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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Research Project #441523

Research Project: Integration of a New Groundwater Flow and Salinity Model in SWAT+

Location: Grassland Soil and Water Research Laboratory

Project Number: 3098-13610-008-091-A
Project Type: Cooperative Agreement

Start Date: Jan 24, 2022
End Date: Jul 31, 2023

Objective:
To develop a salinity module and integrate the module into SWAT+ (Soil and Water Assessment Tool). SWAT+ is a comprehensive river basin model that simulates the impact of land use and climate on runoff, sediment, nutrient and pesticide fate and transport. The salinity model components will include components for multiple salt ions in irrigation water, salt accumulation and leaching in the soil, salt transport in surface and ground water, and impact on plants. The integrated model will be able to simulate the impacts of land management on salt accumulation in soils and aquifers and transport in channels. The model will be available for use in developing conservation policy as part of CEAP (Conservation Effects Assessment Project).

Approach:
A new groundwater model, called GWFLOW, has been developed and linked to the SWAT+ code. The GWFLOW model was written specifically for inclusion into SWAT+ and code and runtime execution have been drastically streamlined and reduced when compared to MODFLOW. This allows efficient linkage with our national agroecosystem model used for LTAR (Long Term Agroecosystem Research) and CEAP. The new flow model will be applied and tested within our National Agroecosystem Model framework for a watershed in the Mississippi delta. The salinity component developed in a previous study will be recoded into a modular format for inclusion into SWAT+. The salinity model will be validated for a watershed in Colorado with irrigation and salinity issues. Development will continue on a nitrogen and phosphorus mass transport model for groundwater systems. These new modules will enhance SWAT+ prediction capabilities in areas with complex surface/groundwater interactions and/or groundwater pumping for irrigation or municipal usage and will provide a new set of scenario capabilities for LTAR and CEAP.