A08

Research Abstracts on Spatial Information ScienceCSIS DAYS 2017

Detecting Urban Wetland Landscape Change in Sri Lanka
Using Multitemporal Remote Sensing Image Data Set
Athukorala Arachchige Sumudu Darshana
Life and Environmental science; Division of Spatial Information Science
University of Tsukuba, Japan.
E-mail: <darshana12594@gmail.com>(1) Motivation： Urban wetlands are affected by bothhuman activities and climate changes. The spatio temporal transformation and seasonal inundation
determine the structure and functions of tropical wetland
ecosystems. Information on the spatial and temporalchangeability of inundation is necessary to understand andmanage these ecosystems. The western region of Sri
Lanka represents one of the most emerging growthcentrees in the country and there is an extreme pressure
on the natural environment and wetland ecosystems. SriLanka is a tropical country with tropical monsoon
climate and it belongs to Keppens´ Amclassification. The wetlands are one of the major
ecosystems in the island and it is also highly
concentrated to the western region of Sri Lanka. It
also can be seen diverse, that the human activities
influence the spatio-temporal changes of thisregion.
(2) Method： A combination of methods of environm
ental history, urban ecology and wetland science based on geographical information system (GIS) and remote sensing (RS) have been applied to the research.
Band 5 is the most important band for wetland classi
fication because they can discriminate soil moisture levels and vegetation types (Ozesmi, S.L.・Bauer, M.E，2002). Maximum Likelihood Classification was usedin mapping the study area.
(3) Result： The long term changes of this research area
show decreased (deep water and Marshland / Abandonedpaddy) and increased (built up and shallow water /sediment) and periods for dry season. Natural process ofwetland propagation has been occurring since declarationof this wetland in 1996. Human impact due toencroachments influences the marsh land. Human impact
of boundary area of this preserved area has an increasing
trend along the period of time. Endemic species inhabit
the marsh land. This is a breeding area. Human settlementof marsh land is illegal and very critical phenomenon tohave solution without delay. Based on the table 1 change
matrix, build up covered an area of 15.44 km2 in 1996:
24.47 km2 of built up had change by 2016. Agriculturalland and Sallow water/ sediments covered and area of
4.20 km2 and 6.72 km2 in 1996: 16.99 km2 and 20, 32 km2
of agriculture and shallow water had change by 2016
respectively.
(4) Data used： The main source of the imageries used in thisresearch is from the longest running Landsatprogram. The available Landsat imageries, which
cover the study area, were taken in 1996, 2006
and 2016 respectively.
 Census department data from 2001 and 2011.
(5) Acknowledgments： I would like to express thanks
to Professor Dr. Yuji Murayama, Division of Spatial
Information Science, University of Tsukuba.
(6) References：Ozesmi, S.L. and Bauer, M.E., 2002. Satellite
remote sensing of wetlands. Wetlands Ecology
and Management, 10(5), pp.381-402.

Table 1: Seven classes change matrix.
Area km2

Figure 1: Land cover and land use change ofMuthurajawela marsh and Negombo Lagoon 1996, 2006
and 2016.

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19962006

2016

Built up

15.44

19.58

24.47

Deep water

25.40

18.58

10.87

Vegetation

5.04

10.59

3.40

Agriculture

4.20

16.69

16.99

Marshland/Abandoned paddy

30.02

12.30

11.21

Mangroves/ scrubs

15.96

12.31

15.53

Shallow water / Sediment

6.72

12.73

20.32