Her Whanganui colleague David Cotton will continue to chair the council's catchment operations committee, as was his wish. His deputy will be new Tararua councillor Allan Benbow.
The two committees handle the bulk of Horizons' work, Keedwell said. All councillors can attend both.
Benbow will chair the audit, risk and investment committee, with new Horowhenua councillor Emma Clarke as his deputy.
The other new Horowhenua councillor, Sam Ferguson, is to chair the passenger transport committee, formerly chaired by Keedwell. His deputy will be new Ruapehu councillor Weston Kirton, who is already pushing for the Northern Explorer train to stop in Taumarunui.
Keedwell will chair the council's strategy and policy committee, and its regional transport committee, with Palmerston North councillor Jono Naylor as her deputy.