In small section of border wall, Trump's promise takes shape

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

A government contractor, surrounded by existing Normandy barriers that separate Mexico and the United States, pours a concrete footer in preparation f

A government contractor, surrounded by existing Normandy barriers that separate Mexico and the United States, pours a concrete footer in preparation f

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors remove existing Normandy barriers that separate Mexico and the United States, in preparation for a section of Pentagon-funded b

Government contractors remove existing Normandy barriers that separate Mexico and the United States, in preparation for a section of Pentagon-funded b

Sections of Pentagon-funded border wall are stacked prior to installation along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. A 30-foot h

Sections of Pentagon-funded border wall are stacked prior to installation along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. A 30-foot h

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

Government contractors erect a section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ariz. The 30-foot hig

A government contractor walks beside a completed section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ari

A government contractor walks beside a completed section of Pentagon-funded border wall along the Colorado River, Tuesday, Sept. 10, 2019 in Yuma, Ari

YUMA, Ariz. (AP) — President Donald Trump says his administration plans to build up to 500 miles (805 kilometers) of border wall by the end of next year, and plans are already taking shape in Arizona and elsewhere.

But some are skeptical about whether the goal announced this week is achievable or even necessary.

Construction crews south of Yuma, Arizona, are putting up tall fencing along 5 miles (8 kilometers) of U.S.-Mexico border. The section is replacing shorter barriers meant to keep out cars, but not people.

The Border Patrol says tens of thousands of people have crossed the border illegally through the area and that the existing barriers don't suffice.

While the number of people apprehended by the Border Patrol is up in Yuma compared with last year, the figure has dropped dramatically there and across the southern border over the past few months.