Continuous monitoring of soil erosion is necessary but challenging, especially in wetland ecosystems like Salehiya where water stress causes soil erosion and poses a threat to the environment of Tehran and Karaj. This study aims to use the perpendicular soil moisture index (PSMI) as a remote sensing index to determine the trend and zoning of soil erosion potential in Salehiya wetland. Moderate Resolution Imaging Spectroradiometer (MODIS) sensor data from 2003 to 2017 were used to estimate adjusted soil vegetation index (SAVI), land surface temperature (LST), and finally PSMI, where higher PSMI values indicate lower soil moisture. Kendall's seasonal time series test results showed a significant increase in PSMI (with tau correlation coefficient τ=0.25) and significant decreasing trends in hydrometric time series data (with the values of the τ −0.36 and −0.27, respectively) from stations located on Kharroud and Haji Arab rivers leading to Salehiya wetland, which indicates the continuation of the water stress in the region. The zoning of soil erosion indicated that human interventions have accelerated soil erosion in addition to water stress.