** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CROPLANDS WORLDWIDE ARE AFFECTED BY HUMAN-INDUCED SALINIZATION, OFTEN DUE TO POOR DRAINAGE CONDITIONS AND THE APPLICATION OF LOW-QUALITY IRRIGATION WATER WITHIN THE PRESENCE OF SALT MINERALS IN SOILS AND AQUIFERS. CONDITIONS IN IRRIGATED LANDS CAN BE EXACERBATED BY ARID CONDITIONS, RISING TEMPERATURES, AND SALT INPUTS FROM UPSTREAM URBAN AREAS. THERE IS A NEED TO QUANTIFY CURRENT LEVELS OF SALINIZATION IN LARGE, HUMAN-IMPACTED RIVER BASINS AND IDENTIFY VIABLE MITIGATION STRATEGIES. THE AIM OF THIS PROJECT IS TO ASSESS AND FORECAST SALT STORAGE, MOVEMENT, CONCENTRATIONS, ACCUMULATION RATES, AND LOADS WITHIN AN IRRIGATED SEMI-ARID RIVER BASIN SUBJECT TO CHANGES IN CLIMATE, LAND USE, AND PRACTICAL MITIGATION STRATEGIES. THE SOUTH PLATTE RIVER BASIN (COLORADO) IS USED AS THE REPRESENTATIVE BASIN. THE PROJECT AIM WILL BE ACHIEVED BY COMPLETING THE FOLLOWING FOUR OBJECTIVES:(1) QUANTIFY SALINITY CONCENTRATIONS, STORAGE, ACCUMULATION RATES, EXTENT, AND MOVEMENT IN SOILS, GROUNDWATER, AND SURFACE WATER, USING A COMBINATION OF FIELD WORK, REMOTE SENSING TECHNIQUES, AND HYDRO-SALINITY MODELING;(2) FORECAST THE IMPACT OF FUTURE CLIMATE, LAND USE, AND WATER RIGHTS TRANSACTIONS ON SALINITY AND CROP YIELD IN THE BASIN;(3) INVESTIGATE THE IMPACT OF PRIORITY ALTERNATIVE LAND AND WATER MANAGEMENT STRATEGIES AND POLICIES ON SALINITY AND CROP YIELD; AND(4) ENGAGE WITH GROWERS AND WATER MANAGERS TO IMPROVE UNDERSTANDING OF SYSTEM OPERATIONS AND IDENTIFY VIABLE STRATEGIES FOR SALT MITIGATION.THIS PROJECT WILL IMPROVE METHODS OF QUANTIFYING SOIL SALINITY AT VARIOUS SPATIAL SCALES, AND PROVIDE AN UPDATED, PUBLICLY AVAILABLE MODELING TOOL FOR SIMULATING SALINITY TRANSPORT IN HIGHLY MANAGED RIVER BASINS.