Human‑created freshwater ecosystems are increasingly common across altered landscapes, yet their biogeochemical dynamics and responses to climate‑driven hydrologic change remain understudied. We used a decommissioned U.S. Fish and Wildlife Service hatchery in southeast Georgia, now a network of long‑abandoned artificial ponds, to examine how hydrologic regime influences organic matter decomposition and benthic macroinvertebrate communities. Twelve experimental ponds were assigned to one of three hydroperiod treatments representing climate‑change‑driven drought scenarios: permanent (n = 4), temporary (n = 4), and dry (n = 4). Leaf packs were deployed and retrieved at 30, 60, and 90 days to quantify decomposition rates and associated macroinvertebrate assemblages. Decomposition proceeded more rapidly in permanent ponds, while temporary ponds exhibited reduced rates as drying progressed. Macroinvertebrate assemblages were initially similar across hydroperiods but diverged by 90 days, with temporary ponds showing lower diversity, density, and biomass as drying intensified. Our findings demonstrate that hydrologic alteration in human‑made wetlands can significantly modify biogeochemical processing and benthic community structure, with implications for the resilience and functional stability of artificial freshwater ecosystems under future climate scenarios.