Sudath Gunasekara 

31.5.2017

The immediate cause of all these disasters is rain. But we all know we cannot stop it. No can we control it either. But certainly we can control and mitigate these disasters by visionary thinking, proper planning and good management.

The most important cause of this calamity as I see it is the land degradation on the upper watersheds. What we witness today is the cumulative results of centuries old land degradation on the upper watersheds caused by large scale removal of the forest cover and indiscriminate and inappropriate new land use practices on the hills by the British for coffee and tea plantations.

Kelani Valley Railway Commission 1894

The earliest concrete evidence of the impact of large scale deforestation on the upper watersheds and colonial land policies on land degradation, earth slips, downstream siltation and heavy floods is found in the Report of the Kelani Valley Railway Commission 1894. In his evidence before the Commission F Lewis an Assistant Conservator of Forests observed that ‘at one time the Kelani river could be made use for rafting of woos, I have had the frequent occasion to use of it; but this is now, year by year becoming more difficult owing to the large sand deposits in long sweeps down the bed of the river. The increase area of land in tea is distinctly the cause for this silting of the river, is a fact that I presume will not be disputed.

The Kelani river (90 miles) was obviously navigable up to the rapids above Yatiyantota (which is about 50 miles from the sea) before the advent of the plantation agriculture, and this sand problem in the river was cited as one of the major reasons for the opening up of the Kelani Valley Railway.

Besides many reports of Commissions and Committees of inquiry appointed by the Government from time to time, repeatedly stressed the damage caused by opening of land for plantations (Eg XL11 of 1905,X11 of 1921 and 111 of 1931) Besides landslides and large scale land degradation have also been  other  disastrous results of deforestation. Its effects on the physical stability of the Islands geographical Heartland, damage done to human life and the economy over the years was enormous. For example the landslides of 1986 claimed some 51 lives and affected 100,000 families The 1989 landslides claim 300 lives and the damage to economic infrastructure was around Rs. 2800 million (Perera 1992) The report on Kotmale landslides and the adjoining river catchments (Sessional paper XV11 of 1954 by Mac Largan Corrie has been described as the most comprehensive report on Lands slides in Sri Lanka by Madduma Bandara.

Plantation Agriculture involved the complete removal of the natural forest cover that protected the central hills for millions of years from the major parts of the upper watersheds. Out of about 13,110 km2  in the hill country (that is 20% of the total area of the Island) today less than 158,000 ha are left as natural forests (NRSR 1991) In other words almost over 80 % of natural forests on the central watersheds has been removed for plantations by the British.

During the pre-colonial times the whole hill country with the exception of few settlement pockets in the river valleys below was fully covered and well protected by natural forests

In addition to deforestation, new land use practices introduced by the British that followed indiscriminately without any understanding of or regard to the disastrous outcomes that would result owing to steep slopes, heavy rainfall and degraded lands on the central highland of this country in opening up of plantations also aggravated earth slips, siltation and heavy floods in downstream areas, causing heavy economic and social losses.

Therefore as a first step, perhaps as the most important, I suggest that we restore the original forest cover on the central watersheds by banning all cultivation above a given contour, say for example 5000 ft above msl and declaring them as strict natural reserves, like in the olden days. This will increase the perennial river flow providing sufficient water for the dry zone tanks even for three seasons , enhance the islands hydroelectricity potential,  arrest land degradation, restore physical stability of the watersheds, improve the ecological balance, minimize earth slips and mitigate downstream silting and floods.

This should be immediately followed by a sustainable land use policy for land below 5000 ft as well. It could be tea or mixed plantations promoting the Kandyan garden type model that is considered to be the next best to the natural forests in protecting the land degradation by minimizing erosion.

This   upper watershed restoration has to be followed by a comprehensive plan of action in the downstream areas to protect the river banks by banning illicit buildings along river reservations, widening physical         bottlenecks like in the case of Kaluganga and regular removal of sand bars at the mouths of main rivers.

However, none of these steps can find a permanent solution to earth slips and heavy floods until and unless we rehabilitate and restore the physical stability of the upper watersheds to their original conditions by restoring the original forest cover.