These reports summarize benthic macroinvertebrate data collected from 148 and 130 sites in 2002 and 2003, respectively. Although the same sites were targeted each year, not all sites were sampled in 2003 due to low stream flows or limited access. The sites were randomly selected from 20 sub-basins in the Green-Duwamish River and Greater Lake Washington watersheds. This analysis included data from 26-30 water quality monitoring stations and 20-23 hydrological gauging stations. Data were compared to land cover/land use classifications to determine correlations with percentage effective impervious area and land use types upstream from each benthic sampling site. Benthic Index of Biotic Integrity (B-IBI) scores were used to characterize water quality conditions.