137 Cultural Transformation and the8.2 ka event in Upper Mesopotamia A Narrow Place can Contain a housand Friends: Irrigation as a Response to Climate in the Zerqa Triangle, Jordan Maurits Ertsen and Eva Kaptijn Abstract In the Zerqa triangle in the Jordan Valley, irrigation would have been an important instrument to deal with the arid climate and its associated uncertainties concerning rainfall for societies in di ferent periods. Before irrigation modernization eforts were started in the 1960s, the people of the Zerqa area used the known ethnohistorical irrigation system, which dates back to the Mamluk period. his system consisted of a number of sub-sys- tems tapping water from the Zerqa river and transporting water to the ields through open canals under gravity. he setlement patern of the Iron Age points to an irrigation system of similar type being in use during this period. he location of Early Bronze Age setlements along natural watercourses suggests that a form of lood irrigation was practiced, without a dedicated canal system. Each of these setings will have had its speci ic uncertainties in terms of water availability to deal with, which will be discussed. In other words, each seting provided speci ic mater ially structuring conditions for societies to develop responses in terms of agriculture, institutions and power relations. his contribution discusses t hese uncertainties and responses for the diferent periods. In the discussion, insights from both archaeology and irrigation engineering will be integrated. Introduction As much as elsewhere, human survival in the Zerqa triangle in the Jordan Valley depended on human ability to adapt to the natural environment. Adaptation can be seen in a reactive sense, but also in the proactive sense of