Quantifying the contribution of sediment sources upstream of Anzali wetland in north Iran using the fingerprinting technique

ABSTRACT Soil erosion and sediment yield are major challenges in environmental science. Identifying sediment sources is crucial for effective watershed management and cost-efficient sediment control. This study uses a multidisciplinary approach to identify sediment sources in the upstream watersheds of the Anzali Wetland by examining the physical, chemical, and biological soil properties. A variety of potential sources were considered, including undisturbed and degraded rangelands, forests, rice fields, tea gardens, gullies, and riverbanks. A total of 93 samples were collected, including 14 sediment samples and 79 soil samples (Inceptisols) from sediment-producing sources. A stepwise diagnostic analysis was employed to ascertain the extent of each source's contribution to sediment production. The sediment sources were effectively distinguished by attributes such as phosphatase enzyme activity, organic carbon content, sand fractions, magnesium, mercury and cadmium concentrations (Tracer). Undisturbed pastures and forests contribute minimally to soil erosion because there is sufficient vegetation to mitigate its effects. The primary identified sediment sources were riverbanks (69.17%) and gullies (12.14%). Erosion control measures in these areas could significantly reduce sediment delivery to the Anzali wetland. This knowledge is valuable in developing watershed management strategies to reduce soil erosion and improve water quality in the wetland ecosystem.