A newly designed dam is to be modeled in the laboratory. The prime objective of the general model study is to determine the adequacy of the spillway design and to observe the water velocities, elevations, and pressures at critical points of the structure. The reach of the river to be modeled is 1200m long, the width of the dam (also the maximum width of the reservoir upstream) is to be 300m, and the maximum flood discharge to be modeled is 5000m³/. The maximum laboratory discharge is limited to 0.90m³/, and the floor space available for the model construction is 50m long and 20m wide. Determine the largest feasible scale ratio (model / prototype) for such a study.