Discover Ancient Agricultural Terraces in the Negev Desert
Join our challenge, investigate ancient structures in the Negev desert with modern AI methods, and contribute to future sustainable farming techniques.
The Negev, Israel, is a subtropical desert with occasional precipitation in the autumn, winter, and spring, while the hot summer is completely dry for almost half a year from about May to October. The average annual rainfall in the region is about 100 mm. Average monthly temperatures range from 8°C (January) to 26°C (August). The highest temperatures may reach 40°C during the spring, summer, and autumn, while light frost may occur in winter.
You will find thousands of ancient dry stonewalls (referred hereafter as terraces), many of them still intact today. These walls were built in the central Negev Highlands during ancient times, mainly between the 4th and the 7th centuries, across ephemeral stream channels (wadis, Figure 1). This water harvesting technique is very common in wadi beds with gentle slopes. As a result of the slow water velocity, eroded sediments and nutrients usually settle in the wadi bed and create good agricultural land. The construction across the wadi, usually no higher than 1 m, reduces the flow speed and allows soil sediment to settle. The top of the terrace should be all at the same level to create uniform land behind it, allowing excess water to overflow along its entire length. The distances between walls along the wadi bed are determined according to the slope of the wadi bed and the height of the wall.
Figure 1: Typical flood water harvesting system consists of a stonewall terraces.
In many cases, but not necessarily, several terraces belonged to a farm (Figure 2). The farm might be surrounded by a stonewall fence (Figure 3). Most of these fences stretched on the hillslopes along/parallel to the channels, but parts may also be used as cross-wadi terraces.
Figure 2: Typical ancient farm.
(1) height spot; (2) building ruin; (3) spillway; (4) height couture; (6) dry stonewall/terrace; (7) stonewall fence surrounded a farm.
Figure 3: Typical stonewall fence, surrounded a farm.
The ancient agricultural terraces have been abandoned since the 7th century, but many stone terrace walls are still intact. Nowadays, the terraces can be observed from the surface either as exposed stonewalls of a few tens of centimeters height (Figure 4) or as buried stonewalls that can be identified by the above-ground vegetation (Figure 5).
Figure 4: Typical exposed cross-wadi stonewall terrace.
Figure 5: Strip of vegetation indicates a buried stonewall terrace.
Significance
Discovering ancient agricultural terraces in desert regions has importance both for archeological and anthropological research, as well as for indicating where the potential use of surface runoff may help increase world food production today. Particularly as climate change impacts food production, there will be a growing need to discover new agricultural land resources. If these regions can be discovered on a large scale by processing image data, rather than by ground surveys, not only will the information so gathered advance our knowledge of ancient human endeavor, it will also reveal locations for enhancing future food production.