As a university teacher, an academic programme coordinator and a researcher in the disciplines of Geo-spatial Science and statistics the overall aim of my professional career is to raise the standards of our teaching, research, administration and outreach activities. I understand that continuously updating the knowledge through reading and participation at various academic forums both locally and internationally contributes for my resourcefulness in the professional arena. I look forward to be making a stronger contribution for academic and research administration. With my experience as the scientist at Geo Sloutions (pvt) LTD, Director of the 3i Solutions (pvt) LTD, and Coordinator extension programmes IHRA University of Colombo and lecturer of many state universities in Sri Lanka I believe that I can lead high quality and output oriented academic and research programmes. Phone: +94112507563 Address: Institute of Human Resource Advancement University of ColomboSri Lanka
ISPRS International Journal of Geo-Information, 2018
Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major re... more Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major research foci in various interrelated fields due to rapid changes in urban ecological environments. Various cities have been investigated in previous studies, and most of the findings have facilitated the introduction of proper mitigation measures to overcome the negative impact of UHI. At present, most of the mountain cities of the world have undergone rapid urban development, and this has resulted in the increasing surface UHI (SUHI) phenomenon. Hence, this study focuses on quantifying SUHI in Kandy City, the world heritage tropical mountain city of Sri Lanka, using Landsat data (1996 and 2017) based on the mean land surface temperature (LST), the difference between the fraction of impervious surfaces (IS), and the fraction of green space (GS). Additionally, we examined the relationship of LST to the green space/impervious surface fraction ratio (GS/IS fraction ratio) and the magnitude o...
Landslide hazard is one of the most common global hazards. In Sri
Lanka, landslides are considere... more Landslide hazard is one of the most common global hazards. In Sri Lanka, landslides are considered as a disaster, and thus, scientific communities have paid attention to monitoring and prediction of landslide hazards. Landslide hazard zonation (LHZ) is a vital factor for preparedness and mitigation phases in a disaster management cycle. In the Sri Lankan contest, LHZ becomes more significant since 20% of the total lands are vulnerable. Spatial distribution of landslides of Sri Lanka is mainly influenced by geospatial criteria, rainfall distribution, geology, hydrology, geomorphology, land-use, and drainage network. However, the above factors do not equally contribute to determining the landslide susceptibility. This study attempted to map the landslide hazard zones in one of the tropical hilly region: Kegalle District and weighting causative factors rationally using statistical method in GIS environment. In this study, causative factors were weighted and modelled to define hazardous zones by geographical information system (GIS)- based spatial multi criteria evaluation (SMCE). The necessary geospatial data were obtained, processed, and converted into a grid format. The contribution level of each factor for triggering landslides was evaluated by the Analytical Hierarchy Process (AHP) and modelled with the SMCE. The developed SMCE model is at an acceptable level because the acquired consistency ratio value is 0.074 (≤ 0.1). The developed LHZ map shows a 90% level prediction accuracy compared to previous landslides. According to landslide hazard zonation map, 13% (227 km2) of the entire area is a very high landslide susceptible zone, while 37% (634 km2) of the total land area has a high susceptibility to slope failure. Moderate and low susceptible zones were 32% (542 km2) and 12% (203 km2) respectively, and only 6% (96 km2) of the entire study area belonged to the very low landslide susceptible zone.
Background: Landslides area controversial issue worldwide and cause a wide range of impacts on th... more Background: Landslides area controversial issue worldwide and cause a wide range of impacts on the socioeconomic systems of the affected community. However, empirical studies of affected environments remain inadequate for prediction and decision making. This study aims to estimate the direct impact of a massive landslide that occurred around areas with Kandyan home gardens (KHGs)in Aranayake, Sri Lanka.
Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major re... more Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major research foci in various interrelated fields due to rapid changes in urban ecological environments. Various cities have been investigated in previous studies, and most of the findings have facilitated the introduction of proper mitigation measures to overcome the negative impact of UHI. At present, most of the mountain cities of the world have undergone rapid urban development, and this has resulted in the increasing surface UHI (SUHI) phenomenon. Hence, this study focuses on quantifying SUHI in Kandy City, the world heritage tropical mountain city of Sri Lanka, using Landsat data (1996 and 2017) based on the mean land surface temperature (LST), the difference between the fraction of impervious surfaces (IS), and the fraction of green space (GS). Additionally, we examined the relationship of LST to the green space/impervious surface fraction ratio (GS/IS fraction ratio) and the magnitude of the GS/IS fraction ratio. The SUHI intensity (SUHII) was calculated based on the temperature difference between main land use/cover categories and the temperature difference between urban-rural zones. We demarcated the rural zone based on the fraction of IS recorded, <10%, along with the urban-rural gradient zone. The result shows a SUHII increase from 3.9 • C in 1996 to 6.2 • C in 2017 along the urban-rural gradient between the urban and rural zones (10 < IS). These results relate to the rapid urban expansion of the study areas from 1996 to 2017. Most of the natural surfaces have changed to impervious surfaces, causing an increase of SUHI in Kandy City. The mean LST has a positive relationship with the fraction of IS and a negative relationship with the fraction of GS. Additionally, the GS/IS fraction ratio shows a rapid decline. Thus, the findings of this study can be considered as a proxy indicator for introducing proper landscape and urban planning for the World Heritage tropical mountain city of Kandy in Sri Lanka.
Drought is a disastrous natural phenomenon and is generally viewed as a sustained and regionally ... more Drought is a disastrous natural phenomenon and is generally viewed as a sustained and regionally extensive occurrence of below average natural water availability either in the form of rainfall, river runoff or groundwater. Droughts are defined based on different factors and their efficient management depends mainly on the correct assessment. Existing methods consider only a few factors which are not effective for drought mitigation programmes. This study assessed the vulnerability of crop production to drought using multi-scale, multi-indicator methods and some of the data were analysed during the collection of data by questionnaire survey. Yield data, rainfall data and socio – economic data were used to analyse the sensitivity, exposure and adaptive capacity. It does this by identifying differences across and within fourteen DS divisions of Jaffna to reflect the three components of vulnerability: exposure, sensitivity, and adaptive capacity. In addition overall mean vulnerability of a particular region was estimated. Jaffna’s agricultural crop drought vulnerability, presented in a map form, was classified in the following categories: very low, low, moderate, high and very high. The results of the study show that the vulnerability of crop production to drought in Jaffna district has discernible geographical and socioeconomic patterns, with Kayts DS division as high vulnerable to drought. Three factors such as very high sensitivity indices, very high exposure indices and low adaptive capacity indices are contributing for this regions’ vulnerability. Chavakachcheri division is a very lower vulnerable region. Because of its better social economic level.In addition according to the questionnaire analysis also Kayts and Velanai divisions are mostly affected by drought. Because the vulnerable regions have low socioeconomic development and are based on rain-fed agriculture. The crop vulnerability to drought can be a step towards mitigation oriented drought management and aid in reducing the impacts associated with drought.
Soil erosion is a widespread problem in Nillambe catchment and it accommodates a pulation that i... more Soil erosion is a widespread problem in Nillambe catchment and it accommodates a pulation that is mainly based on agriculture. Consequently it is important to identify the socio-economic risk in the area in order to carryout necessary mitigation measures to minimize the potential risk. This study attempts to categorize socio-economic risk levels of soil erosion. Based on USLE (Universal Soil Loss Equation), geo-spatial input data representing rainfall, soils, land slopes and land use were used to model soil erosion hazard and a selected set of socio-economic vulnerability and coping capacity indicator variables were spatially modeled based on AHP (Analytical Hierarchical Process) and the outcomes of hazard, vulnerability and coping capacity measurements were further modeled using GIS based Disaster Risk Equation to obtain the socio-economic risk index for Nillambe catchment. The study revealed that approximately 25 % of the catchment is in moderate to extremely high socio-economic risk to soil erosion. Furthermore, it indicates that the majority of such lands are covered with moderately managed tea and a slope greater than 10 % (slope of the catchment varies between 0 – 36 degrees) with a moderately high rainfall erosivity level between 16 - 27. The maps identifying the socio-economic vulnerability, coping capacity and the risk levels to soil erosion can be utilized to identify areas with different vulnerabilities and coping capacities to promote necessary mitigation actions and strengthen socio-economic capacities of the community involved which would eventually minimize the socio-economic risk for soil erosion in the area.
ISPRS International Journal of Geo-Information, 2018
Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major re... more Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major research foci in various interrelated fields due to rapid changes in urban ecological environments. Various cities have been investigated in previous studies, and most of the findings have facilitated the introduction of proper mitigation measures to overcome the negative impact of UHI. At present, most of the mountain cities of the world have undergone rapid urban development, and this has resulted in the increasing surface UHI (SUHI) phenomenon. Hence, this study focuses on quantifying SUHI in Kandy City, the world heritage tropical mountain city of Sri Lanka, using Landsat data (1996 and 2017) based on the mean land surface temperature (LST), the difference between the fraction of impervious surfaces (IS), and the fraction of green space (GS). Additionally, we examined the relationship of LST to the green space/impervious surface fraction ratio (GS/IS fraction ratio) and the magnitude o...
Landslide hazard is one of the most common global hazards. In Sri
Lanka, landslides are considere... more Landslide hazard is one of the most common global hazards. In Sri Lanka, landslides are considered as a disaster, and thus, scientific communities have paid attention to monitoring and prediction of landslide hazards. Landslide hazard zonation (LHZ) is a vital factor for preparedness and mitigation phases in a disaster management cycle. In the Sri Lankan contest, LHZ becomes more significant since 20% of the total lands are vulnerable. Spatial distribution of landslides of Sri Lanka is mainly influenced by geospatial criteria, rainfall distribution, geology, hydrology, geomorphology, land-use, and drainage network. However, the above factors do not equally contribute to determining the landslide susceptibility. This study attempted to map the landslide hazard zones in one of the tropical hilly region: Kegalle District and weighting causative factors rationally using statistical method in GIS environment. In this study, causative factors were weighted and modelled to define hazardous zones by geographical information system (GIS)- based spatial multi criteria evaluation (SMCE). The necessary geospatial data were obtained, processed, and converted into a grid format. The contribution level of each factor for triggering landslides was evaluated by the Analytical Hierarchy Process (AHP) and modelled with the SMCE. The developed SMCE model is at an acceptable level because the acquired consistency ratio value is 0.074 (≤ 0.1). The developed LHZ map shows a 90% level prediction accuracy compared to previous landslides. According to landslide hazard zonation map, 13% (227 km2) of the entire area is a very high landslide susceptible zone, while 37% (634 km2) of the total land area has a high susceptibility to slope failure. Moderate and low susceptible zones were 32% (542 km2) and 12% (203 km2) respectively, and only 6% (96 km2) of the entire study area belonged to the very low landslide susceptible zone.
Background: Landslides area controversial issue worldwide and cause a wide range of impacts on th... more Background: Landslides area controversial issue worldwide and cause a wide range of impacts on the socioeconomic systems of the affected community. However, empirical studies of affected environments remain inadequate for prediction and decision making. This study aims to estimate the direct impact of a massive landslide that occurred around areas with Kandyan home gardens (KHGs)in Aranayake, Sri Lanka.
Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major re... more Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming major research foci in various interrelated fields due to rapid changes in urban ecological environments. Various cities have been investigated in previous studies, and most of the findings have facilitated the introduction of proper mitigation measures to overcome the negative impact of UHI. At present, most of the mountain cities of the world have undergone rapid urban development, and this has resulted in the increasing surface UHI (SUHI) phenomenon. Hence, this study focuses on quantifying SUHI in Kandy City, the world heritage tropical mountain city of Sri Lanka, using Landsat data (1996 and 2017) based on the mean land surface temperature (LST), the difference between the fraction of impervious surfaces (IS), and the fraction of green space (GS). Additionally, we examined the relationship of LST to the green space/impervious surface fraction ratio (GS/IS fraction ratio) and the magnitude of the GS/IS fraction ratio. The SUHI intensity (SUHII) was calculated based on the temperature difference between main land use/cover categories and the temperature difference between urban-rural zones. We demarcated the rural zone based on the fraction of IS recorded, <10%, along with the urban-rural gradient zone. The result shows a SUHII increase from 3.9 • C in 1996 to 6.2 • C in 2017 along the urban-rural gradient between the urban and rural zones (10 < IS). These results relate to the rapid urban expansion of the study areas from 1996 to 2017. Most of the natural surfaces have changed to impervious surfaces, causing an increase of SUHI in Kandy City. The mean LST has a positive relationship with the fraction of IS and a negative relationship with the fraction of GS. Additionally, the GS/IS fraction ratio shows a rapid decline. Thus, the findings of this study can be considered as a proxy indicator for introducing proper landscape and urban planning for the World Heritage tropical mountain city of Kandy in Sri Lanka.
Drought is a disastrous natural phenomenon and is generally viewed as a sustained and regionally ... more Drought is a disastrous natural phenomenon and is generally viewed as a sustained and regionally extensive occurrence of below average natural water availability either in the form of rainfall, river runoff or groundwater. Droughts are defined based on different factors and their efficient management depends mainly on the correct assessment. Existing methods consider only a few factors which are not effective for drought mitigation programmes. This study assessed the vulnerability of crop production to drought using multi-scale, multi-indicator methods and some of the data were analysed during the collection of data by questionnaire survey. Yield data, rainfall data and socio – economic data were used to analyse the sensitivity, exposure and adaptive capacity. It does this by identifying differences across and within fourteen DS divisions of Jaffna to reflect the three components of vulnerability: exposure, sensitivity, and adaptive capacity. In addition overall mean vulnerability of a particular region was estimated. Jaffna’s agricultural crop drought vulnerability, presented in a map form, was classified in the following categories: very low, low, moderate, high and very high. The results of the study show that the vulnerability of crop production to drought in Jaffna district has discernible geographical and socioeconomic patterns, with Kayts DS division as high vulnerable to drought. Three factors such as very high sensitivity indices, very high exposure indices and low adaptive capacity indices are contributing for this regions’ vulnerability. Chavakachcheri division is a very lower vulnerable region. Because of its better social economic level.In addition according to the questionnaire analysis also Kayts and Velanai divisions are mostly affected by drought. Because the vulnerable regions have low socioeconomic development and are based on rain-fed agriculture. The crop vulnerability to drought can be a step towards mitigation oriented drought management and aid in reducing the impacts associated with drought.
Soil erosion is a widespread problem in Nillambe catchment and it accommodates a pulation that i... more Soil erosion is a widespread problem in Nillambe catchment and it accommodates a pulation that is mainly based on agriculture. Consequently it is important to identify the socio-economic risk in the area in order to carryout necessary mitigation measures to minimize the potential risk. This study attempts to categorize socio-economic risk levels of soil erosion. Based on USLE (Universal Soil Loss Equation), geo-spatial input data representing rainfall, soils, land slopes and land use were used to model soil erosion hazard and a selected set of socio-economic vulnerability and coping capacity indicator variables were spatially modeled based on AHP (Analytical Hierarchical Process) and the outcomes of hazard, vulnerability and coping capacity measurements were further modeled using GIS based Disaster Risk Equation to obtain the socio-economic risk index for Nillambe catchment. The study revealed that approximately 25 % of the catchment is in moderate to extremely high socio-economic risk to soil erosion. Furthermore, it indicates that the majority of such lands are covered with moderately managed tea and a slope greater than 10 % (slope of the catchment varies between 0 – 36 degrees) with a moderately high rainfall erosivity level between 16 - 27. The maps identifying the socio-economic vulnerability, coping capacity and the risk levels to soil erosion can be utilized to identify areas with different vulnerabilities and coping capacities to promote necessary mitigation actions and strengthen socio-economic capacities of the community involved which would eventually minimize the socio-economic risk for soil erosion in the area.
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Papers by ENC Perera
Lanka, landslides are considered as a disaster, and thus, scientific
communities have paid attention to monitoring and prediction of
landslide hazards. Landslide hazard zonation (LHZ) is a vital factor
for preparedness and mitigation phases in a disaster management
cycle. In the Sri Lankan contest, LHZ becomes more significant
since 20% of the total lands are vulnerable. Spatial distribution of
landslides of Sri Lanka is mainly influenced by geospatial criteria,
rainfall distribution, geology, hydrology, geomorphology, land-use,
and drainage network. However, the above factors do not equally
contribute to determining the landslide susceptibility. This study
attempted to map the landslide hazard zones in one of the tropical
hilly region: Kegalle District and weighting causative factors
rationally using statistical method in GIS environment. In this
study, causative factors were weighted and modelled to define
hazardous zones by geographical information system (GIS)-
based spatial multi criteria evaluation (SMCE). The necessary
geospatial data were obtained, processed, and converted into
a grid format. The contribution level of each factor for triggering
landslides was evaluated by the Analytical Hierarchy Process
(AHP) and modelled with the SMCE. The developed SMCE
model is at an acceptable level because the acquired consistency
ratio value is 0.074 (≤ 0.1). The developed LHZ map shows a
90% level prediction accuracy compared to previous landslides.
According to landslide hazard zonation map, 13% (227 km2) of
the entire area is a very high landslide susceptible zone, while
37% (634 km2) of the total land area has a high susceptibility
to slope failure. Moderate and low susceptible zones were 32%
(542 km2) and 12% (203 km2) respectively, and only 6% (96
km2) of the entire study area belonged to the very low landslide
susceptible zone.
Key words: drought, vulnerability, sensitivity, exposure, adaptive capacity, crop
socio-economic risk in the area in order to carryout necessary mitigation measures to minimize the potential risk. This study attempts to categorize socio-economic risk levels of soil erosion. Based on USLE (Universal Soil Loss Equation), geo-spatial input data representing rainfall, soils, land slopes and land use were used to model soil erosion hazard and a
selected set of socio-economic vulnerability and coping capacity indicator variables were spatially modeled based on AHP (Analytical Hierarchical Process) and the outcomes of
hazard, vulnerability and coping capacity measurements were further modeled using GIS
based Disaster Risk Equation to obtain the socio-economic risk index for Nillambe
catchment.
The study revealed that approximately 25 % of the catchment is in moderate to extremely high socio-economic risk to soil erosion. Furthermore, it indicates that the majority of
such lands are covered with moderately managed tea and a slope greater than 10 % (slope
of the catchment varies between 0 – 36 degrees) with a moderately high rainfall erosivity level between 16 - 27.
The maps identifying the socio-economic vulnerability, coping capacity and the risk levels to soil erosion can be utilized to identify areas with different vulnerabilities and
coping capacities to promote necessary mitigation actions and strengthen socio-economic capacities of the community involved which would eventually minimize the socio-economic risk for soil erosion in the area.
Lanka, landslides are considered as a disaster, and thus, scientific
communities have paid attention to monitoring and prediction of
landslide hazards. Landslide hazard zonation (LHZ) is a vital factor
for preparedness and mitigation phases in a disaster management
cycle. In the Sri Lankan contest, LHZ becomes more significant
since 20% of the total lands are vulnerable. Spatial distribution of
landslides of Sri Lanka is mainly influenced by geospatial criteria,
rainfall distribution, geology, hydrology, geomorphology, land-use,
and drainage network. However, the above factors do not equally
contribute to determining the landslide susceptibility. This study
attempted to map the landslide hazard zones in one of the tropical
hilly region: Kegalle District and weighting causative factors
rationally using statistical method in GIS environment. In this
study, causative factors were weighted and modelled to define
hazardous zones by geographical information system (GIS)-
based spatial multi criteria evaluation (SMCE). The necessary
geospatial data were obtained, processed, and converted into
a grid format. The contribution level of each factor for triggering
landslides was evaluated by the Analytical Hierarchy Process
(AHP) and modelled with the SMCE. The developed SMCE
model is at an acceptable level because the acquired consistency
ratio value is 0.074 (≤ 0.1). The developed LHZ map shows a
90% level prediction accuracy compared to previous landslides.
According to landslide hazard zonation map, 13% (227 km2) of
the entire area is a very high landslide susceptible zone, while
37% (634 km2) of the total land area has a high susceptibility
to slope failure. Moderate and low susceptible zones were 32%
(542 km2) and 12% (203 km2) respectively, and only 6% (96
km2) of the entire study area belonged to the very low landslide
susceptible zone.
Key words: drought, vulnerability, sensitivity, exposure, adaptive capacity, crop
socio-economic risk in the area in order to carryout necessary mitigation measures to minimize the potential risk. This study attempts to categorize socio-economic risk levels of soil erosion. Based on USLE (Universal Soil Loss Equation), geo-spatial input data representing rainfall, soils, land slopes and land use were used to model soil erosion hazard and a
selected set of socio-economic vulnerability and coping capacity indicator variables were spatially modeled based on AHP (Analytical Hierarchical Process) and the outcomes of
hazard, vulnerability and coping capacity measurements were further modeled using GIS
based Disaster Risk Equation to obtain the socio-economic risk index for Nillambe
catchment.
The study revealed that approximately 25 % of the catchment is in moderate to extremely high socio-economic risk to soil erosion. Furthermore, it indicates that the majority of
such lands are covered with moderately managed tea and a slope greater than 10 % (slope
of the catchment varies between 0 – 36 degrees) with a moderately high rainfall erosivity level between 16 - 27.
The maps identifying the socio-economic vulnerability, coping capacity and the risk levels to soil erosion can be utilized to identify areas with different vulnerabilities and
coping capacities to promote necessary mitigation actions and strengthen socio-economic capacities of the community involved which would eventually minimize the socio-economic risk for soil erosion in the area.