Yamuna is the main river of Union territory of Delhi which flows in its Easterly direction from North to South. This river is an alluvial river and hence has got a meandering tendency. In the past this river has caused serious flood problems in U.T. of Delhi by inundating large areas during flood season, and disturbing the normal life of Delhi-ties. Prior to construction of Shahdara Marginal Bund and Left Marginal Bund in 1956, this river used to inundate the trans-Yamuna areas very often (nearly every year). In right side also before construction of Right Marginal Bund in 1977-78, the most of the areas of Northern Delhi in Alipur block used to be inundated under deep waters. This has been the result of inadequacy of flood protection measures adopted in Delhi area in the past. Even in 1978 floods i.e. after the construction of Right Marginal Embankment upstream of wazirabad upto Delhi-Haryana border the area of Alipur Block and even Model Town colony of Delhi city area was inundated in deep water due to a breach in this embankment. The main city areas of Delhi and New Delhi and Trans-Yamuna Area of Shahdara Block are although protected by embankments but there also remains a danger to breaches which may endanger the normal life of the residents in these areas. The floods of the years of 1924, 1947, 1955,1956, 1967, 1971, 1975, 1976, 1978 are the main examples of the flooding in River Yamuna when the normal lives of the residents of Delhi were either disturbed or threatened, badly.
History of Past floods by River Yamuna :-
Nearly every year there is flooding in River Yamuna, the intensity of which may be low, medium or high. The general water level of Yamuna at old Rly. bridge during dry season is found to be nearly 202.00 m (662 to 663 ft.) The low intesity floods are those which are below warning level i.e. 204.22m (670.00 ft.). During this type of flood, the water generally remains within its regime and no danger is created to life and property. However due care is to be taken by departmental officers to keep a watch on the future discharges, the information for which is to be collected from Tajewala head works, the controlling point in the upstream. The floods attaining water levels above 204.22m and below 205.44 m (674.00) are called medium floods. In this type of flood, the water spreads out of the regime and touches the embankments constructed on both sides
At this stage back flow starts in most of the drains out falling in Yamuna and hence their regulators have to be brought in operation. The patrolling for watch & ward of embankments is to be intensified and done during day and night. Proper watch is kept on seepage points already earmarked and proper check is kept for new seepage points also. When the level in river goes above 205.44m (674.00 ft.), the flood is termed as high flood. During this type of flood proper care is to be taken for watch & ward. The Head Quarters of AE and JE during the period is required be fixed at site to keep a proper watch on the flood situation and the patrolling. As per available records, during the last 40 years, the following years have been the high flood years for River Yamuna, when the water level in the river at old railway bridge was observed to be 206.0m or more.
Years :1967, 1971, 1975, 1976, 1978, 1988, 1995 and 1998
Flood of 1978 :-
Out of the above the flood of 1978 has been the highest recorded in the available history of River Yamuna which was recorded as 207.49 m (680.75 ft.) on 5/6 September, 1978 at Delhi Old Railway bridge, with a discharge of 7175 cumecs (2,53,350 cusecs). The right marginal bund between palla village and Bawana Escape out-fall also breached which caused a very large area of Alipur block and urban colonies like Adarsh Nagar, Model town, Mukerji Nagar submerged under deep water. Apart from the damages estimated at nearly Rs. 10 crores, eighteen lives were lost and thousands of people were rendered home less. On the left bank also Shahdara marginal bund reached the point of distress but could be saved by raising its heights in certain reaches with earth filled bags.