Land degradation as a result of soil erosion is a prime problem in Ethiopia. To avert the problem, soil and water conservation practices (SWCPs) have been implemented by governmental and non-governmental organizations at large spatial scale based on the integrated watershed management approach. Although many studies have been conducted in the highlands of Ethiopia on the impact of SWCPs on soil physical properties, sediment trapping, slope gradient change and maize grain yield, similar studies in the lowlands of Ethiopia are limited. Therefore, this study aimed to investigate the impacts of SWCPs on selected soil physical properties, sediment trapping, slope gradient change and Maize grain yield in Gedel Mender watershed, in the northwestern lowlands of Ethiopia was conducted. Physical and biophysical SWCPs were investigated. Field experiment was designed in four treatments with Fanya juu (FJR), stone-faced soil bund (SFSB), Fanya juu stabilized with vetiver grass (FJ+G), and control (C) with three replications at three landscape positions. The result showed that soil porosity (TSP), moisture content (SMC), the amount of trapped sediment by SWCPs, and maize grain yield and yield components were lower in the upper and middle landscape position compared with the lower landscape position. Higher balk density was observed on the untreated farm lands compared with farm lands treated with SWCPs. TSP, SMC and amount of trapped sediment was higher in farm lands treated with biophysical SWCPs (FJ+G) than fields treated with physical SWCPs (SFSB and pure FJR) alone and untreated farm lands. Soil and water conservation practices also trapped large amount of sediment (30 kg m-1 yr-1 to 100 kg m-1 yr-1 with an average sedimentation rate of 60.87 kg m-1 yr-1) that reduced soil transport downstream. Soil and water conservation practices also played a significant role in changing the slope gradient by forming bench terraces. High Maize grain yield and yield components were recorded inside the treated farmlands than the controlled farmlands. Therefore, this finding is believed to create awareness and convince farmers to implement SWCPs on their farmlands for sustainable land management and crop yield increment, and help policy makers better understand the role of SWCPS.