The state land and water described in AS 41.21.121 as the Chugach State Park is assigned to the department for control, development and maintenance, except that the Department of Transportation and Public Facilities is responsible for the repair and maintenance of all existing public roads within the park. The control of highway access and roadside structures within the Chugach State Park is the responsibility of the department. The Department of Fish and Game shall cooperate with the department to provide for those purposes under AS 41.21.121 relevant to the duties of the Department of Fish and Game. If, in the exercise of management responsibility under this section, conflicts of land ownership, jurisdiction, or authority are unreconcilable or unmanageable other than at an unreasonable cost and expense to the state, the commissioner after public hearing in accordance with AS 44.62 may modify, subject to the approval of the legislature, the boundaries of the Chugach State Park not to exceed 20 percent of the total acreage described in AS 41.21.121.