Faculty of Engineering
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Publication Open Access Profiling Microplastic Pollution in Surface Water Bodies in the Most Urbanized City of Sri Lanka and Its Suburbs to Understand the Underlying Factors(Springer, Cham, 2023-02-23) Bandara, R. M. L. S.; Perera, M. D. D.; Gomes, Pattiyage I. A.; Yan, Xu-FengThis study investigated the microplastic pollution of surface waters in and around the most populated and urbanized city in Sri Lanka from 2019 to 2022. The sampling regime was designed to cover the rainfall-driven hydrology and varying levels of urbanization approximated by the built area fraction. Mass and particle concentrations of microplastics ranged from undetected to 0.01 g/L (average ± standard deviation: 0.00464 ± 0.00528 g/L) and from 2 to 36 particles/L (5.3 ± 6.9), respectively. The highest microplastic pollution was observed in the lake; however, in many cases it was without a statistically significant (P < 0.05) difference with canals. Concentrations in the dry state (i.e., at least 30 days after no rainfall) were about 1.5 times more than the wet state (i.e., at least 50 mm/day rainfall for 10 days) in the lake and in the semi-urban canal, but again, the differences were not significant; however, in urban canals, the concentrations were similar in both states. Over 80% of the microplastics were fibre and fragments. Mass concentrations of microplastics showed moderately positive (Pearson’s r > 0.6) correlations with the built area fraction of the contributing catchment in both states but was significant (P < 0.1) only in the dry state. In the case of particle concentrations, none showed even a weak correlation. The independence of microplastic content against built area fraction and rainfall, as well as twice the concentrations found in point source inputs against the surface waters, gave the following insights. Microplastic content in our study area was governed mostly by the modified catchment hydrology spearheaded by stormwater drainages (some cases trans-catchment) and diffusion factors such as non-residential population.Publication Open Access Spatio-Temporal Rainfall Variability and Concentration over Sri Lanka(Hindawi, 2022-09-28) Pawar, U; Karunathilaka, P; Rathnayake, UChanges in precipitation patterns significantly affect flood and drought hazard management and water resources at local to regional scales. Therefore, the main motivation behind this paper is to examine the spatial and temporal rainfall variability over Sri Lanka by Standardized Rainfall Anomaly Index (SRAI) and Precipitation Concentration Index (PCI) from 1990 to 2019. The Mann–Kendall (MK) trend test and Sen’s slope (SS) were utilized to assess the trend in the precipitation concentration based on PCI. The Inverse Distance Weighting (IDW) interpolation method was incorporated to measure spatial distribution. Precipitation variability analysis showed that seasonal variations are more than those of annual variations. In addition, wet, normal, and dry years were identified over Sri Lanka using SRAI. The maximum SRAI (2.27) was observed for the year 2014 for the last 30 years (1990–2019), which shows the extremely wet year of Sri Lanka. The annual and seasonal PCI analysis showed moderate to irregular rainfall distribution except for the Jaffna and Ratnapura areas (annual scale-positive changes in Katugastota for 21.39% and Wellawaya for 17.6%; seasonal scale-Vavuniya for 33.64%, Trincomalee for 31.26%, and Batticaloa for 18.79% in SWMS). The MK test, SS-test, and percent change analyses reveal that rainfall distribution and concentration change do not show a significant positive or negative change in rainfall pattern in Sri Lanka, despite a few areas which experienced significant positive changes. Therefore, this study suggests that the rainfall in Sri Lanka follows the normal trend of precipitation with variations observed both annually and seasonally.Publication Open Access Challenging Arbitral Awards in the Construction Industry(SLIIT, 2022-02-11) Jayasinghe, R; Dahanayake, R; Edirisinghe, VOne of the most common alternative dispute resolution methods used in the Sri Lankan construction industry is arbitration. However, challenging arbitration awards based on legal grounds at the courts has been a current trend by the disagreeing party. If this situation occurs continuously, the purpose of having arbitration as an alternative dispute resolution method can be abandoned. Therefore, the study aims to identify the causes where arbitration is challenged in multi-story building construction projects in Sri Lanka through a case study. The methodological choice was qualitative and used semistructured interviews from six arbitrators and 2 case studies that referred to courts to challenge arbitration awards as research strategies. The study found the poor attitude of parties, lack of technical knowledge, reliability, and capability of the arbitrator to act according to the arbitrary acts imposed by the government as the main causes. Further. The study recommends arbitrators consider the reasons to act well enough and reject the cases if the arbitration is likely to be challenged in courts, train arbitrators to be reliable and on technical knowledge, and improve parties' attitudes by educating on the arbitration procedure and its benefits.Publication Open Access REGULARITIES AND PATTERNS OF CONSTRUCTION COSTS UPON POLITICAL EVENTS(SLIIT, 2022-02-11) Perera, B. K. C; Jayasena, H. SThough the market prices change before and after political events were often speculated, if such changes could be systematically accounted for in construction cost forecasting was unknown. This study aimed to bridge this knowledge gap by identifying the regularities and patterns of the construction costs upon political events. A decade of period was selected in which the scope of the study started in 2010. Time series analysis was used along with regression analysis, assuming a linear relationship between construction costs and time. After a comprehensive literature review, CIDA construction cost indices were chosen as the most appropriate cost representation for the local context, and these were taken as the dependent variables. All indices were plotted in diagrams and long-term trends were observed, then indices were carried for further analysis of cycles. Major political events were collected through a document survey and the findings were plotted on the time series analysis output. It was noticed that in 2013 indices were changed mostly, where three provincial elections were held, and some more pattern changes had occurred close to the local government elections which took place in 2011 and 2018. The study concluded that there is neither pattern nor regularity in construction costs upon political events where it cannot be systematically incorporated into construction cost forecasting. However, the findings did not deny the impact of political events on construction costs, and novel areas were found where further explorations are required.Publication Open Access Effective Waste Management Strategies of Bentonite in Sri Lanka(SLIIT, 2022-02-11) Guruge, K; Coomasaru, POne of the greatest challenges of Bentonite usage in construction industry is, managing the wastage created in sites thus, it has to be given attention. Therefore, the study would be conducted focusing on the domestic piling construction sites and the process followed by them. Although it is a chemical, it is recognized to be safe for both the environment as well as mankind in an ecological and health protection perspective. However, a proper disposal method in order to reduce the further issues as excessive waste in sites is needed. Therefore, this study aims to explore an effective method regarding the waste management strategies for Bentonite in Sri Lanka. The objectives of the study are, identifying the wasting methods of Bentonite, identifying causes of disposing Bentonite and determining the most suitable method for Bentonite disposal. Data for the objectives one and two were collected through a literature survey and analyzed by using NVivo which was validated using a questionnaire by majority of 5-10 years experienced professionals aligning to mixed method approach. Data for the third objective was found by aegis of the same questionnaire. Noticeably, it was validated through interviews by the industry experts with more than 30 years of experience. The study found that, site conditions are the most relatable reason for the Bentonite waste. Apart from that ‘weather’ and ‘manual handling errors’ can be additional reasons for the wastage. Moreover, most sites consider either ‘when the slurry forms into a cake’ or ‘silos are full’ as the causes for disposal. Furthermore, it has identified that the majority of sites dispose the waste to disposable lands using bowsers as of the disposal method after reusing 3-4 times. The suggested method appears to be cost effective and efficient in comparison to the others. Furthermore, it can be rather safe and environmentally friendly.Publication Open Access Level of risk management knowledge among construction project managers in Sri Lanka(researchgate.net, 2022-06-24) Welikala, D. H. N; Jayasena, H. S; Perera, B. K. CRisk management often becomes a significant concern among the construction professionals especially due to the complex nature of the industry. Though it is a popular subject in project management discipline, it was observed that authentic application of the principles of risk management at times is arguable in practice. As a Project Manager who is a key role player in a project, it is vital to have a solid knowledge on risk management and its related arena. Evidence was found of limited risk management knowledge among construction professionals. Therefore, a study was conducted to find the status of risk management knowledge among the construction Project Managers in Sri Lanka. A mixed method approach was followed by a comprehensive literature review on elements of body of knowledge of risk management and later a questionnaire survey to contextualise the status of the knowledge gap of Project Managers in real. According to the findings of the study, it could be concluded that Sri Lankan Project Managers are not fully confident on their risk management knowledge. It was primarily likely to be due to the limited learning in the subject area when pursuing higher studies. The study also identifies the options to device appropriate strategies to improve risk management knowledge among the Construction Project Managers in Sri Lanka.Publication Open Access Global warming potential of English brick manufacturing in Sri Lanka: A cradle to gate analysis(IEEE, 2021-07-27) Herath, I; Karunaratne, S; Dharmarathna, DClay bricks are one of the most commonly used walling materials in Sri Lanka. The brick manufacturing process poses a notable impact on the environment. Clay excavation leads to resource depletion while diesel fuel utilized for excavation and clay transportation pollutes the air. Additionally, tree cutting for wood fuel contributes to deforestation whilst wood burning promotes air pollution. Thus, this research aimed to quantify the global warming potential due to English brick manufacturing using cradle to gate Life Cycle Assessment (LCA) approach. The functional unit used was one-meter square of the brick wall area. Data collection, analysis and interpretation of results were done by the ISO 14044/14040 standards. Primary life cycle inventory data was gathered via brick kiln owners and workers. The LCA assembly was modelled using the ‘OpenLCA’ software. Three product systems were defined according to the brick bond types and wall thicknesses. The global warming potential related to brick production was assessed using the ‘GWP 100a’ method. Clay excavation, clay transportation and wood chamber firing emerged as emission hotspots. The study revealed that the global warming potential of 225mm brick wall and 115mm brick wall as 11.9 and 5.9 kg CO2-eq/m 2 , respectively. Through this study, local clay brick industry can be driven to improve the overall sustainability of the brick manufacturing sector.Publication Open Access Forecasting Electricity Power Generation of Pawan Danavi Wind Farm, Sri Lanka, Using Gene Expression Programming(Hindawi, 2022-05) Herath, D; Jayasinghe, J.M.J.W; Rathnayake, Uis paper presents the development of a wind power forecasting model based on gene expression programming (GEP) for one of the major wind farms in Sri Lanka, Pawan Danavi. With the ever-increasing demand for renewable power generation, Sri Lanka has started harnessing electricity from wind power. ough the initial establishment cost of wind farms is high, the analyses clearly showcased the economic sustainability of wind power generation in long term. In this context, forecasting the wind power generation at Sri Lankan wind farms is important in many ways. However, limited research has been carried out in Sri Lanka to predict the wind power generation against the changing climate. erefore, to overcome this research gap, a model was developed to forecast wind power generation against two climatic factors, viz. on-site wind speed and ambient temperature. e results showcased the robustness and accuracy of the proposed GEP-based forecasting model (with R2 0.92, index of agreement 0.98, and RMSE 259 kW). Moreover, the results of the study were compared against three dierent forecasting models and found comparable in terms of the model accuracy. e GEP-based model is advantageous over machine learning techniques due to its capability in deriving a mathematical expression. As an acceptable relationship was found between wind power generation and climatic factors, the proposed model facilitates the future projection of wind power generations with forecasted climatic factors. ough the application of GEP in the eld of wind power generation is reported in a few research publications, this is the rst research in which GEP is employed to model the power generation with respect to weather indices. e proposed prediction model is advantageous than machine learning models as the relationship between the wind power and the weather indices can be expressed.Publication Open Access Multidecadal Land Use Patterns and Land Surface Temperature Variation in Sri Lanka(Hindawi, 2022-05-16) Samarasinghe, T; Rathnayake, U; Makumbura, R. KAgricultural land conversion due to urbanization, industrialization, and many other factors is one of the significant concerns to food production. Therefore, analyzing the temporal and spatial variation of agricultural lands is an emerging topic in the research world. However, an agrarian country like Sri Lanka was given weaker attention to the temporal and spatial variation of the land use, including the agricultural lands. This study presents an extended analysis of temporal and spatial variation of land use patterns in Sri Lanka, specifically looking at the agricultural land conversion and land surface temperature (LST) change. Remote sensing techniques and geographic information system (GIS) were used for the presented work. The satellite images from three Landsat’s were analyzed for 2000, 2010, and 2020 to identify the potential land use conversions. In addition, LSTs were extracted for the same period. Significant and continuous increases can be seen in the agricultural lands from 33.94% (of total area) in 2000 to 43.2% in 2020. In contrast, the forest areas showcase a relative decrease from 38.51% to 33.82% (of total area) during the analyzed period. In addition, the rate of conversion from agriculture to settlements is higher in the latter decade (2010–2020) compared to the earlier decade (2000–2010). Only general conclusions were drafted based on the LSTs results as they were not extracted in the same months of the year due to high cloud cover. Therefore, the results and conclusions of this study can be effectively used to improve the land use policies in Sri Lanka and lead to a sustainable land use culture.Publication Open Access Evaluation of Satellite Rainfall Products over the Mahaweli River Basin in Sri Lanka(Hindawi, 2022-04) Perera, H; Fernando, S; Gunathilake, M. B; Sirisena, J; Rathnayake, Ue availability of accurate spatiotemporal rainfall data is of utmost importance for reliable predictions from hydroclimatological studies. Challenges and limitations faced due to the absence of dense rain gauge (RG) networks are seen especially in the developing countries. erefore, alternative rainfall measurements such as satellite rainfall products (SRPs) are used when RG networks are scarce or completely do not exist. Noteworthy, rainfall data retrieved from satellites also possess several uncertainties. Hence, these SRPs should essentially be validated beforehand. e Mahaweli River Basin (MRB), the largest river basin in Sri Lanka, is the heart of the country’s water resources contributing to a signi cant share of the hydropower production and agricultural sector. Given the importance of the MRB, this study explored the suitability of SRPs as an alternative for RG data for the basin. Daily rainfall data of six types of SRPs were extracted at 14 locations within the MRB. ereafter, statistical analysis was carried out using continuous and categorical evaluation indices to evaluate the accuracy of SRPs. Nonparametric tests, including the Mann-Kendall and Sen’s slope estimator tests, were used to detect the possibility of trends and the magnitude, respectively. Integrated MultisatellitE Retrievals for Global Precipitation Measurement (IMERG) outperformed among all SRPs, while Precipitation Estimation from Remotely Sensed Information using Arti cial Neural Networks (PERSIANN) products showed dire performances. However, IMERG also demonstrated underestimations when compared to RG data. Trend analysis results showcased that the IMERG product agreed more with RG data on monthly and annual time scales while Tropical Rainfall Measurement Mission Multisatellite Precipitation Analysis–3B42 (TRMM-3B42) agreed more on the seasonal scale. Overall, IMERG turned out to be the best alternative among the SRPs analyzed for MRB. However, it was clear that these products possess signi cant errors which cannot be ignored when using them in hydrological applications. e results of the study will be valuable for many parties including river basin authorities, agriculturists, meteorologists, hydrologists, and many other stakeholders.