Artificial recharge system.

1. School of Applied Natural Science (SoANS)
Department: Applied Geology
Regular: Master’s Program
Specialization: Hydrogeology
2022/23 Academic year
Tittle: Categories of techniques of artificial recharge
system.
By:
Dida Diriba (PGR/28044/15)

2. Presentation outline
• Surface spreading techniques
Runoff conservation structure
• Bench terracing
• Contour bunds, and contour trenches
• Gully, plugs, Nala bund, check dams
• Percolation ponds

3. Categories of techniques of artificial recharge
system
An Introduction to Artificial Recharge
Artificial recharge is a process by which excess
surface water is directed into the ground either by
spreading on the surface, by using recharge wells,
or by altering natural conditions to increase
infiltration, to replenish an aquifer.
Artificial recharge (sometimes called planned
recharge) is a way to store water underground in
times of water surplus to meet demand in times of
shortage.

4. Continue…
Artificial recharge can also be used:-
 to control seawater intrusion in coastal aquifers
 to control land subsidence caused by declining
ground water levels,
 to maintain base flow in some streams, and
raise water levels to reduce the cost of ground
water pumping.
It is useful to think of the entire artificial recharge
operation as a water source undergoing a series of
treatment steps during which its composition
changes.

5. What are methods?
There are three methods of artificial recharge
• Direct method
• Indirect method
• Combination method

6. Direct method
Direct method can be:-
Surface spreading techniques
 Flooding
 Ditch and furrows
 Recharge basin
 Runoff conservation structure
Sub-surface techniques

7. Runoff conservation structure
It is mechanical or structural measures that control the
velocity of surface runoff and thus minimize soil erosion and
retain water where it is needed.
 Bench terracing
 Contour bunds, and contour trenches
 Gully, plugs, nalah bund, check dams
 Percolation ponds

8. Bench terracing
• Bench terraces are the platform
like construction, which are
constructed along the contour of
the sloping land.
• It plays a significant role to make
the hilly land suitable for
cultivation.
• Generally it intended to control
surface runoff and soil losses.

9. Continue…

10. Contour bunds and contour trenches
• Contour bund (or contour bundling), which involves
the placement of lines of stones along the natural rises
of a landscape, and contour farming.
• These techniques help to capture and hold rainfall
before it can become runoff.

11. Contour trenches
• Contour trenches are ditches dug along a hillside in
such a way that they follow a contour and run
perpendicular to the flow of water.
• The soil excavated from the ditch is used to form a
berm on the downhill edge of the ditch.

12. Gully, plugs, Nalah bund, check dams
• Gully
Gully is a trench cut into land by the erosion of an
accelerated stream of water. Various conditions make
such erosion possible. It is a landform created by
running water, mass movement.

13. Plugs
• Plug is piece used to fill a hole stopper. It is an
obtruding or obstructing mass of material
resembling a stopper.
• A flat compressed cake of tobacco. small core
or segment removed from a larger object.

14. Nala bund
Nala bunds are embankments constructed across nala
for checking velocity of runoff, increasing water
percolation and improving soil moisture regime.

15. check dams
• A check dam is a small dam constructed across a drainage
ditch, swale, or channel to lower the velocity of flow. Reduced
runoff velocity reduces erosion and gullying in the channel and
allows sediments to settle out.
• Check dams reduce flow velocity, allowing sediment to settle
out.

16. Percolation pond
• Percolation pond means a constructed impoundment,
either above or below the natural land surface, which
is designed to allow seepage of wastewater into the
surficial aquifer.

17. Advantages and disadvantages of each method
Method Advantage Disadvantage
Bench terracing Conservation of soil and
water.
Reduce amount and
velocity of moving water
Time consuming
Labor intensive.
Contour band Improve productivity
Keep water in the soil
Not suitable for uneven
terrain and time consume
Contour trenches Water balance is enhanced
Water doesn’t evaporate
Disruption of water
circulation
Deterioration of soil
Gully Effective link for
transferring runoff
Reduce land available
Nala bund Increase surrounding water
level in wells and borehole
May create water logging
problem.
Check dams Inexpensive and easy
install
Less convenient and harder
to track.
Percolation ponds It replenish groundwater
during rainy season
Vegetative and flower
become less.