The history of the Beit Zayit artificial lake is in many ways a very Israeli one; bad planning during the preparation stages but eventual success in turning the bitter into sweet.
The artificial water reservoir was created in the 1950’s after the construction of a dam that was supposed to stop the rains flowing through Nahal Sorek, and let them percolate into the ground to enrich the aquifer and improve its quality.
The aquifer is an underground water source, consisting of layers of rock that allow the passage of water. The intention in this case was to enrich the aquifer west of Jerusalem known as “Yarkon Taninim” that extends from Mount Carmel to Be’er Sheva. However, due to errors in the geological calculations the water did not flow as expected and it was discovered that they were not affecting the aquifer whatsoever. Later it was discovered that the water actually flowed towards the Nachal Perat in the Judean Hills, which wasn’t the intention.
The mistake resulted from a discrepancy between the topological watershed (i.e. the top edge of the mountain) and the hydrologic one, which is where the water actually splits to different paths. Usually both are the same, but in this case due to changes created by the Syrian-African Rift, a gap was created between the two. This gap is what created, in the distant past, the Dead Sea, when water from the rivers in the east of Israel, which previously flowed into the Mediterranean, began to flow into the Dead Sea.
Upon learning the reason for the failure of the project, it was decided nonetheless not to destroy the dam and that the water reservoir should serve at least as a tourist attraction during the winter. Indeed, today it is a central place for tours and picnics, as it is the only lake in the Jerusalem area.