It doesn’t make economic sense,” one of them said.

The time for arguing may be running out. In Washington, the Federal Emergency Management Agency is tired of contributing to mopping up after Central California floods. It has warned leaders in the Sacramento region to get together on a plan of action, or face the loss of subsidized federal flood insurance.

That would mean much higher payments for Sacramento-area residents trying to insure their property, and threatens to put a serious crimp in the region’s development. Sacramento’s representatives in Congress have managed to push back enforcement of that threat until late 1992, but the players in the game now are under warning that this is fourth quarter.

The battle in its present form is almost 4 years old. It began on Feb. 19, 1986, the last day of the biggest rainstorm ever measured in the Central Sierra. With Folsom Dam threatening to spill over, the U.S. Bureau of Reclamation began releasing water into the American River at a record rate of 130,000 cubic feet per second, 15,000 more than the levees along the American were designed to contain.

Sacramento residents packed their cars and stood by radios, preparing to flee if the levees broke. The levees were badly weakened, but they held together all day and the rain tapered off. On the morning of the 20th, the crisis was over.

Northern California’s two largest urban regions are built in danger zones.

The vulnerability of the San Francisco Bay Area to earthquakes got national exposure on Oct. 17, when a damaging quake rocked the region.

Sacramento’s flood problems do not command as much attention, but the dangers are just as real.

Sacramento is known as “River City.” Levees protect it on the west from the Sacramento River, largest in the state, and on the north from the American, a main tributary of the Sacramento. In normal winters, the water level in the rivers often is above the elevation of much of the city.

During big storms the region, including the downtown area, could be swamped by a levee break. There have been estimates that the depth of water around the state Capitol could be as much as 20 feet if the levees along the American gave way.

In 1987, the Army Corps of Engineers estimated that 325,000 people lived on the Sacramento flood plain, and that the potential damage in a disaster could run as high as $15 billion.

The population is larger today and growing. Both the federal Census Bureau and the state Department of Finance have singled out the Sacramento region as one of California’s future urban conglomerates. Land there is still cheap by Bay Area and Los Angeles standards, and there is room for expansion.

It is hard to guess what would happen if the issue eventually is thrown to voters in Sacramento County.

The environmental movement has strong backing in the region. Last June, voters in the Sacramento area became the first in the country to shut down a nuclear electric power plant at a general election.

In general, most Democratic legislators look warmly on the idea of the dry dam, while Republicans favor more water for development.