The White House has announced that President Obama plans to designate Browns Canyon, a popular whitewater rafting spot in central Colorado, as a national monument this week, according to the Denver Post. Doing so would give the area another layer of federal protection to about 21,000 acres around the Arkansas River.

Obama is expected to make the announcement in person on Thursday in Chicago, when he will also designate sites in Illinois and Hawaii as national monuments. The Hawaii site will preserve an area where Japanese Americans were held in internment camps; the one in Illinois will honor the Pullman area in Chicago, an important labor civil rights location.

Last year, Senator Michael Bennet (D-Colorado) and then-Senator Mark Udall (D-Colorado) tried to push a bill through Congress that would have protected a similar area near Salida, Colorado, but it failed to advance, the Denver Post reports. Bennet and Colorado Governor John Hickenlooper then urged Obama to protect the area under the Antiquities Act, which gives the president the power to set aside federal land for protection without approval from Congress.

The designation comes as republican lawmakers in Alaska promote a bill that would strip the president of the authority to designate national monuments. Representative Ken Buck (R-Colorado) echoed that sentiment upon learning of the Browns Canyon decision. “My message to the president is cut it out,” Buck said in a statement, according to the Post. “He is not king. No more acting like King Barack. That is not how we do things in the U.S.”

Some are concerned that the new national monument will neglect grazing and water rights for ranchers, but White House officials told the Post that the new protections for Browns Canyon would honor existing water and grazing rights. The land will be co-managed by the Bureau of Land Management and the U.S. Forest Service.

“Coloradans have been very clear they wanted this protection, along with assurances that existing uses will be protected,” Bennet said in a statement. “We’re glad the administration heard those voices and provided those assurances.”