A canal is a hydraulic structure, which is providedto convey water from a source to a required point. Lining is a coating provided in the surface of canal section to prevent seepage loss and to provide stability to the section. The lining may be uniform lining, csame lining material with uniform cost is provided over the cross section of the canal then it is termed as uniform lining. When different lining material with non uniform cost is provided over the cross section then it is known as compositeuniform lining. When lining is provided either the base or the sides then it is termed a partial lining. In practice generallis provided over the cross section. In this study, an attempt has been made to design an optimal canal section wminimum cost of lining material. Free board is also considered in the design which is considered as discharge dependent as weUniform Lining, Composite Lining, Partial Lining,Optimal Canal SectionProfessor and Head, Dept. of Civil Engg., KITS, Ramtek Email (corresponding author): atmapoojya@yahoo.comAssistant Professor, Dept. of Civil Engg., KITS, Ramtek9 obtained by minimizing the cost of lining materialsovided with composite lining. Free board is also PARAMETRIC RELATIONSHIPS- The flow area A and wetted perimeter ‘P’ of a trapezoidal section as shown in Fig 1 are The cost of lining C for the section per unit length of the = cost of lining material in Rs per sq.m for the base= Cost lining material in Rs per sq.m for the sidesFor the flow computation, manning’s equation is used and the section factor can be expressed asWhere, R = hydraulic mean depth, Q = discharge J. Indian Water Resour. Soc.,Vol. 39, No. 1, Jan., 2019 OPTIMAL CANAL SECTION WITH MINIMISING LINING MATERIAL COSTto convey water from a source to a required point. Lining is a coating provided in the surface of canal section to prevent seepage loss and to provide stability to the section. The lining may be uniform lining, composite lining or same lining material with uniform cost is provided over the cross section of the canal then it is termed as uniform lining. When different lining material with non uniform cost is provided over the cross section then it is known as composite lining or non uniform lining. When lining is provided either the base or the sides then it is termed a partial lining. In practice generally composite lining is provided over the cross section. In this study, an attempt has been made to design an optimal canal section with consideration of minimum cost of lining material. Free board is also considered in the design which is considered as discharge dependent as well as depth