The proprietors of two or more canals, ditches, reservoirs, or other works, taking water from the same source of supply, may, by a consent in writing of those entitled to the use of the water therefrom, agree in like manner for the rotation of the whole or any part of the water lawfully allotted from such stream or source of supply to such ditches, conduit, or other works, in such way and manner and for such time as may be in such agreement specified: Provided, however, That the rotation of the water to which the several consumers, parties to such agreement, are entitled shall not be conducted in such manner as to diminish the supply of water to which any consumer of water from any other ditch, conduit or other works may be entitled.