This power point presentation was created in June 2021.

1. COLLEGE OF AGRICULTURE AND NATURAL RESOURCE
DEPARTMENT OF SOILAND WATER RESOURCE MANAGEMENT
A SENIOR SEMINAR ON:
The Role of Water Harvesting Technology for Domestic and Agricultural Use
By:
Yimam Mekonen
Advisor: Bekalu.M (M.Sc)
June, 2013
Assosa, Ethiopia

2. PRESENTATION OUTLINE
• INTRODUCTION
• OBJECTIVE
• LITERATURE REVIEW
• CONCLUSION

3. 1. INTRODUCTION
 One of the biggest challenges of the 21st century is to overcome the
growing water shortage.
 In many parts of the world conventional piped water is either absent,
unreliable or too expensive.
 Millions of people throughout the world do not have access sufficient
water for agricultural and domestic purposes.
 Rainwater harvesting (RWH) has valuable alternative or
supplementary water resource, along with more conventional water
supply technologies.

4. Cont…
 Storage of water in small ponds, tanks or cisterns has been practiced
widely throughout the world for millennia.
 Water stored in ponds or tanks is used for a variety of purposes in
North Africa since the Roman times.
 A growing awareness about the potential of rainwater harvesting for
improved crop production was observed in Africa during the 1970s
and 1980s when there was a wide spread droughts that resulted in
crop failures.

5. Cont…
 A number of water harvesting projects were constructed in sub-
Saharan Africa during the past three decades.
 water harvesting in Ethiopia has a long history with strong attachment
to the ancient Orthodox churches (Habtamu, 1999).
 During this period harvested water was and stored in ponds and tanks
for agriculture and water supply purposes.

6. 1.2 Objectives
1.2.1 General objective
• The general objectives of this paper was to review the role of water
harvesting technologies for domestic and agriculture use.

7. 2. LITERATURE REVIEW
2.1 Concept of Water Harvesting
 The term “water harvesting” was comprehensively defined by
Reijntjes (1983) to mean all the different techniques to collect runoff
or flood water for storage in the soil profile or in tanks.
 It is a method of collecting, storing and conserving local surface
runoff for agriculture in arid and semi-arid regions.
 The harvested water can be used for the Agriculture and Domestic
use.

8. Cont…
 Water can be collected from rooftops, courtyards and similar compacted or
treated surfaces.
 Rain water harvesting provides an independent water supply during regional
water restrictions and in developed countries is often used to supplement the
mains supply(FERGuSON,2012).
 Rain water harvesting systems are appealing as they are easy to understand,
install and operate.
 They are effective in ‘green droughts’ as water is captured from rain fall where
run off is insufficient to flow in to dam storage

9. Cont…
 The quality of captured rain water is usually sufficient for most
household needs, reducing the need for detergents because rain water
is soft.
2.2 Types of Water Harvesting
 To facilitate the presentation of the various types of water harvesting
techniques.
 Three types of water harvesting are covered by rainwater harvesting
I. Rain water harvesting

10. cont…
A. Water collected from roof tops, courtyards and similar compacted or
treated surfaces is used for domestic purpose or garden crops.
B. Micro-catchment water harvesting
• It is a method of collecting surface runoff from a small catchment area and
storing it in the root zone of an adjacent infiltration basin. The basin is
planted with a tree, a bush or with annual crops.
C. Macro-catchment water harvesting,
• It is called harvesting from external the case where runoff from hill-slope
catchments the cropping area located at hill foot on flat terrain.

11. Figure 1: Micro catchment ‘Negarim’ Type, B: Macro catchment ‘Hillside Conduit’
system, C: Floodwater Harvesting: Floodwater diversion system Sources: A:
Rocheleau et al. 1988; B and C: Prinz
Micro catchment

12. cont…
II. Flood Water Harvesting
 Flood water harvesting, also known as ‘large catchment water
harvesting’ or ‘Spate Irrigation.
flood water harvesting
• The water is forced to infiltrate and the wetted area can be used for
agriculture or pasture improvement.
flood water diversion
 The water is forced to leave its natural course and conveyed to nearby
cropping fields

13. III. GROUND WATER HARVESTING
• It is the part of precipitation that percolate in to the ground surface.
• Groundwater counts in average for one third of the fresh water
consumed by humans.
The Ground Water
0.903
WALL

14. 2.3. Role and Goals of Water Harvesting
aim of water harvesting is to provide water for livestock and agricultural purpose.
•In rain fed areas, WH system water to supplement rain fall to increase and stabilize
production (Prinz etal.2012) THE GOAL
•It is important in the arid and semi-arid areas. In such rain fall is low and unfavorably
distributed
•Increase in the quality of
ground water,
•Mitigate effects of drought
•Reduction in the soil erosion
•Decrease flooding of roads
•Rise in the water levels
•Saving energy lift ground
water
THE GOAL OF
WATER
HARVESTING

15. Cont…
A. Water harvesting for agriculture
• The harvested water for agriculture covers a wide range of
consumptive and non-consumptive water uses.
• Harvested water is water that is used to grow fresh produce and
sustain livestock.
• The use of agricultural water makes it possible to grow fruits and
vegetables and raise livestock, which is a main part of our diet.
• Harvested water is used for irrigation, pesticide External and fertilizer
applications External, crop cooling (for example, light irrigation), and
frost control.

16. B. Water harvesting for domestic use
•Domestic rainwater harvesting (DRWH) is the interception of water from rain on a surface and
subsequent storage for later use
•The Harvested Water Are Important For Domestic Use
FOR CAR
WASH
FOR TOILATE
FOR CLEANING HOUSE
•FORSHAWER

17. 2.4 WATER HARVESTING SYSTEMS
A. Water tanks
•Water tanks mostly harvest
water from rooftops.
• Tanks are popular for saving
Water, are easy to use, and are
available in styles to suit most
homes.
•Harvesting Water with tanks
involves three primary
components: catchment,
conveyance, and a collection
device.
•It simple technology which
provides free soft water that
lathers easily, saving on soap
and detergent.
CATCHMENT
GUTTERS
TANKS
Figure 3. water tanks for domestic

18. B . Zai pits and Negarim
•they are referred to as planting pits
and are boxlike structure BUNDS
•They are constructed by excavating the
soil and returning the rich top soil with
organic mulch.
•The subsoil acts as an embankment
behind the pit.
•A tree crop or several plants like maize
and beans are planted in the pit.
Negarim act in the same way except that they are mostly used for tree crops
and Involve a formation of square embank.
C . Sand dams Sand dams are small impermeable barriers
constructed across the bed of seasonal streams.
D . Bunds are large earth banks on the contour that trap runoff. They
are usually built to prevent runoff and conserve water.
Figure 4 Zai pits
embankment
FANYAA JUU
and Negarim

19. E . Water pans and ponds
o Water pans and ponds are excavations or embankments
o that are constructed on the Path of natural rainwater catchments
o used as water reservoirs.
Water pans
ponds
Rock catchments are systems which mainly use natural rock surfaces
to divert Rainwater to a central collection area.
F . Rock catchment

20. PONDS
•Water tanks mostly
• harvest water
from rooftops.
• Tanks are popular
•for saving Water,
• are easy to use,
•and are available
in
• styles to suit most
•homes.

21. DOMESTICS
USE
AGRICULTURAL USE DOMESTIC AND
AGRICULTURAL
USE
Water tanks Sand dams Water pans
Water pans Road harvesting Farm ponds
Farm ponds Zai techniques Sand dams
Sand dams Bunds
Table 1; Classification of use RWH technologies
oThe collected rainwater passes through sand and gravel before storage
in a water reservoir or tank. The sand and gravel act to filter and make
the water clean.

22. 2.5 Requirements for Water Harvesting Techniques
 The need for WH, arises from many factors such as low rainfall And
uneven distribution, high losses due to evaporation and runoff, and an
increased demand on water due to population growth.
 With a large portion of the human race living in arid to semi-arid
regions of the globe, it is necessary to look to WH to increase water
access in these areas.
 It is important to consider the factors that go into selecting the
appropriate WH methods to maximize hydrological returns.
 there are a number of critical factors that need to be taken into
consideration when selecting the appropriate WH method.

23. Cont…
Rainfall
• WH depends on limited and uncertain rainfall, and thus understanding
the dynamics of precipitation within the environment can influence
the method of WH that would fit best in each context.
Land use or vegetation cover
• the catchment area free from Vegetation to ensure that it is as efficient
as possible the vegetation of the selected Area will heavily influence
runoff, infiltration and retention levels.
Topography and terrain profile
• The ground slope is key limiting factor to water harvesting.
• WH is not recommended for areas where slopes are greater than 5%.
• due to uneven distribution of run-off and large quantities of earth
suitable for irrigation.

24. Cont…
Soil type and soil depth
• Ideally, the soil in the catchment area should have a high run-off
coefficient
• Soil depth is more or equal to one meter deep is suitable to WH
• the loam is most suitable for water harvesting because
 high nutrient
 biological activity
 water holding capacity is high.
• A good soil structure is best suited to water harvesting system.
• It usually associated with loamy soil and has relatively high content of
organic matters.

25. Cont…
Environmental and ecological impacts
• Ecosystems are often fragile and can be adversely affect the water
table.
• Thus it is important to pay attention to these factors
• Understanding where the water flows and how it affects the
surrounding ecology, before implementing any kind of water
harvesting system. Some negative impacts that water
2.6 Factors Affecting RWHT
• The factors that affecting the technology of RWH includes:
o Physical
o Economical
o Social
o Institutional and psychological factors.

26. 3. CONCLUSION
• In the case of Ethiopia, water scarcity is the main problem, and using
of water harvesting is experienced.
• RWH is one option to use runoff better by capturing and storing when
rainfall is abundant for periods when water is scarce.
• To alleviate drought, RWH technologies are proposed by the
government of Ethiopia as a practical and effective alternative to
improve the livelihoods at little cost and with minimal outside inputs.
• RWH, which is a deliberate collection of rainwater, can improve
agricultural production by making water available during the time of
dry season.