Abstract:
In the present study design value of the roughness coefficient for a lined distributary (Chena distributary district Kasur) was validated and its effect on the water drawing capacity of outlets was assessed. Chena distributary, off takes from the left bank of Depalpur canal, at RD 359020. The total length of the distributary is 25.46 km. More than 50 percent of its length has been lined. In this study, a reach from RD 0.00 to 7590 having a trapezoidal lined section was used. The total numbers of outlets being fed by the distributary were 62. The first 17 outlets were included in the study. A comparison was made between design and field measurements of the hydraulic parameters of the canal and the outlets. Simulations of canal and outlet flows were made using the (Simulation Irrigation Canal) SIC model. A considerable difference was observed between the design and the prevailing water surface profiles and resultantly water drawing capacity of the outlets. The results showed that the prevailing value of the roughness coefficient was 0.02 instead of 0.016, the design value. Because of increased roughness coefficient value, due to sedimentation or due to some tempering, the depth of flow increased in the head reaches. Therefore outlets at the head were drawing more than allocated share. In the tail reaches due to reduced discharges, tailenders were deprived of their due share. Not only cleaning and maintenance of lined portion of canal at regular intervals but also strict regulations to avoid tampering are required for sustainable operation of an irrigation system as per design.
Page(s):
26-33
DOI:
DOI not available
Published:
Journal: Technical Journal, Volume: 26, Issue: 2, Year: 2021
Keywords:
Validation
,
Water Equality
,
Lined Distributry
,
Roughness Coefficient