From Flood Risk to Flood Resilience 

In the Glil Yam neighborhood of Herzliya, located in the Tel Aviv district, a unique challenge emerged due to the urban watershed's limited drainage capacity. The entire area relies on a single drainage tunnel, which proved insufficient to handle the volume of stormwater during heavy rainfall events. Recognizing the risk of flooding—especially as a new residential neighborhood was being planned—it became necessary to devise a comprehensive solution that would relieve the load on the drainage infrastructure and ensure the area’s resilience.

The first step involved conducting a thorough hydrological survey to gain a detailed understanding of the complex drainage system and the specific constraints present within the watershed and its flow channels. Building on this data, a complete hydrological model of the watershed was created to accurately predict stormwater flows and calculate the necessary detention volumes required to effectively manage runoff. Various scenarios were modeled in coordination with the plans for the new neighborhood, existing roadways, and the overall drainage network, with an emphasis on designing a robust system that could respond to a range of storm intensities.

The resulting plan included a combination of engineered solutions such as strategically placed gates, detention ponds, and designated floodplains, all designed to withstand and adapt to extreme weather conditions. Through this integrated approach, the runoff management system was optimized to not only handle typical storm events but also offer flexibility and resilience in the face of unpredictable weather patterns.

Implementation of the detention storages and the associated planning measures led to a significant improvement in the area’s capacity to cope with flooding. The new system successfully reduced peak load on the main drainage tunnel during storm events, dramatically enhancing both the resilience of the neighborhood and the watershed as a whole.