Sri Lanka’s Dry Zone; a Misnomer, and its repercussions

By Dr. J. Handawela
jameshandawela@gmail.com

Background

Since Independence the key development policy pursued by the Lankan government has been large scale irrigated paddy farming in the Dry zone (DZ), in the hope of ushering in the same prosperity of its past, particularly the Parakramabahu era (1153-1186). Perakum Yugayak Nevathath Arambaw was a widely flown rhetoric. However, even by about 1985, when the much banked on mighty Mahaweli irrigation project was almost complete, there were no clear signs of the expecte prosperity ever dawning, prompting some citizens to feel skeptical about the whole approach followed to develop the DZ, and thereby the country. I am one of them and see the reason for it as the authorities considering the DZ as being plagued by dryness, farming there requiring additional water as an external input.

In 1994, after leaving formal employment bound to the government, opportunities came on my way to gain a clearer understanding of the DZ’s climate, particularly its implications on agriculture on DZ land. These opportunities, experienced for the first time in my career life as a student of soil science, took me into remote parts of the DZ, spared by the bulldozer that had ripped off DZ’s land to launch major paddy irrigation schemes in all peripheral DZ districts. There, I could see signs of a range of traditional land development measures applied to enable farming, both in a ruined state and in live form. Where it was live, I saw the environment and life there being pleasantly close to nature and safe and sound unlike in major paddy irrigation project lands I had been long accustomed to.

Excitement caused by seeing them evoked an interest in me to seek authentic knowledge on social and farming history of DZ, over and above genuine praise showered on it by local senior farmers. I read Mahawansa and writings of R.L. Brohier, Robert Knox, Leonard Woolf, Emerson Tennent , D L O Mendis, M.S. Randhawa etc., all for the first time in my life, deeply regretting not having read them before.

Following is a gist of what I learned, much of which newly.

Traditional DZ farming has been heavily reliant on local rainfall, received during the main rainy season from October to December and the minor one in April. It has been a highly successful habitat development and farming enterprise.

It has been crucial for it to commence with the onset of rain in October, not only because it broke the four month long rainless weather but also to benefit from the atmospheric character in October over the area which is highly favourable for seed germination and plant growth. The latter reason is implicit in the Sinhala term for October, Vap, which means (time for) seed sowing. Of the two types of crop fields the farmers had: upland Hena and lowland paddy plot, where the farmers first rushed to with the onset of rain was the former for obvious reasons, letting the latter wait until it had also received some runoff and seepage water from adjacent upland and become fully water secure for a crop of paddy.

Though much welcome, the seasonal rain is often too harsh for direct use, as it is, for cropping. Its high intensity causing soil erosion and heavy rains falling over two to three straight days causing flood need to be addressed, and the impacts mitigated and overcome. For that the farmers had chosen individual small watersheds which offered a suitable land base to confront rain, tame its harshness and harness its water for farming, all within their confines. This enabled hazard free farming when it rained and where it rained, without having to forego early rainy time from the cropping calendar or to provide for undue storage and transmission (water) losses we hear of in conventional irrigation.

Specific rain water management measures applied within small watersheds are earthen bunds falling into four types: (1) slender long strips of bund (Wetiya) on the upper aspects of the watershed to delay runoff build-up and slow down runoff flow rate, (2) gulley plugs across transient stream channels to hold up water as water holes ( Wala), (3) further down the stream channel, bunds to hold relatively larger volumes of water Wila and at the very bottom of the small watershed, a larger and stronger bund to hold even more water, both on land surface and in the ground around and beneath it Wewa. All four devices have provision for surplus water to flow out, without hurting the bunds.

Worth reiterating, the unique land layout of the small watershed provides the ideal physical landscape structure to apply the above mentioned measures to delay runoff initiation, slow down runoff flow, check soil erosion and give more time for water to seep into the soil and the ground below, particularly in association with Wewa. They enable commencing upland cropping with early rains, growing of crops fully relying on local rainwater, and equally importantly, generating a ground water resource from rain water.

Crop production could be extended beyond October-December rainy season by choosing crops adapted to lower soil moisture conditions. In some years, it could extend to link up with shorter duration April rains, enabling a cropping period of about eight months. Farmers grew a variety of crops producing a basket of food staples (not only rice) for year round use. The ground water resource generated saw them through the rain water scarce months June-September. All these, thanks to judicious management of rain water, on time and in-situ.

Above observations point to the realization that the wet seasons, October- December and April deserve full credit as characterizing the climate of the DZ, adding value to it and making their beneficial effects felt through the whole climatic year: crops from October- May and ground water, year round.

What matters most is the wisdom the ancient farmers had to understanding that the DZ was wet, at least adequately and not full scale dry. Perhaps it is this wisdom that had brought prosperity to the area, at a time when irrigated paddy farming was little known, prior to initiation of Rajarata kingdom, as reported by archaeaologists Roland Silva and Shiran Deraniyagala ,separately.

Look at the successful farming enterprise in Jaffna, which is even less wet than the inland DZ but manages with local rain, with no need for extraneous water. The reason behind is natural shallow aquifers, which store surplus rain water as a ready source of water for farmer use during the dry months. This makes Jaffna not lament over dryness but appreciate and enjoy its wetness. Ancient DZ farmers, whose soil was less porous to take in rain water and had no natural aquifers, had overcome those limitations by giving more time for rain water to seep into their soil of low porosity and creating an artificial ground water storage facility in association with Wewa in the farmed small watershed.

By the way the term Wewa, being a derivative from “Wapi” – Sanskrit term for water- well, is not a spring or a source of water for flood irrigating a downstream crop as many of us take it to be. It in Sri Lanka is a well of some sort that has created its own ground water support base. In Gujarat, India where the very term Wew is in use, it refers to large wells dug into deep ground water, and they are for community use and habitat enrichment and categorically not for irrigation.

What is stated above is an ideal transcending from my personal experience and observations on a topic of interest and concern to me. Key inferences possible from it are that the climate of DZ is more wet than dry, the ancient farmers saw it in correct perspective and made a success of it, but the modern DZ developers have caught the wrong end of the stick. I want to share these thoughts with like minded researchers with a view to reassessing our current knowledge and understanding of DZ’s climate and its bearing on farming on its land. Emphasize that this is not a simple matter to shrug off but to be concerned with as a real issue with serious repercussions.

DZ ; a misnomer

For an area to be called dry its potential evapotranspiration over the year must exceed annual average rainfall. On this account the Sri Lanka’s DZ is not dry. Though not as wet as the Wet Zone, its annual average rainfall of about 1500 mm is only 25% less than the lower end annual rainfall figure for the Wet Zone, making it 75% as wet as the latter, and hence not its exact opposite.

This rain, though somewhat limited to four months, October – December and April, its residual effect is long lasting rendering the whole period from October to May quite wet during which its evergreen natural vegetation, symbolic of wet environments, not showing any major sign of withering. This leaves only four months June- September with a semblance of dryness.

DZ’s relief with soft contours shows that what has shaped its terrain is wetness and not dryness. In dry environments the contours are rugged.

Common climate related hazards in the area are soil erosion by runoff and damage to crop, property and even death by drowning by flooding, all of them problems associated with wet environments. Drought related incidents like forest fires, heat waves, death from desiccation etc. are very rare.

Most visitors to Sri Lanka see it as a green island. They would not say so if they saw two thirds of its land which make up the DZ as dry.All these point to DZ’s climate being more wet than dry, with the wet months October-December showing up as its most characteristic and hence the climate defining season, affirming that the term DZ is a misnomer for the area referred to by it.

Repercussions

The modern developers, who chose to focus on DZ’s dryness which is a mere negativity – deficiency of water – as its diagnostic character and the key limitation to its development over its wetness, which is a positivity – abundance of much desired water, though fraught with risks which however could be overcome by judicious management as discussed above – may not have foreseen its serious repercussions. The more serious of them are;

Spurning of DZ’s wetness-reliant traditional farming, which is a unique system of indigenously evolved watershed farming as being primitive, destructive on forest etc. denying it policy support and access to new scientific knowledge on modern farming has led to its degeneration and extinction with no prospect for its survival. This is a clear case of elimination and eradication of a valued heritage.

A key component of the above system of farming is Hena farming, It has been singled out and unjustifiably blacklisted as being utterly destructive on forest, more strictly subjected to severely restrictive regulations against its practice. Dereliction of such a farming system, that is so well adapted to the DZ environment and when wisely practiced is not only productive but also supportive of local ecology can lead to its extinction.

Overemphasis on dryness focused farming has led to excessive forest clearing to make provision for accumulation and application of water as an external farm input has also led to supply shortages of local timber, locally grown non-rice foods, rapid decline in forest cover, worsening human- elephant conflict etc.

Most farmers provided with water for free as an external input too fall into the category of state subsidy dependent population, casting doubts as to whether they are net producers relative to heavy investment made on them and ecosystem sacrificed to support them. Statistical records show that contribution made to GDP from districts where such farming is widespread is very low.

In the DZ drainage system, primary valleys are the source points of stream water. When their wet weather hydrology is properly managed for wetness-reliant farming, downstream flooding gets mitigated. This helps downstream land use. Modern management measures designed on the basis that the DZ is dry consider upstream small watersheds as unworthy of management and best left as mere catchments to extract water, without involving them even as stakeholders in rain water harnessing. Its repercussions are increased downstream flood hazard during rain and worsened water scarcity during dry weather, particularly in drier years.

Modern dryness-focused farming need time to accumulate and store runoff water in reservoirs, during which farming is not possible. Farming time thus lost is the month of October, which amounts to the most favourable time for crop establishment (Vap) being lost to farming, utter loss of once in a year opportunity.

All these repercussions are due to trying to adapt to dryness, to fill a deficiency gap, to eliminate a negativity. Instead, if the effort had been directed to dwelling on the main rainy season, banking on its positivities: abundance of water, favourable atmospheric character in October for crop establishment, they may have been avoided. Whether the culprit behind this mishap is the term DZ warrants attention.

Recently UN Climatologists Have come out with a clear assertion, that of the two extreme climatic incidents, namely drought and flood, experienced in a given environment, what really needs to be overcome is flood hazard while drought is a problem that could and should be endured instead of struggling to deal with it. It appears that the ancient DZ farmers had followed it centuries ago.

Conclusion

In conclusion let me present a relevant case study extracted from a newspaper article. Thanthirimale in Anuradhapura district has been a traditional farming village where local rain had been well utilized for farming. It had a system of well managed upstream watersheds and a downstream Wewa, and paddy lands below it. This was modernized in 1950s, by letting the upstream watersheds go into abandonment to merely serve/sub-serve as unmanaged water catchment area for the downstream Wewa, which was widened and capacity increased to provide irrigation water to an expanded paddy acreage below it, now not mainly for the customary Maha season but also for the Yala season as well (hopefully).

A knowledgeable senior farmer there says that prior to modernization the community there raised a variety of crops with rain, had adequate food and enough of forest products including timber, seldom faced floods or drinking water scarcity. After modernization, food production got limited to paddy farming below the Wewa, flooding became more frequent and intense because the upstream area had no control over its runoff water. Water stress during dry months, particularly in less wet years, became more acute because all land upstream of the Wewa no longer subscribed to local ground water resource development.

He says the current system that focuses on mitigating (a seeming) drought is less effective than the traditional system which made the most out of the wetness of the rainy season by slowing down water loss as runoff, mitigating local flooding, commencing cropping at the very beginning (Vap) of the rainy season and continued even beyond the rainy season, and saving a share of water as ground water in every small watershed in and around their Wew. In addition it mitigated downstream flooding during times of very high rainfall and also enabled a better dry weather base flow in the stream that left the area.Therefore, it appears that the term DZ has given a distorted meaning to the climate of the so called DZ and misled the modern day DZ developers. An issue that deserves scientific attention.

(The author has been a researcher attached to the Department of Agriculture from 1968-1994 and thereafter an independent researcher. Holds B.Sc (Agriculture) degree from Peradeniya University and Ph.D. (Agriculture) from Kyoto University, Japan.)