Assumptions made in Lacey’s theory of canal design

Enumerate the Assumptions made in Lacey’s theory of canal design.

Solution:-

Assumptions in Lacey’s theory of canal design:-

(i) Lacey assumed that silt is transported due to eddies generated from the entire wetted perimeter of canal section and that the canal section achieves a semi – elliptical (or cup shaped) profile called as regime canal.

(ii) Grain size of the silt material is considered important in this theory which is related to sit factor as f = 1.75 (dmm)0.5

(iii) Kutter’s formula is used lacey’s theory for computation of flow velocity.

(iv) Lacey assumed that canal slope bears a definite relation with discharge which Kennedy didn’t considered

(v) Lacey assumed a constant discharge through the canal.

(vi) It is assumed that canal flows uniformly in an incoherent alluvium which bears the same characteristics as that is being carried by the canal.