In our Agriculture for Everybody blog series, we will be dealing with Pond Design related to Water Storage. This design is mainly for Dug Out Pond otherwise called as Excavated Pond or Sunken Pond.
Picture to be placed here at a later point of time
- Pond Area or Size
- Based on need
- Min : 1% of Total Land Bank
- Max : 10% of Total Land Bank
- Pond Shape
- Round or Square is optimal
- Reason : Round or Square will have the least surface area and hence evaporation is minimal as well as seepage of water into the soil is also minimal
- Pond Length
- Based on need
- Pond Breadth
- Based on need but similar to Pond Length is optimal
- Pond Depth
- Based on need but 6 ft is minimum. The Pond Depth (Height) is inclusive of the Bund. A gap of 1 ft is required between the top of the water surface and the top of the Pond
- Reason 1: If you wish to do Fish Farming in future, 5 ft is the maximum required water depth
- Reason 2: If the depth is more, need safety measures like fencing of the pond to avoid humans, cattle etc falling into the pond
- Internal Slope
- Min Ratio is 1:2 but can be more like 1:3, 1.4, 1:5 etc
- The Internal Slope should have provision to enable the water to flow without the soil being washed away by placing rocks or similar objects in the path of the water
- Reason 1: Generally, the Min Ratio is suited for most of the soils, but for loose soils, you can go for bigger ratios to avoid collapsing of the soils.
- Tip 1: While making the slopes, pound them hard so that the air & water is removed from the soil and the soil becomes hard. This way we can avoid collapsing of the soil to a great extent
- Tip 2: Plant Vettiver on the slopes. This will ensure the roots of the grass grips the soil and the collapsing of the soil is avoided altogether
- External Slope
- Min Ratio is 1:1 but can be 1:2 or more
- Tip 1: While making the slopes, pound them hard so that the air & water is removed from the soil and the soil becomes hard. This way we can avoid collapsing of the soil to a great extent
- Tip 2: Plant Vettiver on the slopes. This will ensure the roots of the grass grips the soil and the collapsing of the soil is avoided altogether
- Bund or Embankment Size
- Breadth - Min of 1.5 Metres at the top (excluding the Internal Slope & External Slope)
- Height - 2 ft Min
- Reason 1: The Bund is mainly used for walking along the pond to see whether everything is intact and any cracks or gaps have occurred and repair them before the monsoons
- Reason 2: The Bund can also be used to grow fodder for cattle as well as vegetables
- Reason 3 : To a certain extent, can protect humans & cattle from falling into the pond
- Inlet Water Path
- Length : Based on Need
- Breadth : 2 ft Min
- Depth : 1 ft
- The Inlet Water Path should be aligned with the top of the bund
- Outlet Water Path
- Length : Should be at least 1 ft beyond the end of the External Slope
- Breadth : 1 ft Min
- Depth : 1 ft
- Generally, it is recommended that the Outlet Water Path should be at the bottom of the pond. This is possible only when the land is at a higher plane and the water goes out by natural gravitational forces
- For Dugout ponds, the Outlet Water Path should be at the ground level
- Tip 1: To remove the water that is below the ground level, we need to pump out the water by artificial means
- Overflow Water Path
- Length : Should be at least 1 ft beyond the end of the External Slope
- Breadth : 2 ft Min
- Depth : 1 ft
- The Overflow Water Path should be 1 ft below the Inlet Water Path
- There should be an equivalent Outlet Water Path for each Inlet Water Path or at least to the sum of the Inlet Water Paths
- Silt Pit
- Length : 1 Metre Min or more
- Breadth : 1 Metre
- Depth : 0.5 Metre
- This has to be placed across/perpendicular to the Inlet Water Path. This will filter the sediments if the water is coming from rain water harvesting source or from any other sources
- Tip 1: If we have multiple Inlet Water Path, each should have an equivalent Silt Pit
- Misc
- A Pond Example
- Length : (Bund Breadth X 2) + Need Based Length (for eg., 10 ft)
- Breadth : (Bund Breadth X 2) + Need Based Length (for eg., 10 ft)
- Depth : 6 ft (including the Bund Height)
- Bund :
- Height : 2 ft
- Breadth : 9.2 ft (1.5 Metres=3.2 ft + Internal Slope Breadth + External Slope Breadth)
- Internal Slope
- Breadth : 4 ft (Based on Bund Height)
- Slope 1:2
- External Slope
- Breadth : 2 ft (Based on Bund Height)
- Slope : 1:1
- Tip 1: Trees which have longer roots need to be avoided near the pond as this may cause cracks or collapse of the bund
- Tip 2: Trees like Coconut Or Palmyra Tree are best suited as they grip the soil very well
