There are many options and technologies available to apply the 3R concept in a watershed. During the Knowledge Exchange mission several 3R technologies that might be applied in the Kajiado area were introduced to the participants. Sander de Haas (PWN / SamSamWater) gave a presentation on several 3R technologies.

1. 3R techniques (some examples)
Sander de Haas (PWN, SamSamWater Foundation)
31 October 2012, Kajiado, Kenya

2. www.samsamwater.com/climate

3. Rainfall in the Kajiado area
About 600 mm per year (on average)

4. Roof water harvesting

5. Roof water harvesting
• 0,6 m3 per m2
• Roof: 5 x 6 = 30 m2
• 18 m3 per year
= 18,000 litres per year
= 49 litre per day
= 5 buckets per day

6. Roof water harvesting
Advantages
•Available near the house
•Possible (almost) everywhere
Disadvantages
•Small volume
•Relatively expensive (per litre)
•Regular maintenance required
How to identify?
•Suitable roof area (type + size)
•Determine demand (domestic or more)
•Calculate required tank size based on demand + availability

7. Rock catchment

8. Rock catchment

9. Rock catchment
• Rock catchment:
200 m x 200 m x 0,6 m = 24,000 m3
= 24,000,000 litre per year
= 66,000 litre per day

10. Rock catchment
Advantages
•Large volume
•Low investment
•Good quality
Disadvantages
•Storage required
•Need suitable location
How to identify?
•Suitable slope
•(semi) impervious
•Check during rains!
•Calculate amount of water

11. .
.

12. Catchment
• River catchment:
2000 m x 2000 m x 0,6 m = 2,400,000 m3
= 2,400,000,000 litre per year
= 6,600,000 litre per day
Combine 3R techniques to retain a part of this water!

13. Road catchment

14. Road catchment
Advantages
• Large catchment area -> a lot of water
• Reduces road erosion
• Cheap
Disadvantages
• Poor water quality (oil leakage?)
• Losses by evaporation
How to identify?
• Check for runoff traces
• Make use of existing structures / depressions

15. Recharge ponds

16. Recharge ponds

17. Recharge pond
Advantages
• Water quality increased by filtration
• Infiltration reduces evaporation
Disadvantages
• Need suitable geology
• Not all water might be recovered
• Shallow groundwater table needed
How to identify?
• Permeable soil
• Shallow groundwater available after rainy season

18. Sand dams

19. Sand dams / subsurface dams
Advantages
• Sand acts as a natural filter
• No evaporation, no mosquitoes
• Relatively low cost (per litre)
Disadvantages
• Need suitable geology (sandy riverbed, impervious bedrock)
• Risk of dam breach or erosion along sides
How to identify?
• Check for sand in riverbed
• Check for groundwater in sand several time after the rains

20. Flood water diversion

21. Flood water diversion
Advantages
• A lot of water available
• Might reduce flash-flood problems downstream
Disadvantages
• Large surface area needed
• Risk of damage (houses, crops) when diverting flood water
How to identify?
• Check for suitable (flat) areas to divert the water to
• Determine if flooding could cause problems (siltation, water
damage, etc.)

22. Spring protection
Advantages
• Increases water quality
Disadvantages
• Might have to find a solution for watering the animals
How to identify?
• Every spring deserves protection!
• Identify potential risks for water quality
(latrines, fertilisers, pesticides, cattle feaces, playing
children, etc.)
• Think of most suitable method (spring head
protection, runoff diversion, spring catchment
protection, etc.) to reduce these risks.

23. Do you have any suggestions?
Advantages
• ...
Disadvantages
• ...
How to identify?
• ...

24. Case study: Elangata Wuas
Think of these (and other) options when we are in the field.
Which options might be suitable for this site?
How can we determine the possibilities in the field tomorrow?
Can we estimate the potentially available amount? And how
does this fit with the demand (domestic, animals)?

25. Conclusion
No single ‘magical’ 3R technique
Use most suitable techniques for the site
Combine techniques to increase water availability and benefit
from each other
Make use of the natural landscape and existing structures