Continuous beats event-based when intensity is low enough.
SIM treats irrigation as a steady operating condition. The target is application intensity that allows infiltration and redistribution without repeated saturation events.
Appendix A: SIM Toolkit
The working tools behind the standards and academy.
Framework, lab, field validation, and water accounting now support one job: make the SIM standards and training system easier to model, test, and report.
Design Concepts
Three ideas carry the framework.
Use this section when the Standards page needs technical backing or an Academy module needs a shared mental model.
Operate around a measured soil-water band.
Use 7-20 kPa as the preliminary SIM target range for high-moisture continuous low-intensity release evaluation. This is a field validation target, not a universal prescription, and should be adjusted by soil texture, crop sensitivity, sensor depth, ET demand, and observed crop response.
- Below 7 kPa: saturation and oxygen-loss risk rise.
- Above 20 kPa: plant stress and uptake limits become more likely.
- The design target is soil tension validation inside a controlled band, not a wide depletion/refill cycle.
Separate delivery timing from plant demand.
Intermediate storage lets batch delivery feed a controlled low-flow release. That shift changes the sizing basis for pumps, mainlines, filtration, and reporting.
Calculator / Conversion Lab
Turn a current field into a SIM release benchmark.
This is directional modeling for standards conversations, pilot scoping, and Academy exercises. Validate assumptions in the field before using outputs as design documentation.
Current system
Conversion output
Current peak demand0 GPM
SIM release target0 GPM
Peak GPM reduction0%
Pump HP class shiftn/a
Application intensity0 in/hr
Current event-style application rate.
SIM application intensity0 in/hr
Buffered continuous release benchmark.
Outputs use square-spacing emitter density and a simple water horsepower proxy. Use them to frame a pilot, then verify with measured flow, pressure, soil tension, and runtime logs.
SIM outputs are not irrigation prescriptions. They are release benchmarks that must be validated against soil tension, rootzone moisture, pressure, flow, reservoir drawdown, and crop response.
Field Signals
Verify stable delivery before claiming full agronomic performance.
The field section turns demos into repeatable logs that engineers, TSPs, and growers can evaluate without overclaiming.
Gravity-fed release signal
- 275 gallon IBC tote.
- Gravity-fed release across approximately 150 ft of line.
- Observed flow near 20 GPH.
- Runtime near 12-13 hours with steady drawdown.
The first claim is operational: stable low-flow delivery with low intervention under low-head conditions.
Reusable field sheet
- Date/time.
- Reservoir level or drawdown for drawdown-verified delivery.
- Flow rate.
- Pressure.
- Soil tension by depth.
- Soil texture.
- Crop stage.
- Visual crop condition.
- Weather/ET reference if available.
- Intervention notes.
- Runtime window and intervention log.
- Soil tension compliance against the target operating band, or the best available proxy.
- Notes that translate results into NRCS 449, 441, and DIA 163 language.
Operating band status: Stable, Trending dry, Trending wet, Sensor unclear, or Requires field check.
Water Accounting / Context
Use the ledger as a decision guide, not a data graveyard.
Water source, legal class, storage, delivery burden, energy, and field usability determine whether a site wants continuous low-flow operation.
Timing, volume, and application rate
Ledger context explains why the operating schedule matters and how useful water changes when peak delivery burden falls.
Microirrigation architecture
Storage-buffered, low-pressure release fits the microirrigation conversation while shifting attention from peak flow to steady release.
Reportable design outputs
Use demand reduction, storage decoupling, energy burden, and field validation logs as compliance-friendly reporting language.
This water source either wants SIM or punishes peak-load irrigation.
The ledger helps explain which side of that line a site sits on before a pilot starts.
Open the deeper tools
Use the full Water Ledger when you need public records, accounting lab scenarios, energy estimates, maps, pilot scoring, or report outputs.
Use this toolkit from the two product pages.
Standards explains why the framework is legible to conservation and engineering workflows. Academy teaches the operating cadence. The Toolkit supplies the evidence, calculator, field sheet, and accounting context.
Standards make it legitimate. Academy makes it executable. Toolkit makes it usable.
Scheduling reference
Martin, Edward C. "Methods of Measuring for Irrigation Scheduling -- WHEN." University of Arizona Cooperative Extension, AZ1220, January 2009.
Used as a supporting reference for irrigation scheduling concepts, soil moisture measurement methods, Management Allowable Depletion, soil tension, ET-based scheduling, and the limitations of calendar-based irrigation.