The National Park Service has released for public review an Environmental Assessment/Assessment of Effect for the expansion of the sewage lagoon at Walnut Canyon National Monument. The Environmental Assessment/Assessment of Effect (EA/AEF) was prepared according to the National Environmental Policy Act (NEPA) and the National Historic Preservation Act (NHPA), applicable regulations, and agency procedures. The EA/AEF analyzes the environmental impacts of two alternatives: 1) no action and 2) expansion of the existing sewage lagoon. Impacts to geology/soils, vegetation, wildlife, special status species, cultural resources, and visual quality are described in the document. This notice is an opportunity for the public to identify any issues or concerns they may have regarding this project during the 30-day comment period.