Climate Data Source and Usage

Where Climate Data Comes From

The IAMDD model pulls its raw climate data dynamically from the Open-Meteo API. Depending on your chosen simulation dates, the platform seamlessly fetches either historical archive data or 16-day forecast data, localized to the precise GPS coordinates of your project.

How Climate Data Drives the EPANET Model

Here is the step-by-step breakdown of how that raw climate data is transformed into localized hydraulic demand:

1. Reference Evapotranspiration (ETo)
   We extract the daily Minimum/Maximum Temperature, Relative Humidity, Solar Radiation, and Wind Speed from Open-Meteo and process it through the industry-standard FAO-56 Penman-Monteith equation to calculate the daily Reference Evapotranspiration (ETo).

2. Crop Demand (ETc)
   We apply a dynamic Crop Coefficient (Kc) to the ETo to find the specific water requirement of the planted crop. The Kc curve advances dynamically based on the thermal heat accumulation (Growing Degree Days) for that specific year—meaning crops will realistically demand water earlier in hot years and later in exceptionally cool years.

3. Effective Rainfall (Pe)
   Not all rain is usable by the crop. We take the raw daily precipitation and calculate exactly how much of it stays within the root zone based on the local soil type (for example, Clay soils retain a higher percentage of rainfall than Sandy Loam).

4. Final Demand Calculation (GIR)
   The Net Irrigation Requirement (NIR) is calculated by subtracting the Effective Rainfall from the Crop Demand (ETc - Pe). Finally, we divide the NIR by your chosen Irrigation Efficiency (e.g., 90% for Drip vs. 60% for Flood) to calculate the Gross Irrigation Requirement (GIR).

This final GIR volume is automatically converted into a Gallons Per Minute (GPM) flow rate and applied directly to your EPANET hydraulic nodes for simulation!