A look at Sri Lanka’s lost hydraulic knowledge

In this interview, Eng. (Dr.) Chandana Jayawardana traces Sri Lanka’s ancient hydraulic expertise as part of the focus of this page to look at the many facets of Sri Lanka’s indigenous knowledge that kept the life of our ancestors in perfect harmony with nature. The interview is based on aspects included in Eng. Jayawardana’s public lecture on ‘Water utilities at Ranmasu Uyana: A Multifarious Study’ held at the Postgraduate Institute of Archaeology on 12 September, organised by the International Council on Monuments and Sites (ICOMOS) Sri Lanka. Following are excerpts of the interview with Eng. Jayawardana:

Q: Your recent ICOMOS lecture on ‘Water utilities at Ranmasu Uyana’ gave a very insightful look at the role of ancient water supply connected to the Tisa Wewa. From an engineering point of view, what can modern irrigation engineers learn from the engineering feats of ancient Lankan irrigation specialists?

A: Ranmasu Uyana is situated adjacent to the embankment of Tisa Wewa and in the vicinity of its low level sluice. A distribution canal is starting from this sluice. Even though the present arrangement of water supply is along a channel starting from the distribution canal, I highlighted the possibility of an intermediate storage between the distribution canal and the supply channel. Further, I also highlighted the possibility of this supply channel functioning as a level top channel so that the water level was maintained constant by the water released from that intermediate storage. 

Presently, canal irrigation plays a major role in irrigation, where the supply hierarchy is from main canals to secondary canals and then to tertiary canals, etc. In this system, users are highly depending on the supply authorities. Implementation of a system with intermediate storages and level top canals may provide an alternative design strategy in modern irrigation.

Another aspect I need to highlight is the application of gravity flow throughout the supply system. Today, we use water pumps to regulate the flows and design engineers are not very much bothered about the natural topology of the terrains. In the case of Ranmasu Uyana, we can identify several hydraulic structures which were used to regulate the water flows and their forms and relative positioning should provide us much information on designing a water supply system entirely based on gravity flows.

Q: How can we revive Sri Lanka’s hydraulic civilisation, by taking a cue from our ancestor rulers?

A: At the outset, I should mention that our knowledge on the ancient hydraulic systems that prevailed here is extremely poor. Many of the present studies try to analyse and explain the function of ancient system by using the modern principles and design practices. This is how the ancient ‘biskotuwas’ were falsely designated as the ‘equivalents of modern valve-pits’ and misquoting ‘gradient of the ancient Jaya ganga as six inches per mile for its first 17 miles’. 

Before seeking the means of reviving, we should try to understand the ancient system in its real terms. We should understand the actual operation of the system components and specially, the design philosophies behind them. Then only can we think of the possibility of re-establishing that system. 

Q: Could you explain, especially for the purpose of educating today’s youth, how the name Ranmasu Uyana came about and its overall significance as a water resource for monks and lay people?

A: I used Ranmasu Uyana to refer to this particular site, merely following the general parlance. The term Ranmasu Uyana appears for the first time in ancient records, Vessagiri slab inscription no. 2 (late 10th century). Subsequent works like Maha Bodhivamsa Getapadaya (12th century) carry this term in the context of demarcating Mahavihara limits (sima). However, identifying the present site as Ranmasu Uyana first occurred in Prof. Paranavitana’s article titled ‘Magul Uyana (Royal Park) of Ancient Anuradhapura’ in the Journal of Royal Asiatic Society (Ceylon Branch), 1944. 

I think still there is room for studies on this identification, specially based on the ancient and medieval literature like Mahavamsa (5th century), Vamsatthappakasini (ca. 8th century), Pali Bodhivamsa (10th century) and Sinhala Bodhivamsa (14th century). Proper identification of the site itself should contribute to the etymology of the term ‘Ranmasu Uyana’. This should be the scope of linguistic scholars and I would like to refrain from expressing any qualified idea in that respect. 

With regard to your second question, the two ponds situated at the site are significant. Both these ponds are equipped with chambers adjacent to them. Two similar pond sites could be located in the vicinity of the Lovamahapaya, which have now been identified as the Jantaghara pond referred to in Mahavamsa. Pali term Jantaghara stands for ‘hot water baths’, a practice recommended for meditating bhikkhus in the Buddhist vinaya. Once this sequence of findings considered, ponds at Ranmasu Uyana would have been used by the bhikkhus, especially who resided at the adjacent Isurumuniya viharaya. 

At the same time, this questions the identification of Ranmasu Uyana as a ‘Royal Pleasure Park’, as that obviously stands for the secular usage. However, we should bear in mind that this site may have been used for different functions by the different parties in different periods of time, which could be determined only after more archaeological explorations. 

Q: Since you have specialised in Buddhist history, could you go into detail on the significance of water preservation in Sri Lanka’s early Buddhist history, and also if there was a difference in the value given to water resources in pre-Buddhist times?

A: There would have been water preservation methodologies in pre-Buddhist times, but I am not aware of the sources from where such cases could be studied. As such, I would like to remain silent on the subject. But, certainly there are volumes of Buddhist literature from which we can extract information on water preservation strategies and methodologies. 

Buddhist commentaries highlight not only the practical aspects of water preservation but also the underlying perceptual approach. For example, the commentary on the vinaya, Samantapasadika, elaborates many aspects of soil testing, site identification, construction of hydraulic structures like dams, sluices, spills, main and secondary canals, etc. It further notes the regulations adopted in the water releases and the settlements of disputes over water. Other commentaries also embody similar information, which provide us much valuable grounds in understanding the actual nature of ancient irrigation system. 

On the perceptual aspects of water preservation, I would quote two stanzas. The one starting with the Pali narration ‘devo vassatu kalena, sassa sampatti hetu ca,...’, with the meaning ‘may the rain comes in due season, may the crops be plentiful, may the king be righteous, may the world be prosperous’. The second is starting with the Pali narration ‘yata varivaha pura, paripurenti sagaram,...’, with the meaning ‘like in the manner the rivers full of water fill the ocean, the merits thus gained be bestowed upon the deceased’. Both are obviously very prominent in the Buddhist practice and should be known since the early times. 

These stanzas may provide some new grounds to look at the function of our ancient irrigation system. Rather than providing water to a particular entity, the design philosophy behind this ancient system would have been to extend the effects of the rain. While ‘irrigation’ is a ‘space specific’ concept, ‘extending rain’ is a ‘nature enhancing’ concept, directly affecting the ground water levels. The implementation of this concept occurred by subjecting the ground water flows to storing, filling, flowing and again storing, filling, flowing and so on. 

The major works as well as the village tank cascade systems should be the practical manifestation of this user philosophy. If we see our ancient system with this mindset, we may realise the limitations and the inadequacy of the present studies. 

Q: Today we are in an age of plastic and an age of ruining the planet. Sri Lankans who practice Buddhism seem hardly aware of the strict instructions by the Gautama Buddha to protect trees and the environment and where monks were not allowed to cut even a branch for the construction of forest abodes during rainy seasons and were dependent on making their huts with fallen branches and twigs. Today we seem to have forgotten how entwined the Buddhist philosophy was with the natural world and how it decreed its protection. How do you link the Buddhist teachings on nature protection, to the importance Sri Lanka’s kings gave to water resources and its preservation?

A: There are several vinaya rules, advising bhikkhus on the ways to deal with trees, soil, water ways, etc., which are the entities we identify as natural resources today. However, whether this is in the context of ‘nature protection’ is questionable. As I see it, what is important is considering ‘humans’ as a part of the nature itself, subjected to the natural phenomena of birth (jati), decay (jara), illness (vyadi) and death (marana). Once things are treated in that way, there is no issue of ‘nature protection’ as the word itself gives some form of authority to the humans over the nature. 

In human activities, the natural forms need to be changed. This is true to modern as well as ancient times. The only option available to us is to select the way it is changed. Visiting the ruined parts of ancient Jaya Ganga reveal how this inter-basin canal would have been constructed in ancient times. This is a single bunded canal, following along the contour lines, collecting the entire water drainage from the higher lands and distributing thus collected water to the lower lands through spills. 

In this sense, this is not a canal but an elongated tank. There are no flow regulating devices in its course and this makes these ancient works to blend with the nature during functioning as well as when it becomes non-functional. Design philosophy of all engineering products should take the entire cycle of birth, decay, illness and death of that product. Today we are only concerning about the first stage, the birth. 

Q: Your ICOMOS presentation showed the complex knowledge the ancient Sri Lankans had on irrigation. Why is it that we can’t emulate such projects today? 

A: As I said before, our knowledge on this ancient system is minimal and doesn’t provide us a proper base for developing practical applications. Even though we manage to acquire that knowledge, possibility of converting it to practical level is doubtful. Today, the accumulation of knowledge and its practical manifestation are subjects under major debates and investigations on our ancient knowledge (or indigenous knowledge, traditional knowledge, etc.) are not standing in isolation. Along with all these scholarly debates, there are authoritative limitations which marginalise the validity of these knowledge projects. 

At the same time, it should be mentioned that there is a tendency for seeking alternatives to the knowledge developed in the West. But unfortunately many Asian countries blindly follow what they received from colonial masters. The United States, the first home of great super-dams, is now tearing down the concrete and freeing water to review wetlands and fisheries. 

When Bangladesh plans huge embankments to tame the Ganges and prevent floods, European governments – home of Dutch dike–builders and German river straighteners – are breaching the dikes, putting back the menders, and giving rivers back their floodplains, in the name of ecology and for more reliable protection against floods. Considering along those lines, I see a positive side of resurrecting our ancient knowledge and there may be a possibility to generate projects in accordance with that knowledge. 

Q: Would it be possible to explain the hydraulic heritage of other areas in Sri Lanka, such as the east and the north, in ancient times? 

A: The east and north of the island are two major areas accommodating many ancient irrigation sites. I will cite two examples; Vanaddi Palama in North Province and Maduru Oya ancient sluice at Eastern Province. Vanaddi Palama is a dam across Ma Oya, built up with massive rock boulders. Studies on this will reveal many unknown facts on our ancient water diversion methodologies. Ancient sluice at Maduru Oya is a peculiar type of sluice, not evidenced in other ancient works. This should be a tunnel type sluice under a natural embankment and need to be subjected to further studies to identify exact technical features. 

In Jaffna peninsula, the irrigation is provided with the ground water in the absence of the surface flows. Well sweep type (adiya linda) are very prominent in this exercise, and the Samantapasadika (commentary on vinaya) highlights the use of this type of wells as far back as 5th century or before. If these literary narrations could be further supplemented with archaeological findings that would certainly enhance the level of heritage studies in this area. 

Q: You spoke of the Engineering Heritage Group in Sri Lanka. Could you speak of the work and focus of this group?

A: The Engineering Heritage Group is initiated by the Building Services Sectional Committee of IESL (Institute of Engineers, Sri Lanka). The objective is to provide necessary technical knowledge in studying our heritage, which is not up to the level it should be at present. A group of engineers who are very enthusiastic about our heritage are working there and the first project undertaken is studying on hydraulic systems in Ranmasu Uyana. 

The History of Science and Technology Study Group at RASSL (Royal Asiatic Society of Sri Lanka) also contributes to these projects, with inputs of engineering, Buddhist and Pali scholars. The importance of multi-disciplinary approach in heritage studies should be emphasised here and we invite all interested parties to join these groups and contribute.

Notes: 

1. Eng. Jayawardana acknowledges Dr. Susantha Goonatilake and Eng. Mahinda Panapitiya for some of the ideas expressed in this interview.

2. Sinhala and Pali terms are noted without diacritical marks.