The Marquette Reservoir. The inside dimensions of the new reservoir at Marquette. Mich., will be 46×48 ft., the outside dimensions 50×50. The concrete walls are to be 2 ft. thick at the base and will taper to a thickness of 12 in. at the top. The walls will be 12 ft, in height. The concrete floor of the reservoir is to be 5 in. thick and will have a drop of 4 in. to the drain-pipe, which will be 4 in. in diameter and 6 in. below the floor. The inlet-pipe from the pumping station will be 12 in. above the floor of the reservoir.