Unit V - artificial-ground-water-recharge-ppt.pptx

Artificial groundwater recharge is a process by which water is intentionally introduced into aquifers to replenish groundwater supplies. This method is used to enhance the natural recharge rate of groundwater systems, addressing issues such as declining water tables, drought, and the over-extraction of groundwater. Artificial recharge is an important tool for sustainable water management, particularly in regions facing water scarcity.

Objectives of Artificial Groundwater Recharge:
Replenish Depleted Aquifers: To compensate for excessive groundwater extraction and restore water levels in aquifers.
Enhance Water Storage: To store excess surface water (from rainfall, rivers, or treated wastewater) during wet seasons for use in dry periods.
Improve Water Quality: To filter and improve the quality of surface water as it percolates through soil layers into the aquifer.
Prevent Land Subsidence: To avoid ground subsidence caused by the over-extraction of groundwater.
Sustain Base Flow to Rivers: To maintain river flows during dry seasons by ensuring the aquifers remain recharged and can contribute water to rivers.
Reduce Saltwater Intrusion: To prevent the movement of saline water into freshwater aquifers, particularly in coastal areas, by maintaining sufficient freshwater levels.
Methods of Artificial Groundwater Recharge:
1. Surface Infiltration Methods:
These methods involve spreading water on the surface to allow it to infiltrate into the ground and reach the aquifer.

Recharge Ponds/Basins:

Shallow basins are excavated, and water (from rainwater, rivers, or treated wastewater) is spread over the area. The water percolates through the soil and recharges the groundwater.
These are often located in areas with high infiltration capacity and permeable soils.
Benefits: Simple, cost-effective, and can handle large volumes of water.
Limitations: Requires large land areas and suitable soil conditions (permeable and free from contamination risks).
Flooding/Spreading Channels:

Water from rivers or other sources is diverted into channels or spread over large land areas, allowing it to infiltrate into the ground.
Useful in agricultural areas or fields during off-season periods.
Benefits: Enhances natural infiltration over large areas.
Limitations: Limited by soil permeability and the availability of water.
Contour Bunding:

Small barriers or bunds are constructed along contours in sloping areas to slow down surface runoff, increasing water infiltration and reducing erosion.
Benefits: Promotes groundwater recharge and soil conservation in hilly or sloping terrain.
Limitations: Effective only in regions with slopes and sufficient rainfall.
2. Subsurface Infiltration Methods:
These methods involve directly injecting water into the aquifer or enhancing natural recharge pathways.

1. KONGUNADU COLLEGE OF ENGINEERING AND TECHNOLOGY (Autonomous ) Department of Agriculture Engineering Course: Groundwater and Well Engineering Topic : Artificial Recharge Techniques By Mr. M.Sundharan , Assistant Professor, Department of Agricultural Engineering, Kongunadu College of Engineering and Technology