Master of Engineering in Environmental Water Resources Engineering and Management

Permanent URI for this collectionhttp://192.248.9.226/handle/123/16122

Browse

Now showing 1 - 14 of 14

item: Thesis-Abstract
Assessment o f the degree of public awareness on Tsunami Galle District , Sri Lanka
(2014-08-15) Kumara, GGA; Samarawickrama, S; Rathnasooriya, H
Tsunami is one of the most devastated coastal hazard, which may perhaps yields serious damages to both human lives and properties in affected islands like Sri Lanka. As an island, Sri Lanka has also become a Tsunami prone risk zone as frequent earthquakes reported in Java Sumathra region. Knowledge and the awareness on such coastal hazards of the community is a vital facts, which results is minimizing its adverse effects. Developing awareness processess and effective communication systems will definitely assist in the designing of hazards maps and evacuation plans. 26th December 2004 Tsunami has hit the Sri Lankan coastal regions creating many lives losses and property damages as a result of lack of previous experience in similar typed hazard. and post second anniversary of 26th December 2004 Tsunami event. At the survey, 1200 sample was selected based on geographical representations of affected Grama Niladhari Divisions. School community and the general public are substantially encountered at the survey. A questionnaire was used to collect data from the sample and informal discussions were conducted to collect additional information. The survey was conducted by a team comprising of Engineers, Sociologist etc. The data collected was analyzed and results are presented in the report. Media effect, communication gaps, reliability of early warning systems, public responsiveness, suggested countermeasures are the critical outcomes of the study which needs to address at policy level.
item: Thesis-Abstract
Urban drainage network generation using geographical information systems - a case study of three catchments in Greater Colombo Area
(12/2/2011) Attygalla, N; Wijesekera, NTS
Establishing proper drainage system has become a major challenge especially in the urban areas. Drainage systems consist of canal network and drainage structures such as culverts. Once the drainage system is established, it can be expanded to identify the discharge at the outlet of a watershed or in flood plains for a given precipitation. Therefore identification of drainage network is a primary requirement for drainage design. Drainage network identification through engineering survey is a time consuming and costly effort. Some of the engineering applications related to drainage network such as culvert design, flood plain analysis, do not need very high accuracy. The drainage network identification can be done using less time-consuming computer technology, if the generated accuracy is satisfactory for engineering applications. Therefore this research is concentrated on the aspects related streamline generation and accuracy assessment. The main objectives of this study are, - Generation of streamline network - Accuracy comparison of generated streamline - Identifying the parameters affecting the accuracy - Accuracy comparison of observed culvert location The study is carried out in three watersheds in the Greater Colombo region. The Torrington watershed is selected as the primary watershed for the study and the watershed area is around 450 ha. The Attidiya and Katubedda watersheds areas are found as 190 ha and 250 ha respectively. The study requires data in digital format. Digital data extraction is carried out in three processes. Part of digital data such as existing stream network is extracted from paper maps, through scanning and geo referencing. Also digital base map features of building, roads, contours and spot heights are extracted from the database of National Water Supply & Drainage Board (NWSDB). Rest of the digital data such as culvert locations are extracted using Global Positioning System (GPS) technology. Data processing and analysis component is carried out using the extracted digital source data. Streamlines are generated from DEM (Digital Elevation Model) by varying the resolution from 2m, 5m, 10m, 20m and 50m. While generating streamlines on GIS, it is necessary to provide a threshold value. This threshold value is selected in a way that the level of branching off of generated and extracted streamlines at the outlet of watershed are similar. Accuracy assessment is carried out with the newly established raster based accuracy assessment method. Other than that a reference box analysis is carried out to obtain a general impression of the possible streamline pattern comes under a particular Root Mean Square Error (RMSE) value range. Accuracy variation with the change of DEM resolution at particular location and the accuracy variation along the streamline with the watershed parameters such as stream order, stream slope, surface slope, building density and stream sinuosity are observed. It is found that stream order and surface slope has a relationship with streamline accuracy. In the same way culvert location accuracies are identified by varying the resolution. Result and discussion sections focus on the key results of data processing and analysis. It is discussed that raster based accuracy assessment is more representative when compared with vector based methods. Once the accuracies are assessed, the average accuracy variation (RMSE) with respect to different watersheds is discussed. Also accuracy variation with the resolution and the accuracy variation along the streamline with the affecting factors of stream order and surface slope are discussed. The possible reasons for unexceptional variation of streamline from the expected patters are analyzed. It is also discussed about establishing a representative per cell threshold value for urban watersheds. Once that is established it is possible to identify the threshold value should be given for newly selected watersheds. Finally accuracy variations of culvert locations with respect to the resolution are also discussed in depth. It was found that raster based accuracy assessment methodology is more realistic. Average Root Mean Square Error value (RMSE) of streamline is increased with the surface flatness of the watershed. Also in general RMSE value of generated streamline is reduced when cell size become finer. The per cell threshold value is determined as 0.016. It can be utilized to generate streamline network having same stream order of actual streamline at the outlet. It is shown that accuracy of generated streamline improves with the increment of stream order and surface slope. The deviation of observed culvert
item:
Evaluation of operational performance in Rajangana major irrigation sche
De Alwis, SMDLK
Managing the resources in a major irrigation scheme needs more attention on system performance to get the optimum production out of the available resources. In Sri Lanka, most of the major irrigation schemes are managed with conventional management strategies along with the traditional experiences gained by both farmers and officers. Some instances, systematic observation of resource use and management are not adhered by the scheme managers as well as by the farmers. This situation has effected to low productivity of the schemes. Providing adequate effort for integration of inter-related activities and combining the physical, biological and human factors on productivity is not so easy task in the irrigated agriculture sector. Therefore assessing the issues and constraints and evaluating the scheme performance in a systematic way enhance the managers to take prompt action when required while delivering the services in operational procedures./ In view of developing a suitable performance assessment programmed for a major irrigation scheme a study was done on performance assessment under water use efficiency, irrigation practices and land productivity in the LB Tract 01 area of Rajangana Irrigation Scheme. This study included turnout area basis assessment with the collection of data and information through literature review and field surveys along with the statistics collected from related institutions and departments. Study was carried out to evaluate the performances of Irrigation system through performance indicators by using systematic observations, documentation and interpretation methods. Several assumptions were made during the analysis with regards to data that were out of reach or inaccessible. Data and information used were from year 1990 Yale season to Year 2002 Yale season. The Rajangana Major Irrigation Scheme is one of the Major Irrigation Schemes in dry zone of Sri Lanka and it is considered as a water abundant scheme following the restoration of Kalawewa under the system "H" of Mahaweli Development Program. Rajangana reservoir provides irrigation water to 5520 ha of lands under gravity irrigation system and 1602 ha of lands under the lift irrigation system. At present there are about 6275 ha of lands under gravity irrigation system and area under the lift irrigation system has reduced to 1050 ha mostly due to other constraints of lift irrigation system such as irrigable land being utilized for homestead purposes and abandoning of some lands as a result of inadequate operation and maintenance of pump houses. This scheme has been divided in to 25 tracts to provide irrigation facilities. Out of these 7 tracts belong to the LB irrigation system and 18 tracts belong to the RB irrigation system. It appears that the productivity of the scheme does not show a good performance in utilization of water & land when compared with yield and income of the farmers and as a result the living standard of the settlers too does not indicate as satisfactory./ This study examined the cultivation patterns of past seasons, irrigation water use by the farmers, production cost, farmer incomes, cost of operation and cost of maintenance of the system. In this study the command area under the Tract 01 of LB system was selected as a pilot area because similar variations were observed in other tracts during preliminary surveys. Outputs of the study are expected to be generalized to whole scheme./ Performance of the irrigation system depends on a large number of variables. In this study 11 performance indicators assessed the system performance in four main areas via, service delivery, agriculture production, agriculture economics & financing an system sustenance. Spatial and temporal variation of water deliveries were found ire terms of adequacy and irrigation duty. Water use efficiency measured in terms old grain mass per unit volume of water reflects that the water use efficiency of the study area is far below the established benchmark value of 0.372Kg/m3. Stud)M revealed that the irrigation system of the study area is subjected to deterioration due to inadequate attention on operation and maintenance. The efficiency of getting potential yield in the area is 68% with medium level productivity performance. Recommendations of this study would be useful to managers who deal with major irrigation system management in planning the cultivation seasons by optimizing the productivity of land and water.
item: Thesis-Abstract
The Estimation of probable maximum precipitation for Sri Lanka
Fernando, WCDK; Wickramasuriya, SS
On 24 and 25lh of December 1957 heavy rain fell in the North Central Province; 206.5mm and 219.7mm of rainfall were recorded at Anuradhapura meteorological station and were nearly twice that recorded during the previous high floods. Some of the major tanks such as Kalawewa, Nachchaduwa and Huruluwewa in Anuradhapura breached, resulting in catastrophic damage to infrastructure. The storm of 392.5 mm on 8,h June 1996 over Ratnapura resulted in a disastrous flood which caused enormous damage and rendered many people homeless. The design of a hydraulic structure often requires an estimate of the design flood which has considerable uncertainty about its magnitude. However it should be determined in relation to the project feature for which it is required. When 100% virtual security against failure is required, then the design criteria should be based on the Probable Maximum Flood, which in turn requires the estimation of Probable Maximum Precipitation (PMP). The research compares the results of 24-hour PMP obtained by two methods. One is based on storm maximization or a hydro-meteorological method and the other uses the statistical method developed by Hirschfield. In this study, the last 105 years (1896-2000) of daily rainfall data from the meteorological stations at Anuradhapura and Ratnapura have been analyzed. The 24-hour point PMP for Anuradhapura showed that the results were in the range of 600-625mm based on the statistical method while storm maximization yields a PMP of 425mm with the adjustments of moisture and wind maximization. On the other hand the statistical result for Ratnapura was in the order of 990 to 1120mm and the PMP calculated by storm maximization was 1025mm. If storm maximization was based on true rainfall, PMP values were increased up to 623mm and 1058mm for Anuradhapura and Ratnapura respectively. Finally suggestions have been made to improve the effectiveness of the different approaches, in estimating PMP.
item: Thesis-Abstract
Rainwater harvesting in the context of changing social and economic trends in Colombo metropolitan area, Sri Lanka
Adhihetty, A; Wickramasuriya, SS
The objective of this research work is to investigate whether rainwater harvesting can satisfactorily reduce the social and economic impact on the population, resulting from development and increasing water tariff within the Colombo metropolitan area of Sri Lanka. Human need and people experience adverse social pressures without access to adequate amounts of water. Hence it is vital to seek alternative measures urgently. The use of rainwater as a supplement to pipe borne water to fulfill the non-potable water demand will be an attractive alternative for the water problem in Colombo metropolitan area. Developing a spreadsheet based method on past rainfall data is a valuable tool for decision makers to make a rapid preliminary assessment about the likelihood of success of a rainwater harvesting project. The methodology requires daily rainfall, roof area harvested, storage capacity and daily demand as parameters. The cost effectiveness of using rainwater harvesting as a supplementary source to pipe borne water to alleviate the social and economic burdens of the population, is demonstrated by a cost analysis./ The vision of the government of Sri Lanka is to stimulate substantial growth, by developing the Colombo metropolitan area, which will be a hub of economic and development activities in the 21st century. This will result in a major increase in the demand for suitable water, which is presently met by surface water resources. The population in the area will encounter serious problems of using ground water due to Lack of lands to dig wells and the issue of increasing ground water pollution. Thus people will have to depend on pipe borne water for their domestic needs. However due to increasing water tariff, many have found difficulty in paying their water bills. Non-payment of water bills result in disconnection of water supply. Unlike other services such as electricity and telecommunication, water is a critical
item: Thesis-Abstract
Upgrading of Ambatale pulsator
Kaluarachchi, AS; Ratnayake, N; Wickramasuriya, SS
ABSTRACT The major drinking water treatment plant in Sri Lanka, the Abatable Water Treatment Plant (WTP) is located on the south bank of the Kelang Ganga at F 79° 56' N 6° 55'. The Ambatale WTP was constructed in the early 1960s, and produces nearly 90% of total drinking water supply to the Colombo district. The treatment plant was expanded and rehabilitated on four occasions, and brought up to its present capacity of 117 mad in 2003./ The raw water for all the clarifiers at Abatable WTP is from the same source, the Kelang Ganga, The deterioration or ageing of the plant and the operational inconsistencies lower the quality and quantity of water produced at a WTP; if not upgraded regularly./ Increasing die capacity and the efficiency of the Abatable WTP are necessary due to the increase in domestic and industrial water demands in Colombo./ Increasing the capacity by upgrading the existing treatment units at Abatable rather than building new ones could reach the goal of production of more drinking water. It saves the capital cost. Furthermore, in case of limited funds, upgrading the existing facilities in an optimal way by improving efficiency is more advantageous./ There are three pulsed sludge blanket clarifiers at Abatable; a Pulsator (1979), a Superpulsator (1992) and a Pulsatube (2003). These Pulsator clarifiers are using a sludge blanket process combined with pulsed flow and providing combined flocculation & clarification in one vessel. The configurations of above the above three types of clarifiers are almost similar to each other. Therefore conversion of a Pulsate into a Pulsatube clarifier or Superpulsator clarifier could be done by a simple modification to the structure./ The objective of this research is to study the possible options of rehabilitating the Abatable Pulsate (1979) and identify the best possible rehabilitating option.
item: Thesis-Abstract
Improved water conservation practices using rain water harvesting in the wet and intermediate zones of Sri Lanka
Ranasinghe, RKWK; Wickramasuriya, SS
Fresh water is a limited and precious resource that is often taken for granted. However many areas of the developing world suffer a lack of safe water. Therefore, water bome diseases account for an estimated 80% of all illnesses in developing countries. In addition, millions of women and children walk several kilometers every day just to fetch a minimum quantity of water for their families. Furthermore, the Sri Lankan government also faces many problems in finding safe water sources to meet the growing water needs of the entire population. Roof rainwater harvesting is the only feasible option in some parts of the country, to deal with this issue to a certain extent where no other water sources are available./ The research is targeted to study the water conservation practices using Rainwater Harvesting in the wet and intermediate zones of Sri Lanka. To analyze performance of a selected roof rainwater harvesting system, thirty years (1968-1998) of daily rainfall data from Galle, Rathnapura, and Kurunegala districts have been used. The roof sizes considered were 50 m2,75 m2, 100 m2 & 200 m2 and tank capacities considered were 1 m3, 2 m3, 5 m3 & 7.5 m3 for family size of five members. The daily water demand is taken as 120 liters per capita per day./ The results show that there is a 79% probability of success in the Galle district for supplying 300 liters of water per day per family (i.e. 50% demand fulfillment) by using a 5 m3 tank with a roof catchment area of 75 m2. The equivalent result for Rathnapura is 93% while for Kurunegala it is approximately 71%. Hence, the results clearly show that rainwater harvesting is an excellent alternative option for the partial fulfillment (50%) of daily domestic water demand within the wet and intermediate zones of Sri Lanka./ Finally, it can be concluded that roof rainwater harvesting is a very promising alternative solution for increasing water demand of the country. However, the research also shows that during a few months in the year, domestic users will be unable to survive comfortably only with rainwater harvesting.
item: Thesis-Abstract
Drought mitigation using rainwater harvesting in the dry zone of Sri Lanka
Kumari, DMCS; Wickramasuriya, SS
The government of Sri Lanka proposed to provide safe drinking water to all by 2025. However, this proposal is becoming a challenging task due to depletion and pollution of water resources combined with a growing demand and conflict among users. On the other hand, pipe borne water to all households is becoming costly due to the high level of investment required and increased operation & maintenance cost. Due to this situation, a large percentage of the both urban and rural population would be deprived of any form of safe drinking water. Therefore it becomes nationally important to look for low cost options which could be managed and afforded by the communities themselves. A rainwater based water supply system is an alternative option to solve this problem./ The objective of this research work is to investigate the more suitable storage volume required for rooftop rainwater harvesting system and determine the probability of success of practicing rainwater harvesting for domestic use in the dry zone of Sri Lanka./ The analysis uses thirty years of daily rainfall data (1968-1998) from Puttalam, Hambantota and Anuradhapura districts in the dry zone of Sri Lanka. The results show that the probability of success of a rainwater harvesting system shows a bimodal pattern during the year./ It has been found that the more suitable tank capacity required is 5 m3 corresponding to a roof area between 75m2 to 100 m2. Such a system can provide 120 liters per capita per day to a household of five persons and give an overall probability of success of approximately 30%. At 300 liters per day per household (ie. 50% of demand), the probability of success improves significantly to 50%.Thus rainwater harvesting can be a valuable tool of drought mitigation within the dry zone. The probability of success of a system varies throughout the year due to the seasonal variation of rainfall. In particular, during the period February to March and June to September a rainwater harvesting system alone will not be able to meet the required demand. The percentage saving of monthly water bills for urban schemes can vary from 25% - 33% considering the subsidy given by NWS & DB, and for consumers in rural schemes the amounts are 25% - 35%. These rainwater harvesting systems utilize 5 m3- 7.5 m3 tank capacities with 75 m2 - 100 m2 roof areas.
item: Thesis-Abstract
An Evaluation of the status of integrated water resources management (IWRM) in the Kelani river basin of Sri Lanka
Wijesundera, SP; Wijesekera, NTS
Increasingly countries world over are experiencing difficulties in accessing safe sources of water for all their consumptive purposes in wake of rapid population growth and environmental degradation. Consequently, there is increased competition for this scarce resource. In this backdrop, Integrated Water Resources Management (IWRM) is fast emerging as a legitimate alternate management model to previously sect orally fragmented management practices to better utilize the available resource more prudently and to ensure its long-term sustenance. IWRM is defined as "a process which promotes the coordinated development and management of water, land and related resources in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems". This in essence requires a fundamental paradigm shift in the management and governance of water./ The Kelani River Basin of Sri Lanka which hosts its capital city and has the largest basin population is one of the most important basins in the country. The basin experiences many problems related to its water resources of which most are attributed to weaknesses in management that is divided along sect oral lines. /Additionally, the country's policies and laws are outdated and fragmented, making their implementation difficult. Given this situation, a rethink on water management and its governance has become and issue of primary importance.\ The research objective is to evaluate the application of the principles of IWRM in Kelani River Basin to identify where the current management practices departs from the stated principles and its affect on water resources of the basin; and propose improvements for water management./ The research was conducted by means of a desk study and a basin wide field survey. /The desk study consist the review of current literature on IWRM, study reports conducted on the development of the Kelang River Basin and other academic publications on IWRM. The field survey consisted, a survey of General Stakeholders in sixty locations, consultations with ten Institutional Stakeholders, of which seven were state institutors and three independent It was evident that if not managed properly water resources in Kelani will be under severe stress in the near future, particularly during the dry seasons. Considerable pollution of water is seen with rapidly increasing population and the removal of forest cover degrading the watersheds./ In the context of IWRM practice in the Kelani River Basin, the study rates the current implementation status as a "Low" at 1.41 of 5.0; or 28.2%. The key water sector institutions believe that this rate needs to be at 3.71 of 5.0; or 74.2%; for water management in an IWRM context be considered as effective and thus be rated as "Substantial". The study reveals that there is informal, fragmented and unplanned implementation of IWRM in the Kelani basin and that this level of intervention is inadequate to ensure the sustainable use of water, both within or outside an IWRM context. /Therefore, it can be argued that an overarching water policy framework together with the necessary institutions geared towards integration in management and empowerment of the community, underpinned by sound economics and equity criteria; are necessary mainstays for the long run sustainable utilization of water resources in the Kelani River Basin
item: Thesis-Abstract
Sustainable water resources management for optimum utilization of Walawe river basin
Abeysekara, SSM; Gamage, NPD; Gunarathna, PP
The basin is undergoing extensive changes due to agro-ecological, socioeconomic and institutional developments. Livelihoods vary from area to area depending on the physiographic conditions and availability of land and water. Irrigation development has been the major strategy- for livelihood enhancement of the people in the basin// However, tea plantations have replaced the natural vegetation that covered the mountains in the past and abandoned tea lands have been degraded by severe soil erosion. Newly introduced trees like pine and eucalyptus were planted under reforestation programs in the 1950s in this area . They have had a negative impact on the hydrology of the basin, causing some small streams to dry up.// The increasing trend of agro-chemicals usage for irrigated agriculture by the basin farmers is likely to have adverse impacts on the biodiversity of the lagoons. Irrigation development has had negative impacts on the aquatic environment also Specially, large scale deforestation, removal of vegetation cover and encroachment of reservations and other conservative areas with in the basin have drastically reduced watershed performance and environmental friendly behaviors which have severely affected the maximum efficiency of the catchments. An increasing competitive usage of water resources by several sectors can also be seen within this basin An accurate topographical maps to scale 1:50,GOO have been used to digitized the basin and it's sub catchments using geographic Information System(GIS1. Divisional Secretariat Divisions |DSD) falling into the Walawa basinand different types of land usages in the basin were identified using Multi Layer Analysis in GIS - Geoprocessing.// To obtain an average rainfall value over the catch men and sub catchments of Walawa basin, the Thiessen polygon method was used The runoff coefficients for the sub catchments Samanalawewa and Udawaiawaof the basin were calculated from the daily reservoir water balance computations under some assumptions for the period. Irrigation recharge contribution to ground water were also calculated. But, in this study, river recharges were not calculated due to the non-availability of required data. Ground water withdrawal for each seasons were also calculated separately for each zone.// Human, livestock, agio and industrial water consumptions were also calculated under some assumptions from year 2000 lo 2005.Collected the necessary data and information required for the identification of mitigatory measures towards watershed protection to promote soil and water resources conservation within the basin Therefore, the output objectives are directly related to draw our attention lo identify the suitable strategics for the equitable, efficient and effective water resources management and watershed management practices preserving soil, water and other natural resources, reducing waste to a minimum and meeting the water requirement of a given demand site. This will be very useful for the sustainable development of the basin.
item: Thesis-Abstract
Development of a decision support tool for monitoring water quality of the Colombo canal system
Eriyagama, AMNAK; Ratnayake, N
The Colombo Canal System comprises of a rather complex network of large open drainage canals, smaller tributary canals and low lying marshes functioning as natural retention ponds. It caters to the drainage needs of the Greater Colombo area, reducing incidence or flooding, and thereby improving the health and sanitation conditions of the urban community.// Pollution of the Colombo Canal System has been recognized as a major issue o(concern for the past two decades. It is especially detrimental to the health and well-being or the urban poor w ho frequently inhabit canal hanks and low-living regions of Colombo. Although a commendable effort has been made to improve the canal water quality under the Greater Colombo Flood Control and Environment Improvement Project (GCFC&EIP>. the pollution levels of some of the canals arc significantly high even at present. A Comprehensive Water Quality Monitoring Program has been carried out by Sri Lanka I .and Reclamation and Development Corporation(SLLR&DC) from IW to date under GCFC&EIP. where monthly measurements have been recorded at 16 locations in the greater Colombo Canal System for 10 physical and chemical Parameters. However, no detailed study has been carried out so far to analyze the short term and long-term variations in water quality, or the relationship between water quality and other variables, such as rainfall. There fore ,the present study aims to fill the above gap by Integrating the available raw data, analyze is of the water quality regime of each location, as well as a study of its relationship with canal water level, average daily rainfall and canal discharge in a single user-friendly computer package The end product of this exercise as a simple informative decision support tool called the Water Quality Monitor (WQM).// Al present there exists an array of water quality models incorporating hydrodynamics arid rater quality, and the majority of these have been developed in the USA cither by the United States environmental Protection Agency (USEPA) or the US Army Corps of Engineers. In addition, the Danish Hydraulic Institute (DHII) Has also developed a few water quality models These models serve as decision support tools for adopting water quality improvement measures. Many of the above models appear very complex. Requiring a plethora 01 input data .and are intended TO BE USE ONLY BY specialists in the field. Therefore. it Was felt that there existed a need (or a simple tool, which serves the dual purposes of knowledge dissemination as well as decision support, with regard to surface water quality in the Colombo area, while utilizing the existing wealth of data; hence this study. In addition, this report also disuses some of the more complex models along with earlier studies on water quality of the Colombo Carol System.// An attempt has been made to look at the total quality regime of each monitored location, and assist in arriving at a realize qualify criteria, which could actually be met by improving canal water quality. In addition, the relationships between canal water level and water quality. are also between average daily rainfall and water quality are also examined. The relationship between water quality and canal discharge a examined for one location where discharge data is available At the end of the analyses a user of the package will be aided in making a decision regarding the reachable level of quality for a particular site in Colombo, and also examine the relationships between Hs water quality and Other variables such as water level and rainfall A special feature of the tool is the facility provided to analyse the user's own set of data other than the built in Colombo data This report also discus some prominent outcomes of applying the tool to the Colombo Canal System, and winds up by discussing some feasible interventions for improving canal water quality, bused on those outcomes.
item: Thesis-Abstract
Numerical Modeling of Tsunamis for Early Warning and Evacuation
Udayakumara, ERS; Samarawickrama, SP
Its creation was prompted by the 2004 Indian Ocean earthquake and resuhing tsunami, which lel^; some 230,000 people dead or missing. Many analysts claimed that the disaster would have been mitigated if there had been an effective warning system in place, citing the wellestablished Hawaii-based Pacific Tsunami Warning Center, which operates in the Pacific Ocean. People in some areas would have had more than adequate time to seek safety if they were aware of the impending catastrophe. The only way to effectively mitigate the impact of a tsunami is through an early warning system.Other methods such as tsunami walls only work for a percentage of waves, but a warning system is effective for all waves originating outside a minimum distance from the coastline. Based on the above information, great attention was paid towards the Indian Ocean Tsunami Warning System. But the still Indian Tsunami Warning System has only two deep water buoys to detect the tsunami waves and two number of buoys are not enough to issue accurate warning at all. Due to this reasons, in most of the occations tsunami warnings had been issued for Indian Ocean countries including Sri Lanka, mainly based on the magnitude of the earchquake which causes the tsunami. This is a blind issue of warning such as the Sri Lankan experience in 2007 September tsunami. Therefore in order to issue a warning accurately and with confidence, there must be a properly developed thunami warning system. In this project, I'm going to develop such system for Sri Lanka considering the earthquake on Sunda fault, which lies in the Indonesian region. This fault is considered as a most critical fault for Sri Lanka. The selected region of the fault has divided in to several segments which act as tsunami sources. Tsunami modeling software "WinlTDB" is used to model the tsunami under each earthquake case. After runing the model for several magnitudes of earthquake for each source, wave heights and reaching time was measured at selected Six coastal points around the country. A database was created using the observed data for the analysis purpose. 11
item: Thesis-Abstract
Tsunami mitigation measures, awareness & response in Sri Lanka
Lawrance, MKD; Dr. Saman Samarawickrama [supervisor] | Mr. Harsha Ratnasooriya;
Knowledge on coastal hazards among the community is very important in minimizing properly damage and also safe the Uves of people who Hve in the coastal region. Among the several coastal hazards, the Tsunami is the most destructive natural hazard that can be occurred. On 26th December 2004, the Sri Lankan community at the coastal belt experienced this massive disaster due to the Tsunami caused due to the huge earthquake occurred at off the coast of Sumathra. This resulted widespread damage both property and human lives. It was reputed that the loss of Uves in Sri Lanka is around 40,000 and which was around 250,000 in the region. The millions of people loss their homes. The damage for Sri Lankans were very high due to the unawareness and unprepardness. In Sri Lankan History, it was not experienced such dramatic hazard in the recent past. That was the main reason for increasing the damage. In this survey, it was planned to assess the degree of awareness among the community about Tsunami and its mitigatory measures. The survey was carried out in two steps in December 2006. i) Before the 2"^ anniversary of Tsunami ii) After the 2"^ anniversary of Tsunami The survey was planned for both school children and the general public. It was possible to coUect around 1200 samples from both categories. The selection of G.N Division was carried out based on the effectiveness of Tsunami whether they were effected, moderately effected or severely effected. While concentrating on G.N Divisions on such a way the schools were selected from the data obtained from the Southern Provincial Education Department. Students as well as pubUc were very keen in answering questions at the survey. Once collecting data, it was presented in graphical and tabulator forms in order to compare the results. According to the results, it was found that the community was fuUy unaware at the time of Tsunami hitting the coastal belt of the country. The media effect was not sufficient to disseminate the message among the community. This has been remarkably improved at the time of Tsunami warning given on 28*^ March 2005. But the knowledge on present developments of integrated Tsunami monitoring system, evacuation plan are not suflicient. The survey shows that the continuous actions on awareness, updating knowledge and capacity building to be carried out in order to minimize the damage that can be caused by future Tsunamis.
item: Thesis-Abstract
A Study of the sustainability of a water supply scheme utilizing a costal aquifer with particular reference to the Koggala export processing zone
Mahinda, AKA; Senarath, DCH
Koggala Export Processing Zone of the BOI was setup in 1991 and functions with 20 Nosfactories and work force of over 10,000 in the Galle district just adjacent to the sea andcoastal belt. Total extent of the KgEPZ area is 225 Acres. Since there were no surface waterscheme to provide the required water for this project, a groundwater scheme was consideredas an appropriate alternative resource. NWS&DB has plan to supply water from the TalpeReservoir of Gin Ganga Project (KfW) with part of the cost shared by the BOI.The purpose of this study is to study the sustainability of the existing water supply schemein Koggala EPZ where a coastal aquifer is used as the source. Since about 50% of the landare vacant and could be given for future investment projects in the KgEPZ, the possibilityof continuation of operation of existing groundwater scheme supplemented with surfacewater supply is considered as an economical solution for the KgEPZ.For estimation of recharge water balance calculations were done for time step of 1 day,since in a time step of 1 day would capture all the relevant changes that occur.This study estimated that recharge to the aquifer is 0.4 Million cubic metres per year whichis equivalent to 357 mm/year.n

Browse

Recent Submissions