diff --git a/calc_gate.c b/calc_gate.c
index 33c4911..3079fca 100644
--- a/calc_gate.c
+++ b/calc_gate.c
@@ -457,6 +457,10 @@ int Calculation_of_InstantaneousFlow(double *value,struct param_gate *param)
 				*value = cal_gate_control_with_submerged_flow(param->water_depth_front_of_gate,param->water_depth_behind_of_gate,\
 				param->openning_height_of_gate,param->gate_width,param->wingwall,param->drop_step);
 		break;
+		default:
+				*value=0;
+				return -1;
+			break;
 	}
 	return 0;
 }