Evaluating Hybrid Tools to Analyze Agricultural Production and Water Use in Alabama

The Regional Hydrological Extremes Assessment System (RHEAS) is an ensembled regional crop model system that simulates predicated crop growth and seasonal yields. RHEAS is a two-part system made up of a hydrological model- Variable Infiltration Capacity (VIC) and a cropping system model- Decision Support System for Agrotechnology Transfer (DSSAT). Typically, yield production can be a good indicator of crop stress and irrigation demand. Knowing when a crop is in distress can lead to a better understanding of crop water use and the impacts of drought on agriculture production. Analysis of the system will allow planners and policymakers to better understand irrigation water use during periods of short-term drought in order to help mitigate climate risks and better understand overall water availability. This research focuses on the creation of an automated script in python that is used for validation purposes of RHEAS, specifically analyzing corn at the county level for the state of Alabama. This methodology includes implementing corn yield predictions from RHEAS using different forcing datasets and comparing them to reported corn yields from USDA NASS for the years 2010-2012. This is done to understand the model's performance and how well it operates across years and during extreme drought. Through analysis of the system, the percent difference was calculated between the actual yields and the RHEAS predicted yields and displayed as geospatial maps. Furthermore, a combination of scatterplots, box plots, and bar graphs were used to analyze trends and show the correlation between USDA and RHEAS model yields. Future work will include incorporating higher resolution forcing variables and the assimilation of datasets of soil moisture into RHEAS to evaluate improvements. The validation framework will allow various simulations to be tested and evaluated across model state variables and derived drought indices.