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Research Project: Determining Subsurface Hydraulic Properties and Water Content Using Geophysical Methods and Limited Soil/Sediment Datasets

Location: Sustainable Agricultural Water Systems Research

Project Number: 2032-13220-002-007-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2021
End Date: Oct 1, 2024

Objective:
The overall objective of this research is to develop and apply geophysical methods, models, and limited soil/sediment datasets to predict 3D maps of subsurface hydraulic properties, water content, water table elevation, and land subsidence at managed aquifer recharge (MAR) and irrigated agricultural field sites.

Approach:
Geophysical methods (e.g., time-domain electromagnetics) will be employed to characterize subsurface heterogeneity in soil/sediment properties at MAR and irrigated agricultural field sites. These geophysical measurements will be used in conjunction with statistical approaches to develop design-or model-based sampling plans to characterize subsurface physical heterogeneity. In situ (e.g., cone penetrometer readings) or soil/sediment samples will be collected from the field and analyzed to establish ground truth values of key properties (e.g., resistance, water content, salinity, particle size distribution, and/or bulk density). Hydraulic properties from measured soil/sediment properties will be determined and correlations (e.g., regression equations, transfer functions, or machine learning algorithms) between hydraulic properties and geophysical measurements will be established and utilized to predict 3D maps of subsurface hydraulic parameters and/or water content. Mathematical modeling and geostatistics will be used to characterize uncertainty in predicted 3D maps of subsurface hydraulic properties and water content.