United States precipitation data for the twentieth century have indicated an increasing trend in both frequency and intensity of events. Karl and Knight (1998) found that precipitation occurred more frequently during the past century (6 days/100 years). Furthermore, days with very heavy precipitation, that is amounts greater than 50.8 mm, have likewise increased (Karl and Knight 1998). The North Central United States (NCUS) has similarly experienced this higher intensity phenomenon. More days with precipitation, as well as greater amounts, enhance wet deposition, soil infiltration, and runoff of chemical species. A multimedia hybrid compartmental model was used to explore the behavior of selected semi-volatile chemicals for the Lake Michigan watershed. Rainfall information including user-input frequency and precipitation rates is included in the simulation. Higher chemical concentrations at greater depths in the soil profile and diminished atmospheric concentrations in the runs including more precipitation are indicated by the results. This is likely due to increased soil infiltration, rain scavenging and wet deposition resulting from the more frequent, intense rainfall. If the current trend were to continue, higher relative surface and soil chemical concentrations could be expected. Increased atmospheric cleansing may keep levels in the air somewhat lower