EL CALABOZ , Texas ( CNN ) -- Eloisa Tamez said she is n't scared anymore , just determined . `` I am not backing down , '' she said . The U.S. government wants to build a border fence like this one . About 100 landowners are fighting it . Tamez owns three acres of land along the Texas-Mexico border where the Department of Homeland Security would like to build a border fence . The property is a remnant of a 12,000-acre grant from Spain to her family in 1767 , before the United States even existed . `` It is my history . It is my heritage , '' Tamez said . This week , the Justice Department began legal action against landowners and municipalities who have refused to give government surveyors access to their land . Tamez expects she will be sued sometime soon , but she is not intimidated . Asked how long she will fight , she said , `` As long as I have to . '' Michael Chertoff , the Secretary of Homeland Security , said the fence will not be stopped by opponents like Tamez . `` Can we simply abandon an enterprise because it is a problem for a particular individual ? '' Chertoff told CNN . `` I do n't think I can accept that . '' Watch Chertoff say it 's `` civic responsibility '' to give up land » . Chertoff believes a fence would curb the steady stream of illegal immigrants making their way across the border and lessen the flow of drugs . He also argues it will increase the safety of Border Patrol agents who have faced increasing violence . The government wants to build 700 miles of fence along the Mexican border , including 370 miles of it by the end of this year . About 70 miles of fence is to be built in the Rio Grande Valley by year 's end , if the government gets its way . The Rio Grande forms a natural barrier along this stretch of the border , but in some places it is narrow enough to swim across . On the banks of the river there is ample evidence that people do so . Piles of underwear lie discarded by swimmers after they make it across . The swimmers change into dry clothes they have carried across in plastic bags . Then they disappear into the United States . The Border Patrol has stepped up its efforts in the Rio Grande Valley with more lights , and sensors to pick up movement . A levee built along the river has a muddy road on top used by Border Patrol vehicles to patrol the area . Richard Cortez , the mayor of the border town of McAllen , Texas , believes hiring more Border Patrol agents , deepening the Rio Grande , and clearing its banks of tall vegetation would provide better border protection than the fence . Cortez calls the fence `` a multibillion-dollar speed bump , '' which will slow , but not stop , illegal immigration . `` It is a false sense of security , '' he said . `` America will not be safe . America will continue to waste resources on something that is not going to work . '' Cortez and other border mayors who oppose construction of the fence formed a group called the Texas Border Coalition . The coalition wrote to Chertoff asking for further consultations on the fence , but this week the Department of Homeland Security turned them down . While expressing support for open dialogue with residents and officials , David Pagan of U.S. Customs and Border Protection wrote in an e-mail , `` We do not plan to suspend work on the construction of fence in order to hold a series of additional consultation meetings . '' Cortez said his city is contemplating a court test of the law that mandated the construction of the border fence . And so a battle is being waged by about 100 landowners , those like Eloisa Tamez who are standing firm . `` I will not allow them to come and survey my land . I have an American-given right to protect my property , '' she said . E-mail to a friend .
Government wants land for border fence ; landowners refuse . The government is now trying to force the issue by threatening legal action against those who don't want a fence. Eloisa Tamez says her property has been in her family since 1767 . Border town mayor calls the fence `` a multibillion-dollar speed bump ''