Lessons from the terraces – travels in the Philippine Cordilleras

MA Landscape Architecture student Charles Lamb is one of the two winners of the 2016 Landscape Institute Student Travel Award. Charles travelled to the Philippines to research indigenous forms of water management in the Cordilleras, the chain of mountain ranges in the northern region of the island of Luzon.

For over 2,000 years, tribes in the high mountain regions of northern Luzon – the Philippine Cordilleras – have developed and managed an irrigation system that captures water, slows its progress, and ultimately provides the lifeblood of the area by irrigating the terraces carved into the hillsides. Could aspects of such a system have contemporary applications, and if so, how practical would it be to translate these to the other side of the world? With these considerations in mind, the Philippines beckoned.

The rice terraces of the Philippine Cordilleras are unique in the Philippines not only for their scale, but also for the way in which they are managed and cultivated by the local tribes. It is thought that the early settlers originated from mainland China, bringing with them their knowledge of terrace construction. In any event, the indigenous tribes have developed and managed a system that utilises the entirety of the watershed, in particular the high, forested mountainsides above the terraces. This, coupled with an understanding of rain patterns and geology, help them to manage the environment and topography in such a way as to sustain life in an otherwise seemingly inhospitable, rugged and impenetrable terrain.

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The amphitheatre of terraces at Batad, Philippines

In contrast to many other terrace systems that utilise naturally occurring springs as their main source of water, those created in the Philippine Cordilleras access the majority of their water via a managed forest ecosystem (the muyong), a multi-layered forest stretching above and through the cultivated rice terraces. Under usual rainfall conditions, rainwater is absorbed into the ground and gradually percolates downhill, eventually emerging into dedicated channels at the level of the terraces (the kinnaw). These direct the supply as needed to the terraces where, through a system of secondary channels, it overflows from one terrace to the next (the kula). Purposefully leaky walls regulate the flow downstream whilst helping to ensure that all terraces are equally irrigated.

In preparation for heading up to the mountains, I was fortunate to have a very productive meeting with some of those leading the Landscape Architecture programme at the University of the Philippines, Diliman campus, in Manila. Those I met in the department were Cathe Nadal (Head of UP College of Architecture Environmental Design Studio Laboratory, University of the Philippines – Diliman), Franklin Fontanoza Jr. (University Research Associate at UP College of Architecture; Master of Tropical Landscape Architecture student) and Avegail Casono (landscape architect). The subject of the rice terraces in the Philippine Cordilleras turned out to be of special interest to them, having undertaken their own research on the terrace system relatively recently.

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At the Landscape Architecture Department at the University of the Philippines

We also discussed contemporary landscape practices in the Philippines, and whether knowledge gained by the indigenous peoples of the Philippines was being applied to new developments. The consensus was that this was generally not the case: many developments are often short-sighted in their outlook in terms of water management systems, and are primarily concerned with moving water away from their development as quickly as possible. Rectification is often only sought after a problem has occurred, usually after a significant flood event. Arguably, this could be mitigated by a more sensitive approach to water management from the outset.

To supplement my discussions with those at the University of the Philippines and my research in the Philippine Cordilleras, I had hoped to have a meeting with a large developer in the Philippines regarding the water management techniques they utilise in their schemes. Unfortunately, this was not able to come to fruition during my time in the country, although I did investigate one of their previous developments – the Ayala Land Technohub at the University of the Philippines, Manila, which utilises swales and retention ponds to capture and absorb significant quantities of rain water on site. However, and from my observations of other developments around the Philippines, using such systems would seem to be the exception rather than the norm. Whilst this particular development had the luxury of space to create such water management systems, the pressure on the existing stormwater network – certainly in Manila – was evident in many a downpour, with roads quickly becoming lagoons as the drainage network proved unable to cope with the volume of water.

Notwithstanding the shortfalls of many modern Filipino developments in terms of their water management systems, that is not to say that the more indigenous methods operating in the Philippine Cordilleras are without their own problems. Whilst at the University of the Philippines, we discussed the challenges currently faced by the terrace system, which can broadly be split into two: environmental and social issues. Both impact the long-term future of the terraces, ranging from more macro themes of an increasingly unpredictable global climate and the pull of work in towns and cities away from agricultural labour, to more localised problems such as the changing ecosystem of the muyong due to variances in maintenance regimes, increased pressures for the cultivation of different crops, and the draw of money to be made from tourism in certain areas of the mountains.

Eventually leaving Manila behind, I headed north. After an overnight bus ride, complete with a morning alarm call from a disgruntled cockerel also making the journey, I arrived in the largest town in the area – Banaue – to be greeted by my rather wonderful, and incredibly knowledgeable, guide, Irene Binalet. Introduced through the Landscape Architecture Department at the University of the Philippines, she is a member of the local Tuwali tribe and fizzed with energy, knowledge and connections. Rather appropriately, she also possessed a few terraces which are still farmed for rice.

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Irene Binalet inspecting rice

Wending our way out of Banaue on a motorbike tricycle, we switched up hairpin bends hugging the mountainside and were soon deep into the rice terraces that surround the town and spread through the mountains. Discussing the ownership structure of the terraces, an interesting revelation was the impact that the inheritance system has on the overall management of not only the terraces but also the muyong. Inheritance of the terraces in the area operates by age, rather than by primogeniture. The younger siblings, regardless of sex, will often not receive terraces. Instead they may have historically foraged for plants and materials in the muyong, or specifically cleared areas on an ad hoc basis to grow crops or harvest building materials as a way of supplementing their income. This pattern of temporary clearing and periodic harvesting resulted in a multi-layered forest canopy developing, with the consequence of increasing rainwater absorption and helping to further regulate the flow of water from the upper hillsides into the terrace network. However, Irene suggested that such a trajectory in life for the younger siblings is now not so clearly followed, with many seeking other ways to make a living, such as in more urban centres or from the tourist trade.

The impact of tourism, however, remains relative. To exclaim that your destination is at the end of the road takes on a more literal meaning once you are in the hinterland of the Philippine Cordilleras. This was certainly the case for my journey to Batad, some way outside the main settlement of Banaue, where I based myself for my time in the mountains. The road leading to Batad unceremoniously ends in a jungle clearing, with a final trek along often narrow, washed-out paths, accompanied by precipitous drops into the pine and tree fern-clad forest below.

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Local farmer cleaning the kinnaw channel between two sets of terraces

The terraces of Batad are monumental in scale, with its setting of a natural amphitheatre revealing itself as you round the final bend on the track. Terraces stretch seemingly impossible distances up and around the hillside. Small, often thatched, houses perched on stilts cluster on the more level parts, with people bent double working in the fields below under the early afternoon sun.

At close quarters with the terraces, the genius of their operating system becomes apparent. A slow but constant stream of water either trickled from the muyong along the kinnaw, or flowed from one terrace to another through the kula. Ferns protruded from the damp walls, where water seeped through at a much slower rate, while rice ready for harvesting created a wheaten patchwork across the valley. There were, however, scars in the form of landslides, with terraces having collapsed on each other like dominoes. Irene mentioned that these have become more frequent due to heavier, more unpredictable rain that follows unprecedented periods of dryness. As a result, the clay-based structure of the terraces dries out to such an extent that, come the rains, they are unable to absorb the volume of water that falls, occasionally leading to collapse.

The Philippine government has tried to mitigate further collapses by renewing one of the uppermost retaining walls that border the surrounding muyong above the Batad terraces. Significant amounts of concrete predominate, with only a few plastic pipes protruding through to allow some water seepage. The end result jars with the vernacular, with little acknowledgement of local, more environmentally sensitive construction techniques. The argument for using the concrete was that the entire section of hillside was at imminent risk of collapse, and by using concrete the stability of that section was assured, at least in the short term. At present, walls elsewhere in the terraces are yet to be replaced in such a way and are maintained to retain their more porous nature.

Coupled with this, I discussed with Irene whether the periodic collapse of the terraces was compounded by the varying maintenance regimes in the muyong. From her experience, this has certainly been the case: as fewer people have cleared areas in the muyong for their own enterprise, a denser, higher-level tree canopy has developed at the expense of many of the plants in the medium and lower layers of the canopy. Her experience is that any rainfall therefore has fewer layers to fall through before reaching the ground, leading to more frequent and high-volume run-offs. I had also discussed a similar scenario with those at the University of the Philippines, but at present there is little, if any, scientific data to corroborate such presumptions.

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Kinnaw running down through the terraces

Notwithstanding the issues that the terraces face for their long-term survival, there are some interesting potential applications of how the system operates that could be utilised elsewhere. The potential effect that a multi-layered forest canopy has on reducing rainwater run-off is an intervention that could mitigate run-off in areas with the space to implement such a scheme, although it would require ongoing management in order to maximise its efficiencies. The channelling of water to dedicated areas – the terraces themselves in this instance, although possibly equally applicable to retention ponds or similar – allowing for overflow from one basin to the next, could be another application. A recent article in the Journal of the Landscape Institute (Summer 2016) highlighted the use of similar techniques in the UK at Pickering, North Yorkshire, to seemingly positive initial results.

Whilst it may be impractical to try to emulate the highly labour-intensive management system that operates in the terraces of the Philippine Cordilleras, it should be remembered that the challenges faced by peoples from other times and cultures are often not so dissimilar to our own, and it would be imprudent to dismiss their techniques out of hand as archaic. Whilst some may prove to be only of historical or cultural interest, the ability of a landscape to survive for two millennia in a tropical, ever-changing and challenging environment does provide ideas for how we may adapt our own landscape for a more sustainable future.


Acknowledgements

I would like to thank the Landscape Institute for the travel award that made this trip possible. I also owe a debt of gratitude to those at the University of the Philippines who helped to make this trip much more insightful, in particular Zenaida Galingan, Cathe Nadal, Frank Fontanoza and Avegail Casono of the Landscape Architecture Department for their time both before and during my visit. Final thanks go to Irene Binalet for her time and expertise whilst in the Philippine Cordilleras – I would not have learnt half as much without her.


This post was first published on the Landscape Institute’s website and was re-posted with permission.

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