(1) Whenever it shall appear to the director that a master program should be developed for a region of the shorelines of the state which includes lands and waters located in two or more adjacent local government jurisdictions, the director shall designate such region and notify the appropriate units of local government thereof. It shall be the duty of the notified units to develop cooperatively an inventory and master program in accordance with and within the time provided in RCW 90.58.080.

(2) At the discretion of the department, a local government master program may be adopted in segments applicable to particular areas so that immediate attention may be given to those areas of the shorelines of the state in most need of a use regulation.