POLA SPASIAL DAN TEMPORAL DAERAH SASARAN BANJIR DI DAERAH KHUSUS IBUKOTA JAKARTA

Mangapul Parlindungan T., Drs.,MS., Prof. Dr. Sutikno.

2014 | Disertasi | S3 Geografi

Penelitian daerah sasaran banjir ini dilaksanakan di DKI Jakarta. Penelitian ini bertujuan untuk: (1) mengkaji persebaran keruangan daerah sasaran banjir potensial dan aktual; (2) mengkaji karakteristik banjir mencakup luas, kedalaman, dan lama banjir; dan (3) mengkaji pola persebaran spasial dan temporal daerah sasaran banjir aktual. Banjir dikaji dari bidang ilmu geografi dengan menggunakan pendekatan keruangan. Penelitian lokasi, persebaran, kedalaman dan lama banjir dilakukan dengan pendekatan keruangan daerah banjir pada satuan bentuklahan sebagai satuan analisis. Dalam penelitian ini bentuklahan di daratan DKI Jakarta mempunyai keragaman, demikian juga pola spasial dan temporal karakteristik banjir aktual dan potensialnya. Bentuklahan di DKI Jakarta sebagian besar telah digunakan untuk lahan terbangun seperti permukiman dan fasilitasnya, sehingga mempengaruhi pola sebaran daerah sasaran banjirnya. Pengumpulan data kondisi fisik bentuklahan diperoleh melalui interpretasi Peta Topografi, Peta Geologi, dan Peta RBI. Data daerah banjir (luas, kedalaman dan lama) diperoleh dari survei dan data kejadian banjir diperoleh dari Kimpraswil (PU) DKI Jakarta, data hujan diperoleh dari BMKG dan data penggunaan lahan didapat dari BPN DKI Jakarta tahun 1996,2002 dan 2007. Analisis persebaran banjir dan sasarannya dilakukan secara spasial dan temporal dengan menggunakan alat bantu Sistem Informasi Geografis (SIG), sedangkan analisis data sosial yakni penduduk dilakukan secara deskriptif. Metode penelitian berupa pendekatan keruangan daerah banjir di bentuklahan dengan menggunakan survei pragmatik. Dalam penelitian ini bentuklahan sebagai hasil dari survei analitik dipadukan dengan data penggunaan lahan sebagai hasil survei sintetik untuk mengkaji daerah sasaran banjir di DKI Jakarta. Sampel menggunakan purposif. Peta bentuklahan disusun berdasarkan data relief (ketinggian dan lereng), struktur dan material batuan, dan proses; kemudian ditumpang susunkan lagi dengan peta banjir, maka dihasilkan peta daerah sasaran banjir pada skala 1:50.000. Analisis deskriptif digunakan untuk mengetahui bentuklahan keruangan banjir. Hasil penelitian menunjukkan bahwa 1) daerah sasaran banjir pontesial tidak selalu diikuti oleh banjir aktual. Daerah sasaran banjir aktual di utara, barat dan timur DKI Jakarta sedangkan daerah sasaran banjir potensial di lereng datar, landai hingga agak terjal terdapat di kipas aluvial, dataran aluvial, beting gisik dan dataran aluvial pantai; 2) ada perbedaan karakteristik banjir di beting gisik, dataran aluvial pantai, dataran alluvial dan kipas alluvial; dan 3) pola banjir di dataran aluvial, dan dataran aluvial pantai adalah tidak merata; dan di beting gisik adalah merata dan mengelompok sedangkan di kipas aluvial berpola merata. Berdasarkan hasil penelitian dapat disimpulkan 1) daerah sasaran banjir potensial tidak selalu diikuti oleh banjir aktual; 2) ada perbedaan karakteristik banjir; dan 3) pola persebaran spasial dan temporal daerah sasaran banjir aktual berbeda di antara bentuklahan yang satu dengan yang lain.

The study of flood prone area was conducted in DKI Jakarta Province, Indonesia. The aim of this research are: 1) to study the spatial distribution of potential and actual of flood prone area; 2) to study the characteristic of flood, such as the area, the depth and the duration; and 3) to study the distribution pattern of the actual flood prone area; The flood was studied from the geographic point of view using spatial approach, while the study of the location, the distribution, the depth and the duration of flooding was conducted using spatial approach flood area and emphasize on the detailed landform unit as analysis unit. In this study the landforms in DKI Jakarta have been a diversity, as well as spatial and temporal pattern of the actual and potential flood prone areas. Landform at DKI Jakarta has been largely used as built up area for settlement and it facilities, thus affecting the distribution pattern of flooding area. The collection of the physical condition of landform in DKI Jakarta data prone were conducted through interpretation of the topographic map / RBI map and geological map. The flood data were obtained by survey and secondary data from Kimpraswil (Public Work) of DKI Jakarta Province for 3 years (1996, 2002, and 2007). Data of rainfall were obtained from BMKG and land use data were obtained from BPN DKI Jakarta. The analysis of the causal factors and distribution of flooding was made spatially and temporally using geographic information system, while the analysis of the social data as population and distribution were carried out descriptively. This study used survey method with a pragmatic approach. In this study landform as result from the analytical survey was settlement land use as result the synthetic survey. The primary data consist of landform, and the flood characteristic obtained by survey. The samples were using purposive sampling. Landform map was composed by relief, structure and material stone, and process data Landform map was overlay with flood map the flood prone area in DKI Jakarta in scale 1:50,000 to show. Descriptive analysis was used the spatial distribute of the flood prone area The results of the study show that: 1) potential flood prone area is not always followed by the actual flood. Actual of flood prone area in the north, west and east of Jakarta lowland both in beach ridge, coastal alluvial plain, and alluvial plain; while the flood potential area on the slope is found flat and steep at alluvial fan, alluvial plain, beach ridge, and coastal alluvial plain in DKI Jakarta; 2) there are differences flood characteristics in beach ridge, coastal alluvial plain, alluvial plain and alluvial fan; and 3) the pattern of flooding in coastal alluvial plain and alluvial plain is random pattern; and in beach ridge is dispersed and clustered pattern; in alluvial fan is dispersed pattern. Based on the result of study can be concluded that 1) potential flood prone is not always followed by actual flood prone area; and 2) flood area is different from its characteristic, and 3) spatial distribution pattern and temporal at actual flood prone area is different from landform each other.

Kata Kunci : bentuklahan, karakteristik banjir, daerah sasaran banjir, DKI Jakarta