This paper presents results of numerical modeling work carried out with the scope to verify and optimize hydraulic characteristics of one non-standard U-shaped open trench-type wastewater lifting station, whose general geometry is determined by serious spatial constraints, so typical for downtown/harbor areas in small and mid-size coastal settlements in Croatia. Although initially suspected to imply pretty “unfavorable pump environment” with bad hydraulic characteristics, 3-D numerical experiments have shown that even such a significant alterations from standard solutions can be compensated by appropriate wet well geometry filleting aimed to provide better pump environment, with minimum cross currents, swirling and/or vorticing in the pump intake zone.