Design of Village Ponds for Effective Groundwater Recharge
Objective: To design village ponds that maximize groundwater recharge and provide a sustainable water source for rural communities.
Key Design Features
Site Selection:
- Choose low-lying areas with permeable soils (e.g., sandy or loamy soils) to enhance infiltration.
- Ensure proximity to agricultural fields and residential areas for easy access.
Size and Depth:
- Size: The pond should be large enough to capture significant runoff but balanced to the available land area.
- Depth: A depth of 3-5 meters is ideal to store a substantial volume of water and reduce evaporation losses.
Catchment Area:
- Ensure the pond has a well-defined catchment area with proper channels to direct runoff water into the pond.
- Use contour bunding and check dams to slow down and capture runoff.
Inlet and Outlet Structures:
- Inlet: Design the inlet to allow maximum water inflow during rains. It can be an open channel or a pipe with a screen to filter debris.
- Outlet: Install an overflow structure to manage excess water and prevent erosion of embankments.
Embankments:
- Construct sturdy embankments around the pond using locally available materials.
- Vegetate embankments with grasses or shrubs to prevent erosion and enhance stability.
Percolation Pits and Trenches:
- Create percolation pits or trenches around the pond to enhance groundwater recharge. These structures capture runoff and allow it to percolate slowly into the ground.
Desilting and Maintenance:
- Regularly desilt the pond to maintain its storage capacity and enhance percolation.
- Establish a community management system to oversee maintenance and operation.
Example of a Village Pond Design
Village Pond in Thiruvannamalai, Tamil Nadu:
- Size and Depth: The pond measures 100 meters in length, 50 meters in width, and 3 meters in depth.
- Catchment Area: The catchment area includes nearby fields and village roads, with contour bunds guiding runoff into the pond.
- Inlet and Outlet: The pond has an inlet channel with a debris screen and an overflow outlet that directs excess water to nearby fields.
- Embankments: Earthen embankments, 2 meters high, reinforced with grass cover.
- Percolation Pits: Ten percolation pits, each 2 meters in diameter and 3 meters deep, are dug around the pond.
- Maintenance: A village water committee is responsible for desilting and maintaining the pond and its structures.
Conclusion
By understanding and implementing traditional systems like the Eri in Tamil Nadu and designing effective village ponds, communities can significantly enhance their water security and agricultural productivity. Proper planning, community involvement, and regular maintenance are essential for the success of these water management systems.