What is a rainwater harvest recharge pit?
A rainwater harvest recharge pit is a pit to replenish the groundwater artificially. Consultants for civil design study the geophysical survey to understand the aquifers. They then plan the location of the recharge pits.
A recharge pit helps improve the quality of underground water, increasing the level of underground water. Hence, the recharge pits are located near a fracture underground, so the aquifers are replenished.
Why is recharging of aquifers necessary?
Due to the excessive withdrawal of water from underground resources, the water gets depleted. It is essential to restore the reserves by recharging the aquifers. Some of the reasons are:
- Recharging improves the groundwater table.
- It helps conserve rainwater.
- To improve the water quality.
The runoff and rooftop rainwater travels through drains, and first-level filtration happens at the silt trap. So, housekeeping of the area and regular maintenance of the silt trap is necessary.
Location of recharge pits
The consultants for civil design locate the recharge pits after thoroughly studying the geophysical report and the site conditions. Moreover, the geophysical report helps understand the sub-surface, the aquifers and the fissures that can expedite water penetration.
The civil design consultants have to design the rainwater harvesting system based on the size of the catchment area, rainfall intensity and frequency and rate of recharge. The civil consultants should check for site conditions like site layout, suitable roof catchment, rainfall history, water percolation, and calculate the runoff. The site evaluation helps in designing a proper recharge pit.
Layers of boulders, gravel and coarse sand fill the pit. The coarse sand layer prevents silt from percolating into the groundwater. So, periodic cleaning of the coarse sand layer is essential for the pit to function correctly. Most importantly, the contractor must test the recharge pit’s percolation rate before the completion of the project.
Advantages:
- No adverse impact on the surroundings.
- Recharge pits are environmentally friendly and reduce flooding.
- It controls soil erosion.
- It recharges the groundwater and increases the water table.
- The quality of groundwater improves.
However, a disadvantage is that periodic maintenance of the recharge pits and silt traps is necessary to avoid groundwater contamination.
To conclude, the recharge pits ensure that the aquifers are replenished, and the rainwater harvesting system works properly. The civil design consultants must ensure that the rainwater harvest system works effectively through proper checks in the tender.
