(2) that a county road, bridge or watercourse which is under the exclusive control of the county corporation, shall for the future be a local road, bridge or watercourse under the control of the corporation of the local municipality in which it is situated, or which it separates from another municipality.A county corporation, after having declared that a local road, bridge, or watercourse shall be a county road, bridge or watercourse, may, when occasion requires, determine by by-law or procès-verbal, which corporation shall be liable for the construction, opening, maintenance and repair of such road, bridge or watercourse, and may declare in such by-law or procès-verbal what proportion each corporation shall contribute.