Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2023
Authors
Mounir TakritiAbstract
No abstract has been registered
Abstract
swap is an R-package designed to help interface and work with SWAP4 model. It consists of a variety of functions that assist the user in otherwise tedious and repetitive tasks.
Authors
Kushan D. Siriwardhana Dimantha I. Jayaneththi Ruchiru D. Herath Randika K. Makumbura Hemantha Jayasinghe Miyuru Gunathilake Hazi Md. Azamathulla Kiran Tota-Maharaj Upaka RathnayakeAbstract
No abstract has been registered
Authors
Sanjana Zoysa Vindhya Basnayake Jayanga T. Samarasinghe Miyuru Gunathilake Komali Kantamaneni Nitin Muttil Uttam Pawar Upaka RathnayakeAbstract
No abstract has been registered
Authors
Imiya M. Chathuranika Erandi Sachinthanie Phub Zam Miyuru Gunathilake Denkar Denkar Nitin Muttil Amila Abeynayaka Komali Kantamaneni Upaka RathnayakeAbstract
Access to safe drinking water and improved sanitation are important fundamental rights of people around the world to maintain good health. However, freshwater resources are threatened by many anthropogenic activities. Therefore, sustainable water supply is a challenge. Limited access to safe drinking water and unimproved sanitation facilities in some of its urban and rural areas are two of the major challenges for Bhutan in the 21st century. The water quality in the natural water systems in the cities and suburbs has significantly decreased while the urban infrastructure is being improved in Bhutan. Therefore, this study presents the state-of-the-art of water resources in Bhutan and the challenges for a sustainable water supply system. The current water status, drinking water sources and accessibility, factors affecting water quality degradation in urban and rural areas, water treatment methods, and implementation of sustainable drinking water accessibility with population growth in Bhutan are discussed in detail. Results of the review revealed that the water quality has deteriorated over the last decade and has a high challenge to provide safe water to some of the areas in Bhutan. Geographic changes, financial difficulties, urban expansion, and climate change are the reasons for the lack of safe drinking water accessibility for people in town areas. It is, therefore, recommended to have a comprehensive integrate water resources management (IWRM) approach while considering all stakeholders to find sustainable solutions for the challenges showcased in this paper.
Abstract
This paper explores the utilisation of gauge rainfall and satellite-based precipitation product (SPP)-TRMM3B42, to develop IDF curves for the Fiji Islands. The study compares the application of remote sensing data against rain gauge (RG) data for two main stations, Nadi and Nausori (1991 to 2020). The accuracy of SPPs is evaluated through statistical analysis, employing continuous and categorical evaluation indices. The results indicate that TRMM3B42 tends to overestimate light precipitation and underestimate heavy rainfall in low elevations when compared to rain gauge data. Rainfall intensities derived from satellite data exhibit relative changes within ± 10%. This study also performs future projections. Two greenhouse emission scenarios, Shared Socioeconomic Pathways (SSP) 2–4.5 and 5–8.5, are employed for IDF curve projection. The analysis reveals that changes in IDF curves are more pronounced for short-duration rainfall as compared to high-duration rainfall. Additionally, higher emission scenarios demonstrate greater changes compared to lower scenarios. These findings emphasise the importance of accounting for climate change and future projections in designing urban infrastructure, particularly considering potential urban expansion and human settlements. This study helps in solving design problems associated with urban runoff control and disposal where knowing the rainfall intensities of different return periods with different durations is vital.
Authors
Susanthika Dhanapala Helitha Nilmalgoda Miyuru Gunathilake Upaka Rathnayake Eranga M. WimalasiriAbstract
The energy in agricultural systems is two-fold: transformation and utilization. The assessment and proper use of energy in agricultural systems is important to achieve economic benefits and overall sustainability. Therefore, this study was conducted to evaluate the energy balance of crop and livestock production, net energy ratio (NER), and water use efficiency (WUE) of crops of a selected farm in Sri Lanka using the life cycle assessment (LCA) approach. In order to assess the diversification, 18 crops and 5 livestock types were used. The data were obtained from farm records, personal contacts, and previously published literature. Accordingly, the energy balance in crop production and livestock production was −316.87 GJ ha−1 Year−1 and 758.73 GJ Year−1, respectively. The energy related WUE of crop production was 31.35 MJ m−3. The total energy balance of the farm was 736.2 GJ Year−1. The results show a negative energy balance in crop production indicating an efficient production system, while a comparatively higher energy loss was shown from the livestock sector. The procedure followed in this study can be used to assess the energy balance of diversified agricultural systems, which is important for agricultural sustainability. This can be further developed to assess the carbon footprint in agricultural systems.
Authors
Chathura Palliyaguru Vindhya Basnayake Randika K. Makumbura Miyuru Gunathilake Nitin Muttil Eranga M. Wimalasiri Upaka RathnayakeAbstract
Soil degradation is a serious environmental issue in many regions of the world, and Sri Lanka is not an exception. Maha Oya River Basin (MORB) is one of the major river basins in tropical Sri Lanka, which suffers from regular soil erosion and degradation. The current study was designed to estimate the soil erosion associated with land use changes of the MORB. The Revised Universal Soil Loss Equation (RUSLE) was used in calculating the annual soil erosion rates, while the Geographic Information System (GIS) was used in mapping the spatial variations of the soil erosion hazard over a 30-year period. Thereafter, soil erosion hotspots in the MORB were also identified. The results of this study revealed that the mean average soil loss from the MORB has substantially increased from 2.81 t ha−1 yr−1 in 1989 to 3.21 t ha−1 yr−1 in 2021, which is an increment of about 14.23%. An extremely critical soil erosion-prone locations (average annual soil loss > 60 t ha−1 yr−1) map of the MORB was developed for the year 2021. The severity classes revealed that approximately 4.61% and 6.11% of the study area were in high to extremely high erosion hazard classes in 1989 and 2021, respectively. Based on the results, it was found that the extreme soil erosion occurs when forests and vegetation land are converted into agricultural and bare land/farmland. The spatial analysis further reveals that erosion-prone soil types, steep slope areas, and reduced forest/vegetation cover in hilly mountain areas contributed to the high soil erosion risk (16.56 to 91.01 t ha−1 yr−1) of the MORB. These high soil erosional areas should be prioritized according to the severity classes, and appropriate land use/land cover (LU/LC) management and water conservation practices should be implemented as recommended by this study to restore degraded lands.
Abstract
This study assessed the meteorological and hydrological droughts and their relationship over 30 years from 1985 to 2015 in the largest river basin (Mahaweli River Basin (MRB)) in Sri Lanka. Data from 14 rainfall, 5 temperature, and 5 streamflow stations in and near the MRB were used in the present study. Universal drought indices including Standardized Precipitation Index (SPI) and Standardized Precipitation–Evapotranspiration Index (SPEI) were used to assess meteorological droughts. The Standardized Streamflow Index (SSI) was used in investigating hydrological droughts. Correlations between meteorological and hydrological droughts were obtained, annual variations were observed (in terms of SPI, SPEI, and SSI), and the spatial distributions of selected drought events were analyzed. Our results revealed that the highest correlation was found in long-term dry conditions in the wet zone. In addition, some negative correlations found showed the opposite behavior of correlations. Furthermore, in annual variations of droughts, extreme droughts were recorded in the dry zone as maximum values, while results were more prominent in the wet zone. In addition, the spatial distribution performed using SPI, SPEI, and SSI showed an extremely dry condition in 2004. Our findings are beneficial for policymaking and for the decision-makers in assessing meteorological and hydrological drought risks in the future.
Authors
Jayanga T. Samarasinghe Charuni P. Wickramarachchi Randika K. Makumbura Pasindu Meddage Miyuru Gunathilake Nitin Muttil Upaka RathnayakeAbstract
Climate change has had a significant impact on the tourism industry in many countries, leading to changes in policies and adaptations to attract more visitors. However, there are few studies on the effects of climate change on Sri Lanka’s tourism industry and income, despite its importance as a destination for tourists. A study was conducted to analyze the holiday climate index (HCI) for Sri Lanka’s urban and beach destinations to address this gap. The analysis covered historical years (2010–2018) and forecasted climatic scenarios (2021–2050 and 2071–2100), and the results were presented as colored maps to highlight the importance of HCI scores. Visual analysis showed some correlation between HCI scores and tourist arrivals, but the result of the overall correlation analysis was not significant. However, a country-specific correlation analysis revealed interesting findings, indicating that the changing climate can be considered among other factors that impact tourist arrivals. The research proposes that authorities assess the outcomes of the study and conduct further research to develop adaptive plans for Sri Lanka’s future tourism industry. The study also investigated potential scenarios for beach and urban destinations under two climate scenarios (RCP 4.5 and RCP 8.5) for the near and far future, presenting the findings to tourism industry stakeholders for any necessary policy changes. As Sri Lanka expects more Chinese visitors in the future due to ongoing development projects, this study could be valuable for policymakers and industry stakeholders when adapting to changing climate and future tourist behavior. While more research is needed to fully understand the effects of climate change on Sri Lanka’s tourism industry, this study serves as a starting point for future investigations.