EXTRA-77303 - USA (California) - Groundwater Modelling and Reporting Services - Deadline October 20,2026

(1) Vendor needs to provide groundwater modelling and reporting services to the government authority located in California.– The annual model updates, along with all supporting information about calculations and statistical tests and indices, shall address the following:• Mass balance to determine the portion of recycled water in the groundwater, and also to demonstrate that blending is occurring in the aquifer. • Determine injected recycled water flow paths from groundwater elevation contours, and compare with the flow and transport model’s flow paths. • Predict density dependent seawater/freshwater advancement and recycled water migration in saturated porous media. • Revise groundwater flow and solute transport model and calibrate results as appropriate to match as closely as possible the actual flow patterns and water quality (e.g., chloride levels) observed within the aquifer. • Temporal and spatial trends in the data used for the model, with particular reference to comparisons between stations with respect to distances from the monitoring wells, water quality data collected during previous years, recycled water injection, domestic supply well extractions, and attributes of the basin and the Barrier. Include any appropriate statistical tests used. (2) All the questions must be submitted no later than October 12, 2026.