Long-term road salt application has caused widespread salinization of water bodies, contributing to aquatic species loss and drinking water contamination. Understanding chloride transport at the watershed scale can inform green infrastructure design for managing excessive chloride loads. Researchers analyzed chloride transport across 18 watersheds with road salt inputs in the Twin Cities Metropolitan Area, developing a coupled stochastic model to reconstruct streamflow and chloride dynamics and validating it with watershed data. Land use was examined as a determinant of both chloride input and its retention and release in soil and shallow groundwater, with input concentrations and retention-release efficiency quantified by land use type using Bayesian inference. Results indicate developed areas are the dominant source of chloride input, while lakes and wetlands demonstrate greater ability to trap chloride. Natural landscapes showed the least chloride input but emerged as potential hotspots for releasing legacy chloride through groundwater recharge, a finding with direct implications for where green infrastructure should be sited.