40
Table 4.2 Summary of land cover changes in Palu Catchment between period of 1990-2001 and 2001-2009.
CLASS 1990-2001
2001-2009 CL. 1 Agricultural Land
139.21 339.94
CL. 2 Barren Land
1.93 0.32
CL. 3 Build Up area
8.12 7.76
CL. 4 Forest
‐130.59 ‐250.94
CL. 5 Shrub Land
‐19.05 ‐97.79
CL. 6 Water Body
0.17 0.32
4.1.3 Change Detection
Statistical analyze was used to assess the land cover changes between 1990-2009 periods. It aimed to identify the changes in probability distribution of
land cover classes whether it has changed or unchanged within given time period. An 30 x 30 meters of Landsat images were used for the change detection process.
Three multi temporal satellite imagery producing two change statistics reports, first for changes between 1990 to 2001 and the last for changes on period of 2001
to 2009. It presents the changes of land covers in Palu catchment in last 20 years. Table 4.3 – 4.4 presents the changes of land cover class to another class. The
unchanged classes are shows on the major diagonal of these matrixes. Table 4.3 Change detection statistics report on 1990 – 2001 in km
2
CLASS CL. 1
AG CL. 2
BL CL. 3
BU CL. 4 F
CL. 5 SL
CL. 6 W
Total 1990
CL. 1 Agricultural Land 310.46
0.00 1.54
1.54 9.76
3.60 326.91
CL. 2 Barren Land 0.11
47.18 0.23
0.00 0.00
0.13 47.65
CL. 3 Build Up area 0.00
0.00 42.82
0.00 0.00
0.0 42.82
CL. 4 Forest 23.96
0.00 0.14
2,040.78 109.66
0.37 2174.91
CL. 5 Shrub Land 127.31
2.41 6.36
1.22 273.92
1.77 412.99
CL. 6 Water Body 4.26
0.00 0.10
0.13 1.15
39.26 44.90
Total 2001 466.11
49.59 51.18
2,043.66 394.51
45.35 3,050.16
Table 4.4 Change detection statistics report on 2001 – 2009 in km
2
CLASS CL. 1
AG CL. 2
BL CL. 3
BU CL. 4 F
CL. 5 SL
CL. 6 W
Total 2001
CL. 1 Agricultural Land 450.02
0.00 4.16
0.63 7.50
3.80 466.11
CL. 2 Barren Land 0.00
49.33 0.10
0.16 0.00
0.00 49.59
CL. 3 Build Up area 0.0
0.00 50.84
0.00 0.00
0.00 50.84
CL. 4 Forest 169.55
0.58 0.14
1,791.68 81.09
0.76 2043.8
CL. 5 Shrub Land 181.86
0.00 3.39
0.55 207.52
1.38 394.7
CL. 6 Water Body 4.67
0.00 0.28
0.19 0.57
39.43 45.14
Total 2009 806.10
49.91 58.91
1,793.21 296.68
45.38 3,050.16
41
Table 4.3 – 4.4 demonstrate the land cover changes by providing information “initial state” into a “new state” to the respective period. Mostly, the
forest cover decreased due to the new agricultural land development. During the period of 1990 to 2009, is about 250 km
2
of forest cover on Palu catchment has been converted into agricultural and other land-use type such as urban area or
settlement. Based on Table 4.3, the statistics report shows that between 1990 and
2001, about 134 km
2
of forest cover has been converted into other land use type such as agricultural land, shifting cultivation, and also use as settlement. During
this period, agricultural land has increased by 132 km
2
from previous state with only 327 km
2
in 1990 become 466 km
2
on 2001. In addition of forest cover, shrub land also decreased during this period. About 127 km
2
of shrub land has been converted into agricultural land and about 11.5 km
2
of shrub land has been converted into other land use.
Between 2001 and 2009 the statistics report shows that 250 km
2
of forest cover has been converted; 169 km
2
into agricultural land and 82 km
2
into shrub land. On the other hand, shrub land had also change. About 182 km
2
have changed into agricultural land, 3.5 km
2
into build up area, and 1.4 km
2
into water or marshy land.
Figure 4.6 Land use on the Palu catchment
