Dr. P.B. Dharmasena - Academia.edu (original) (raw)

Videos by Dr. P.B. Dharmasena

This video explains: Ten commandments (self-governance) of traditional rural societies; ancient w... more This video explains: Ten commandments (self-governance) of traditional rural societies; ancient water resources management master plan ie. river basin level planning, inter-river basin-level planning, inter-reservoir level planning; tank cascade systems; traditional tank-village ecosystem; the traditional vision of water management; development activities of tank cascade systems i.e tank rehabilitation, tank catchment area development, ecosystem restoration, downstream development, cultivation scheduling, crop diversification, and institutional development.

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වැරදි භූමි භාවිතය, පස සෝදා පාළුව, පසට ඇතිවන විපාක, ජලාශ වල ධාරිතාවය අඩුවීම misuse of land, soil e... more වැරදි භූමි භාවිතය, පස සෝදා පාළුව, පසට ඇතිවන විපාක, ජලාශ වල ධාරිතාවය අඩුවීම
misuse of land, soil erosion, consequence of soil erosion, reduction of reservoir capacity

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සම්ප්‍්‍රදායික කාලගුණ අනාවැකි, ගමේ ගොඩේ අණ පණත් Traditional weather forecasting. ten commandment... more සම්ප්‍්‍රදායික කාලගුණ අනාවැකි, ගමේ ගොඩේ අණ පණත් Traditional weather forecasting. ten commandments in rural villages

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රන්මසු උයනේ තාරකා දොරටුව, ලෝකයේ ගිලා බසින නගර, අපේ දාගැබ් ඉරිතලා යයි, පැරණි වාරි කලමනාකරණ යෝධ සැළ... more රන්මසු උයනේ තාරකා දොරටුව, ලෝකයේ ගිලා බසින නගර, අපේ දාගැබ් ඉරිතලා යයි, පැරණි වාරි කලමනාකරණ යෝධ සැළසුම Stargate in the Ranmasu uyana, Collapsing cities of the world, Cracking Dagobas in Sri Lanka

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ශ්‍රී ලාංකේය ඉතිහාසය පුරාවටම විහිද ගොස් ඇත්තේ ජලයේ අපරිමිත වූ බැඳීම් සමූහයයි. පරිපාලනය, කලමනාකරණය... more ශ්‍රී ලාංකේය ඉතිහාසය පුරාවටම විහිද ගොස් ඇත්තේ ජලයේ අපරිමිත වූ බැඳීම් සමූහයයි. පරිපාලනය, කලමනාකරණය, දිවිපෙවත, සෞන්දර්යය, සංස්කෘතිය ආදී සියල්ල ජලයෙන් එකට ඈඳී ඇත. මේ ජල සංස්කෘතියෙන් වත්මනට උගත හැකි පාඩම් බොහෝය.
The whole Sri Lankan history is largely knitted with water. Governance, management, lifestyle, aesthetics, culture, etc. of Sri Lanka were closely linked with the behaviour of water. There are many lessons that could be learnt from this water culture.

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වැව් පොකුරු පද්ධති, එහි පරිසර පද්ධති සංරචකයන්ගේ වැදගත්කම, මේ පරිසර පද්ධතිය කඩාවැටුනේ ඇයි? Tank... more වැව් පොකුරු පද්ධති, එහි පරිසර පද්ධති සංරචකයන්ගේ වැදගත්කම, මේ පරිසර පද්ධතිය කඩාවැටුනේ ඇයි? Tank cascades, the importance of ecosystem components, Why this ecosystem has collapsed?,

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වැවේ වතුර පිරිසිදු වුනු හැටි, කැලේ වැව් කැලේට අයිතියි. හැම වැවක්ම හදන්න යන්න එපා. කුණු නැති අපේ ග... more වැවේ වතුර පිරිසිදු වුනු හැටි, කැලේ වැව් කැලේට අයිතියි. හැම වැවක්ම හදන්න යන්න එපා. කුණු නැති අපේ ගම් Natural filtering system, wild tanks for the wild, natural waste recycling system

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Experiencing aesthetic beauty of nature with tank-village youth වැව් ගම් දරුවන් සමගින් ගතකල එක් ... more Experiencing aesthetic beauty of nature with tank-village youth වැව් ගම් දරුවන් සමගින් ගතකල එක් සුන්දර දවසක්
It would be better to make the next generation aware of the importance of our heritage for them to get cognition from our deep-rooted customs and traditions for a safe healthy future.
ඉදිරි පරම්පරාව අ‍පේ උරුමයේ වැදගත්කම පිළිබඳ දැනුවත් කිරීම වඩාත් සුදුසු වන්නේ ඔවුන් එහි මුල් බැසගත් සිරිත් විරිත් සහ සම්ප්‍රදායයන් උකහාගෙන නීරෝගී ජීවිතයක් ගත කිරීමට ඒවා උපයෝගී කරගනු ඇත යන බලාපොරොත්තුවයි.

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අප නොදන්නා පැරණි තාක්ෂණය හෙළිවන යෝධ ඇල ජාලය, නියං ගංවතුර සමහන් කල පොකුරු වැව්, ජල සංස්කෘතියේ භෞත... more අප නොදන්නා පැරණි තාක්ෂණය හෙළිවන යෝධ ඇල ජාලය, නියං ගංවතුර සමහන් කල පොකුරු වැව්, ජල සංස්කෘතියේ භෞතික, පාරිසරික සහ ආධ්‍යාත්මක දිශානති
Giant canals network disclosing the unknown ancient technology, tank clusters reduce drought and flood disasters, physical, ecological and spiritual dimensions of the water culture

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අපේ අභිමානය රැක ගතයුත්තේ අපමය. තම දේශයට අවමන් කරගන්නා ලෝකයේ එකම රට ශ්‍රී ලංකාවයි. ලෝක විද්‍යා දින... more අපේ අභිමානය රැක ගතයුත්තේ අපමය. තම දේශයට අවමන් කරගන්නා ලෝකයේ එකම රට ශ්‍රී ලංකාවයි. ලෝක විද්‍යා දිනයේ ප්‍රධාන දේශනය
We should protect our prestige. Only the country insulting itself is Sri Lanka. Keynote address of the World Science Day on 1st November 2019

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First GIAHS in Sri Lanka ශ්‍රී ලංකාවේ මුල්ම ගෝලීය කෘෂිකාර්මික උරුමයTank ecosystem should be rest... more First GIAHS in Sri Lanka ශ්‍රී ලංකාවේ මුල්ම ගෝලීය කෘෂිකාර්මික උරුමයTank ecosystem should be restored and conserved, for which youth come forward to take the leadership. වැව් පරිසර පද්ධතිය ප්‍රතිශ්ඨාපනය කොට රැක ගැනීමේ කටයුත්තට තරුණ පරපුර පෙරට පැමිණ වගකීම බාරගත යුතුය. We all should come forward to maintain our pride and heritage අප සියල්ල අපේ අභිමානය සහ උරුමය පවත්වා ගැනීමට එකට පෙරට ආ යුතුය

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දුර්මත ඉවතලා පරිසරයටත් අපටත් හිතැති ගොවිතැන් ක්‍රියවලියකට මාරු වීමට මේ හොඳම කාලයයි This is high ... more දුර්මත ඉවතලා පරිසරයටත් අපටත් හිතැති ගොවිතැන් ක්‍රියවලියකට මාරු වීමට මේ හොඳම කාලයයි This is high time to shift to eco-friendly farming leaving the misconceptions behind

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වැව් පරිසර පද්ධතිය, පරිසර උපාංගවල වැදගත්කම, වැව ගොඩ වීම Tank ecosystem, importance of ecological ... more වැව් පරිසර පද්ධතිය, පරිසර උපාංගවල වැදගත්කම, වැව ගොඩ වීම
Tank ecosystem, importance of ecological segments, tank sedimentation

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මෙම වීඩියෝව පෙන්වන්නේ ගලේවෙල සිල්වත්ගම වෙල් යායයි. එහි කිවුල් ඇල නැත. අප එහි කිවුල් ඇල පෑදීමත් සම... more මෙම වීඩියෝව පෙන්වන්නේ ගලේවෙල සිල්වත්ගම වෙල් යායයි. එහි කිවුල් ඇල නැත. අප එහි කිවුල් ඇල පෑදීමත් සමගම වෙළේ කිවුල ඒ දිගේ පිටවිය. වෙළ සරුසාර වෙමින් පවතී. වීඩියෝකරනයේ ප්‍රශංසාව යායුත්තේ පර්යේෂණ නිළධාරිනී අනුරාධා පරණවිතාන වෙතටය.
This video shows the paddy field under Silwathgama tank at Galewela. The drainage was absent. Once we opened up the drainage all salt matters left the field and it is getting recovered. Captured by Ms. Anradha Paranawithana, Research Officer who was behind this endeavor.

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This is a role play on collective effort to tank rehabilitation වැව් පුණරුත්ථාපනයට සාමූහික ප්‍රයත... more This is a role play on collective effort to tank rehabilitation වැව් පුණරුත්ථාපනයට සාමූහික ප්‍රයත්නයේ වැදගත්කම දැක්වෙන භූමිකා නිරූපනයකි

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හරිත විප්ලවය අපට ගෙනා ශාපය Execration brought by Green revolution

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අපි භාවිතා කරන කෘෂි රසායන, විකුණන රටවල් තහනම් කරලා ගොඩක් කල් _ countries selling agro-chemicals ... more අපි භාවිතා කරන කෘෂි රසායන, විකුණන රටවල් තහනම් කරලා ගොඩක් කල් _ countries selling agro-chemicals have banned in their countries long ago.

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සීගිරිය සහ පිදුරංගල ගැන අප නොදත් ඉතිහාසය The unknown history of Sigiriya and Pidurangala

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පාංශු සංරක්ෂන පණත, සියල්ල දැනුවත් කිරීමේ වැදගත්කම, අතීතයෙන් උගත හැකි පාඩම්, සාකල්‍ය ප්‍රවේශයක්, ත... more පාංශු සංරක්ෂන පණත, සියල්ල දැනුවත් කිරීමේ වැදගත්කම, අතීතයෙන් උගත හැකි පාඩම්, සාකල්‍ය ප්‍රවේශයක්, තීරණ ගැනීමට එක් තැනක්
Soil Conservation Act., Importance of awareness, lessons from the past, Wholistic approach,

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හරිත විප්ලවය අපට ගෙනා ශාපය Execration brought by Green revolution

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සීගිරිය සහ පිදුරංගල ගැන අප නොදත් ඉතිහාසය The unknown history of Sigiriya and Pidurangala

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Teaching material 1, 2024

Content of the Lecture 1. Introduction – Palaeolithic (Old Stone Age), Mesolithic (Middle Stone A... more Content of the Lecture
1. Introduction – Palaeolithic (Old Stone Age), Mesolithic (Middle Stone Age), Neolithic (New Stone Age), Early Iron Age
2. Historic Period – Anuradhapura City, Water Civilization, Ancient kings
3. Evolution of Tank Cascade Ecology – Traditional tank-village irrigation system, Some early studies, Tank cascade system typology

Sri Lankan agriculture first evolved from foraging (hunting and gathering) communities. They face... more Sri Lankan agriculture first evolved from foraging (hunting and gathering) communities. They faced the challenges of finding food and water and seeking protection from wildlife. They practiced hunting and collecting edible parts from the forest for their living. The evolution made them practice a very preliminary level of farming and rearing and the excess food was shared with others. This system was gradually transformed into a sedentary type of subsistence agriculture. With time these people gathered experience in farming (both crop and livestock) and slowly inclined to practice more advanced traditional agriculture systems and developed their own traditions and culture unique to Sri Lanka. This traditional system developed a strong knowledge base and practiced sustainable agriculture until the recent past.
The country was affected continuously with foreign invasions from the Portuguese (1505), Dutch (1658), and British (1796). With the introduction of Plantation crops natural watersheds were distorted by removing the forest cover. From the early days of the Green Revolution in the 1960s, Sri Lanka has subsidized farmers to use synthetic fertilizer, chemical pesticides, and new high-yielding varieties driving farmers to commercial agriculture. However, some of the environmental impacts of commercial agriculture widely known are deforestation and land degradation, loss of valuable ecosystems and biodiversity, depleted soil fertility, leading to erosion, and reduced long-term productivity.
Regenerative agriculture is an evolution of conventional agriculture, reducing the use of water and other inputs, and preventing land degradation and deforestation. It protects and improves soil, biodiversity, climate resilience, and water resources while making farming more productive and profitable.
The following two concepts are introduced in adopting regenerative agriculture.
Evergreen Agro-ecosystem Concept – Cultivation of crops to maintain a green cover year around and leaving zero fallow period of the land.
Boundary Green Avenue (BGA) Concept – Mixture of plant species established along the farm boundaries. The BGA provides many benefits such as biodiversity, nutrient recycling, soil moisture sharing, micro-climate effects, pest control providing habitats for predators, supply of human needs, etc.

The Sri Lankan agriculture was evolved first from foraging (hunting and gathering) communities. T... more The Sri Lankan agriculture was evolved first from foraging (hunting and gathering) communities. They faced the challenges of finding food and water and seeking protection from wildlife. They practiced hunting and collecting edible parts from forest for their living. The evolution made them to practice very preliminary level of farming and rearing and the excess of food was shared with others. This system was gradually transformed to a sedentary type of subsistence agriculture. With time these people gathered experience in farming (both crop and livestock) and slowly inclined to practice more advanced traditional agriculture system and developed their own traditions and culture unique to Sri Lanka. This traditional system developed a strong knowledge base and practiced a sustainable agriculture until recent past.

This is a part of the study for identifying the environmental, agricultural, and socio-cultural s... more This is a part of the study for identifying the environmental, agricultural, and socio-cultural status of the minor tanks rehabilitated recently in Kilinochchi District. The restoration of minor tanks in these areas has created Economic, Environmental and Social changes in and around the surrounding villages of the tanks. Study of the changes and impacts are crucial to ensure the sustainability and further improvements to enhance the resilience of the drought, adoption of mitigation measures in the future and promote agriculture and other income generation activities.
The findings of this study will provide the basis and guidance further improvements of minor tanks to enhance the resilience of the drought, adoption of mitigation measures and promote agriculture and other income generation activities.

Facilitation document, 2024

This document was prepared to support the resource persons who intend to conduct training program... more This document was prepared to support the resource persons who intend to conduct training programs, which include:
1. Climate and Soil
2. Climate Change on Agriculture
3. Climate Change Mitigation and Adaptation Strategies
4. Climate Resilience and
5. Climate Smart Agriculture

Concept note, 2009

This document suggests the following strategies to restore the land and water resources potential... more This document suggests the following strategies to restore the land and water resources potential in the tank cascade systems.
• Formulate an integrated development plan for each major reservoir watershed.
• Rehabilitate all small tanks in the watershed considering cascade as the smallest planning unit.
• Develop tank catchments allocating the most appropriate and productive land uses (forestry, agroforestry, wind barriers, rainfed farming, pasture, etc.)
• Launch soil and water conservation programs in all types of agricultural lands.
• Establish strong institutional mechanisms and inter-institutional linkages to manage the entire watershed through the formulation of village management committees, cascade management committees, and the watershed management committee.

ICID, 17th Congress on irrigation and Drainage, 1999

The use of shallow groundwater for small scale irrigation has become popular in the metamorphic h... more The use of shallow groundwater for small scale irrigation has become popular in the metamorphic hard rock basement areas of Sri Lanka to help alleviate the water shortages which are currently being experienced. The regolith aquifers are shallow and the specific yield is low therefore, any abstraction quickly lowers the water levels almost to bedrock. Serious environmental side effects also arise, particularly a deterioration in the health of the trees. A study was carried out during 1996/97 in order to determine the availability of water in the aquifers and simultaneously to establish an optimal approach for development. A study catchment was chosen which contained 25 minor tanks and covered an area of 3,970 ha. Measurements were made of rainfall, evaporation, tank water levels, groundwater levels, irrigation discharges and stream flow. Field surveys were carried out to prepare a base map with physical features, topography, soil and land use maps and an overburden thickness map. The tank beds were surveyed to establish area-volume-elevation relationships. A pumping test was carried out to determine the specific yield and transmissivity of the aquifer. This type of catchment demonstrates many extreme characteristics which are difficult to quantify. Of particular difficulty are the measurement of runoff and recharge to the aquifer. This paper discusses the results of the study and indicates how some of the difficulties were overcome.

ශ්‍රී ලංකාව තුල එහි හෙක්ටෙයාර මිලියන 6.54ක භූමි ප්‍රමාණයේ පැතිරී ඇති පාරිසරික තත්වයන්ගේ විවිධත්වය... more ශ්‍රී ලංකාව තුල එහි හෙක්ටෙයාර මිලියන 6.54ක භූමි ප්‍රමාණයේ පැතිරී ඇති පාරිසරික තත්වයන්ගේ විවිධත්වයෙන් (උස්බිම්, පහත් තැනි. මුහුදුබඩ) සහ වෙනත් විවිධ පරිසර පද්ධතීන් (කඩොලාන, වගුරු බිම්, විල්ලු ආදිය) හේතුවෙන් දිවයින තුල පොහොසත් පරිසරයක් නිර්මාණය වී ඇත. එසේම මධ්‍යම කඳුකරය ලෙස හැඳින්වෙන දකුණු මධ්‍යම පෙදෙස හැරෙන්නට ඒ වටා ඇති සෙසු ප්‍රදේශය තැනි තලා ස්වභාවයක් උසුලයි. ශ්‍රී ලංකාව යනු භූ විෂමතාවයේද, දේශගුණය, පස සහ වෘක්ෂලතාදියේ ද මහත් විවිධත්වයක් පවතින දිවයිනකි. භූ විෂමතා කාණ්ඩ ලෙස තැනිතලා සිට රැලි සහිත (0-8 %), පෙරලෙන සුළු සිට උස් භූමි (8-30%), උස් භූමි සිට කඳු සහිත (30-60%) සහ අධික බෑවුම් (60% ට වැඩි) යන සියල්ල අඩංගු බැවින් කෙටි දුරක් ඇතුලත පස් වර්ග වෙනස් වේ. ලෝකයේ ඇති පාංශු ගණ 12 අතරින් 7ක්ම ශ්‍රී ලංකාව තුල හඳුනාගෙන ඇත. මේ සඳහා ප්‍රධාන වශයෙන් හේතු වන්නේ කෘෂි පාරිසරික තත්වයන්ගේ වෙනස් වීමයි.

Technical Paper No. 6, 2006

The book was published by the Soil Science Society of Sri Lanka in 2006. In our traditional agric... more The book was published by the Soil Science Society of Sri Lanka in 2006. In our traditional agriculture system, the farmers were sensitive to soil and water management practices as those are limited and susceptible to deterioration. They adopt traditional conservation practices, especially in harmony with nature and the environment.
The book discusses traditional land use systems, farming methods, selection of suitable crops, sharing lands for farming, tank cascade systems, food security, biodiversity etc.

Journal of Environmental & Analytical Toxicology, 2024

Sri Lanka was among the 171 countries that signed the Paris Agreement in 2016 at the High-Level S... more Sri Lanka was among the 171 countries that signed the Paris Agreement in 2016 at the High-Level Signature Ceremony of the Paris Agreement
held at the United Nations Headquarters in New York. Subsequently the country submitted the updated Nationally Determined Contribution (NDC)
to the United Nations Framework Convention on Climate Change (UNFCC) in 2021. The Ministry of Environment, Sri Lanka prepared Carbon Net
Zero 2050 Roadmap and Strategic Plan in 2023. The authors are responsible for the agriculture sector.
Agricultural lands contribute to the greenhouse effect primarily through the emission and consumption of Greenhouse Gases (GHGs) such as
methane, nitrous oxide, and carbon dioxide. Synthetic fertilizers and organic materials after harvesting, and animal manure deposited during
grazing are the most common sources that contribute to N2
O emission. Emission of CH4
from agriculture is mainly from paddy fields and enteric
fermentation of the livestock. Carbon dioxide is emitted from agricultural fields due to the use of machinery, the application of urea, dolomite gypsum
, and tillage operations. However, when comparing the total GHG emissions from CH4
, N2O and CO2
from agricultural fields in Sri Lanka, it can be
seen that the emission of CO2
is negligible compared to other GHGs.
In the study three scenarios were adopted to predict GHG emissions from agriculture up to 2050 – Baseline scenario, NDC 2030 scenario extended
to 2050, and Improved mitigation scenario. The study included a literature review, stakeholder discussions, and analysis to determine strategies to
minimize GHG emissions from the agriculture sector.
The study results showed that the NDC 2030 extended scenario and improved mitigation scenario can reduce GHG emissions by 30% and 60%
respectively up to 2050 compared to the baseline situation. However, in achieving these targets the paper discusses issues constraints, and
policy gaps, which would hinder the success of the efforts.
Keywords: Climate change • GHG emission • NDC 2030 • Carbon net zero 205

A concept document, 2023

No abstract found

BBC News සිංහල, 2023

ශ්‍රී ලංකාවේ වියළි කලාපයේ පිහිටි බොහෝ කුඩා වැව් කෙමෙන් අකාර්යක්ෂම තත්ත්වයකට පත්වෙමින් පවතියි. මාස... more ශ්‍රී ලංකාවේ වියළි කලාපයේ පිහිටි බොහෝ කුඩා වැව් කෙමෙන් අකාර්යක්ෂම තත්ත්වයකට පත්වෙමින් පවතියි. මාස කීපයක නියඟයකිනුදු වියළි කලාපීය ගොවීන්ට ජලය හිඟකමට මුහුණපාන්නට සිදුවෙයි. කුඩා වැව්වල රොන්මඩ තැන්පත්වීමෙන්, ඒවායේ ගැඹුරත්, ඒ සමගම ධාරිතාවත් අඩුවීම මීට ප්‍රධාන හේතුව යි.
පසුගිය නියං සමයේ දී ඇතැමුන්, ඩෝසර් ලබාදී කුඩා වැව් හාරන්නැ යි සමාජ මාධ්‍ය හරහා යෝජනාකර තිබුණි. නමුත් එයින් වැවට හානිවනබව කියමින් ප්‍රතිපක්ෂ අදහස් ද ඉදිරිපත්වී තිබුණි.
මෙනිසා අපි, වැවක් පුනරුත්ථාපනය කිරීම යනු එතරම් සරල කටයුත්තක් නොවන්නේ මන්දැ යි ජලය හා කෘෂිකර්මය පිළිබඳ ජාතික උපදේශක ආචාර්ය පී. බී. ධර්මසේනයන්ගෙන් විමසා සිටියෙමු.

The following four results are expected at the end of the project period. i. Three thousand small... more The following four results are expected at the end of the project period.
i. Three thousand smallholder farmers will contribute to intensified production and improved productivity of groundnuts in the Mullaitivu and Kilinochchi districts.
This will be achieved through: the distribution of quality groundnut seeds of improved varieties; conducting training programmes and field demonstrations; provision of agriculture inputs to the most vulnerable farmers and farm implements and equipment to women headed/ disabled households and farmer organizations; and establishment of effective producer groups to store and sell raw groundnut through collective efforts to retailers, wholesalers and intermediary collectors.
ii. An extent of 120 ha will be cultivated by 600 farmers for seed production of groundnuts to ensure increased supply and availability of quality groundnut seeds for the two districts.
The main activities to make this achievement are the establishment of seed producer groups for the production of recommended varieties of groundnut seeds in at least 10 villages of the operational area of the project; conducting block demonstrations with 30 farmers each (male and female) at seed village sites through Farmer Field Schools; establishment of seed processing facilities with community-based organizations and entrepreneurs; organizing collection, conditioning and bagging of seeds; Providing tools and technical training to introduce seed processing technology; and organizing distribution, transport and marketing of seeds.
iii. Seed certification support services and seed production will be strengthened in project districts.
This will be accomplished by strengthening Seed Certification Units and providing certification services to seed production farmers.
iv. The supply of value-added groundnut products will be increased by demonstrating the processing methodology.
The demonstration will be made through: the establishment of a community-based groundnut processing facility to carry out market-based value-addition operations; the provision of necessary processing equipment and technical training on post-harvest losses, processing technologies, appropriate storage, quality assurance, packaging, transport, and marketing; and supporting marketing efforts by involving the partnership of a broad range of stakeholders.

The process of desiltation in this concept is not essentially aimed at expanding the present capa... more The process of desiltation in this concept is not essentially aimed at expanding the present capacity of the tank. The main objective of the concept is to reduce tank water losses by manipulating the tank bed geometry through desiltation. It is clear that the said objective cannot be successfully achieved by a complete desiltation, which would not alter the capacity/ water spread area ratio of the tank storage.

A sedimentation study indicates that the amount of sediment deposited in minor tanks is in the range of 20 - 35 percent, and half of the sediment is found within one-third of the tank bed area closer to the bund (Dharmasena, 1992). Thus, the same capacity can be maintained by removing sediment in this area and heaping up in the upstream tank bed. Such partial desilting effort would increase the Capacity/ water spread area ratio remarkably and keep more than 50 percent of the tank bed free of water.

Rehabilitation of minor tank systems is one of the components implemented to achieve project obje... more Rehabilitation of minor tank systems is one of the components implemented to achieve project objectives. The vulnerability of the communities to natural disasters such as drought, flood, cyclone, epidemics, etc. can be effectively reduced by ensuring the sustainability of irrigation systems. Absorption of excessive runoff of intensive rains to reduce flood, conservation of water for use in the dry season, formation of a biological windbreak system to drive away the high winds, the existence of high bio-diversity, and the use of biological barriers to get rid of epidemics are the main strategic mechanisms found in this minor tank system. The tank ecosystem plays a key role in these mechanisms.
The benefits of restoring the ecosystem are multi-fold. Some of them are: reduction of tank water losses; prevention of structural damages; reduction of sedimentation; increased cropping intensity; reduced impact of natural disasters; resources for cottage industries; and enhanced biodiversity.

Workshop on Rainwater Harvesting in the Dry & Intermediate Zones of Sri Lanka, 2001

No abstract found

Proceedings of the 3rd Annual Forestry Symposium, 1997

An attempt was made to develop an assessment indicator combining the most important parameters, w... more An attempt was made to develop an assessment indicator combining the most important parameters, which decide the environmental richness of a plant community. Strata coverage, species richness and plant density were included in the following formula to describe the environmental richness as: ER = S. √ , where ER is environmental richness, K is acoefficient to represent stratal coverage and N is the number of plants per 100 sq.m for large (L), medium (M) and small (S) canopy types and S is the number of species per 100sq. m. A plant composition survey was carried out in a selected forest block of 25 m x 25 m at Paindikulama in the Nachchaduwa watershed in 1997 to assess the environmental richness in natural forest. A comparison was then made with results obtained from a previous home garden survey conducted in the same watershed. During the survey 31 plant species were identified and the total number of plants surveyed was 1360. The average plant density was 218 per 100 m 2. Environmental richness of this forest block was found as high as 108, whereas the value for home gardens has ranged from 0.7 to 34.7. Results also revealed that the contribution made to environmental richness was higher (75%) by small canopy plants compared to large (3%) and medium (22%) categories. This may be due to the selective felling of large trees and subsequent emergence of small plants in the exposed patches. Results conclude that man-made home gardens could only achieve about one third of the environmental richness of natural forest.

Proceeding of the Conference on Cascade Ecology & Management – 2021, 2021

An ecology-based definition for the tank cascade and the term ‘cascade ecology’ as a new concept ... more An ecology-based definition for the tank cascade and the term ‘cascade ecology’ as a new concept have been introduced during the planning phase of the HLP. Tank cascade has been defined as ‘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 the sustainable basis’ .
The concept of cascade ecology can also be defined as ‘the study of the interactive relationships between living organisms (flora and fauna), including humans, and their physical environment (soil, water, and geo-morphology) within the cascade boundary as well as its surrounding area of influence’.

PhD Thesis on ‘Soil erosion control measures for rain-fed farming in the dry zone of Sri Lanka’, 1992

No abstract found