Consumptive Use of Water Calculator

Consumptive Use Formula:

\[ Cu = Q - \frac{C \times Q}{Cs} + Reff \]

Total Quantity of Water Applied to Soil (Q):

Liters

Concentration of Salt in Irrigation Water (C):

ppm

Salinity Concentration of Soil Solution (Cs):

ppm

Effective Rainfall (Reff):

Consumptive Use of Water in Irrigation (Cu):

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1. What is Consumptive Use of Water in Irrigation?

Consumptive use of water in irrigation refers to the portion of water withdrawn that is evaporated, transpired, incorporated into products or crops, consumed by humans or livestock, or removed from the immediate water environment. It represents the water that is not returned to the water source.

2. How Does the Calculator Work?

The calculator uses the Consumptive Use formula:

\[ Cu = Q - \frac{C \times Q}{Cs} + Reff \]

Where:

\( Cu \) — Consumptive use of water in irrigation (cm)
\( Q \) — Total quantity of water applied to soil (Liters)
\( C \) — Concentration of salt in irrigation water (ppm)
\( Cs \) — Salinity concentration of soil solution (ppm)
\( Reff \) — Effective rainfall (cm)

Explanation: The formula calculates the actual water consumed by accounting for salt concentration effects and adding effective rainfall contribution.

3. Importance of Consumptive Use Calculation

Details: Accurate consumptive use calculation is crucial for efficient water management in agriculture, determining irrigation requirements, and ensuring sustainable water resource utilization.

4. Using the Calculator

Tips: Enter total water quantity in liters, salt concentrations in ppm, and effective rainfall in cm. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is effective rainfall in irrigation?
A: Effective rainfall is the portion of total rainfall that is available for crop use, equal to the difference between total rainfall and actual evapotranspiration.

Q2: Why is salt concentration important in consumptive use calculation?
A: Salt concentration affects the amount of water actually available for plant use, as high salinity can reduce water uptake by plants.

Q3: What are typical values for salt concentration in irrigation water?
A: Most surface irrigation water from snow-fed rivers has total salinity less than 0.5-0.6 ds/m, while groundwater sources may have higher salinity levels.

Q4: How does this calculation help in water resource management?
A: It helps determine the actual water consumption, enabling better planning of irrigation schedules and conservation of water resources.

Q5: Are there limitations to this equation?
A: The equation assumes steady-state conditions and may need adjustments for specific soil types, crop varieties, and local climatic conditions.