Presentation made at History & Heritage Forum, the Institution of Engineers, Sri Lanka on 15th September 2022. Present crisis of water Ancient master plan of water resources management Water based city planning - Anuradhapura Rainwater harvesting – Pidurangala Tank cascade systems: The first agricultural heritage in Sri Lanka Traditional tank-village ecosystem- Lessons for future ‘evergreen agro-ecosystems’ concept

1. Presentation made at History & Heritage Forum, the
Institution of Engineers, Sri Lanka on 15th
September, 2022
Probing Unresolved
Mysteries of Ancient
Water Technology
P.B. Dharmasena – dharmasenapb@gmail.com

2. • Present crisis of water
• Ancient master plan of water resources management
• Water based city planning - Anuradhapura
• Rainwater harvesting – Pidurangala
• Tank cascade systems: The first agricultural heritage in Sri Lanka
• Traditional tank-village ecosystem- Lessons for future „evergreen
agro-ecosystems‟ concept
CONTENT

3. Present crisis of water
• High discharge to sea causing drought and flood while wasting
productive water – lost more than 50% of annual incidence
• Sea water intrusion especially in Mannar and Jaffna
• Ignorance of the ancient water resources management systems
• Less attention paid on restoration of tank cascade ecosystems
• Lack of effective coordination among water related agencies -
There are over 40 agencies dealing with water in one way or
another
• Lack of a National Water Policy – Submitted by a Cabinet
appointed committee in January 2021

4. Annual average rainfall: 2,000 mm
Land extent: 65,610 km2
Total volume of water: 131.22 bil. m3
Discharge to sea: 66.18 bil. M3 (>50%)
No. of river basins: 103
Major reservoirs and dams: 80
Small tanks: 16,476
Small anicuts: 14,468
Source: N. Eriyagama et al 2015
Shortage of water or wastage of water?

5. River basins – Water losses to Sea
River Basin Total Basin
Area (km2)
River
lengths
(km)
Total Rainfall
(million m3)
Drainage to
Sea
Major/
medium
reservoirs
Minor tanks
(mil. m3) %
Deduru Oya 2,616 142 4,794 1,608 34.0 4 2,408
Kala Oya 2,772 148 4,424 587 13.0 3 1,015
Malwathu Oya 3,246 164 4,592 568 12.0 5 1,731
Yan Oya 1,520 142 2,269 300 19.0 2 746
Kelani Ganga 2,278 145 8,692 5,474 62.0 0 9
Gin Ganga 922 113 3,039 1903 62.0 0 0
Kalu Ganga 2,688 129 10,122 7,862 77.0 0 3
Walawe Ganga 2,442 138 9,843 2,165 22.0 12 750
Mahaweli Ganga 10,327 335 26,804 11,016 41.0 9 552
Meeoya 1,516 109 2,176 338 16 1 750
Shortage of water or wastage of water?

6. Multipurpose and multifunctional water management in
ancient Sri Lanka
Water management was of multi-purpose and multifunctional:
• Food production – irrigation;
• Human needs – settlement, drinking water, bathing, recreation, other
domestic needs;
• Rainwater harvesting systems;
• Existence of the environment (flora, fauna, environs);
• City planning (Anuradhapura, Sigiriya)
• Parks, landscaping etc. (water springs, ponds)
• Administrative boundaries
• Natural disaster mitigation (Flood, drought, cyclone, epidemics)

7. Ancient master plan of water resources management in Sri Lanka
Country level
Inter-river basin level
Inter-reservoir level
Sub-watershed level
Village level
Field level

8. Prince Vijaya (543–505 BC) invaded our country
• Sailors entered the country from Alli Rani
Harbour for trading
• Vijaya also came along Western coastal boarder
using NE monsoonal winds passing Alli Rani
Harbour to Kudiramalai (Thammenna)
• There were 10 regional kings (including the
Princess Kuweni ) ruled the country at that time
• Prince Vijaya killed most of them with the
support of Princess Kuweni
• That was the end of 10 kingdoms in Sri Lanka
Alli Rani Harbour
Kudiramalai

9. Kevesastha (Northern)
Upulwangiri
Rakungiri
Mahagiri
Chalaka
Neelagiri
Kawasthalabha
Dhumaka Kaddeera Indra
Agni
Source: Manewe Wimalarathana Thero from Wariga
Poorinikawa
Ancient 10 kingdoms of Sri Lanka

10. Kevesastha - (Northern)
Upulwangiri (Kala Oya)
Rakungiri (Malwathu Oya)
Mahagiri (Samanala mountain area) –
Kelani, Kalu, Walawe, Mahaweli
Chalaka (Mi Oya)
Kawasthalabha (Yan oya)
Dhumaka Kaddeera (Deduru Oya)
Agni (Kumbukkan Oya, Menik Ganga,
Kirindi Oya
Indra (Maduru Oya, Mundeni Aru, Gal
oya)
Neelagiri (Modaragam Aru)
These local Kings must have
placed kingdoms on
mountains to protect the
major river basins

11. • Inter-river basin water resources sharing
• (1) Dambulu Oya - Malwathu Oya
diversion canal (860 AD)
• (2) Malwathu Oya - Kanadara Oya
diversion canal (860 AD)
• (4) Yoda Ela - Nachchduwa feeder
canal (540 AD)
• Inter-reservoir water resources sharing
– (3) Kalawewa - Thisawewa Yodha
Ela (470 AD)
– (5) Nachchaduwa - Nuwarawewa
feeder canal (290 AD)
– (6) Balaluwewa -
Siyambalangamuwa feeder canal
(290 AD)
– (7) Basawakkulama - Maha
Vilachchiya feeder canal (470 AD

12. Manewa cascade
Mahakanumulla cascade
• Single bank canal
• It runs along contour
• Water is collected from upstream
• Water is released to both sides
• Canal moves along tank upstream
• Tank cascade systems are fed
Kalawewa-Thisawewa Giant Canal

13. April – May 2010
A confession from an Irrigation
Engineer
“Inconvenient Truth” behind
Engineering Designs of Irrigation
Projects developed during the Last
Century.
“……….Those days we thought that
the canal was planned to avoid rock
barriers as the ancient people did not
own the technology to break them
……..”
- Eng. Mahinda Panapitiya

14. Left bank
Sedimentation
Diyakaliya
Natural rock
Soil mound
Mahailluppallama
Amunukole
Diyakaliya
Source: Dr. Ashoka Karunaratne, 2021

15. Upper land and Lower land sluice
gates of Yodha Ela
Position of upper Sluice gates
Position of lower Sluice gates
Aluth wewa
Amunukole
wewa
Koon wewa
Wew and diya kali
Source: Dr. Ashoka Karunaratne, 2021
diya
kaliya
diya
kaliya

16. Diyakaliya Wewa
1 Placed above the canal Placed below the canal
2 Canal has been connected
to the diyakaliya
Constructed the canal running
above the wewa
3 Diyakaliya has been
connected to a natural rock
line or soil ridge
Bund of the wewa has been raised
to a higher contour
4 Issue of water through a
natural process
Release of water to wewa is
through sluice placed on the left
bank of Yodha Ela canal
5 Controlling the Sediment Controlling the sediment and
providing water to paddy tract
6 Providing water to upland
cultivation
Combined with human settlement
and cascade systems
Source: Dr. Ashoka Karunaratne, 2021

17. • Inter-reservoir water
resources sharing
– Kalawewa -
Thisawewa Yodha Ela
(470 AD)
– Nachchaduwa -
Nuwarawewa feeder
canal (290 AD)
– Yodha Ela –
Nachchaduwa feeder
canal (540 AD)
Kalawewa-Balaluwewa
Thisawewa
Siyambalangamuwa
Nachchaduwa
Nuwarawewa
Mahavilachchiya
Basawakkulama
Malwathu oya
Thalawa oya
Kala oya
Anuradhapura city is fed by Giant canals
(600 BC – 1200 AD)

18. It could be the city plan of
Ancient Anuradhapura kingdom
Mystery of Star gate

19. Top 10 Star gates in the world (unidentified structures)
1. Gate Of The Gods, Hayu Marca, Peru
2. Abu Ghurab, Egypt, The Place Of The Gods
3. Ancient Stone Arrangement In Lake Michigan
4. Stonehenge, Wiltshire, England
5. The Ancient Sumerian Star gate At The Euphrates River
6. Tiahuanaco, Bolivia, „Gate of the Sun‟
7. Ranmasu Uyana Stargate, Sri Lanka
8. Abydos, Egypt
9. Gobekli Tepe, Turkey
10. Sedona Vortexes And The „Doorway of
the Gods‟in Arizona

20. Nuwarawewa
Thisawewa
Basawakkulama
Bulankulama
Groundwater
forces are focused
to the city
This symbol represents an
area well exposed to
sunlight planned for
settlements, gardens etc. -
Manewe Wimalarathana
Thero, 2015

21. Jethawanaramaya
Ruwanwelisaya
Thuparamaya
Abhayagiriya
Lowamahapaya
Ancient water based city
planning (Anuradhapura)
Isurumuniya
Jayasrimahabodhi
Mirisawetiya
Inner
City

22. Water culture in Anuradhapura Kingdom
• Water cordon around the kingdom (Thisawewa, Nuwarawewa,
Basawakkulama, Bulankulama)
• Focused to enrich groundwater in the kingdom
• Paddy lands under these tanks are relatively low
• Catchments are not adequate
• Tanks are fed by an adjoining river basin
• Alluvial soil is found due to Malwathuoya and Halpanoya
• How these gigantic structures could be sustained?
• Hard bedrock to trap groundwater (granitic gneiss and charnockite
gneiss)

23. Gaminiwapi (Bulankulama)
Abhayawapi (Basawakkulama)
Thisawewa
Nuwarawewa
Perimiyankulama
Thuparamaya
Jethawanaramaya
Abhayagiriya
Ruwanwelisaya
Lowamahapaya
Mirisawetiya
Source: Thusitha Wagalawatte et al 2015
Charnockite gneiss
Granitic gneiss
Quartzite

24. Granite is a very hard, granular,
crystalline igneous rock (free of
orthopyroxene)
Charnockite (granite with orthopyroxene
(Mg2Si2O6 and Fe2Si2O6, )
Granite Charnockite

25. Ponds, moats, water tunnels and wells are scattered in the kingdom to
replenish and monitor groundwater

26. Beijing China
Bangkok, Thailand Tokyo, Japan
Mexico city
Manila, Philippines
Land subsidence

27. Cities being sunk due to depletion of groundwater table
1. Beijing in China by 11
cm/ year
2. Mexico by 28 cm/ year
3. Jakarta by 28 cm/ year
4. Bangkok by 12 cm/ year
1
2
3
4

28. Land subsidence and crack formation

29. What contributes to the sinking of cities
• The weight of buildings
• Groundwater depletion
• shifting of tectonic
plates

30. Why our Stupas are getting cracked?
• Vertical Cracks in
Ruwanwelisaya
• Four cracks in
Jethawanaramaya
• Vertical cracks in
Thissamaharamaya
Most probably due to
groundwater depletion

31. TOUR (EXPEDITION) TO SIGIRIYA & PIDURANGALA

34. Sigiriya kings
must had been in
need of clean
drinking water

35. Three water conveyance
systems
• Open water conveyance
canals (brick work)
• Sealed subsurface clay pipes
• Sealed subterranean
conveyance canal (stone)
2 ft.
1 foot.

36. Octagonal pond
Water garden 1 – Interconnected garden complex for bathing
Water garden 2 – Fountain gardens
Water garden 3 - Royal water palaces surrounded by moats
Water garden 3
From Western Entrance
Water garden 1
Water garden 2
Water garden 3

37. Altitude at the lowest point of
Pidurangala rock top: 324 m
Altitude at the water spring
point of Sigiriya: 198 m
Elevation difference: 126 m
Direct Distance: 1225 m
Smooth slope path
distance:1612 m

38. Elevations:
Sigiriya tank: 204 m
Fountain garden: 204 m
Octagonal pond: 212 m
Head difference: 8m (26 ft)
Atapattam Pokuna: 212 m
Fountain ponds 204 m
Octagonal pond relatively at a higher level

39. Is this natural?

41. Convex
Concave

42. Evidence of a
huge explosion
Not a natural
decay

43. Rainwater flow
pitch (convex)

54. Balancing Stone Concave
Convex
Like a mirror
image of the rock

55. So called
balancing
stone

56. Finally ……….
The platform area of Pidurangala rock is about 2 ha. If it is
assumed that 80% of monthly rainfall could be collected from
this flow pitch, the volume, which could be stored monthly is:
Months Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Total
Rainfall
(mm) at
75%
probability
30.3 12.6 26.0 87.7 31.8 3.1 3.4 4.4 25.9 132.0 168.3 105.7 631.2
Runoff (m3) 485 202 416 1,403 509 50 54 70 414 2,112 2,693 1,691 10,099

57. • According calculations at least 10,000 m3 of water can be collected
from this system.
• What does it mean?
• This historical perception can be rejected as a myth.
• However, this system if rehabilitated will supply annual water storage
of 10,000 m3 to the people, who are living around and are threatened
with the chronic renal disease with unknown aetiology.
Then …..

58. • If the daily drinking water requirement is 3
lits./head, the problem of annual drinking
water requirement of 9,000 people can easily
be solved

59. How did they locate
ancient reservoirs?
Kantale
Huruluwewa
Minneriya
Giritale
Parakrama Samudra
Maduruoya
Mapakadawewa
Udawalawa
Kalawewa &
Balaluwewa
150 m contour
Nachchaduwa

60. Network of tanks
and streams
No flood and no
drought
Malwathuoya
Kalaoya
Yanoya

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

62. Tank clusters or cascades
Hydrology based definition
• 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‟. – Madduma Bandara, 1985
Ecology based definition
• Tank cascade is 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‟.
– Dharmasena, 2017

63. Distribution of tank
cascades in Sri Lanka
North and North
Central cascade zone
North Western
cascade zone
South and South
Eastern cascade zone

64. Tank clusters or cascades
Kendewa cascade
Kapiriggama cascade
Bandara Rathmale
cascade
Kallanchiya tank

65. Tank clusters or cascades
Mahakanumulla cascade
Thirappane cascade
Ulagalla cascade

66. We searched for a Globally Important Agricultural Heritage System in Sri Lanka

67. Globally Important Agricultural Heritage System (GIAHS)
Food & Agriculture Organization declared Village Tank Cascade System
(VTCS) as the first Globally Important Agricultural Heritage System
(GIAHS) on 19th April 2019 in Sri Lanka. It is 39th in the World.

68. „Evergreen Agro-ecosystem‟ Concept
to reach net zero C level
• Cultivation of crops with different duration to keep green cover;
• Cultivation of crops leaving zero fallow period of the land;
• Farming models, which combine seasonal, semi-perennial and perennial
crops ensuring the green cover around the year;
• Green manure plants are grown as hedges with strict frequency of pruning;
• Shade management is adopted to minimize light competition and to
maintain the crop land with evergreen situation;
• Live fence is maintained with plants to create a stratification enabling to act
as wind barrier as well as favourable micro-climate in the crop field; and
• The farmer should have a field management schedule for his convenience
to ensure the sustainability of the agro-ecosystem
Some features are reflected from our traditional agriculture

69. Sanitary places of
women and kids
Sanitary places of men
Faeces as a nutrient source to paddy fields
A Self sustained System based on precise management of water
Lessons
for future
„Evergreen
Agro-
ecosystem‟
Concept

70. Godawala
Perahana
Gasgommana
Iswetiya
Tank water – no pollution, no sedimentation: safe drinking water, good storage
Lessons
for future
„Evergreen
Agro-
ecosystem‟
Concept

71. Landa
Thisbambe
Gangoda Kattakaduwa
Kiul-ela
Paddy field - no salinity, good fertility: High productivity
Lessons
for future
„Evergreen
Agro-
ecosystem‟
Concept

72. Agro-silvopastoral systems – Free roaming model
Traditional village ecosystem – Year around cattle grazing areas
paddy lands in
fallow period
Landa (to be
improved as
silvopastoral system)
Chena as Agro-
silvopastoral system
Lessons
for future
„Evergreen
Agro-
ecosystem‟
Concept

73. Multi-disciplinary
approach is required to
Probe the Unresolved
Mysteries of Ancient
Water Technology
Archaeology
Hydrology
Architecture
Anthropology
Geology
History

74. Mysteries of
Ancient
Water
Technology
Hydrologist
Anthropologist
Architect
Geologist
Archaeologist