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3.1.3 Land Cover Condition
Based on the topographic map which is issued by the National Coordinating Agency for Surveys and Mapping BAKOSURTANAL now is
Geospatial Information Agency BIG, in 1991 the land cover composition of Palu Catchment is dominated by the forest, which is covered more than 70 of total
watershed area, followed by the shrub land, and agricultural land. The forests are mainly found on the southern part of the catchment, since this area is part of the
Lore-Lindu National Reserves. The main populations were concentrated on the northern part of the catchment, which is the capital of Central Sulawesi namely
Palu City.
3.1.4 Geological Condition
The geology condition of Palu River Watershed is almost the same for the overall area. Generally, alluvial soil, innocuous intrusive rocks, metamorphosed
rocks, and sediment compose the geology structures. The mountainous areas generally consist of acid rock such as gneisses,
schist and granite possessing sensitive to the erosion. The other rock formation, lacustrine formation can be found on the east side of the study area. On the west
side, alluvium rock that derived from metamorphosed rocks and granite can be found.
3.1.5 Demography Condition
Demography is important aspect that leads to land cover change in a catchment area. Most of the changes of the land use are influences by population.
Increasing of the human population means that the needs to the space are increasing also. Palu Catchment with wit area about 3,050 km
2
consists of 13 sub-districts that intersect on the whole catchment area. Where mostly of the
population works as a farmer, which is are utilize a space to farming. Based on the statistical bureau, the total population that settled in those 13 sub-districts is about
187,535 or 88,763 of households. The demography conditions of study area are shows in Table 3.1.
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Table 3.1 Population on sub-district level across the sub-basin
CODE Subdistrict
Male Female
Householder
7210110 Dolo 10,101
10,116 5,046
7210090 Dolo barat 6,145
7,184 3,423
7210080 Dolo selatan 8,641
7,976 4,070
7210030 Kulawi 7,468
6,991 3,691
7210020 Kulawi selatan 4,576
4,529 2,233
7210040 Lindu 2,398
2,359 1,174
7210130 Marawola 10,207
9,815 4,188
7210140 Marawola barat 5,423
5,461 2,883
7210060 Palolo 13,838
12,840 7,112
7210120 Sigi biromaru 19,577
19,163 10,270
7271010 Palu barat 44,179
44,194 19,782
7271020 Palu selatan 50,041
51,766 22,658
7271040 Lore utara 4,941
4,321 2,233
Jumlah
187,535 186,715
88,763
Source: National Statistical Bureau, 2009
3.2 Data Availability
3.2.1 Raster and Vector Datasets
Time series of satellite images of Landsat were used to estimate the land cover changes. Three different acquiring times of Landsat imagery were used to
analyze the land cover changes. The imageries were acquired in 1990, 2001, 2007 and 2009. The imageries data are available to download freely at U.S. Department
of the Interiors U.S. Geological survey USGS at the global visualization viewer website
http:glovis.usgs.gov . The images consist of eight electromagnetic
channels including visible, near infrared, middle infrared, thermal, middle thermal 2 and panchromatic, except the images on 1990 that only have five
electromagnetic channels. Besides of Landsat images, other raster data were used for analysis. The
elevation data of SRTM Shuttle Radar Terrain Mission were obtained from USGS. It has approximately 90 meters of spatial accuracy. The elevation data
were used to delineate the watershed on the study site.
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