Government of Bombay Public Works Department Technical Paper No. 26. Report on Tests Made on a Model of the Group of Regulators at Oderolal at Mile 169 Approximately of the Rohri Main Canal Sind

(c) To find the loss in head through such of the Regulators as are designed for no afflux " conditions and (d) To examine generally the suitability of the whole " lay out." Further :— (e) When the experiments were started a study was made of the distribtion of flow at the surface and bed with a view to ascertaining the probable behaviour of the Regulators in regard to silt draw-off under dif [...] The drawdown in surface round the upstream entrance curve to the Nasir Branch was less pronounced and the working of the other channels the entrances of which were altered was improved by the changes made. [...] the Nasir Branch and the Escape) conditions for full supply discharge are very interesting/ In both cases the surface flow coming round the upstream entrance curve of approach channels crosses diagonally to the other side of the approach and then dives downwards and turns back diagonally along the bed towards the upstream (referred to Main Canal) side of the approach channel. [...] Surface water which strikes the end of the Downstream approach channel curve but does not enter the approach channel dives downwards along the side of Main Canal flume and turns on reaching the bed towards the centre of the M. C. flume thus pushing the bed flow lines and the bed silt away from the edge of the flume towards the middle of the stream. [...] therefore there is a distinct spiral tendency the surface water diving down to the bottom and then tending to converge towards the middle of the stream thus squeezing the bed water—containing the heavy bed silt—towards the middle of the stream.