OTTAWA — A public hearing on new flood plain maps will be 6:30 p.m. Thursday at Ottawa City Hall. The Federal Emergency Management Agency have redone flood maps for the Ottawa area and reflect more detailed research of flood levels especially along Rock Creek and Nugent Creek, said assistant city planner Tom Yahl. The new maps could have some significant changes including especially in areas south of Ottawa that have some development planned, he said. The property owners have been working with city, state and federal officials to resolve the issues, he said. The city is also planning another public hearing on changes in federal rules regarding the city’s levee system, he said.