Your search found 11 records
(Location: IWMI-HQ Call no: P 4580 Record No: H021401)
(Location: IWMI-HQ Call no: IWMI 631.7.6.2 G744 PIE Record No: H038165)
(Location: IWMI HQ Call no: P 7925 Record No: H040239)
4 Gunawardana, I. P. P.; de Silva, R. P.; Dayawansa, N. D. K.. 2005. Identification of appropriate technology for rainwater harvesting in Moneragala District. In Galagedara, L. W. (Ed.). Water resources research in Sri Lanka: Symposium Proceedings of the Water Professional’s Day 2005. Peradeniya, Sri Lanka: PGIA. pp.63-67.
(Location: IWMI HQ Call no: IWMI 631.7 G744 DAY Record No: H040706)
5 Dayawansa, N. D. K.. (Ed.) 2006. Water resources research in Sri Lanka: symposium proceedings of the Water Professional’s Day 2006, Postgraduate Institute of Agriculture, University of Peradeniya, Sri Lanka, 1 October 2006. Peradeniya, Sri Lanka: University of Peradeniya. Postgraduate Institute of Agriculture (PGIA). 170p.
(Location: IWMI HQ Call no: 631.7 G744 DAY Record No: H040719)
(0.54 MB)
6 Dayawansa, N. D. K.. (Ed.) 2006. Geo-informatics for environmental conservation and management: proceedings of the Third National Symposium on Geo-Informatics, 25 August 2006. Peradeniya, Sri Lanka: Geo-Informatics Society of Sri Lanka (GISSL) 124p.
(Location: IWMI HQ Call no: 526.0285 G570 DAY Record No: H040856)
7 Jayasekare, A. S.; Dayawansa, N. D. K.; De Silva, R. P.; Muthuwatta, Lal P. 2005. Spatially distributed hydrological modeling of Upper Uma Oya Catchment using soil and water assessment tool SWAT. In De Silva, R. P. (Ed.). Sweden International Training Course on Remote Sensing Education for Educators, Decadal Proceedings 1990-2004: a collection of selected papers submitted by former participants. Peradeniya, Sri Lanka: Geo Informatics Society of Sri Lanka (GISSL) pp.65-85.
(Location: IWMI HQ Call no: 526.0285 G570 DES Record No: H040879)
8 Amarasekara, M. G. T. S.; Kumarihamy, R. M. K.; Dayawansa, N. D. K.; De Silva, R. P. 2010. The impact of inappropriate soil management on river water quality: a case study in the Kurundu Oya Sub-catchment of the Upper Mahaweli Catchment, Sri Lanka. In Evans, Alexandra; Jinapala, K. (Eds). Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka, BMICH, Colombo, Sri Lanka, 9-11 June 2009. Vol. 2. Water quality, environment and climate change. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.49-60.
(Location: IWMI HQ Call no: IWMI 631.7 G744 EVA Record No: H042858)
The results of many studies have revealed that intensive farming on steep slopes, coupled with over application of fertilizers and accumulation of nutrients in downstream water bodies due to soil erosion, have contributed to environmental hazards in the Upper Mahaweli Catchment Area (UMCA) of Sri Lanka. The encroachment of riparian zones for exotic vegetable cultivation has aggravated this situation. In view of this, a study was conducted in the Kurundu Oya catchment, a micro-catchment of the UMCA, to investigate the soil management practices within the farming systems and their impacts on river water quality. Three villages were selected along the Kurundu Oya: Mahakudugala, Kumbalgamuwa and Batagolla. The study consisted of a survey of 150 households in 2007 and 2008, to gather information on the characteristics of householders and on soil management practices. A soil survey was carried out to analyze the soil fertility of farmlands. Water quality parameters were measured periodically in different sections of a selected stream. The results revealed that nearly 50 % of the riparian zones in the upper catchment of the Kurundu Oya stream are encroached to cultivate potato and other exotic vegetables. In addition, it was observed that over application of fertilizers on the vegetable plots was causing nutrient accumulation and the plots also recorded high levels of phosphorous (P) (above 75 ppm). Results of the water quality analysis showed that nitrate and available P levels were within the standard limits, but nitrate nitrogen (NO3-N) levels were close to the upper level of the standard limit. Therefore, in order to minimize water pollution, it is strongly recommended that fertilizer application is based on soil tests. In addition, encroachment of sensitive lands has to be addressed. Priority should be given to strengthening institutional capacity in order to facilitate the implementation of existing environmental legislation.
9 Bandara, M. A. C. S.; De Silva, R. P.; Dayawansa, N. D. K.. 2010. Household water security through stored rainwater and consumer acceptability: a case study of the Anuradhapura District. In Evans, Alexandra; Jinapala, K. (Eds). Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka, BMICH, Colombo, Sri Lanka, 9-11 June 2009. Vol. 2. Water quality, environment and climate change. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.87-97.
(Location: IWMI HQ Call no: e-copy only Record No: H042862)
Rainwater harvesting has increased in popularity in Sri Lanka over the past two decades due to the number of water supply projects funded by the government and non-governmental organizations (NGOs). The stored rainwater can provide accessible, reliable, timely and adequate supplies of water to households but there are uncertainties as to safety, in terms of water quality, and consumer acceptability. A study was, therefore, conducted in the Anuradhapura District, in the dry zone, to assess consumer acceptability of stored rainwater for household purposes and to conduct rainwater quality tests in a laboratory. The majority of households in Anuradhapura meet their drinking water requirements from protected wells (59.6 %). Prior to the project, people greatly preferred open wells as a source of domestic water, followed by tubewells, because they believed that water in open wells is of good quality and drinkable. However, stored rainwater has become the priority source now, especially through roof rainwater harvesting (RRWH), which is used during the dry periods. The study revealed that more than 85 % of households use stored rainwater for drinking although some have concerns over the quality and only drink it after boiling. The easy accessibility of water and the assurance by the project team that it is of good quality are the main reasons that people are willing to drink it. The acceptability of stored rainwater for consumption was very high in water-scarce areas and with the increasing distance to the nearest and alternative sources of good-quality water. Of those who felt that they had adequate water, 84 % of the sample households found it adequate in the wet season but only 21 % in the dry season. Water quality analysis revealed that the chemical and physical quality of stored rainwater is within the acceptable range with respect to Sri Lankan Standards, SLS: 614, for potable water quality (SLIS 1983). Other domestic water sources exceeded standards for electrical conductivity, total alkalinity, hardness, ammonium nitrogen, fluorides and total iron. However, stored rainwater was of lower biological quality than other domestic water sources.
(Location: IWMI HQ Call no: e-copy only Record No: H050986)
(1.53 MB)
Irrigation plays a vital role in world food security. Agriculture accounts for 70% of freshwater withdrawals worldwide, and the figure is even higher in developing countries like Sri Lanka. The rapid expansion of anthropogenic activities, together with the anticipated climatic risks associated with them, is exacerbating the problem of increasing agricultural water demand. Although it has been recognized for decades, improving irrigation water-use efficiency and water productivity is still considered the most realistic option for addressing the challenge of sustainable management of water resources. However, adoption of recommended water-efficient technologies and concepts remains elusive in practice, highlighting the gaps created by failing to consider social perspectives in developing water management strategies. As a result, the effectiveness of water governance has often been questioned in terms of performance and adoption of innovative technologies. This paper reviews and discusses the complexity of innovation through a technical, social, and institutional lens by reviewing available research on Sri Lanka's river basins and presents a perspective on opportunities for improving irrigation water management.
(Location: IWMI HQ Call no: e-copy only Record No: H051615)
(3.87 MB)
CONTEXT: Village Tank Cascade Systems (VTCSs), which are ancient irrigation systems in Sri Lanka have undergone various pressures over time including climate variability, population growth, land use changes and agricultural intensification. VTCSs have provided irrigation and vital ecosystem services for generations, while facing these pressures. As external pressures have increased drastically over the last century, it is worthwhile to investigate VTCS's current capacity to tolerate pressures exerted on them while sustaining their functions.
OBJECTIVE: The objectives of this study were to (i) assess the pressures exerted on Mahakanumulla VTCS due to climate change, population growth, land use changes and agricultural practices, (ii) evaluate the impacts of the pressures on the system in terms of water quality and quantity.
METHODS: Rainfall data from 1906 to 2020 were analyzed to identify the rainfall trends over the last century. Land use maps were developed for 1910, 1979, 2002 and 2018. To identify current farming practices, a questionnaire survey was carried out targeting 357 respondents followed by field investigations. Environmental impacts due to pressures on the system were evaluated using water quantity estimations and quality tests.
RESULTS AND CONCLUSIONS: Paddy extent has increased from 6.3% to 20.2% while the homestead extent has increased from 1.6% to 11.5% during the last century. The lands used for sustainable shifting cultivation have encroached with permanent agricultural lands and human settlements. The runoff coefficient rose from 0.29 to 0.45, indicating a high outflow of water during rains and limiting water retention within the system. This is an indication of increasing water scarcity in dry periods due to limited recharge capacity. Although the system continues to function without significant water quality deterioration, agricultural activities can cause threats in the future. Hence, the system needs immediate attention in the context of proper land use planning, farmer awareness and integrated nutrient management at the cascade level to minimize these pressures exerted upon the system.
SIGNIFICANCE: Identifying and quantifying various pressures exerted on VTCSs is the fundamental step in setting management and mitigation plans. Project planners and policymakers need evidence-based information in this regard. Therefore, this study's findings and the research framework that may be extended to other VTCSs and similar systems are significant in creating a favorable policy environment and implementation programmes to reduce the risks the VTCSs are exposed to.
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