The Arizona border will have 32 miles of existing wall replaced starting next April.

The $324 million project has been given the green light by federal immigration officials, U.S. Customs and Border Protection announced Thursday.

The project will switch out an old barrier that runs from the Border Patrol's Tucson Sector west into the Yuma Sector, which is just miles from Arizona's border with California. The replacement wall is meant to keep pedestrians and vehicles from entering the U.S. Older barriers were largely to prevent cars from driving over, but were only a few feet tall and did little to keep people from trespassing from Mexico.

The undertaking, which will be paid for by congressional funding for CBP from 2018 legislation, is part of President Trump's January 2017 executive order to secure the country by improving barriers in vulnerable and high-traffic areas.

Barnard Construction Company, which was not among the six companies that built the eight wall prototypes in San Diego, was given a $172 million contract for 14 miles of replacement wall near Yuma, CBP said in a news release. Another 13 miles of barrier will be completed as part of this project but CBP did not share who it awarded that funding to.

CBP also did not indicate how the remaining $152 million would be spent.

Five miles of work will take place near Lukeville, Ariz., and the other 27 miles are in Yuma's territory.

Last month, CBP was given permission to bypass environmental laws to build 18 miles of new wall on the U.S.-Mexico border in the Rio Grande Valley of South Texas.

The Department of Homeland Security announced in the Federal Register on Thursday that it has given CBP permission to ignore environmental and land regulations so it can speed up the process of building miles of new barrier in Hidalgo County.

CBP will move forward on six projects in the busiest of the southern border's nine Border Patrol sectors. The largest portion of wall construction is 8 miles long and will stretch from near Goodwin and Abraham roads east to near the International Boundary and Water Commission levee.

The announcement came a day after DHS said Secretary Kirstjen Nielsen waived regulations for two miles of other border projects in the Rio Grande Valley's Cameron County.

In both decisions, the memos stated Nielsen had the authority to make the exceptions under the Illegal Immigration Reform and Immigrant Responsibility Act of 1996, which states a chief can waive all legal requirements if a wall, road, or other infrastructure is immediately needed.

The Center for Biological Diversity slammed the department's use of waivers and said the administration is ignoring 28 relevant laws to build a wall and issued the Thursday waiver despite having been in the midst of collecting comments from local residents on the plan.

“The Trump administration is ignoring thousands of people in Hidalgo County who don’t want these disastrous border walls,” Laiken Jordahl, borderlands campaigner at the Center for Biological Diversity, said in a statement. “The Rio Grande Valley is one of the most spectacular and biologically important landscapes in the country. Every acre is irreplaceable."

Trump campaigned in 2016 to build a "beautiful" wall between the U.S. and Mexico. When he took office in January 2017, the barrier between the countries' 1,954-mile border covered approximately one-third of that length.

In April, CBP announced several projects that would replace and build new barriers on 100 miles.

DHS had not published a waiver for the Arizona project in the Federal Register as of late Thursday.