Abstract:
Even though humans are a part of the environment, possibilism has influenced them to
make many changes within the concept of sustalnability. This has created many adverse
effects on mankind such as climate change. Therefore, correct decisions should be made
when interacting with the environment while following the roots of sustainable
development. Geographic Information Systems (GIS) are a tool of decision making
used in many fields. This study is focused on the application of interpolation techniques
when monitoring ground water quality in spatial analysis. This case study is based on
the coastal area within 2 km buffer from the coastline to the inland of Panadura DS
Division, using 20 selected wells as an access to ground water. pH value and Electric
Conductivity (Ec) were used as parameters for the study to determine the most
appropriate technique of interpolation. The methodology of the study is a combination
of statistical and spatial analysis where extract values for two known points in the study
area. Based on five interpolation techniques of Kriging, Inverse Distance Weighted
Method (IDW), Natural Neighbour, SP line, Topo to Raster, values have been extracted
for two known points separately. Where the technique got exact or the most
approximates values was determined as the most suitable for the water quality analysis.
According to the analysis out of five interpolation techniques SP line has given the most
appropriate values for the known two points where as known pH value of point 03 and
08 is 8.5 and 7.3 respectively and extracted pH values of the same points are 8.33 and
7.42 respectively. Also known Ec values of the two known points are 149 and 681
respectively and extracted Ec values are 148.99 and 681 respectively. All the other
techniques have extracted values with high deviation from the known values. Therefore,
this study has pointed out that spline can be used as the most appropriate interpolation
technique in water quality analysis.
