Conceptual Merge of Ecohydrologic Watershed and Sponge City Techniques for Managed Sustainability and Strengthened Adaptive Capacity of Nile Delta Coastal Lakes, Egypt

Abstract

Nile Delta coastal zone in Egypt has special socioeconomic and environmental importance, with internationally acknowledged wetland systems. However, sustainability and adaptive capacity are compromised with progressive developments. Coastal lakes serve basins with intermixed industrial, urbanized and agricultural activities, which require an integrative approach for strengthened adaptivity and sustainability management. This research study presents an innovative management plan that conceptually merges the EcoHydrology approach with the recently initiated Sponge City approach. Principles of both approaches are reviewed to select components that are applicable and practically approved in the Egyptian conditions and evolving changes in the study area of Edku coastal lake. With an analysis of regional activities as well as the use of remote sensing techniques, the study first establishes a base insight into the historic spatiotemporal alterations in Edku lake and its served basin. Then, the climate change impact is incorporated by water balance-related factors to consider potential flood and/or drought risks in the adaptation plan. The study presents preliminary results with System Dynamics (SD) simulations. Various scenarios have been examined using VensimPLE×32-based SD modeling. The scenarios covered alternate combinations of the proposed measures. Optimal 25-year managerial EcoHydro-Spongic Strategy is found with gradual application of Sponge City measures to prevent 30% of wastewater discharges, while Ecohydrology measures are projected to reduce 60% of pollutant loads into Edku lake from agricultural lands. Further 10% of pollution reduction is achievable with applied phyto-technology within the Lake