A retrospective analysis of decedent fluvial transport.

Abstract

The search for human remains from river systems presents significant challenges due to the complex and variable nature of fluvial environments. Estimating transport distances is critical for defining search areas; yet, no reliable predictive methods exist. Scientific literature on the fluvial transport of human bodies is limited, and the extent of variability in transport outcomes remains poorly documented. This study investigates patterns of body transport in 101 medicolegal cases across Iowa, a state characterized by diverse river systems and seasonal climatic variation, to assess how factors such as postmortem interval (PMI), river discharge rate (volume of water flowing through a river channel), season, clothing, and body mass index (BMI) affect fluvial transport distances. Results show that larger rivers with higher discharge rates are generally associated with longer transport distances and PMIs. River discharge explained approximately 20% of the variation in transport distance, and PMI accounted for 5%. However, substantial variability exists, with some bodies traveling significant distances in short periods (e.g., 1.2 miles in 30 min), even in medium-sized rivers. The longest transport was 89 miles in the Mississippi River. Seasonal timing and clothing had minor effects, with heavily clothed winter entries traveling further with higher PMIs. BMI had no significant correlation with transport outcomes. Understanding the range of possible transport distances can inform search strategies. The potential for long-distance transport advocates for increased inter-jurisdictional coordination in search efforts. These results contribute to the limited forensic literature on riverine body transport and provide insight into search and recovery operations.