Irrigation Evap Loss Calculator

Estimate irrigation evaporation loss using water volume and efficiency.

gal
%
gal
%

Quick Facts

Evap
Loss
Evaporation reduces effective water
Efficiency
System
Efficiency increases delivery
Wind
Factor
Wind increases losses
Decision Metric
Coverage
Need coverage

Your Results

Calculated
Weekly Water
-
Weekly applied water
Loss Gallons
-
Evaporation loss
Net Water
-
Net to plants
Coverage Percent
-
Coverage of need

Evap Plan

Your defaults show a clear irrigation loss estimate.

What This Calculator Measures

Estimate irrigation evaporation loss using water volume, evap rate, and efficiency.

By combining practical inputs into a structured model, this calculator helps you move from vague estimation to clear planning actions you can execute consistently.

This calculator estimates irrigation evaporation loss and coverage.

How to Use This Well

  1. Enter daily irrigation and evap percent.
  2. Add wind factor and days per week.
  3. Set plant need and efficiency.
  4. Review net water and coverage.
  5. Adjust schedule.

Formula Breakdown

Weekly water = daily x days
Loss: weekly x evap % x wind.
Net: weekly x efficiency - loss.
Coverage: net / need.

Worked Example

  • 120 gal x 4 days = 480 gal.
  • Loss about 95 gal.
  • Coverage about 86%.

Interpretation Guide

RangeMeaningAction
90%+Strong.Good coverage.
70-90%Good.Minor adjustments.
50-70%Moderate.Increase watering.
Below 50%Low.Review system.

Optimization Playbook

  • Water early: reduce evaporation.
  • Improve efficiency: upgrade emitters.
  • Reduce wind exposure: add barriers.
  • Monitor need: adjust for seasons.

Scenario Planning

  • Baseline: current watering.
  • More efficiency: add 10%.
  • Higher evap: add 5%.
  • Decision rule: keep coverage above 80%.

Common Mistakes to Avoid

  • Ignoring wind effects.
  • Overestimating efficiency.
  • Skipping seasonal changes.
  • Not tracking plant need.

Implementation Checklist

  1. Measure irrigation volume.
  2. Estimate evap loss.
  3. Set plant need.
  4. Review weekly.

Measurement Notes

Treat this calculator as a directional planning instrument. Output quality improves when your inputs are anchored to recent real data instead of one-off assumptions.

Run multiple scenarios, document what changed, and keep the decision tied to trends, not a single result snapshot.

FAQ

What evaporation percent should I use?

15-25% is common for warm climates.

Does wind matter?

Yes, wind can increase losses.

How do I improve efficiency?

Use drip systems or smart controllers.

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