This work evaluate hydrologic and hydraulic functioning of a couple of prototype hydraulic structure as used in natural channels of small agricultural watersheds, by generating some of the basic information & other relevant parameters for area under study. The overall values of key flow parameters ( h, v, E, n, Fr, Re) has been suitably worked out and analyzed, which all together gave a broad ranges under hydraulic structures with varied configurations in regards to discharges and the channel bed slopes. Physical model study play vital role in planning and designing of hydraulic structures. A vast review was done on updated progress on hydraulic structure and their relevant monitoring and evaluations in hydraulic flume as well as real channel flow conditions The discharges inside the hydraulic flumes were varying in between 0.5 to 5 L/s in majority of experimental runs. Similarly the channel bed slopes were kept varying in between 0.5 to 2 percent longitudinal slopes. Efforts are made to derive the real limits of flow conditions all along the channel with in depth evaluations of flow parameters, flow regimes, and all associated flow conditions. Also the values of Cd for a specific hydraulic structures are attempted here with an effort to further extend its applicability to similar ungauged situations. Not only the values of Cd are derived, but certain alternate predictive equations in this regards too also synthesized in this study.