Impervious Surface and Macroinvertebrates in the South Atlanta Metropolitan Area

Studies utilizing volunteer stream monitoring data are rare, particularly in in the Atlanta metropolitan area. This study investigated how the macroinvertebrate communities of 20 different stream sites in the south metropolitan Atlanta area were affected by the imperviousness of their surrounding watersheds. These sites were in a diverse landscape which included forests, wetlands, suburban day-use parks, and parking lots. Percentage impervious surface area was measured using Geographical Information System (GIS) analysis. Macroinvertebrates were collected using Georgia Adopt-A-Stream’s volunteer monitoring protocols, and a water quality index (WQI) was calculated from these data. The relationship between WQI and imperviousness was curvilinear and best fit by a quadratic equation. In watersheds having more than 8% imperviousness, WQI clearly decreased