TUCSON, Ariz. – The new year will bring the first new U.S.-Mexico border barriers to be built under President Donald Trump's administration.

The administration has so far announced eight projects to build new fence or replace existing barriers. Three of the projects have been completed; two are underway. Three others will begin during 2019's first half, including areas of south Texas that previously had no barriers.

More new fencing could soon follow.

U.S. Customs and Border Protection has received more than $1.6 billion in fiscal years 2017 and 2018 for border infrastructure. That money is paying for the eight scheduled projects, and a few more that have not been announced yet. Homeland Security officials said more contracts will be awarded in coming weeks.

In late December, officials unveiled how additional money they've requested from Congress for border security would be spent. Those plans include more than 100 miles of completely new barriers, mostly along south Texas.

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Here are the locations of the two projects expected to be finished in 2019 and the three construction projects slated to begin in 2019:

Rio Grande Valley, Texas

In February, crews will begin building 14 miles of levee walls just south of McAllen, Texas, in the Rio Grande Valley – the busiest point for illegal entries along the southwest border.

Customs and Border Protection awarded two contracts worth a total of $312 million to SLSCO Ltd. of Galveston, Texas, to build the barriers.

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The new barriers will be built on top of existing levees north of the Rio Grande, which tends to flood with seasonal rains. The barriers consist of the solid concrete levees built to their existing height, with 18-foot-tall bollard-style fencing at the top. The barriers will be built in six segments along the Rio Grande, Customs and Border Protection said.

East of these levee walls, a San Antonio-based company is installing at least seven gates along sections of the border fence north of the river that were built during the last decade.

That work is the first phase of a project to install 35 border gates.

The gates, besides stemming the flow of people and narcotics, are intended to give landowners access to their lands south of the barriers, as well as the Rio Grande to irrigate their fields.

Yuma and Lukeville, Arizona

In April, construction will resume along the Arizona-Mexico border as crews begin replacing 32 miles of existing primary fencing in the southwestern part of the state.

Twenty-seven of those miles are in Yuma; 5 miles are in Lukeville.

Customs and Border Protection awarded a contract worth $172 million to Barnard Construction Co. of Bozeman, Montana. It will work to replace 14 miles of aging, Vietnam-era landing mat fencing east of the San Luis port of entry.

Crews will remove the 18-foot-tall landing mats and install bollard-style fencing that's 30 feet tall.

Customs and Border Protection said it also plans to replace an additional 11.5 miles of landing-mat fencing east of that area, along with a 1.5 mile stretch of mesh-style fencing near the Colorado River. But the agency has not said when construction will begin.

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Both Lukeville and Yuma have seen large groups of migrant families, some numbering as many as 150, crossing the border illegally in the last year and voluntarily turning themselves over to agents.

El Centro and San Diego, California

In July, construction crews will begin to replace 15 miles of primary fencing along the California-Mexico border. Eleven of those miles are in Calexico, 3 are in Tecate, and 1 mile is near Andrade, across the California-Arizona line from Yuma.

Customs and Border Protection awarded a contract worth $156 million to SLSCO of Galveston for the project. In its announcement, the agency said it also had awarded the company an additional $131 million contract to replace 14 miles of secondary fencing in San Diego.

All four segments will employ the 30-foot bollard-style fencing.

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The San Diego-Tijuana border area has received attention in recent months as thousands of migrants traveling in caravans arrived there, hoping to seek asylum.

But with waits of up to six weeks to present their claims at the port of entry, many asylum seekers, and migrants with no plans to seek asylum, have been breaching the border illegally.

"Given the high-density population in San Diego-Tijuana urban area, the stronger infrastructure is critically important," Customs and Border Protection said in its announcement.

Completed projects

The three replacement projects that have been completed are in Calexico, California, El Paso, Texas, and Santa Teresa, New Mexico.

Work crews finished 2.25 miles of 30-foot-tall bollards in Calexico in October, the first project completed under the Trump administration. Homeland Security Secretary Kirstjen Nielsen visited the site a few days later.

During her visit, the agency welded a plaque to the fence to mark "the completion of the first section of President Donald Trump's border wall," even though it was a replacement project.

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A few weeks later, Customs and Border Protection completed the replacement of four miles of bollard style fencing near the Chihuahuita neighborhood in downtown El Paso. Unlike Calexico, CBP officials there did not mark the project's conclusion.

In November, crews finished 20 miles of vehicle fencing with 18- to 30-foot bollards in Santa Teresa, west of metropolitan El Paso.

Customs and Border Protection spent about $113 million to complete the three projects.

Contributing: David Jackson and Eliza Collins, USA TODAY. Follow Rafael Carranza on Twitter: @RafaelCarranza