This study aimed to identify the sedimentary environment of the Podong wetlands through an analysis of landforms and sediments. The results of the landform analysis indicated that the dominant fluvial features in the study area were sand bars, abandoned channels, meander cores, bedrock riverbed, and river terraces. The sediment grain size analysis revealed that the mean grain size was classified as very fine silt, and the sorting was categorized as very poorly sorted. The upper and middle reaches of the wetland had high sand and gravel content, whereas the lower reaches were predominantly composed of silt and clay. The physicochemical analysis of the sediments indicated that the middle section of the wetland had been cultivated prior to the construction of the dam. After the dam was completed, cultivation ceased, leading to soil acidification due to progressive land formation. No accumulation of salts was observed; however, a significant accumulation of organic matter, dominated by silt and clay sediments, was found in the lower part of the wetland, where the energy for sediment transport and deposition was relatively low. The results of this study can provide a foundation for future research on the ecological value of inland wetlands and support proposals for the designation of wetland protection areas.