Introduction
Angkor is an amazing place. You cannot fail to be impressed even stunned by the grandeur, detail and scale of the monuments. The true wonder of the Angkorian Empire and what it achieved has only started to dawn on me in the last few years. It was when the findings of the Lidar survey surfaced that I grasped the extent of what was one of the world’s greatest civilisations.
Lidar in layman terms emits an electromagnetic pulse i.e. a laser, that is strapped to a helicopter and fired as it passes over the ground to be surveyed. The reflected light is fed through the software that strips away the vegetation to show the topography and reveal previously unidentifiable structures.
The results are phenomenal! Phnom Kulen had a city on top. Angkor Thom was laid out in a grid of roads and canals framing wooden houses and their trapaeng or pools. There were thousands of temples not hundreds, and it was all made possible by the management of water in a climate where at the best of times 6 months of rain is followed by 6 months of drought.
I also began to realise that many of our cycle routes, hiking trails and even kayaking adventures followed these ancient waterways. I’d heard Roland Fletcher give fascinating talks at Amansara and on the banks of the West Baray. It wasn’t until Damian Evans (also from Sydney University) spoke to the guides that I knew he could tell us what we needed to understand Angkor.
The Water Connection
Boeung Ta Neue – our Secret Lake where we kayak, was an Angkorian reservoir formed by an extension of the North Wall of the East Baray, a much larger reservoir connected with the Angkorian cities of Ta Prohm and Angkor Thom. Boeung or lake Ta Neue caught the rain run off from the Kulen Hills to the North, which fed the Baray and in turn the conurbations of Angkor.
Kayaking on Lake Ta Neue
Nearby the corner of the East Baray, where we discovered a wall separating the Baray from Lake Ta Neue, is the 7 arched Spean Tor Bridge. Clearly visible by kayak from the water, we managed to reach it through the bush. We searched on the Baray side for a connection with Lake Ta Neue but none was to be seen. We couldn’t work out the purpose of the bridge though to be sure a thousand years ago it had one.
Spean Tor Bridge
The main water flow in and out of the East Baray was through Kral Romeas, a sluice built into the banks of the East Wall. Cycling and hiking through Phum Samre, the village that lines the walls I’d noticed large laterite stone blocks. Closer inspection revealed 1 large thick wall and 30 metres away another running parallel. These formed the sides of the sluice, the raised ground in front of us was a laterite weir. Kral Romeas acted over time as an inlet and outlet to the East Baray and may have been connected by another laterite wall running parallel with the East Bank, to Lake Ta Neue via the bridge Spean Tor.
An outlet has also been discovered opposite in the West Bank at the far end of the Baray, which provided water for the wooden houses between Angkor Thom and fed into the Ta Prohm moat. 7km long and 2km wide the Baray seems to have been a huge body of water to supply what appeared as a compact area of habitation but it would also have been used for irrigation.
Damian put this into context by working out that the 50 million litre3 in the West Baray reservoir of similar size to the East Baray, could provide irrigation for 5000 ha of rice, perhaps 10,000 tonnes for each crop. The rice fed a population of hundreds of thousands of priests, the aristocracy and merchants who lived in and around the ancient temple cities.
The West Baray at the end of the rainy season
It was also unlikely that the 3 great water reservoirs of the West, East and North Barays were in simultaneous use but acted as a safe-guard for times of drought and flood.
The scale of these man made hydraulics are unparalleled in human history and mind-boggling. To truly understand you have to think about the 3 spatial dimensions in combination with a 4th dimension – time, the chronology of the kings and climate. History seems to have been determined by the weather as the peaks in the empire, first during the reign of Suryavarman II in the 12th century and second under Jayavarman VII in the 13th century coincided with the peaks in rainfall we saw from the ancient records on Damian’s computer screen.
The ultimate decline of Angkor was also linked to periods of extreme drought followed by flood years, which washed away this finely tuned hydrological infrastruture needed to supply water during the dry season and get rid of it during the flood. This is most clearly seen at Spean Thmor near Angkor Thom where the old bridge lies high up the banks of the Siem Reap River, which now runs meters below.
Prasat Tor (prasat meaning temple) and Troung Chruk (pigs temple) it’s ruined sister temple to the South lie between Lake Ta Neue and the East Baray next to an unexplained mystery, a 10 x 10 grid of a 100 mounds.
Prasat Tor and it’s 3 laterite towers
Similar grids have been found beside the River of a Thousand Linga’s, Kbal Spean at the West end of Phnom Kulen and Sambor Prei Kup near the modern day city of Kampong Thom, both associated with major water systems. No artifacts or remains have been unearthed to help solve the mystery of what the mounds are.
Walking across where the grids were revealed by Lidar, we spotted fragments of curved roof tiles in a papaya plantation that in an act of unintended vandalism, has been planted right over the mounds, which may help solve the mystery.
Most of what is known about Prasat Tor comes from a 4 sided stele (a stone pillar with carved enscriptions) discovered by the French in the 1930’s and now stored in The Angkor Centre for Conservation. The Sanskrit engravings were translated and available on line, which Damian translated for us in his office that morning. The stele had been installed by a Brahmin priest during the 13th century referring to the Great King Jayavarman VII. The inscription mentions the Ganges River in association with water, which may have had something to do with the Kral Romeas sluice and was the same as an inscription found at Phnom Dai temple to the North, also the site of another grid of mounds. The temple itself appears to predate the stele and may have been built at the same time as the 10th century East Baray.
Randomly cast on the ground around Prasat Tor were the now eroded but once richly carved blocks that adorned the structure including the stone crown that sat atop the central tower. Interestingly it had a hole in the middle, where a bronze finial in the form of a trident could have been positioned. Possibly removed at certain auspicious times of the year to bathe the Goddess Shiva sitting 15 meters below in sunlight.
Now set amongst brilliant green paddy fields in November, on the other side of Lake Ta Neue is Leak Neang Temple dated to the 10th century. A stele has recently been removed from the site to the Angkor Conservation but has yet to be translated.
Leak Neang with its single brick tower
The bricks themselves are another mystery as no kiln has ever been found. A theory speculates that the bricks were fired close to the temples then used in it’s construction. The apparent black scorching seen on the walls seemed to support this idea.
Not only was this masterly management of water used to supply The Angkorians and irrigate their crops, it was also conveyed the enormous amount of stone required to build the temples. Laterite is an iron rich clay that is soft and easy to dress into blocks when it comes out of the ground. On exposure to the sun it becomes very hard but relatively light making it ideal for the foundations but not the decoration as its pock-marked surface is not easily carved. The laterite quarries lay in the hills to the West. Dams collected water from streams, which was released into the Great North Channel that carried the stone blocks South to Angkor.
At the Eastern end of the Kulen escarpment were quarries that supplied sandstone, which was carved into the marvelous facades of the temples.
A channel ran from Beng Melea past the Temples of Banteay Ampil and Chau Srey Vibol to Prasat Batchum inside Angkor. A path still connects these sites and makes for a great cycle ride with temple stops for sustenance heading East to the Tamarind Temple – Banteay Ampil.
We were beginning to get a handle on the Eastern end of the water connection, now it was time to explore the Western end. The Siem Reap River flows South from the Kulen Hills to the the city and then onto the Tonle Sap Great Lake but during Angkor it was diverted into the North East corner of the Angkor Thom Moat. History is being repeated as subsequent to the floods of 2011 the channels have been reopened and another dug in parallel on the North side of the moat as the river is diverted into the West Baray with the aim of stopping the floods in Siem Reap. The fact that now the town of Puok to the West floods instead is not part of the discussion – tourists don’t go there.
Angkor Thom was Jayavarman VII’s and his 2 wives, city. The largest of all the Angkorian Cities its wall’s 3km long enclose 9 km2, which is now mainly forest but once housed a thriving metropolis of wooden houses and their trapeang, surrounded by a grid of canals and roads as the Lidar survey revealed.
View over the moat from the walls at the S.E corner of Angkor Thom
The data was detailed enough to show the individual houses, which can be extrapolated to give a guessed population of 70,000 based on an assumed family size. This would need a lot of water but during the rainy season any excess flowed out of Boeung Thom reservoir in the South West of the city and through Runta Dev a canal that runs under the city walls into the Angkor Thom moat. We’ve got a stunning cycle route that runs along the 8m high walls of Angkor Thom to Prasat Chrung or corner temple – there’s one at each corner. A great late afternoon spot for watching the sun set over the moat, paddy fields and palm trees beyond. We didn’t realise the engineering marvel that lay 8m below us until Damian lead us down the inner banks to a stream that on closer inspection disappeared into a laterite tunnel under the walls and out to the glinting light of the moat 30m away.
The West Baray 500m to the West is one more mystery. How was this vast body of water replenished and released during times of flood? The current outlet of the Angkor Thom moat is a canal running parallel with the road through the West Gate dug by the French, which destroyed any trace of what was there before. It is possible it was a replacement otherwise how did 50 million litres of water get into The Baray.
Runta Dev runs under the walls of Angkor Thom
What had we learnt that morning?
We understood that water running off the Kulen Hills to the North fed streams, which flowed into the reservoir / lake of Beoung Ta Neue in turn feeding the East Baray, which was a water supply for the population of Angkor Thom and Ta Prohm.
Damian confirmed that our cycling path to Chau Srei Vibol and on to Banteay Ampil, lay along the route a canal had taken bringing sandstone from the quarries at the Eastern end of the Kulen escarpment via Beng Melea to Angkor.
He explained how the laterite used to build the foundations of the J VII temples were carried by water released into the Great North canal which flowed to the North Baray and Preah Khan.
And the Western hydrological connection was made by the Siem Reap River coming from the Western end of Kulen flowing South into the Angkor Thom moat and maybe on into the West Baray.
And much else besides!
With great thanks to Damian Evans for a really fascinating morning and apologies for any misinterpretations.
Indochine Exploration with Smiling Albino Cambodia is pleased to take our guests on a introductory investigation of the main temples along the water courses described or an adventure to experience this incredible landscape on foot, by bicycle or kayaking.