Modeling Study of Produced Water Release Scenarios Provides a scientific basis for oper ators, regulators, and landowners to determine if assessment or remediation of produc ed water releases will provide a meaningful environmental benefit. The two principal research objectives of this study are (1) the identification of produced water release scenarios that have a potential to cause groundwater quality impairment in homogeneous subs urface geologic profiles and (2) the prediction of chloride movement through the vadose zone for different release scenarios. Secondary objectives of the study incl uded evaluation of the effect of heterogeneity on the migration of ch loride through the vadose zone, the impact of repeat releases, and the e ffect on groundwater quality of surface soil restoration by revegetation and soil leaching. The sensitivity analysis performed in th is study provides an overview of the likelihood of groundwater impairment for large release volumes (100 bbls and 10,000 bbls). Assuming homogeneous un saturated zone soil profiles, the results of over 1000 modeled release sc enarios reveal that 49 % of single - event releases do not cause impairment of groundwater above drinking water standards for chloride (250 mg/L) in a m onitoring well that is adjacent to the edge of the release. In 70 % of thes e scenarios, chloride concentrations in groundwater do not exceed 1000 mg/L. Although these numbers give no information about the fate of chloride fr om a specific produced water release, they do indicate that a release do es not necessarily cause groundwater impairment