Mahaweli System Research Articles

Behavioral Intention of Paddy Farmers Towards Adoption of Organic Sources for Soil Nutrient Management Consequent to Policy Decision to Ban Agro-chemicals in Sri Lanka: A Case Study

This stu dy was aimed at investigating the behavioral intention towards and factors influencing adoption of organic soil nutrient management by paddy farmers, consequent to the banning of agro-chemicals in April 2021 in Sri Lank a. A questionnaire survey, supplemented by key informant discussions was used to collect the primary data after six months of the banning when farmers were preparing for the next Maha season (starting from Novemb er 2021). Paddy farmers (N=120) from the Mahaillu ppallama irrigation block of the Mahaweli system H in Anuradhapura district were randomly selected as the respond ents. The Theory of Planned Behavior (TPB) was used as the conceptual framework of the study. The study revealed that the majority (85%) of farmers did not agree with the sudden decision of the government to ban agro-chemicals to enable a complete transformation of agriculture to one that is totally organic. Only 11% of the farmers preferred a fully organic paddy production system. The majority (58%) preferred to use both organic and inorganic fertilizers. However, 31% of the farmers preferred conventional farming as usual. Perceived difficulties were the major barriers for farmers to use organic f ertilizers. Attitude on production, age, perceived knowledge of organic agriculture, and farming income significant ly affected (P < 0.1) paddy farmers’ intention to adopt organic fertilizers. It is concluded that a scientifically designed gradual transition would be more appropriate for nutrient management in paddy cultivation.

Spatial Variability of Selected Soil Chemical Parameters in Low-yielding Paddy Production Block in Mahaweli System H, Sri Lanka

Although water availability for paddy production in Mahaweli System H is abundant, paddy yield is lower in Nochchiyagama (278 km2), chosen for soil assessment. Paddy yield data were used to identify the low-yielding division using the area-weighted average. Twenty-five random locations were generated, and soil samples were collected for pH, soil conductivity (EC), salinity, and total dissolved solids (TDS) analysis. ArcGIS software was used to create spatial distribution maps and related geostatistical analyses for each parameter. Vector files were created with their associated properties, and thematic maps were generated using spatial interpolation techniques, such as universal kriging (UK), ordinary kriging (OK), and inverse distance weighted (IDW) methods of interpolation techniques to identify the best interpolation method for soil chemical parameters mapping. The entire Nochchiyagama land was observed to have a slightly acidic pH (5.6-5.9) range that may have affected rice crop growth due to nutrient mobility and uptake issues. The spatial interpolation evaluation suggests that at least two-thirds of the area observed for lower TDS levels (591-654 mg/L) is potentially unsafe paddy production. Elevated levels of EC (3.1-7.24 dS/m) along with TDS may lead to physiological drought due to interferences in ion uptake. In overall, spatial interpolation evaluation indicators suggest that the UK method was observed with a lower mean relative error (MRE) than the other two interpolations. However, EC distribution showed low MRE in both IDW and OK interpolation techniques. The IDW method was observed to have a lower RMSE (Root mean square error). The UK spatial interpolation performed better for TDS and salinity predictions than other methods. This study found consistent regional differences in low paddy yields in Mahaweli system H using the UK method for analyzing soil chemical parameters. 
 Keywords: Electrical conductivity, Interpolation errors, Salinity, Spatial interpolation

Vulnerability of Other Field Crop (OFC) Cultivating Farmers to Climatic Variability – A Study in Palugaswewa Cascade and Mahaweli System H in Anuradhapura, Sri Lanka

Official journal of the Postgraduate Institute of Agriculture, University of Peradeniya. Tropical Agricultural Research publishes complete accounts of research of outstanding significance, together with critical review articles on all aspects of agriculture including agronomy and crop production, horticulture, agricultural biology, food and nutrition, soil and water resource management, agricultural engineering, agricultural economics, animal science, biotechnology, plant protection, genetics and plant breeding.Tropical Agricultural Research is now indexed in DOAJ.

The Contribution of Women in Rebuilding Livelihoods in the Long-Term After Involuntary Resettlement: A Case Study of Resettlers of Kotmale Dam, Sri Lanka

The experiences of resettlers of Kotmale Dam, Sri Lanka is revisited, with a focus on the involvement of women in shaping the well-being of the family, more than 35 years after their resettlement. This study is based on field visits to eight resettlement sites in Mahaweli System B, C, and H, in which interviews were held mainly with the women of the first generation of resettlers. In most cases, women had to contribute to farm labour apart from housework. With time, women were instrumental in saving enough money, which enabled them to purchase agriculture machinery that lessened the burden of women who engaged in agriculture. The time thus saved could be used for additional income generating activities. Resettlers who were resettled in Mahaweli areas have now reached a stage where they have been successful in the formation of social/community networks and satisfactory economic development. The contribution of women has been a catalyst for such successes. The second/third generations have better opportunities for the future. The results indicate that resettlers, especially women, have made conscious choices for their future, especially for their children. For future resettlement programmes, it is essential that considerations of women’s economic role in the household should be given prominence.

Hydro Chemical Assessment of Agro-well Water for Irrigation in Thalawa Block in Mahaweli System-H in Anuradhapura, Sri Lanka

Purpose: Large diameter agro-wells are the most valuable water resources for farmers in Mahaweli system H in Sri Lanka to sustain crop production during the dry spells. Deterioration of water quality is harmful to the crop growth. Present study evaluated the variation of irrigation water quality and water levels of agro-wells in Thalawa irrigation block of Mahaweli system H. Research Method: Water samples from 10 agro-wells were collected during October 2016 to July 2017 once in a month and tested samples for irrigation water quality parameters using standard methods. Water levels were recorded for each sampling date. Findings: Most of the water quality parameters tested in almost all wells are within the acceptable range for irrigation except for Residual Sodium Carbonate (RSC). 50 % of the wells are safe and rest 50 % of the wells are within marginal range in terms of RSC. Irrigation water quality index (IWQI) was assessed and it varied from 32.6 to 87.7. Considering the mean IWQI (48.2), water of Thalawa block can be characterized as good. The study also revealed that there was sufficient water in wells even during the dry spells and it varied with both the variation of rainfall and canal water availability. Research Limitations: Sampling was limited to 10 agro-wells for a period of 10 months. This was avoided by selecting representative wells and months covering both dry and wet spells. Originality/ Value: Overall, results envisaged that there is higher potential to use this water for any crop and soil without detrimental to crops grown.

An Economic Analysis Based on Equivalent Variance of the Fertilizer Subsidy: A Case of Mahaweli System H in Sri Lanka

The theory of equivalent variance postulates that, cash transfers are preferred over material subsidies as overall production is expected to increase if the government grants a cash transfer equivalent to the value of the material subsidy. In line with this theoretical argument, the government of Sri Lanka recently undertook a major change in the agriculture subsidy policy by converting the material fertilizer subsidy in to a cash transfer. However this policy reform has received many criticisms from several parties, including the farmers and farmer representatives. The study aims at analysing the economic impact of this policy change on the paddy output by employing macro and micro perspectives. The analysis is based on time series data from 1961 to 2013 at national level and survey data on the Yala seasons of 2015 and 2016 at micro level. The survey was conducted using cluster sampling method and Meegalewa Grama Niladhari division in Mahaweli System H was selected for this purpose. The findings of this study indicate that fertilizer is a significant determinant of the paddy output in Sri Lanka. Further, it was revealed that the government has not allocated a cash transfer equivalent to the material fertilizer subsidy provided under the former subsidy scheme. Thus, a significant reduction can be expected in the paddy output in the Yala 2016. The study recommends that the government should grant equivalent cash transfer or encourage organic fertilizer usage in order to reap the benefits of this policy change.

An analysis of the technical and allocative efficiency of paddy farming: the case of Mahaweli system H

This study estimates the technical and allocative efficiency of paddy farming in Sri Lanka. Household-specific technical efficiencies were computed using cross-sectional data collected from the household survey conducted in 2014 using a Stochastic Frontier approach. The Cobb-Douglas functional form was adopted for the frontier production function and the distributional assumption made for the inefficiency term was half normal. The results of this study show that the estimated mean technical efficiency of the farmers is 78.32 percent, suggesting there is a scope of 21.68 percent to increase paddy productivity using present technology. The estimated Returns to Scale is 0.2806, which implies that a proportional increase in all factors of production leads to a less than proportional increase in paddy productivity. Age, schooling, alcohol consumption, agricultural training, farmers’ attitudes, and the distance between the land and the main watercourse are significant determinants of technical efficiency. According to the analysis of allocative efficiency, there exists inefficiency in allocating resources, where land and machinery resources are underutilised while labour is over utilised.

Assessment of Irrigation System Performance with Socio-economic indicators: A GIS-based study in the Medagama Block of Mahaweli System C

The performance assessment is a strategy to diagnose the deficiencies in existing irrigation systems and to take appropriate management options to correct those. Socio-economic evaluation is a part of this assessment to get a better understanding of the performance of the farming society within the irrigation system. This study was carried out to analyze the performance within Mahaweli System C by means of spatially varying socioeconomic indicators considering the Medagama management block as the study area. The education attainment, quality of housing, access to household consumer durables, access to vehicles in households, and income level of household were the selected indicators to study the socio-economic variability within the study area. A hamlet was taken as the smallest spatial unit to collect data and for mapping purposes. The overall performance index was obtained by summing up the set of indicators by providing relative weights. All the indices were mapped to show the spatial distribution and variability. According to the derived results, the origin of the settlers, the literacy level of the children, their motivation to achieve a better living condition are the factors, which influence on the variability of the socio-economic performance. A medium socio-economic performance was observed in all hamlets except in Henanigala South, where the Adiwasi people are settled. It seems that they have not well adjusted to the system even after three decades of settling. The stakeholder analysis identified the Mahaweli Authority of Sri Lanka and farmer organizations as key stakeholders who can influence on the success of the system performance. A socio-economic evaluation is important to get a feedback of the system performance. Irrigation system performance is highly influenced by other factors such as rainfall and climate conditions, cropping patterns and crop water requirement, soil type, management factors, marketing and other monetary factors. Therefore, an overall irrigation system evaluation is needed with an overall assessment, considering the technical and socio-economic indicators. Thus, this system should be further evaluated by using indices of water delivery performance, financial, productivity and environmental performances. It is important to assess the spatial variability as well as the temporal variability of the performance to identify the improvements of the system performance with time. Tropical Agricultural Research Vol. 24 (3): 215-227 (2013)

IMPACT OF MAHAWELI DIVERSION SCHEME ON BIOLOGICAL DIVERSITY OF DOWNSTREAM FLOOD PLAINS AND ASSOCIATED VillUS

Flood plains of Mahaweli River cover an area of 50,000 hectares. The flood plain extends fromthe river mouth in Trincomalee at its bottom end, to a little way south of the old settlement ofYakkure situated southwest of Manampitiya in the Polonnaruwa district. The flood plain iscomposed of various ecological zones consisting of river channels, villus(Riverine marshes) seasonally flooded grasslands and swamp forest. Villus are shallow andsaucer-shaped depressions on ground their water level is maintained by the annual cycle ofrainfall and river flooding. Most of these are directly connected to the Mahaweli River bychannels. There are 38 identified Villus located in the Mahaweli River floodplain system.A study program was initiated in early 2000 to evaluate the changes that are taking place in thebiotic components of this importantecosystem due to the Mahaweli Development activities suchas reservoir construction and water diversiou.Villus and floodplains have direct or indirect connection with the river or its tributaries. Whenthe river is high, water flows into the Villu or floodplains, and when the water level falls thereverse flow may occur towards the river. It was anticipated that upstream diversion schemes ofMahaweli River would reduce the river flow at Manampitiya by 50%. However fieldinvestigation carried out during our survey indicated that water levels of the Villus have notchanged significantly due to the diversion scheme.Accelerated Mahaweli program provided irrigation water for large areas of undeveloped landaround villus, thus converting them in to paddy fields. All These paddy field receive water forboth 'Yala' and 'Maha' rice growi l.g seasons. Today, vast extents of paddy fields drains in toVillus of the Mahaweli System. As a result, villus in the Mahaweli flood plain now receive ayear-round supply of water. Before the river diversion scheme villus received water from theriver only during the flooding season (i.e. January.) This has brought changes in the waterregimes of the villus.At the moment there is a booming development of Eichhomia crassipes (Japan jabara) due toexcessive loading of nutrients in villus.The study found that the river diversion schemes have resulted considerable changes in the biotaof the Villus and other ecosystems associated with the river. Therefore, steps should be taken torelease floodwater to Villus during the natural floor period of the river in order to sustain thenatural faunistic and floristic diversity in the villus and associated flood plains.

AN ANALYSIS OF AND LESSONS LEARNED FROM CASE STUDIES OF COLLABORATIVE RESOURCE MANAGEMENT IN MAHAWELI SYSTEM H

Collaborative resource management has been a focus of a number of nationalenvironmental policy developments in Sri Lanka. The irrigation sector provides a richsource of experiences and lessons in user participation. The Mahaweli System H beganan accelerated programme of transferring management responsibility to DistributoryCanal Farmer Organisations (DCFOs) in 1998. This study attempted to construct asuitable weighted composite performance index (WCP!) to evaluate the participation andperformance of DCFOs in the co-management of the Mahaweli System H. Data werecollected from 60 DCFOs from Madatugama and Eppawala blocksOutcomes of the co-management provide evidence of a significant (36%) increase inwater productivity of the D~FOs. There was a marginal increase in agriculturalproductivity and profitability. Irrigation fee collection rates (90%) and accumulation ofreserves (27%) in DCFOs had improved significantly in the DCFOs in both blocks.However, financial self-sufficiency was affected due to inadequate opportunities for newsources of income and less control on cost. Relative less participation was found amongtail-end farmers compared to head-end farmers in meetings and decision-making. Thismeans that they risk not gaining the crucial benefits that can be realised from comanagement.Compared to Eppawala the DCFOs in Madatugama had gained controlover many operational decisions and secured the opportunity to stabilise theirperformance. WCPI analysis shows that in both the studied blocks future sustainabilityremains on 50% of the weakly performing DCFOs. Systematic continuos monitoring andevaluation of the performance particularly in financial and institutional aspects, as wellas more training and additional time will improve the performance of the weak DCFOs

Agricultural Production Efficiency of Bethma Cultivation in Mahaweli System H

This study attempts to examine the agricultural productivity and efficiency of owner cultivators and sharecroppers, under Bethma cultivation in two Irrigation Units in the Madatugama block of the Mahaweli System H area. A stochastic frontier production function analysis reveals significant differences between productivity and technical efficiency among these types of cultivators during Yala 2004. One of the key reasons for such a result is the lack of land tenure security, which inhibits any long-term investments in shared land. Stronger farmer organizations were more likely to be efficient in productivity and technical efficiency than weaker ones. This suggests the need for strengthening the farmer organizations to increase agricultural production efficiency under the Bethma system. DOI: 10.4038/sjae.v7i0.1820 <em>Sri Lankan Journal of Agricultural Economics</em>, Vol. 7, 2005 pp.1-20

Resettler choices and long‐term consequences of involuntary resettlement caused by construction of Kotmale Dam in Sri Lanka

AbstractInvoluntary resettlement caused by dam construction, especially in developing countries, is being criticized as an additional cause of impoverishment of the poor population being resettled. Despite current improvements in planning and implementation of involuntary resettlement, there is little experience or research on the medium‐ to long‐term consequences of involuntary resettlement on those being resettled.Within the comprehensive water resource development programme in Sri Lanka under the Mahaweli Accelerated Development Programme, Kotmale Dam was constructed in 1985 for the purpose of hydroelectric power generation and irrigation water supply. Construction of the dam caused ≈ 3000 households to be evacuated and relocated. There were two resettlement alternatives for the families being affected by the dam construction project. The first was to stay close to the reservoir, and receive smaller land plots. The other was to settle in newly developed areas for Mahaweli Development Programme, being located &gt;100 km from original villages, but receive larger, irrigated land plots. In order to determine the consequences after 25 years of the resettlement caused by construction of Kotmale Dam, these authors conducted socioeconomic interview surveys of ≈250 households in three resettlement areas, including Mahaweli System H, System B, System C and villages located near the reservoir site.The study results indicated that the majority of the resettlers perceived their livelihoods as being improved after their resettlement. Furthermore, the majority of them expressed their satisfaction regarding their resettlement choices and their current livelihoods, either in the resettlement sites located near the reservoir or in resettlement sites located far from the original settlement sites. However, their satisfaction is usually based on different perceptions on the part of the resettlers that reflect different strategies for coping with involuntary resettlement. The major factors affecting the choices of resettlers were land ownership and/or the educational opportunities for their children. These survey results indicate that the resettled people made conscious choices for their future, especially for their children. For future resettlement programmes, these authors propose that it is important that the considerations of future generations be incorporated in a feasible, sustainable manner, particularly in regard to educational opportunities.

Investigation of Integrated Management of Large-Scale Irrigation and Aquaculture Systems

The importance of nonirrigation uses of irrigation water to the livelihoods of the rural poor living close to irrigation systems has generally been ignored both in planning and operating these systems. An improved understanding of competition and complementarity of irrigation and nonirrigation uses is essential for increased productivity of irrigation water. This paper selected two typical types of large-scale irrigation systems as case study sites, i.e., the Lower Bhavani Project in Tamil Nadu, India—a canal-based irrigation system and Mahaweli System H, Sri Lanka—a tank-based irrigation system, and explored their potential for and constraints to integrated management for irrigation and aquaculture. The results revealed that for irrigation canals water supply reliability, canal flow velocity, and cage anchorage but for irrigation tanks water, supply reliability may impose constraints to integration of cage-based fish farming. However, the potential can be improved through more responsive operation and ma...

A Daily Water Balance Modelling Approach for Simulating Performance of Tank-Based Irrigation Systems

Tanks are small reservoirs, which are widely distributed in South India and Sri Lanka, where they represent an important water resource for people, crops, livestock and fish. Considerable efforts have been made to rehabilitate tank irrigation systems in recent decades, but there have been few studies carried out to improve understanding of their hydrology. This paper presents a daily water balance approach, which aims to simulate the dynamic behaviour of tank storage. The model was validated over four seasons for two representative tanks within Mahaweli System H, a major irrigation system in the dry zone of Sri Lanka. Use of the model to evaluate current performance and scope for improvement is demonstrated.

Multiple-Use Management in a Large Irrigation System: Benefits of Distributed Secondary Storage

Large-scale canal irrigation projects are commonly seen as profligate users of water. Their low water productivity has been attributed by many authors to deficiencies in management or to actions by farmers to circumvent management control over water distribution. Inadequate design has sometimes been cited as a contributing factor, but the relationship between design and manageability has received too little attention. In most conventional large-scale irrigation systems imperfect matching between water supply and demand is an inescapable fact of life that leads to operational spillages and low efficiency. Provision of auxiliary storage reservoirs at strategic points within the canal system can buffer this mismatch and improve service delivery and also aid recovery of return flows. Such reservoirs may bring additional benefits in that they provide opportunities for multiple-use management and increased productivity of irrigation water. This paper presents a case study of Mahaweli System H in Sri Lanka, which incorporates a large number of secondary reservoirs within its 25000 ha command area. The paper examines current operational performance and considers scope for and constraints to multiple-use management.

Management of the Mahaweli, A River in Sri Lanka

ABSTRACT The Mahaweli is the most important river in Sri Lanka in terms of discharge and drainage area. It carries the largest volume of water amounting to one seventh of SriLanka's total runoff and has a basin that covers 15 per cent of the country's land. The multipurpose reservoirs at Kotmale, Victoria, Randenigala, and Rantembe provide seasonal regulation of the Mahaweli flow to satisfy demands for irrigation and energy generation. Numerous irrigation tanks located within the Mahaweli system also provide storage for the diverted Mahaweli water The physical and organizational complexity of the Mahaweli System provides a difficult water management undertaking. The Mahaweli Authority of Sri Lanka has overall authority over development within the project area. It is also responsible for coordinating the activities of the constituent agencies The Water Management Secretariat, a technically specialized unit of the Mahaweli Authority, recommends operating policies and prepares operating plans for the Mahaweli system. These operating plans are based on the irrigation and energy requirements. The Irrigation Demand Model and the Acres Reservoir Simulation Program are the mathematical models that are used to prepare the operating plans. These models are also used to test various operating policies for the Mahaweli system. This article describes the management of the complex water distribution network that serves the power plants and the irrigation systems under the Mahaweli Development Programme.

Operation of Large Multireservoir Systems Using Optimal‐Control Theory

The utility of optimal‐control theory for the deterministic operation of very large multireservoir systems is demonstrated for a real situation, the complex multireservoir Mahaweli system in Sri Lanka. This system includes 19 nodes, or reservoirs, and 35 release links. The model developed for the Mahaweli is designed to minimize a hydroelectric energy shortage objective and satisfy prespecified irrigation demand constraints. Two alternative approaches are explored for optimal operation of the Mahaweli system. The first involves monthly application of the optimal‐control algorithm to find an optimal policy for the next year, based on current storage and forecasted or historical inflows and demands. The second alternative is an implicit stochastic approach, in which linear operating rules are derived using deterministic optimal control and historical data. Both of the alternatives give reasonable and comparable results. The implicit stochastic optimization alternative has a great advantage regarding computer time and storage requirements. This makes it usable on a small personal computer, providing the system operator with decisions in a few seconds, even with very large systems.

Importance of Demand Estimation in Irrigation‐System Management

Systems engineering research is conducted to analyze improvements in performance of a water‐storage and ‐distribution system in response to improved monitoring of irrigation demands. The Mahaweli system in Sri Lanka, a multireservoir system with both hydropower and irrigation objectives, has been selected as a case study. The operation of the Mahaweli system is simulated using a regression model obtained through implicit stochastic optimization. Spatially independent, cross‐correlated, and systematic errors in irrigation demands are considered. These three, types of errors have similar patterns in their effects on system operation. When the Mahaweli system is operated optimally, both energy shortages and irrigation shortages increased with increasing standard deviations of error. This indicates that improving the measurements of irrigation demand would be beneficial to both farmers and hydropower recipients.