How A Leak Changed History

When generating content for my website (swimmingpoolsteve.com), one of my requirements was to create compelling and unique articles that I, personally, would find interesting. For example: What’s the most iconic swimming pool failure in history? Is there even such a thing? At first I was thinking along the lines of perhaps a famous person who built an extravagant pool only to have it fail or the contractor to go belly up (or missing) during the construction phase. What I ended up finding was so, so much more interesting than that.

In and around the year 800 A.D. an enormous series of temples were constructed, or at least started, in the city of Angkor, in what is now Cambodia. This city of temples was not just big, it was among the largest cities in the world, being home to as many as a million people. Researchers estimate that the downtown core of Angkor could have housed as many as 500,000 people alone. (For comparison, London had perhaps 20,000 to 25,000 people during this same period of time.) Around the year 1200, Angkor Wat, the largest temple on the Angkor grounds, was constructed. It represented the height of the city’s glory and the apex of its power and influence. By 1500 the entire Angkor complex, the city, the people and all the temples were deserted and overgrown by thick Asian jungle. They were lost to the world for another 300 years or so.

So what happened that caused Angkor to go from being the largest and busiest city in the world to being a literal ghost town? You have to keep reading to find out. I can't tell you yet, except to say that it has something to do with water. But first you need to understand a little more about what makes Angkor, and Angkor Wat special.

To help you picture this better, just imagine a great city filled with 1,000 stone temples ranging from modest to gargantuan, set in an area of the world that never gets cold and experiences alternating seasons of drought and monsoon. Right in the middle of the city is the Angkor Wat temple, which is surrounded by water on all sides.

It is a densely populated, thriving city for a reason — the ancient builders and owners of Angkor had a very advanced (for the time) understanding of how to manipulate and store water. In an area that is flooded half the year and in drought the other half, the ability to control water literally meant the difference between life and death. When the temperature is 104 degrees Fahrenheit with 70% to 100% humidity, you are not going to make it for very long without water. And your massive stores of water must remain clean to see you through the long drought season. This was the magic of Angkor and the reason why people flocked here — to live in the relative security of a place that had access to water all year long.

You might be thinking that the ancient designers and builders of Angkor must have developed agriculture, drainage ditches, holding pools and similar elementary water control measures, and you would be right...but you would also be vastly underestimating the majesty of the accomplishments of these skilled builders. Remember Angkor Wat, the grand temple situated in the center of the city that is surrounded by a giant moat? Indeed it is not surrounded at all. The entire Angkor temple, 500 acres in total, with stone monuments standing at peaks up to a towering 699 feet tall...is all floating on a permanent, manufactured swamp. The ground under its stone foundations is sand that remains damp year-round fed from ground water and irrigation systems. This system has allowed the Angkor complex grounds to survive for almost 1000 years while being exposed to constant flood and drought conditions. (Today, this remarkable hydraulic achievement is under threat due to unrestricted building of mega-resorts in the immediate area around Angkor, tapping into and changing the groundwater table. It is feared that the 1,000 year old wet sand foundations under the Angkor floating grounds will begin to dry, crack and crumble.)

The engineering of the Angkor Wat grounds was designed to work with water as opposed to against it. With grounds that can deviate between flooded to fissure-cracked dry, how could you ever build any type of foundation or permanent structure? The answer was to dig down and completely excavate the grounds and replace with sand. This was actually done also because the nature of the build site was to be a holy grounds, or holiest grounds more accurately, and so all the ground had to be removed in order to be pure. The sand bed was intended to remain wet at all times, allowing for a stable, or at least consistent, build site. So long as the groundwater kept the sand wet then the sub-foundation of Angkor would remain intact.

During the dry season the groundwater would not be sufficient to maintain the desired moisture level in the sand, so a massive reservoir, or moat, really, exists on all sides of the Angkor complex. This moat collects all runoff from the temple grounds and protects the sand from drying out, even during the hottest and driest parts of the year. While building on a swamp is not ideal, how else could you build in an area with such seasonal variation? In essence, Angkor Wat was built like a ship, floating on a swampy, sandy ocean. This amazing feat of 1,000-year-old engineering exists even to this day, more or less unchanged, and should continue long into the future if the ground water tables are not drastically changed by unrestricted development.

Truly, every aspect of this amazing culture was built on the back of water mastery, and the of the empire’s hydraulic system was breathtaking. Through complex water catchment systems they collected and diverted water for use in growing rice and providing for livestock. These same water systems were used to create watercourses that traveled throughout the Angkor kingdom, but most specifically back to sandstone quarries 20 to 50 miles away. These waterways were used to transport between five to ten million stones, some weighing as much as 3,000 pounds each or more, to build the city. The stones were transported to the Angkor site by floating them down these constructed canals.

The system of reservoirs, embankments, moats, dykes and dams stretched over an area of almost 600 square miles. This massive water containment system, easily the largest and most advanced in the world at the time, allowed the city of Angkor to flourish from its start in 800 AD up until the 1300's. Over time as the population of Angkor grew and the water system grew more and more complex, they passed a critical stage of no return where the size and complexity of the system outgrew the ability of the people residing there to maintain and repair these systems. By the time the floods of the 1300's came, the city of Angkor was already straining the aging water systems that sustained their existence.

Periods of intense flooding, the likes of which had not been experienced in that area of the world for hundreds of years, brought about the beginning of the end for Angkor. Researchers conclude that unusually high water tables caused ditches, rivers and reservoirs to overflow. There were attempts to shunt the flow of water but the volumes could not be controlled. Moats overflowed, fields flooded, rivers widened and found new paths of least resistance, and the system that had brought a million people together finally broke.

Despite manpower in the hundreds of thousands, and resources and riches beyond imagination (such as Preah Khan temple which contained over 60 tons of gold, worth over three billion dollars by modern standards) there was no way to fix the damage done by flooding and ultimately entire vast sections of the network were damaged beyond repair and abandoned. Even attempts to fix parts of the complex hydraulic system that had taken hundreds of years to build failed due to the size and complexity of the system, and the state of deterioration from both age as well as flood damage.

Despite the best advice from Jeff Goldblum, life, uh, didn't find a way this time. In fact the population of the Angkor area plummeted due to the loss of ability to control water, grow crops and survive the dry season. The faltering city became susceptible to attack from warring neighbors, and by the beginning of the 1400's Angkor Wat and the entire empire of Angkor were a shadow of their former majesty. Raiders infiltrated once safe lands and the jungle crept back toward the heart of the stone city. Already broken and battered, there was no line of defense left against the next disaster to befall this once glorious place.

Two periods of unprecedented drought, each 20 years long, doomed the remaining Angkor survivors in the 1400's. By 1500 only a skeleton crew of devoted monks remained to honor the holy grounds of Angkor Wat. All others had died, been captured or fled the area in search of stable water. Eventually the entire landscape of Angkor became lost to the jungle, overgrown and deteriorating with the earth slowly reclaiming the resources back into the landscape, until the late 1800's when a French explorer stumbled onto the apparent ruins of some great city in the middle of a dangerous and sweltering Asian jungle. There he found the ruins of Angkor Wat — a great civilization brought to its knees and destroyed by the worst swimming pool leak in history.

As soon as I read about the epic story of the rise and fall of one of the greatest ancient civilizations, all on the back of water mastery, I knew what I had found. This is the greatest example in history of how the slow erosion of water was the downfall for some of the greatest water masters that have ever lived. Indeed an entire empire was built on the ability to control water, to work with it as opposed to against it, even to build on it — only to one day lose control and crumble completely. But was the writing on the wall for this downfall from the beginning?

Steve Goodale is a second generation swimming pool expert located in Ontario, Canada. You can learn more about Steve, as well as swimming pool construction, maintenance and repair from his website: SwimmingPoolSteve.com.