This calculator helps estimate the daily and annual water needs for your irrigation system based on the type of plants you are watering, the size of the area, and local climate conditions. Understanding your irrigation water needs is crucial for efficient water management, preventing over or under-watering, and ensuring the health of your plants.
Inputs
Turf (Grass)
Vegetables
Ornamentals (Shrubs/Flowers)
Trees
Check local weather data for this value.
Varies by plant type and growth stage (e.g., Turf = 0.6-1.0, Vegetables = 0.7-1.2, Ornamentals = 0.5-0.8, Trees = 0.5-0.7).
e.g., Drip is 90-95%, Sprinklers are 70-85%.
Results
Daily Water Need: — gallons
Annual Water Need (approx.): — gallons
function calculateWaterNeeds() {
var plantType = document.getElementById("plantType").value;
var areaSize = parseFloat(document.getElementById("areaSize").value);
var eTo = parseFloat(document.getElementById("eTo").value);
var cropCoefficient = parseFloat(document.getElementById("cropCoefficient").value);
var irrigationEfficiency = parseFloat(document.getElementById("irrigationEfficiency").value) / 100; // Convert percentage to decimal
var dailyWaterNeedGallons = 0;
var annualWaterNeedGallons = 0;
// Basic validation
if (isNaN(areaSize) || isNaN(eTo) || isNaN(cropCoefficient) || isNaN(irrigationEfficiency) || areaSize <= 0 || eTo < 0 || cropCoefficient < 0 || irrigationEfficiency <= 0) {
document.getElementById("dailyWaterNeed").innerHTML = "Invalid input. Please enter valid numbers.";
document.getElementById("annualWaterNeed").innerHTML = "";
return;
}
// Constants and Conversions
var inchesToGallonsPerSqFt = 0.623; // Approximate conversion: 1 inch of water over 1 sq ft is ~0.623 gallons
// Calculate daily water need in inches
var dailyWaterRequirementInches = eTo * cropCoefficient;
// Calculate daily water need in gallons
// Water needed per sq ft (gallons) = (Daily water requirement in inches) * (inches to gallons conversion) / (Irrigation efficiency)
dailyWaterNeedGallons = (dailyWaterRequirementInches * inchesToGallonsPerSqFt * areaSize) / irrigationEfficiency;
// Approximate annual water need (assuming 365 days of similar needs, adjust for seasonal variations if needed)
// For a more accurate annual calculation, you would typically average daily ET over the growing season.
// For simplicity here, we multiply daily need by 365.
annualWaterNeedGallons = dailyWaterNeedGallons * 365;
document.getElementById("dailyWaterNeed").innerHTML = dailyWaterNeedGallons.toFixed(2);
document.getElementById("annualWaterNeed").innerHTML = annualWaterNeedGallons.toFixed(0);
}