(Associated Press) ASTRID GALVAN September 13 2019 YUMA Ariz. On a dirt road past rows of date trees just feet from a dry section of Colorado River a small construction crew is putting up a towering border wall that the government hopes will reduce for good the flow of immigrants who cross the U.S.-Mexico border illegally. Cicadas buzz and heavy equipment rumbles and beeps before it lowers 30-foot-tall (9-meters-tall) sections of fence into the dirt. Ah est!" There it is!" a Spanish-speaking member of the crew says as the men straighten the sections into the ground. Nearby workers pull dates from palm trees not far from the cotton fields that cars pass on the drive to the border. South of Yuma Arizona the tall brown bollards rising against a cloudless desert sky will replace much shorter barriers that are meant to keep out cars but not people. This 5-mile (8-kilometer) section of fencing is where President Donald Trumps most salient campaign promise to build a wall along the entire southern border is taking shape. The president and his administration said this week that they plan on building between 450 and 500 miles (724 and 806 kilometers) of fencing along the nearly 2000-mile (3218-kilometer) border by the end of 2020 an ambitious undertaking funded by billions of defense dollars that had been earmarked for things like military base schools target ranges and maintenance facilities. Two other Pentagon-funded construction projects in New Mexico and Arizona are underway but some are skeptical that so many miles of wall can be built in such a short amount of time. The government is up against last-minute construction hiccups funding issues and legal challenges from environmentalists and property owners whose land sits on the border. The Trump administration says the wall along with more surveillance technology agents and lighting is key to keeping out people who cross illegally.