Rainwater Harvesting Structure

RAIN WATER HARVESTING FOR ARTIFICIAL GROUND RECHARGE

• The following considerations become important before undertaking artificial recharge through surface spreading techniques.
• The aquifer to be recharge should be unconfined permeable and sufficiently thick to provide storage space
• Surface soil should be sufficiently permeable to maintain high infiltration rate
• Vadose zone should be permeable and free from clay lenses, which may cause perched water conditions
• Groundwater levels in the phreatic aquifer should be deep enough to accommodate the water table rise to avoid possible water logging condition.

The aquifer material should have moderate hydraulic conductivity so that the recharged water is retained for sufficiently long period in the aquifer and can be used at the time of need. Very high permeability results in the loss of recharged water due to subsurface outflow whereas very low permeability may come in way of desired recharge rate.

Topography plays an important role in controlling the recharge rate. Areas with gently sloping land without gullies or ridges are most suited for surface water spreading techniques.

Advantages

• Provides self-sufficiency to water supply
• Reduces the cost of pumping
• Reduces soil erosion in urban areas
• Less expensive and simple and can be adopted by individuals
• Utilizes the rainfall runoff
• Improves the quality of existing groundwater through dilution
• Removes bacteriological and other impurities from sewage and wastewater so that the water is suitable for re-use
• Rainwater may be harnessed at place of need and may be utilized at time of need
• In costal areas, it provides good quality water as well as helps in maintaining balance between the fresh saline water aquifers
• In islands, it provides the most preferred source of water for domestic use
• In desert, it provide relief to people