Pathanamthitta: The swelling waters in the Manimala River, locally known as Manimalayar, wreaked havoc on its banks as the eastern parts of Kottayam district bore the brunt of heavy rain in the last couple of days. The water level in the river, which cuts through South and Central Kerala, rose by seven meter in five hours in the heavy rains that occurred on Saturday! Old-timers in the region aver that this could be the first time that the water level rose to such a height in the river.
This record water level was recorded in the meter reader installed at its tributary, Pullakayar. This mark went 3 m above the water level which was recorded during the floods that occurred in the year 1924, which is better known among Malayalis as "99-le vellapokkam".
It is estimated that heavy rains brought about by atmospheric low pressure and the accumulated sand deposits in the river contributed to the floods as well as to a series of landslides on the sloppy areas on the banks of the river.
According to the satellite images released by the Meteorology Department, the extreme rain hit almost 20 micro-level watersheds (drainage basins) in the gateway to Idukki high range, from Kanjirappally to Peerumede on the borders of Kottayam and Idukki district.
It is estimated that the heavy rain hit almost 100 square kilometer area on Saturday.
A geographical study of Poonjar, Kanjirapally and Peerumedu indicates that the heavy rain and the resultant landslides mainly hit the hilly terrains, which are having a slope of minimum 15 degrees.
The water equivalent to that of the total storage in one or two dams were literally received as rain in the areas on Saturday, in deaths and destruction of property.
There was every chance of soil becoming fragile on the impact of the rain of 10 cm or above magnitude which occurred for more than 5 to 10 hours.
The Manimala River and the Meenachil River do not have dams in their course. It seemed that the rain water, which first shook soil and rocks and entered the underground, might have resurfaced as landslides through different hill slopes.
Interestingly, the floods did not affect the Cheruvally Estate, where the Sabarimala airport is proposed. Though the low-lying areas in the panchayats of Manimala, Erumely and Vellavur got fully inundated, not a single area in the Cheruvally estate was affected by the floods.
The Cheruvally estate has 24 small hills. The presence of small streams might have prevented the rise of water level in the estate. The absence of big hills might be the main reason landslides didn't happen there.
Since the water from the estate goes through small streams to the surrounding Manimala River, the area is not usually affected by torrents and the resultant flooding. The nearby areas that come within 10 km radius of the estate such as Kuruvamoozhi, Vizhikkithodu, Kannimala Road, Koratty, Erumely bus stand, Mungani and Manimala were submerged in flood water.