There are seven forts as part of the desert chain of forts: Alexandrion, Doc, Kypros, Herodion, Hyrcania, Machaerus and Masada. Kypros Fortress is overlooking the city of Jericho. Herod the Great built the fortress over a Hasmonean fortress and gave it the name of his mother. Like any structure Herod built on top of an existing structure, he enlarged it and added to it splendor and power.
If the water needs of the fortress during the Hasmonean dynasty were supplied by local water sources, then the many magnificent pools and baths that Herod added, required additional water sources. The beginning of the system for supplying water to Kypros was in Mabua Spring, in Hebrew named Ein Mabua and in Arabic named Ein Fawar. Of the three main springs in Prat stream which are: Kelt spring (Ein Kelt), Mabua spring (Ein Mabua) & Prat spring (Ein Prat), Mabua spring is the most abundant spring. At the same time, due to its geological structure, there are extreme fluctuations in the amount of water it supplies, both during the year and also between years. The Mabua spring can provide a maximum of 3,000 cubic meters per hour, and in the summer can potentially even dry up, and on an annual bases it can generate between 2 and 3.5 million cubic meters, a significant amount – but due to the unpredicted amount of water it will provide, it was decided during Herod’s reign to add another aqueduct and connect Mabua spring with Prat spring located six 6 km west of Mabua spring. What causes the instability in the amount of water flowing from Mabua spring?
Mabua spring is a rhythmic spring, meaning a spring that flows intermittently, and this is explained by the diagrams in the video – As the water level reaches the high point of the tube – the exit channel, it creates a siphon effect and the water comes out by gravity, due to the connected vessels. The water will come out at once, to the point where air enters the tube and breaks the siphon, and by that the flow stops. The spring will not provide more water until water accumulates again up to the pulse level. In winter, in rainy years, in this spring, the rate of incoming water is such that the water level is constantly higher than the pulse level and therefore the water flows continuously like a regular spring. As summer approaches, there is less rain here and the pulse level decrease, and the outcome is that the pulse mechanism goes into action again.
Mabua spring is located at an altitude of 100m above sea level. From here an open aqueduct carrying its water plus the waters from Prat spring, to the underground water reservoir located just below Kypros Fortress at an altitude of 45 m below sea level. The distance as the crow flies between Mabua spring and the fortress is 7.25 km, but due to the topography of Wadi Kelt, the length of the aqueduct is double, 14 km. To the east, that is, towards Jericho, between Mabua spring, and Kelt spring, four aqueducts have been built throughout history: (1) The aqueduct I’ve just described – This is an open aqueduct, originates at Prat spring to compensate for the instability of the water flowing out of Mabua Spring. (2) The 2nd aqueduct is named the pipes aqueduct. It is located on the south bank and its target was a water reservoir named Beit Jabar El Fukani, mostly under the ground located near the Saint George Monastery observation point in wadi kelt, today it is actually blocked. (3) The modern aqueduct built in the early 20th century that is occasionally located on the south bank, originated at Kelt spring and from there it continues to Jericho for irrigation of agricultural land. (4) In addition, there were short local aqueducts in the north bank for irrigation of nearby agricultural land.
So Kypros fort was fed by Mabua spring + the water that was fed from Prat spring to Mabua spring. Regarding the clay pipes aqueduct – this is a water aqueduct from the early Arab period, which for the most part consisted of a pair of adjacent clay pipes, yet in some parts the aqueduct was open. The clay pipes are made of clay vertebrae glued together. The average diameter of the vertebrae is 45 cm and their length is 60-70 cm. On the steep cliffs the pipes aqueduct is using the aqueduct built by Herod without placing pipes because of the difficult terrain conditions that made it impossible to lay and connect the pipes. In the video about Kelt spring, I expand on the largest of the three bridges that survived, used for carrying the pipes aqueduct, and are all located east of Kelt spring. The bridge is spread over Wadi Abu-Daba near Kelt spring. The aqueduct & the bridge are attributed by archaeologists to the days of the Umayyad Caliphate of the Muslim Empire that ruled the Syrian Israeli territory in the 7th and 8th centuries. The Umayyad period was a period of great construction when in this area they built, among other things, the Hisham Palace in Jericho.
And finally, as usual, a question for you – there are very few rhythmic springs in Israel and less than 100 in the world. A well-known one is located in Jerusalem and stopped beating at the beginning of the 20th century and has been behaving like an ordinary spring ever since – what is the name of the spring and what was its purpose in the biblical period. The answer is provided at the end of the video.