As flood risks increase due to climate change and urbanization, it is essential to integrate effective solutions for environmental challenges into urban settings. Green spaces and blue-green infrastructure, which combine water management, vegetation, and recreational areas, can play a significant role in mitigating flood risks and alleviating the urban heat island effect, while also improving overall quality of life in cities. Thus, substantial emphasis is given to converting the nuisance of urban floods into a resource that supports constructed wetlands. These spaces foster biodiversity and ecological resilience, supporting stable ecosystems and providing open, green recreational areas even in the heart of bustling urban centers. A prime example of such integration is the Gazelle Valley Urban Nature Park in Jerusalem, Israel’s densely populated capital. The establishment of this park represents a major social and environmental achievement, driven by the efforts of local residents, activists, social organizations, and the Society for the Protection of Nature in Israel. Designed to the highest ecological standards, the park has quickly become a popular destination for both residents and visitors, offering a model for embedding eco-hydrological solutions into urban landscapes. The water system within Gazelle Valley Park, which relies on stormwater during the wet season (winter) and treated wastewater during the dry season (summer), is monitored and sampled for detailed laboratory investigations, revealing the composition and the characteristics of alternating water sources. Alternating salinity and organic concentrations directly affect water pH, dissolved oxygen and redox potential, as well as the concentration and bioavailability of various metals, revealing the risks involved in harnessing urban surface flow into wet habitats within nature-based-solutions.