MISSION, Texas (AP) – Jeff Reed offers outdoor dining on the Rio Grande at his restaurant, Pepe’s on the River. But with the U.S. government planning to build 700 miles of fence along the Mexican border, he has to wonder: Will his restaurant soon be “Pepe’s on the Fence”?

Downriver in Brownsville, where the jalapeno and lima bean fields run down to the water’s edge, farmer Fermin Leal is wondering whether the government intends to cut through his crops, run irrigation pipes under the fence, or buy him out.

“Most of our land goes up to what’s supposed to be the border, and yes, we need access to river water,” Leal said.

President Bush signed a law Thursday to erect more fences along the border to secure it against illegal immigrants, drug smugglers and terrorists. Republicans in Congress see it as their most significant accomplishment on immigration. The president called it “an important step in our nation’s efforts to secure our borders.”

But up and down Texas’ watery boundary with Mexico, farmers, ranchers and business owners are worried a fence will endanger their livelihoods and encroach on their property.

Texas landowners – sick of illegal immigrants cutting their fences, stealing and trespassing, and tired of worrying about smugglers of humans and drugs endangering their families – have been demanding for years that Congress tighten the border.

But not, some say, with a double-layer, $6 billion fence cutting through their land and keeping them and their livestock from the river.

“It’s not going to work in Texas,” said Michael Vickers, who owns a cattle ranch on the border. “Who wants to close off the river to Mexico? The river is the lifeblood for a lot of cities.”

Vickers said he worries that either his land will be cut off from the rest of the state and the country or he will lose access to 50 acres of water rights he has and can sell to area municipalities for up to $2,000 an acre.

“I’d be in a DMZ-type zone, in between two countries,” Vickers said.

The exact route the fences will take is not yet clear. And it is not yet known what the fences will look like – how tall they will be, whether they will be solid walls, or bars.

Much of the land along the Texas side of the river is privately owned, some dating back to Spanish land grants. The government’s $1.2 billion “down payment” on the fences is only a fraction of the estimated cost, which will also include the expense of compensating property owners for any land taken through eminent domain.

Environmentalists say the fence also would destroy decades of government work building up wildlife corridors to allow endangered species like ocelots and jaguarundi access to the river.

The legislation calls for one Texas section of fence stretching from Del Rio to Eagle Pass and a much larger piece along the 361 river-miles from Laredo to Brownsville, where much of the border population lives.

“I could see if they put the fence in desolate areas and isolated areas, but to come down here and interfere with businesses and stuff such as mine?” said Reed, the waterfront restaurant owner. “Nobody’s crossing right here anyway, not with a lot of activity. We’ve got 500, 600 people sitting out here. They’re not going to pull up a boatload and start unloading.”

Mexican President Vicente Fox has called the plan “an embarrassment for the United States” and said a fence would not stop millions of Mexicans from heading north in search of jobs.

Similarly, mayors of U.S. cities close to the river have spoken out against the economic and diplomatic effect of a fence in a region where Mexico and the United States interact fluidly.

“Here we are in the midst of an economic mega-boom and we’re building fences,” said Laredo Mayor Raul Salinas. “What ridiculous symbolism. Here we are tearing walls down around the world and we’re putting up walls.”

Mexican customers make up about 35 percent of the city of McAllen’s retail trade and have been buying real estate and opening businesses in the city at a rapid pace.

A fence “sends the message that you’re not wanted or you’re not welcome. I know I would be insulted,” said Steve Ahlenius, president of the McAllen Chamber of Commerce. And he questioned whether a fence would even work: “Human instinct is that if you have a 10-foot fence, you’re going to find an 11-foot ladder.”