Urbanization and the expansion of gray infrastructure have greatly increased impervious surfaces, creating significant challenges to stormwater management not only due to the volume of runoff but also the pollutants it carries. The problem is further exacerbated by the rising frequency and severity of storm events driven by climate change. A critical challenge in stormwater management is the removal of mixed contaminants—including nutrients, metals, pathogens, and organics—which the runoff collects from waste, manure, litter, oils, and detergents. These contaminants threaten the quality of surface water bodies and groundwater. Traditional storm sewer systems and detention ponds fail to address the quantity and quality of stormwater runoff effectively. A case study of Chicago city highlights the limitations of conventional methods and underscores the need for innovative, locally adapted solutions to mitigate urban flooding and stormwater pollution. Civil engineering solutions like retention/containment systems offer a solution by storing excess runoff, with liners placed beneath them to prevent contaminants from reaching groundwater. Bentonite is commonly used as a liner material in retention ponds and impoundments, but its limitations in contaminant compatibility necessitate using alternative materials. This study presents the potential of combining bentonite with chitosan and biochar into a novel chitosan-biochar-bentonite composite (CBBC), which could provide broad contaminant affinity while retaining the low permeability necessary for liner applications. Additionally, green infrastructure (GI), such as bioswales and infiltration trenches, promotes local stormwater infiltration while incorporating filter media for contaminant removal. Biochar has been widely studied in GI applications as filter media due to its large surface area and surface functional groups that aid in contaminant adsorption. This review examines various GI strategies and materials, emphasizing the need to evaluate their sustainability and resilience to climate impacts and other external stressors or shocks. Further, it explores the potential of modifying biochar with chitosan to enhance its contaminant removal capabilities as a filter media. This study also presents an in-ground-permeable reactive filter developed by the University of Illinois Chicago and implemented at Rainbow Beach, Chicago. This system intercepts stormwater at entry points at the beach, capturing contaminants before they reach Lake Michigan. The research emphasizes the importance of designing stormwater management systems that address urban flooding and pollution and integrate sustainable practices while ensuring resilience against external stressors.