To calculate the borewell capacity, follow these steps:
1. Measure Borewell Dimensions
- Borewell Diameter: Measure the internal diameter of the borewell (in inches or centimeters).
- Borewell Depth: Measure the total depth of the borewell from the ground surface to the bottom (in feet or meters).
2. Determine Static Water Level (SWL)
- The static water level (SWL) is the level at which water stands in the borewell when the well is not being pumped. This can be measured using a water level meter. Note this depth from the ground level to the static water level.
3. Calculate Water Column Height
- Water column height is the difference between the depth of the borewell and the static water level (SWL). Water Column Height=Borewell Depth−Static Water Level\text{Water Column Height} = \text{Borewell Depth} – \text{Static Water Level}Water Column Height=Borewell Depth−Static Water Level
4. Volume of Water in Borewell
- The volume of water in the borewell can be calculated using the formula for the volume of a cylinder: Volume of Water (in cubic meters)=π×(Borewell Radius (in meters)2)2×Water Column Height (in meters)\text{Volume of Water (in cubic meters)} = \pi \times \left( \frac{\text{Borewell Radius (in meters)}}{2} \right)^2 \times \text{Water Column Height (in meters)}Volume of Water (in cubic meters)=π×(2Borewell Radius (in meters))2×Water Column Height (in meters) Convert the volume to liters (1 cubic meter = 1000 liters).
5. Pumping Test for Yield
- Conduct a pumping test to determine the borewell’s yield, which is the rate of water flow out of the well when pumped. This is typically measured in liters per minute (LPM) or cubic meters per hour (m³/h).
- Pump the well at a constant rate and measure the water level after a set period to see how fast it recovers. The faster the recovery, the higher the borewell yield.
6. Calculate Borewell Capacity
- Static Capacity: The volume of water stored in the borewell’s water column (calculated earlier).
- Dynamic Capacity: The borewell’s yield over a specific period, based on the pumping test results.
By following these steps, you can determine both the static volume of water available in the borewell and the rate at which it can sustainably provide water through pumping (yield).