Rainfall Floods as a Result of Land Use Alteration in a Syrian Refugee Camp in Jordan

The Zaatri Refugee Camp (ZRC) established summer 2012 shortly after the Syrian conflict started. Due to high flux of refugee fled the conflect south of Syria to Jordan and in a short notice, the international organizations with the Government of Jordan started to establish the camp with limited data on socio-economic and environmental impacts of the selected site. The camp is located in a nearly flat area which forms natural soil pan that used for cultivation. One of the environmental impacts for the selected site is the flooding in parts of the camp due to altering the hydrologic response of the area. This alteration is resulted in two ways: the first on is the building of earth wall around the camp which stops the runoff floods from getting into the natural water courses, the second alteration is the building of dense metal houses with compacted pathways in between. After establishing the camp, the land use changed completely, dense metal housings are built covering around 50% of the area. Networks of compacted roads between the housing blocks are built using imported crushed limestone aggregates. The change in land cover increased the Curve Number (CN) from 84 for the natural agricultural land to 92.5 for the built up area. The increase in CN due to altering the hydrologic parameters within the camp area increased the runoff depth by 82% to 614%, this resulting in more flood water trapped inside the boundaries of the camp. The flood volumes that accumulated can cover more than 10% of the camp area with average water depth 25 centimeters (cm) for 25-years return period storms. In other hand, the storms event that most probably occurs every other year (2-years return period) could result in flood that covers about 1.5% of the camp area with water depth that reaches 25 cm. Keywords: Rainfall floods, Land use alteration, Zaatari Refugee Camp, Jorda