This is the part 2 of 5th lesson in the course 'Traditional Knowledge in Sri Lankan Agriculture' taught at the Faculty of Agriculture, Rajarata University of Sri Lanka

1. P.B. Dharmasena
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dharmasenapb@ymail.com , dharmasenapb@gmail.com
https://independent.academia.edu/PunchiBandageDharmasena
https://www.researchgate.net/profile/Punchi_Bandage_Dharmasena/contributions
http://www.slideshare.net/DharmasenaPb
Traditional Technology in Sri Lankan Agriculture
Lesson - 5
Traditional Water Resources Management
Part-2
Course code: AS 3210 (2/ 25:10)
Faculty of Agriculture, Rajarata University of Sri Lanka,
Puliyankulama

2. Network of tanks
and streams
No flood and no
drought

3. Nachchaduwa
Kanadarawewa
Vilachchiya
Kalawewa and
Balaluwewa
Huruluwewa
Main factors:
1. Morphology (landscape)
• Lower elevation,
• Moderate undulation
2. Rainfall
• Bimodality
• ~1500 mm/ year
3. Soil and geology
• Regolith aquifers
• Low infiltration
• RBE – LHG
Network of tanks and streams in the form of cascades

4. Tank clusters or cascades
• A ‘cascade’ is a connected series of tanks organized within a
micro-catchment (meso catchment) of the dry zone
landscape, storing, conveying and utilizing water from an
ephemeral rivulet’.

5. Tank clusters or cascades

6. Tank clusters or cascades

7. Tank clusters or cascades

8. Distribution of tank
cascades in Sri Lanka

9. Tank cascades
are found in:
Northern;
North Central;
North Western;
Uva; and
Southern
Provinces

10. Tank cascades
are found in:
Mullaitivu;
Vavuniya;
Anuradhapura;
Trincomalee;
Puttalam;
Kurunegala;
Hambantota;
and
Monaragala

11. Tank cascades
are found at the
elevation range
of 100-500m
amsl

14. North and North
Central cascade
Zone and North
Western cascade
Zone are located in
the Wanni Complex
South and South
Eastern Cascade
Zone is located in
the Vijayan
Complex

15. Tank cascades
are found mainly
on RBE and
LHG soils and
some on RYP
and IBL

16. Tank cascades
are found mainly
between 800 –
2000 mm
isohyets of
annual rainfall

17. Poverty (head
count ratio) is
low to moderate
in Tank cascade
system areas -
2015

18. CKDu spreads
over all tank
cascade zones

19. Cascade defines surface water movement
alone
• Cascade ecology (Ecology is the study of the interactions of
living organisms with one another and with their physical
environment).
• Land (extent covered by cascade catchment)
• land use (specific land use systems with natural and
agricultural land uses and commons),
• Soil properties (changed soil properties due to
cultivation, water table and groundwater movement),
• Flora (different floral communities and ecosystems),
• Fauna (different faunal communities and ecosystems),
• Groundwater (water table fluctuation and groundwater
movement with chain of surface storages),
• Human activities

20. Stopped here

21. New definition of the tank
cascade system
• An ecosystem, where water and land resources
are organized within the micro-catchments of the
dry zone landscape, providing basic needs to
human, floral and faunal communities through
water, soil, air and vegetation with human
intervention on sustainable basis’

22. Evolution of Traditional
Settlements

23. Tank-village
Tank-village
Olagam tank
Kuluwewa
Kuluwewa
Kuluwewa
Kayanwewa Kayanwewa

24. A Traditional Settlement