ADVERTISEMENT ENVIRONMENTAL NOTEBOOK: Navigation system deadline extended | Volunteers swell for spring cleanup by Ashton Eley | Today at 2:43 a.m. Navigation system deadline extended The U.S. Army Corps of Engineers has extended the time allotted for public input to Aug. 13 for the McClellan-Kerr Arkansas River Navigation System's Master Plan revision, according to a news release. The master plan covers the classifications of all the federal land along the river within Arkansas' borders. The Corps' Little Rock district is looking to revise the 40-year-old plan with the consideration of factors such as environmental and socioeconomic, recreation trends and public input, project manager Dana Coburn has said.