At the local level also human actions have heightened the danger of flood through the cutting of trees in the mountains as well as in the plains. In the case of India, the ecological damage through deforestation of the Himalayas has lead to large-scale erosion of the mountain slopes and high levels of siltation. This leads to deposition of silt on the riverbeds in the plains and hence spill over of water whenever the volume in the river reaches a certain level. With siltation on the river beds, flooding occurs even at very shallow water levels. The vulnerability of the population has increased substantially because of population pressures, symbolized, for instance, by the stubborn and perhaps helpless settling of slum dwellers on the banks of the river Yamuna in Delhi, which is merely a trickle most of the year, but bursting its banks during the monsoons as has been the case this year.
Flood forecasting is critical to minimizing the damage from floods.
It is for this reason that the Central Water Commission has set up a network of forecasting stations, which cover the most important flood prone interstate rivers in the country. These stations produce forecasts that are used to alert the public and to mobilize various official agencies so that they take both preventive as well as relief measures whenever required. However, even in cases where forecasts have been timely and generally accurate, people have often been reluctant to move away, because in most cases they lack the means and physical options for moving away from a danger zone to one that is relatively safe. In the case of flash floods, forecasts are difficult to make, and often the time available for relief is very short. For instance, this year as early as June flash floods resulting from heavy monsoon rains affected about a quarter million people in the state of Assam itself.