The accuracy of LULC change along with the overall accuracy and the Khat coefficient are summarized in Table 14.3. This table shows that the user’s accuracy of individual category ranged from 50 % to 100 % and the producer’s accuracy ranged from 68 % to 100 %. The overall accuracy of image classification was 81.93 % and the kappa coefficient was 0.776. The kappa coefficients indicated that the classified images showed moderate classification performance or moderate agreement.
Table 14.3 Accuracy assessment for supervised classification of land use/land cover (LULC)
The distribution of LULC and its changes for 1990, 2000, and 2010 are summarized in Table 14.4. The spatial distribution of LULC over time is clearly visible in Fig. 14.2. The dynamic patterns of LULC change are also represented in Fig. 14.3. Throughout the period of study, several LULC categories had increased such as settlement, agricultural land, and mixed plantation. For example, settlement areas have increased from 1,150.29 ha in 1990 to 1,530.51 ha in 2000 and 1,587.48 ha in 2010. Mixed plantation areas have also shown an increase of 36.60 % (period 1990-2000) and 3.44 % (period 2000-2010). On the other hand, forest decreased from 20,297.58 ha in 1990 to 16,989.12 ha in 2000, and to 15,536.66 ha in 2010.
Table 14.5 and Fig. 14.4 show a clear pattern of changes characterized by potential land degradation levels. There was an increase in the total area with very high levels of land degradation, namely, 19.55 % in the period of 19902000 and 10.17 % in the period of 2000-2010. At the same time, the area with very low level of land degradation decreased by —5.70 % and —16.54 % in 1990-2000 and 2000-2010, respectively. Batang Merao Watershed also exhibited potential land degradation as the mean annual land degradation increased from 128.03 tons ha—1 year—1 in 1990 to 144.68 tons ha—1 year—1 in 2000, and to 194.14 tons ha—1 year—1 in 2010.