Showing papers in "Journal of Geospatial Surveying in 2022"
Sewage waste is one of the major environmental issues in Sri Lanka. Various studies reveal that about 50% of sewage waste is disposed of unscientifically in to open areas or water bodies. It creates problems to both the public health and the environment. As such, this study identified potential locations for sewage disposal sites using the Analytical Hierarchy Process (AHP) based Multi-Criteria Analysis (MCA) methods with Geographical Information System (GIS), for the Badulla Urban Area (BUA). Environmental aspects, geological and topographical aspects, and socio-economic aspects are identified as key parameters to be considered when doing land suitability analysis for sewage disposal in BUA. The study identified that of the total area, 87.36% of was not suitable, 1.10% less suitable, 9.37% moderately suitable, and 2.17% as suitable. Using the resultant classified suitability map, field verification was carried out to determine the final optimal site. Hence, the application of GIS-based MCA has been demonstrated as an appropriate methodology to solve multiple choices in sewage disposal site selection. This would be very much needed in the concept of city planning across the country. |
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Wind behavior in Sri Lanka, mainly exposed to two major monsoon seasons, is complex to model spatially. The acute changes in the topography further make it difficult to map the wind patterns. Irregularly distributed wind measurements are the main source of data available to interpret and model this dynamic geographic phenomenon. Sri Lanka is in need of an accurate and timely wind map in order to support wind energy resource planning and to enable weather prediction systems to be more accurate. Strong and continuous winds in the southern part of the island encourage wind harvesting for energy. Wind energy is arguably the most affordable per megawatt-hour renewable energy source, and it is growing nearly as quickly as conventional energy generation techniques in the country. The objective of this paper is twofold. First is to use the spatial autocorrelation structure of 23 data points using diurnal data measured every 10 minutes on an irregularly distributed grid to construct continuous wind speed fields for the 4 monsoon seasons. This has been done for the year 2015 as a reference year, where a complete set of data was acquired. Secondly, it was intended to provide the reader how R opensource with advanced statistical modelling capabilities and graphics could be utilized conveniently for vague geographic phenomena analysis. The spatial autocorrelation of the wind speed and the direction was determined in the beginning by using the semi-variograms. Candidate semi-variogram models, especially spherical and exponential models, were tested to be more suitable for the observations. Ordinary Kriging, which uses the samples in the local neighborhood to avoid the mean estimation, was used to perform the spatial interpolations Kriging. For each month of the year 2015, four weekly wind maps were generated, both for the direction and speed. These 48 wind maps were further analyzed for the wind patterns. The changes in the morning and evening wind patterns, and the significant wind pattern changes along the coastal areas and the central highlands are extracted and presented in the study. The generated maps could be useful in identifying potential areas for wind farming. By feeding the data in a time series to the presented model, it would be possible to deduce wind pattern changes in Sri Lanka on a yearly basis. As a whole, the paper presents a reasonable model that could be used to model a diverse set of vague phenomena with an understanding of the uncertainties involved.
2 citations
The International Maritime Organization (IMO) was established in 1948 as a specialized agency of the United Nations (UN). They provide international standards on the safety, security, and environmental performance of ships involved in international trade. International shipping is effective only if the regulations and standards are agreed upon, adopted and implemented on an international basis. IMO Instruments Implementation Code (III code) is one such attempt where it looks into states’ capacities of implementing obligations. Here, we present in what way the hydrographic rapid assessment survey support the above obligation of ensuring safety of navigation for ships visiting Colombo Port in the aftermath of MV X-Press Pearl accident in West coast of Sri Lanka. The comprehensive Side Scan Sonar (SSS) survey that was conducted over the area found some of the fallen containers and debris lying on the seabed. Due to the extent and the nature of the incident, and due to the ocean current dynamics, a larger area had to be investigated and a number of relevant agencies in the maritime field were involved. As a country, the responsible authorities have taken timely actions to disseminate the safety related information to the mariners and subsequent measures were taken to update the relevant nautical charts by conducting necessary systematic hydrographic surveys to fulfill the obligations of the International Convention for the Safety of Life at Sea ( SOLAS) of IMO. |
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