Paper Title
Impact of Urbanization on Hydrological Responses and the Efficiency of Low Impact Development (LID) Implementation in Amman, Jordan

Abstract
Water scarcity is a continuing concern in Jordan which is currently experiencing the two contradictories: droughts and floods. This implies applying innovative solutions to manage stormwater. The present paper investigates the efficiency of LID in mitigating urbanization impacts in Jordan. The performance of LID devices (infiltration trenches) was evaluated. The analysis was based on comparing the hydrological responses of a 500-hectare catchment located in Amman, in different scenarios using the software Personal Computer Storm Water Management Model (PCSWMM). The predevelopment conditions were compared with two hypothetical future settings of post-development with and without LID implementation. Results showed that the peak flow increased by 183% whereas the lag time was reduced by 78% when the level of urbanization increased from predevelopment conditions to 60%. However, by implementing LID devices, the predevelopment conditions could be partially restored. LID effectively controlled storms at smaller return periods (2, 5, and 10 years) while storms at higher return periods (25, 50 and 100 years) required more mitigation. Continuous modelling of historical rainfall data for the period (1990-2016) indicated the potential to manage approximately 80% of annual rainfall through infiltration trenches. Index Terms - Hydrological Responses, LID, PCSWMM, Urbanization.