Supply of water to the fish ponds from a tidal river depends on the response of water level in ponds due to the tide motion through the weir and gate. The most simple case is introducing single fish pond connected to a tidal river and the flow over the weir can be applied Dr. M. Homma's equation. The patterns of flows over the weir are four cases. Those are free flow and submerged flow in both directions river to pond and pond to river. This paper is sumarized numerical analysis of water level respons in fish ponds using trial data and comparing to the measurement data from model experiment.