Sains Malaysiana 38(5)(2009): 655–664

Land Use and Deforestation Modelling of River Catchments

in Klang Valley, Malaysia

(Pemodelan Guna Tanah dan Nyahutan Kawasan Tadahan  di Sekitar Lembah Klang, Malaysia)

Othman Jaafar

Dept. of Civil Engineering, Faculty of Engineering

Universiti Kebangsaan Malaysia

43600 Bangi, Selangor D.E., Malaysia

S.A. Sharifah Mastura*

School of Social, Development and Environmental Science

Universiti Kebangsaan Malaysia

43600 Bangi, Selangor D.E., Malaysia

Alias Mohd Sood

Department of Forest Production, Faculty of Forestry

University Putra Malaysia 43400 UPM Serdang

Selangor D.E., Malaysia

Diserahkan: 23 Oktober 2008 / Diterima: 22 Disember 2008

ABSTRACT

This paper presents analyses of the land use and land cover change of the Langat-Dengkil sub-catchment and the deforestation of the Klang-Langat catchment in the context of water resource availability. The Langat-Dengkil sub-catchment lies within the upper catchment of Klang-Langat. For both catchments, the landsat TM and ETM satellite imageries, ERDAS Imagine 8.4 and ArcView/Arc GIS softwares were used to detect spatial and temporal changes in land use and deforestation between the year 1990 and 2001. For Klang-Langat deforestation, CLUE model was used to forecast change up to year 2020 using two set scenarios. Langat-Dengkil sub-catchments experienced multiple changes of land use and land cover at varying quantum for the years 1990 and 2001. It was found that forest land and agriculture were reduced by 9.5% (4,303 ha) and 17.3% (11,598 ha), respectively. During the same period (1990 to 2001), urbanised land has increased by nearly six folds (18,860 ha). Land use change matrix has indicated that the increase of urbanised area was at the expense of agriculture and forest land. For Klang-Langat catchment, the deforestation for 1989 – 1999 were also serious. About 36,351 ha were deforested including 12,244 ha of Permanent Forest Reserve. Deforestation prone areas are located within 1000 m from major access, 2000 m from town, confined to altitude less than 100 m and within slope of less than 5^o. Projection for year 2020 has predicted that if the Permanent Forest Reserve is strictly protected, deforestation will be reduced to 22,340 ha or 22%. Otherwise, it will be heavily deforested at 50,851 ha or 50%. Both results showed that the accelerated land use change and deforestation can only be mitigated through stringent management of land conversion, and as for the forest, it has to be through the total protection by law. This can be achieved by strengthening the Permanent Forest Reserve law and the commitment in adopting sustainable resource policy.

Keywords: Deforestation; land use and land cover; land use modelling; river catchment

ABSTRAK

Kertas ini membentangkan analisis perubahan guna dan litupan tanah sub tadahan Langat-Dengkil dan nyahutan di kawasan tadahan Klang-Langat dalam kontek penghasilan sumber air. Sub tadahan Langat-Dengkil terletak di bahagian hulu tadahan Klang-Langat. Bagi kedua-dua kawasan kajian tersebut, imej satelit Landsat TM dan ETM, perisian ERDAS Imagine 8.4 dan ArcView/Arc GIS digunakan untuk mengesan perubahan masa dan ruang guna tanah dan nyahutan antara tahun 1990 dan 2001. Untuk kawasan tadahan Klang-Langat, model CLUE digunakan untuk meramal perubahan hingga tahun 2020 bagi dua scenario. Sub tadahan Langat-Dengkil mengalami pelbagai perubahan guna dan litupan tanah pada kadar yang berlainan. Dalam tempoh kajian, didapati tanah hutan dan pertanian telah berkurangan masing-masing sebanyak 9.5% (4,303 ha) dan 17.3% (11,598 ha). Dalam masa yang sama tanah perbandaran bertambah hampir enam kali ganda kepada 18,860 ha. Matrik perubahan guna tanah menunjukkan kebanyakan peningkatan kawasan perbandaran adalah daripada pertanian dan hutan. Untuk tadahan Klang-Langat, nyahutan antara tahun 1889 hingga 1999 adalah serius. Kira-kira 36,351 ha telah dinyahutan termasuk 12,244 ha hutan rizab kekal. Kawasan yang kerap dinyahutan adalah yang terletak dalam lingkungan 1000 m dari jalan raya, 2000 m dari Bandar, altitud kurang daripada 100 m dan cerun kurang daripada 5%. Unjuran bagi tahun 2020 meramalkan jika hutan rizab kekal diurus rapi, kawasan yang dinyahhutan akan berkurangan kepada 22,340 ha atau 22%. Jika tidak nyahhutan akan melibatkan 50,851 ha atau 50%. Kedua-dua keputusan ini menunjukkan perubahan guna tanah percepat dan nyahutan hanya boleh dimitigasi melalui pengurusan ketat perubahan status tanah dan perlindungan undang-undang bagi hutan rizab kekal. Ini boleh dicapai dengan menguatkan lagi perundangan berkait dengan rizab hutan kekal dan komitmen dalam menerapkan polisi kelastarian sumber.

Kata kunci: Guna dan litupan tanah; kawasan tadahan; nyahutan; pemodelan guna tanah

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*Pengarang untuk surat-menyurat; email: sharifah@eoc.ukm.my