Decide when to irrigate and how long to run the system
This daily water-balance calculator uses CIMIS ASCE Penman-Monteith actual ETo and CIMIS rainfall, Open-Meteo forecast ETo and rainfall, almond Kc, soil water storage, irrigation events entered as runtime or flow-meter volume, and irrigation system capacity to create a practical irrigation recommendation.
Daily operations mode
Use this screen for daily decisions: select an orchard block, check the recommendation, record irrigation events, and review the daily schedule. For blocks using CIMIS, current weather and the forecast refresh automatically when the block opens. Each block keeps its own setup and season records in this browser.
Orchard blocks
Select a block to continue its saved season record. Each block keeps separate setup, Target MAD entries, irrigation events, rainfall corrections, soil-water measurements, and weather history.
Farm & Irrigation Data
Storage preference not selected
Data saves automatically according to your selected storage preference. Browser storage is not a permanent backup.
1. Irrigation recommendation
Orchard Block
Decision
Monitor
Projected end-of-day depletion on 09-13-2026 is comfortably below the Target MAD depletion. Continue monitoring.
Decision guide: Green = Monitor, Amber = Irrigate soon, Red = Irrigate now.
Today's soil-water thresholds
Read-only values that show today's modeled depletion relative to the crop-stress and irrigation-management thresholds.
Current root-zone depletion
The calculator's estimated end-of-day depletion from field capacity in the wetted root zone for the current calculation date. A larger number means more root-zone water has been used or lost.0.25 in
Stress threshold — FAO-56 RAW
The depletion threshold where modeled crop water stress begins. RAW = p × TAW. Today's p is 40%. Below this depletion, the FAO-56 stress coefficient Ks remains 1.0.67 in
Irrigation trigger — Target MAD
The management depletion level used to trigger an irrigation recommendation. Target MAD depletion = Target MAD% × TAW. Today's Target MAD is 40% of TAW.0.67 in
Status
Compares current depletion with both thresholds. Below both thresholds means neither threshold has been reached. Stress threshold reached means RAW has been reached but the Target MAD trigger has not. Irrigation trigger reached means the Target MAD depletion has been reached; this status takes priority if the thresholds are ordered differently.Below both thresholds
Projected depletion vs. Target MAD
37%
Recommended gross application
Not triggered
Recommended runtime
Not triggered
Recommended gallons/tree
Not triggered
Today's scheduled runtime
0 hr
2. Weather
For blocks using CIMIS, observed weather and the 7-day Open-Meteo forecast refresh automatically when the block opens. Use the refresh button only when you want to update again during the same session, or use manual ETo and rainfall when needed.
3. Irrigation events
Add irrigation events that occurred or are planned. The calculator subtracts the net applied water from the daily depletion balance.
Past irrigation events are historical records. Editing or removing one recalculates the water balance from the affected date forward. Volume entries are whole-block totals.
No irrigation events have been entered yet.
4. Target MAD to schedule irrigation
Set the desired MAD level and enter the date for the desired MAD moving forward.
Past Target MAD entries are historical records. Editing or removing one recalculates irrigation results from its effective date forward.
No Target MAD schedule entries yet. The calculator uses the Default Target MAD until a dated Target MAD is added.
5. Daily schedule
Manual weather mode is active. ETo is editable below, and local rainfall can be entered for any date.
| Date | ETo | Ks | Kc | ETc | ETc act | Target % MAD | Rain | Run time | Net Irrigation | DP | End dep | Soil water content % | Irrigation recommendation |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 09-13-2026 | 1 | 1 | 0.25 | 0.25 | 40% | 0 | 0h | 0 | 0 | 0.25 | 16.5% PWP 8% · FC 18% | Monitor | |
| 09-14-2026 | 1 | 0.99 | 0.25 | 0.25 | 40% | 0 | 0h | 0 | 0 | 0.5 | 15% PWP 8% · FC 18% | Monitor | |
| 09-15-2026 | 1 | 0.99 | 0.25 | 0.25 | 40% | 0 | 0h | 0 | 0 | 0.74 | 13.6% PWP 8% · FC 18% | Irrigate now | |
| 09-16-2026 | 0.93 | 0.98 | 0.25 | 0.23 | 40% | 0 | 0h | 0 | 0 | 0.97 | 12.2% PWP 8% · FC 18% | Irrigate now | |
| 09-17-2026 | 0.7 | 0.98 | 0.25 | 0.17 | 40% | 0 | 0h | 0 | 0 | 1.14 | 11.2% PWP 8% · FC 18% | Irrigate now | |
| 09-18-2026 | 0.53 | 0.98 | 0.24 | 0.13 | 40% | 0 | 0h | 0 | 0 | 1.27 | 10.4% PWP 8% · FC 18% | Irrigate now | |
| 09-19-2026 | 0.4 | 0.97 | 0.24 | 0.1 | 40% | 0 | 0h | 0 | 0 | 1.37 | 9.8% PWP 8% · FC 18% | Irrigate now |
09-13-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-14-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-15-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-16-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-17-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-18-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
09-19-2026
Manual fallback
ETo
Ks
Kc
ETc
ETc act
Target % MAD
Rain
Run time
Net Irrigation
DP
End dep.
Soil water content %
Dates follow California civil time; CIMIS observations remain assigned to the PST-based dates reported by CIMIS. ETc = ETo × Kc. Ks uses the estimated FAO-56 readily available water (RAW) stress threshold, which is separate from the grower-selected Target MAD irrigation trigger. ETc act = ETc × Ks is used in both historical and forecast water balances; a forecast Ks below 1 indicates predicted water stress, not reduced irrigation demand. Rain shows the rainfall used by the calculator; an optional local rain entry overrides the weather-source rainfall for that date, the effective rainfall fraction is then applied, and the water balance recalculates from that date forward. Decision guide: Green = Monitor, Amber = Irrigate soon, Red = Irrigate now. DP = deep percolation in inches. Soil water content % is modeled as volumetric water content (VWC) from field capacity and root-zone depletion in the routine wetted root zone. A measured VWC resets End dep for that date and carries the corrected wetted-zone depletion forward; separately modeled rain carryover outside the routine wetted area is retained. Modeled physical overflow remains in DP, while measurement residuals are reported as unaccounted water loss or gain in the season CSV.
The 14-day view remains the default operational window. The 30-day view adds recent tracked history while keeping the current date and available forecast in view.
6. Weekly summary
Daily ETo, ETc, ETc act, rainfall, irrigation runtime, and applied water are summed into weekly values for the dates shown above.
| Week | ETo (in) | ETc (in) | ETc act (in) | Rain (in) | Eff. rain (in) | Net irr. (in) | DP (in) | Runtime | Ending depletion (in) | Highest status during week |
|---|---|---|---|---|---|---|---|---|---|---|
| 09-13-2026 to 09-19-2026 (7 days) | 1.75 | 1.72 | 1.37 | 0 | 0 | 0 | 0 | 0 hr | 1.37 | Irrigate now |
7. Season trends
See how crop water demand, irrigation, rainfall, and root-zone depletion have changed since tracking started.
Weekly Water Demand and Water Supplied
Three bars show potential ETc, net irrigation applied, and effective rainfall. The line shows ETc act after modeled water-stress effects so the weekly water balance can be interpreted consistently.
Root-Zone Depletion versus Target MAD
Daily modeled root-zone depletion compared with the Target MAD trigger, estimated RAW stress threshold, and routine wetted-zone TAW. Irrigation-event dates are marked along the bottom.
Cumulative Seasonal Water
Season-to-date cumulative ETc, actual ETc after modeled water-stress effects, and retained water supply as net irrigation plus effective rainfall minus modeled deep percolation.
8. Season summary
Cumulative water use and irrigation records for Orchard Block from the date this block started being tracked through 09-13-2026.
Tracking started
09-13-2026
Set automatically when this block was first created or its saved history was reset.
For CIMIS blocks, completed-day observations are refreshed from the tracking start date forward. If CIMIS reports a missing ETo or rainfall value, the calculator uses the manual fallback for that measurement and flags the fallback in the daily table and CSV.
Gross irrigation applied
0 in
Net irrigation applied
0 in
Full crop water requirement (ETc)
0.25 in
Actual crop ET (ETc act)
0.25 in
Rainfall
0 in
Effective rainfall
0 in
Deep percolation
0 in
Irrigation runtime
0 hr
The 14-day Daily schedule remains the default operational view, with an optional 30-day view. Season Trends and Season Summary include records only from the date this block was first set up in the calculator. Irrigation events, Target MAD changes, local rainfall, soil-water measurements, and saved weather are retained separately for each block. The calculator does not reconstruct a water balance for dates before tracking started. For CIMIS blocks, completed ETo and rainfall are maintained automatically from the tracking start date forward.
Advanced setup: block, soil, and Kc settings
These settings are usually entered once for a block. If you change a calculation setting after tracking has started, the calculator will warn you before applying the new value to the entire tracked season and recalculating historical and current results.
Block setup
Enter the orchard, soil, and irrigation system information once for each block.
Farm and irrigation data are saved automatically according to your storage preference.
Young-orchard Kc adjustment (% of mature Kc)
Defaults are Year 2 = 45%, Year 3 = 65%, and Year 4 = 85%. Mature orchards use 100%. These percentages are editable for field-specific conditions.
The calculator applies this percentage to active-season mature-orchard Kc values. Dormant Kc remains independent because orchard-floor evaporation and cover-crop water use do not scale directly with tree canopy. Changing a percentage recalculates the tracked season for blocks of that selected age.
Target MAD is the irrigation-management trigger. The separate FAO-56 stress depletion fraction p controls when Ks begins reducing ETc; the default is 40% for almonds. The initial depletion is the starting soil-water deficit at the tracking start date.
Leaching requirement is applied in addition to irrigation efficiency in the net-water calculation; do not enter leaching losses again inside the efficiency value.
Soil and Kc guide
Use field-specific FC and PWP when available. TAW, the FAO-56 stress threshold, and dated Target MAD irrigation triggers are calculated for the wetted root zone.
Calendar Kc stage dates
California almond defaults are shown first. Farmers may adjust these recurring MM-DD dates for local phenology or seasonal conditions. Changes recalculate the tracked season.
Dormant Kc period (calculated)
December 1 through February 28 (December 1 through February 29 in leap years)
Dormancy starts one day after Active season ends and ends one day before Leafout. These dormant dates are calculated automatically and are not separately editable.
Kc currently used for Mature: 100% of mature Kc
Adjusted active-season values: leafout 0.62 · mid-season 1.11 · end-season 0.69. Dormant Kc remains 0.4 for all orchard ages.
Enter mature-orchard Kc values above. The selected orchard-age percentage is applied automatically, so do not pre-adjust these Kc inputs for age unless you intentionally set the age percentage to 100%.
Effective rainfall first refills depletion in the routine irrigation-wetted root zone. Additional rainfall can be retained as carryover water in the rest of the full root-zone profile, up to its available storage capacity; only rainfall beyond both capacities is reported as deep percolation.
Soil texture reference table
This table is informational only. Use field-specific soil test values when available.
| Soil texture | FC | PWP | AWC (in/ft) |
|---|---|---|---|
| Sand | 0.09 | 0.04 | 0.6 |
| Loamy sand | 0.12 | 0.05 | 0.84 |
| Sandy loam | 0.18 | 0.08 | 1.2 |
| Loam | 0.27 | 0.12 | 1.8 |
| Silt loam | 0.31 | 0.14 | 2.04 |
| Clay loam | 0.36 | 0.2 | 1.92 |
| Clay | 0.4 | 0.25 | 1.8 |
Learn more
Supporting irrigation scheduling resources
Check these public extension and industry resources for additional information.