By Rene Marsh, CNN

(CNN) -- Key provisions in the Clean Water Act are now under the control of one person at the US Environmental Protection Agency -- Administrator Scott Pruitt, according to a leaked memo obtained by CNN.

In the new directive, Pruitt states he will make final critical decisions about preservation of streams, ponds and wetlands.

Public Employees for Environmental Responsibility provided CNN with a copy of the memo dated March 30, 2018. In the memo calling for "regulatory certainty," Pruitt directed EPA regional offices to "cede their Clean Water Act determinations" to him, said Kyla Bennett, the New England director of Public Employees for Environmental Responsibility.

The memo states: "With this revised delegation, authority previously delegated to regional administrators to make final determinations of geographic jurisdiction shall be retained by the Administrator. ... As part of effectuating this revision, I ask that you involve the Administrator's Office early on in the process of developing geographic determinations."

The move appears to change the approval process to lessen the role of EPA employees and scientists when it comes to evaluating whether a project has a significant negative environmental impact on waterways or wetlands.

These projects could be anything from transportation projects to new residential housing, coal mining, oil projects, even President Donald Trump's border wall or "any other project that discharges ... fill material into a wetland or waterway," according to Public Employees for Environmental Responsibility.

The projects must receive permits from the Army Corps of Engineers and final approval from the EPA. Traditionally, regional EPA offices and career EPA scientists review the requests for permits to determine whether the project is detrimental to the local environment and the larger goal of waterway and wetland preservation.

Environmentalists are sensitive to this because they say waterways, streams and wetlands are critical to the drinking supply and flood storage due to the impact of climate change. They're also necessary for fishery and wildlife habitats.

Scientists from the regional EPA offices go into the field to make the assessments.

"Now a man in DC who knows nothing about local environmental conditions will be making the decisions about wetlands and waterways he's probably never seen," Bennett said.

Before this memo, if a regional office determined it was best to veto a project proposed by the Army Corps of Engineers, EPA headquarters would approve the veto, Bennett said. "Headquarter approval was just a rubber stamp because they knew regional offices and scientists had the expertise," she said.

CNN has reached out to the EPA for comment.

"This action subjects safeguards for clean water across the US to filtration through one politician's hands," said Bennett, an attorney, scientist and wetlands specialist who formerly worked for the EPA. "Every corporation that wants a pass on Clean Water Act compliance is invited to privately meet with the most user-friendly EPA administrator in history."

Bennett pointed out that last year, Pruitt announced a plan to shrink by as much as two-thirds the scope of the protected "Waters of the United States" rule that defines the jurisdiction of the Clean Water Act. Now, without waiting to outline, let alone complete, his legal rewrite, this new move will unilaterally nullify current standards, Bennett said.

"This latest move by Pruitt is his Plan B, as it is becoming increasingly clear that his Clean Water rewrite plan is illegal and will be tossed out in court," she said.

One of the authorities that makes the EPA powerful is its ability to review and veto permits for building projects.

Bennett says the move "emasculates" the agency.