An ancient water reservoir at Petra. (photo by Orli Fields)
Desert living is tough. The toughest part of it is having water fit for consumption. Nobody knew this better than the Nabatean people. The desert was their home.
Some 2,600 years ago, the Nabateans daringly accepted the challenge of finding and supplying water to their people. They did this by building desert towns with life-sustaining water systems.
Archeologists and hydrologists have studied the waterworks at the Nabatean town of Petra. They report that Petra stood in a huge desert canyon, in what is today the country of Jordan. This area receives little rain. Petra gets only about six inches of rain a year. Temperatures go from a low of 34°F to a high of 94°F (1.1°C-34.4°C). For about half the year, the daytime temperatures are quite high. Yet 30,000 people once lived in Petra.
Petra is far from any ocean, sea, river or lake, but the Nabateans did not lack for water. Three things made this possible: the Nabateans had very smart water engineers, they had skilled builders and they had talented water managers.
The engineers’ biggest worry was getting Petra to save as much water as possible. So, first, they designed a water system covering the whole city. The system collected a maximum amount of water from two sources: from rain and from local springs.
The engineers had several considerations. For instance, they had to worry about the ups and downs of yearly rainfall. They had to take into account the ups and downs of temperature. And they had to overcome the ups and downs of Petra’s mountainous surroundings.
The engineers also had to lower the risk of the system getting blocked. They realized that water pipes that ran along the side of a mountain would be hard to clean. Thus, they designed special water filters. These filters made it easy to trap and remove rocks or silt. If there were particles, they would settle in the reservoirs, not in the pipes. The engineers’ design was practical. It functioned throughout the year and, importantly, provided for a lot of water storage. It included crisscrossing water pipelines, channels, dams, tunnels, reservoirs and cisterns (totaling some 200 surface and underground units).
When looking at Petra’s water system, it is important to note how it was built. There were no motorized digging machines or hauling trucks, of course. All work was done by hand. The chisel was probably the most commonly used tool and, with this simple tool, builders carved an amazing water system.
Water managers had to maintain good water pressure and water flow. Too much pressure, for example, would cause a pipe to break, and that would result in wasted water. The managers’ goal was to maximize flow while minimizing leakage. They did this in part by operating a partial flow of water.
Also to reduce water leakage, the water managers used a particular kind of pipe. This pipe was often made from clay baked at high temperatures; it was short, with thin walls. Even with this innovation, Petra’s mountains and its irregular rainfall and temperatures must have meant that water managers were always on the alert.
And, sometimes, they were really “put to the test” – for example, when a large camel caravan entered Petra. When a large group of dusty and thirsty traders and animals arrived, it meant one thing: a sudden increase in the demand for water. Water would be needed for drinking and bathing. For such situations, water managers needed to ensure that back-up water sources were working.
In times of real emergency, the Nabateans had numerous storage centres. Scientists figure that some sites held three weeks’ emergency supply while other sites held several months’ supply. Thus, inhabitants had some insurance against a siege or drought.
Scientists have estimated that about 12 million gallons (or more than 45 million litres) of fresh spring water ran through Petra’s water channels daily. Water was relatively plentiful and also accessible – residents could easily reach the water that ran into nearby fountains.
The Nabateans also traveled through present-day Israel. Along what is today recognized as the UNESCO World Heritage Incense Route, the Nabateans established forts and settlements. In agricultural communities such as Shivta, they “captured” rainwater to grow grapes for wine production.
Both in travel and at home, the Nabateans’ water systems were as complex as they were practical. Even in ancient times, they overcame the harshness of desert living. They harnessed its unpredictability and thrived.
Deborah Rubin Fields is an Israel-based features writer. She is also the author of Take a Peek Inside: A Child’s Guide to Radiology Exams, published in English, Hebrew and Arabic.