Supporting urban development master plans by hydraulic invariance concept: the case study of Acquicella catchment

Understanding potential impacts of urban development on storm water drainage modifications is a crucial issue since early design stages of urban development master plans (UDMPs). This paper applies the concept of Hydraulic Invariance (HI) to a case study catchment in the southern part of the City of Catania, Italy. Comparison between pre- and post-development catchment storm-water release scenarios is presented. The latter referring to the UDMP’s re-design proposal, recently carried out for the city. Simulations of scenarios were run using the SWMM model provided by EPA. The study shows the need for careful consideration of HI in land use planning actions. In particular, a set of flow release restrictions to assign to clusters of development (i.e. areas of transformations designed by the UDMP) were determined, based on the achievement of hydraulic invariance at the sub-catchment scale for different return period of the storm-water event. The criterion adopted to allocate release restrictions has been chosen on the base of the increase of storm-water release flows discharged from the same clusters of development.