WHERE THE GROUND SLOPES ARE GENTLE,IT MAY BE PROTECTED BY WAY OF BUILDING SOLID AND HIGH APPROACH ROADS ,IN CASE OF FLOOD WATER SPILL OVER ONE OR BOTH THE BANKS OR RELIEF CULVERTS MAY BE DESIGNED .

The rainy season is going from bad to worst in the hilly state of Himachal Pradesh and in addition to land slides on various roads of the hill terrains some of alluvial streams in plain profile and levels natural width is required as to much in excess of that required for regime, particularly in the Balh area of Sunder Nagar and Mandi circle,said width required for stability has lost it's natural profiles due to increase in water and silt factor which could not be protected without providing the training works and increase of the road level however no such provision and control has been arranged by the National High way authority of India .As for as in the case of plains where the ground slopes are very gentle and the natural velocities of flow in streams are also very low and the flood water may spill over one or both the banks of the stream at places .In case where the bulk of the discharge is carried by the main channel and a small fraction of its flow over the banks ,strikes high ground at a short distance from the banks ,it can be forced back into the stream and made to pass through the bridge .This can be done by building the approach roads of the bridge solid and high so that they intercept the over flow .In such type of arrangement the linear water way of the bridge must be ample required to handle the whole discharge without detrimental afflux .Also the top level of the approach roads must be high enough not to be overtopped .Some times however the overflow spreads far and away from the banks,where the ground level falls continuesly away from the banks of the stream .In such cases it is impossible to force the overflow back into the main stream .The correct way is to follow and pass the overflow through the relief Culverts at suitable points in the road embankment however these culverts have to be carefully designed,they should not be too small to cause detrimental ponding up of the overflow, resulting in damage to the road or some property ,nor should they be so big as to attract the main current.