ANNUAL WATER DEMAND
659,513 m³ / year Crops99.6% Livestock + households2,373 m³
Delivery is not the constraint. The cropping plan is.
Can the property supply it?
annual volumeHarvestable runoff15–44% of demand
Runoff alone cannot meet the plan. A borehole could close the volume gap, but only with chemistry conditioning.
The land is already thirsty
atmospheric demand518 mmactual ET
of 1,267 mm reference41% met59% unmet
The land is already water limited before the planned crops are planted.
MONTHLY DEMAND AGAINST EFFECTIVE RAINFALL
Effective rainfallCrop demandTo irrigate
10 months of twelve need irrigating; April and November do not. May looks balanced here and still needs 2,116 m³: the file sums each crop separately, and coffee is short in a month when the farm-wide balance is in surplus.
DEMAND AGAINST SUPPLY
Demand659,513 m³
Harvestable runoff96,600 – 289,801 m³
Solid to 96,600 m³, which every soil type in the table delivers; hatched to 289,801 m³, which only a clay pan does. Shortfall against the best case: 369,712 m³.
THE BOREHOLE CANNOT CLOSE IT AS IT STANDS
The borehole delivers 40 cubic metres an hour but carries a sodium adsorption ratio of 25.2 at low salinity, classified C2 to S4, very high sodium hazard. Residual sodium carbonate is 4.81 milliequivalents per litre, above the 2.5 threshold conventionally described as unsuitable for irrigation without treatment. Irrigating at that chemistry would extend across the farm the sodicity that already disqualifies three of five soil profiles for coffee, macadamia and citrus.
The condition for using it: The pilot design specifies calcium conditioning through an inline gypsum dissolver at about 113 mg/L to hold applied water below SAR 6, roughly 450 kg per hectare a year. That is the condition under which borehole water becomes usable for irrigation.
8 hours a day, all year116,800 m³
12 hours a day, all year175,200 m³
24 hours a day, all year350,400 m³
WHAT THE LAND ALREADY USES
Through plants — 71% beneficialOff bare soil
148 mm of the 518 evaporates off bare soil rather than passing through a plant. Across 165 hectares that is about 243,000 cubic metres a year consumed growing nothing - two and a half times the low runoff estimate. Raising the beneficial fraction from 71 to 80 per cent would redirect roughly 80,000 cubic metres a year into growth.
The farm is not short of water arriving. It is short of water staying.
THE CROP BLOCKS ARE A PROPOSAL
Proposed crop blocks, derived from the landscape, water flow and soil steps rather than surveyed.
ONE BLOCK CONTRADICTS THE SOIL REPORT
Every property iSDA carries reads well at NP3: measured pH 7.48, organic carbon 3.93%, nitrogen 0.39%, phosphorus 107.4 ppm. What disqualifies it is exchangeable sodium, 32.9% at its worst horizon — and sodium is not a property iSDA carries at all.
The macadamia block landed on , the one profile the report rates suitable for all four crops, with the same rules and the same blindness. Both placements are the rules working exactly as written.
SURFACE
BUDGET LAYERS
▦Crop blocks (proposed)165 ha in 8 blocks, shaded by the irrigation each needs
