Cross Drainage

Cross drainage work involves the construction of a drainage system at the crossing of a canal which helps to dispose drainage water without interrupting the continuous canal supplies. The cross drainage work can be reduced but never avoidable. reduction in cross drainage work is possible by the alignment of artificial canals along the ridge line called water-shed. Cross drainage works are not essential once the canal reaches the water shed line. Aqueduct and symphon aqueduct is a type of cross drainage work, where the canal is taken over the natural drain in such a way that the drainage water runs below the canal either freely or under syphoning pressure. In super-passage and symphon method, the drain is taken over the canal in such a way that canal water runs below the drain either freely or syphoning pressure. In the level crossing method, the canal water and drain water are allowed to intermingle with each other. Choice of cross drainage work depends on many factors such as  suitable canal alignment, nature of available foundation, position of water table, availability of dewatering equipments, head loss in canal, suitability of soil for embankment and of course the availability of funds.