How Canal Alignment should be done ?
Canal Alignment should be done in such a way that
- It should serve the entire area proposed to be irrigated.
- Cost of construction including cross drainage works should be minimized.
- A shorter length of canal ensures less loss of head due to friction and smaller loss of discharge due to seepage and evaporation, so that additional area may be brought under cultivation.
- A canal may be aligned as a contour canal, a side slope canal or a ridge canal according to the type of terrain and culturable area.
A contour canal irrigate areas only on one side of the canal.
- Where canal crosses valleys, different types of cross drainage works are required.
A side slope canal is aligned at 90 degree to the contours of the region.
- A watershed or ridge canal irrigate areas on both sides.
- Cross drainage works are eliminated in case of ridge and side slope.
- Main canal is generally carried on a contour alignment.
- Branch and distributories take off from a canal from or near the points where the canal crosses the watershed.
- There should be Consideration of economy in alignment of contour canals.
- All possible alignments should be studied and the best suited alignment should be selected.
- Number of rinks and acute curves should be minimized.
- They should be aligned as far as possible in partial cutting partial filling.
- Deep cutting should be avoided by comparing the overall cost of alternative alignments.
- A canal section is economical if there is equal amount of cut and fill.