Hydrological and Hydraulic Analysis of the Stormwater Drainage System in the City of Biograd na Moru

Osnovni cilj ovog rada je analizirati postojeći sustav odvodnje oborinske vode u gradu Biograd na Moru, identificirati probleme postojećeg sustava te predložiti rješenja za problem plavljenja javnih površina pomoću implementacije zelene infrastrukture. Prvo je provedena analiza pokrova zemljišta, udjela nepropusnih površina te infiltracijskog kapaciteta prema SCS metodi te su definirane topografske karakteristike promatranog područja u QGIS-u. Nakon hidrološke obrade oborina u SWMM računalnom programu definirana su tri matematička modela sustava odvodnje. Jedan model za postojeće stanje, jedan sa implementacijom LID elemenata na 10% površine podslivova, te jedan sa implementacijom LID elemenata na 30% površine podslivova. Nakon provedenog hidrološko-hidrauličkog proračuna provedena je procjena učinkovitosti mjere smanjenja nepropusnih površina. Rezultati ovog istraživanja mogu pružiti važne smjernice za planiranje budućih infrastrukturnih intervencija i poboljšanja u gradu.The primary objective of this study is to analyze the existing stormwater drainage system in the city of Biograd na Moru, identify the issues with the current system, and propose solutions to the problem of public area flooding through the implementation of green infrastructure. First, a land cover analysis and assessment of impervious surfaces and infiltration capacity were conducted using the SCS method, and the topographical characteristics of the observed area were defined using the QGIS software. Following the hydrological processing of rainfall data using the SWMM computer program, three mathematical models of the drainage system were defined. These included one model representing the existing conditions, another model with the implementation of LID elements covering 10% of the sub-basin areas, and a third model with LID elements covering 30% of the sub-basin areas. After the hydrological and hydraulic calculations were completed, an evaluation of the effectiveness of reducing impermeable surfaces was carried out. The results of this research can provide valuable guidance for planning future infrastructure interventions and improvements in the city