Application of an innovative jet pump system for the sediment management in a port channel: Techno-economic assessment based on experimental measurements

The realization of infrastructures in coastal environment modifies water and sediment natural current regime. In particular, sediment can be entrained and accumulated in port infrastructure like docks, haling basins, or port entrances and channels, creating problems for navigation and limiting the human activities. The result is that marine basins and approaches are frequently silted and require maintenance dredging. Dredging is a consolidated and proven technology which implies relevant drawbacks, like high environmental impact on marine flora and fauna, mobility and diffusion of contaminants, and pollutants already present on the seabed, limitations to navigation, relatively high and low predictable costs. Starting from 2001 an innovative plant for sediment management, alternative to maintenance dredging, has been developed and tested. The core of the plant is the "ejector", an open jet pump fed by pressurized water that is able to suck and convey in a pipeline the sediment that may accumulate in a certain area. On August 2018, a pilot plant has been installed in the haling basin of Cattolica (Italy), as part of a pilot initiative included in the Interreg-Med project "Promoting the co-evolution of human activities and natural systems for the development of sustainable coastal and maritime tourism" (CO-EVOLVE). The aim of the specific experimental activity was to test and monitor the efficacy of the technology applied in a port channel and working with sediments like silt and clay instead of sand. The paper shows the results of the monitoring campaign carried out by the University of Bologna from August 2018 to July 2019.