The Risks of Urban Sprawl on Wadi Channels: A Case Study of Wadi Al-Ghorab in the City of Zintan, Libya

الملخص

This study centers on the phenomenon of urban sprawl encroaching upon wadi (intermittent stream valley) courses, specifically Wadi Al-Ghurab in the city of Zintan, Libya. It identifies this encroachment as a critical environmental challenge stemming from unplanned and inadequately considered urban expansion. To investigate this, the research employed an integrated approach combining geographical analysis tools, surface runoff models, and estimated hydrological calculations to assess the hazard level associated with unregulated urban development within the wadi's channel. The findings indicate that moderate-intensity thunderstorms (60 mm/hour) have the capacity to generate in excess of 155,000 cubic meters of water within a single hour within the Wadi Al-Ghurab drainage basin, which encompasses an area of 5.17 km² and exhibits a longitudinal slope of 2.11%. This significantly increases the potential for high-risk flash flood events, particularly in the context of accelerating climate change and its accompanying anomalies in rainfall patterns, including timing and intensity. Furthermore, the difficulty in predicting near-term climate change scenarios exacerbates this risk. The study revealed the precariousness of the current situation due to substantial infringement upon the wadi's channel and its buffer zone. This necessitates the urgent implementation of proactive measures, including the immediate cessation of construction within the wadi's course, the precise demarcation of the wadi's natural boundary, and the development of robust drainage infrastructure. Additionally, the enforcement of local regulations and the intensification of public awareness regarding the risks associated with this phenomenon are deemed essential.