Rain water, a major natural resource of Kerala

Kerala depends, to a large extent, on rain water for its water needs. If in a particular year rain fails the State faces drought. Kerala's rainy season is generally divided into two parts based on the wind direction, the first one is South – West monsoon and the second North – East monsoon (the word Monsoon is derived from the Arabic word 'Mouseen' meaning 'seasonally happening' ).

Traditionally the first portion is known as 'Edavappathi', meaning half of Edavam, the Malayalam month. This season starts on the first of June, which coincides with half of the Edavam month, every year and extends up to August end. Almost every year June – July period gives maximum rain. The second season is in October – November, which coincide with the Malayalam month Thulam, hence called Thula- varsham in Kerala.

Sixty percent of Kerala's total rain is estimated to be from the South-West monsoon. The North – East monsoon's share is about 25%. The rest is from rains during other months, especially the rain during summer periods.

The average total rain fall estimated for Kerala is 300 cm, estimate based on previous readings, which is more than the nation's total average (119 cm) almost two and a half times. But there are years in which the rain fall is less than this rate, one such recorded rate is 224 cm. If we look at the month-wise data, the maximum, 68.72 cm rain is in July, followed by 65.32 cm in June. Minimum, 1.46 cm, is reported in January. The rain figures of the four months, December, January, February and March are less than 10 cm. Unlike the Northern States where the melting of ice adds to the water availability, Kerala faces the problem of shortage of water when rain fails since no other source of water is available here. Ground water stock also will be affected by the shortage of rain.

Rainfall is not uniformly distributed in every districts of Kerala. It is generally more in the Northern districts. Quantity of rain shows a decreasing trend when moved towards South. From East to West also almost a similar trend could be seen. If a specific place is considered Neriyamangalam is getting maximum rain (on an average 451 cm). Top ten places getting maximum rain are either in the North or in the East.

Kerala's topography is typical with mountains on the East and sea on the West. Forty four rivers originate from these mountains and forty one of them flow westward (three of them flow eastward) to join the Arabian sea. It is estimated that 7,000 to 8,000 crore cubic meters of water is flown through these 44 rivers. This quantity works out to something slightly more than 65 % of total rain water. Thus maximum quantity of rain water join the sea through these rivers. And at present, because of human interference on rivers almost within twenty four hours the rain water is taken to sea causing water shortage problems on the banks of these rivers. Sand mining is the major problem faced by rivers which causes irreparable damage to the environment of the river and its surroundings.

It is the lakes in Kerala which retain water to a large extent. There are 32 natural lakes out of which three are fresh water lakes. Others are located near the sea, hence the water get mixed up with sea water and are brackish in nature. Vembanad lake, extended in the three districts, Ernakulam, Kottayam and Alappuzha, is the biggest of the lakes with an area of 15,846 hectare. Ashtamuti lake with 6,424 hectare area stands in the second place. Sastham kotta fresh water lake, Vembanadu lake and Ashtamuti lake have been included in the Ramsar sites and actions are underway to protect and preserve them as per the specification of Ramsar agreement.

Rain water being the major natural source of water every step has to be taken to protect and preserve it. The steps to propagate and implement rain water harvesting at all possible locations are a major step taken by the authorities. All the new buildings are to provide provision for preserving rain water falling on the roof. Steps are to be taken to check the flow of complete water through the rivers by constructing check dams at different locations.

Forest conservation is another major action to be strictly followed. Tampering with hills and mountains must be stopped totally, so that rivers will not get filled with soil . This filling of soil reduces the water storing capacity of rivers. So a proper planning and management mechanism will be a must in order to address the water shortage problem the State is going to face soon.