Articles

Model Sebaran Penurunan Tanah di Wilayah Pesisir Semarang Ismanto, Aris; Wirasatriya, Anindya; Helmi, Muhammad; Hartoko, Agus; Prayogi, Prayogi
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 14, No 4 (2009): Jurnal Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

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Banjir rob merupakan fenomena bencana yang melanda daerah pesisir Kota Semarang sejak 30 tahun terakhir yang sampai saat ini belum dapat tertanggulangi dan bahkan semakin meluas. Penyebab utama timbulnya banjir rob adalah terjadinya penurunan tanah yang dapat mencapai + 15 cm/tahun. Untuk mengatasi masalah tersebut diperlukan informasi yang akurat mengenai penurunan tanah yang terjadi, terutama mengenai zona sebaran penurunan tanah yang dikaitkan dengan penggunaan lahan. Penelitian ini bertujuan untuk mengetahui sebaran spasial Penurunan Tanah di Pesisir Kota Semarang sehingga diharapkan bisa menjadi acuan bagi Pemerintah Kota Semarang dalam rangka penanggulangan banjir rob. Data spot height peta RBI dan hasil pengukuran lapangan dengan menggunakan DGPS digunakan dalam penelitian ini. Laju penurunan tanah dihitung berdasarkan perbedaan ketinggian wilayah pada saat ini dengan ketinggian wilayah pada spot height peta RBI, tahun 2001. Data citra satelit IKONOS yang didownload dari Google Earth digunakan untuk mengetahui penggunaan lahan eksisting. Pengolahan data dilakukan berbasis Sistem Informasi Geografis dengan menggunakan tool Spatial Analyst pada software Arc GIS 9.1. Hasil penelitian memberikan gambaran bahwa Kota Semarang  mempunyai luas 17.073,23 ha dan laju penurunan tanah <1 cm/thn terjadi seluas 3.355,93 ha (19,7%); 1,1-4 cm/thn seluas 6.515,77 ha (38,2%), 4,1-8 cm/thn seluas 5.048,51 (29,6%); 8,1-12 cm/thn seluas 1.685,6 ha (9,9%); dan 12,1-15 cm/thn seluas 467,45 ha (2,7%). Penurunan tanah tersebut menyebar secara spasial di Kecamatan Genuk (8.1-15 cm/th) dan Semarang Utara serta sebagian Semarang Barat (4.1-12 cm/th). Kecamatan Tugu memiliki tingkat penuruan tanah yang relatif rendah, yaitu kurang dari 1 cm/th. Kata kunci: Semarang, Banjir Rob, Penurunan tanah, Since the last 30 years, Tidal flood hazard in the Semarang Coastal Area has never been clearly solved and even getting worse time to time. Most possible cause of this tidal flooding is believed land subsidence which reaches up to 15cm/year. Accurate information of land subsidence distribution, in relation to land use, is therefore needed to ease this flooding problem. The study is aimed to identify spatial distribution of land subsidence in Semarang coastal area which hopefully can be used as scientific reference for Semarang City Government on solving this tidal flooding problem. A spot height data of Indonesian Land Surface (RBI) map was used as the main information of the study collaborated with comprehensive field measurement using DGPS. Land subsidence rate was then calculated as differences between actual height of the location with spot height indicated on 2001 RBI map. An IKONOS satellite image of the same spot was then used to determine existing land use of the area. The dara were processed using a GIS-based analysis ‘Spatial Analyst’ of ArcGIS 9.1. The result showed that among total of 17.073,23 ha of the study area 3.355,93 ha (19,7%) has rate of land subsidence of <1cm/year, 6.515,77 ha (38,2%) of 1.14cm/year, 5.048,51 ha (29,6%) of 4.1-8cm/year, 1.685,6 ha (9,9%) of 8.1-12cm/year and 467,45 ha (2,7%) of 12.1-15cm/year. Spatial distribution of land subsidence in Semarang is spreading in Genuk (8.1-15 cm/th), North Semarang and West Semarang District (4.1-12 cm/th). Land subsidence in Tugu District is relatively lower, that is less then 1 cm/th. Key words: Semarang, tidal flood, land subsidence,
Zonasi Ekosistem Alami dengan Pendekatan Ekologi Lanskap Menggunakan Pemodelan Spasial Berbasis Sel di Pulau Karimunjawa dan Kemujan, Kabupaten Jepara, Jawa Tengah Helmi, Muhammad
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 12, No 3 (2007): Jurnal Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

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Abstract

Artikel ini difokuskan pada pendekatan ekologi lanskap dan pemodelan spasial berbasis sel untuk penyusunan zonasi ekosistem alami di Pulau Karimunjawa dan Kemujan. Zonasi ekosistem alami pada penelitian ini dilakukan pada 5 (lima) ekosistem yang terdiri dari terumbu karang, padang lamun, mangrove, hutan pantai dan hutan tropis dataran rendah. Karimunjawa dan Kemujan adalah dua pulau kecil yang berpenghuni dan terletak besebelahan.di dalam kawasan Taman Nasional Karimunjawa. Ekologi lanskap merupakan konsep yang mengintegrasikan aspek ekologi dan aspek spasial. Kondisi lanskap yang kompleks di pulau ini dapat disederhanakan dan direpresentasikan sebagai layer-layer tematik, diintegrasi menggunakan pemodelan spasial. Cell based modeling adalah pemodelan data spasial yang berbasis raster, sel atau piksel yang merepresentasikan area sebagai obyek yang spesifik. Kondisi ekologi lanskap pulau Karimunjawa dan kemujan direpresentasikan dalam sel dengan resolusi 10m x 10m dan dianalisis menggunakan teknik pemodelan topografi, hidrologi dan pembobotan untuk menyusun zonasi. Data spasial lanskap ekosistem alami diekstrak dari satelit penginderaan jauh Terra/ASTER, peta tematik dan survei. Hasilnya adalah zona konservasi yang terdiri dari subzona preservasi, sempadan (sempadan sungai, pantai dan mata air), rehabilitasi, situs bersejarah, pemanfaatan tradisional dan sub zona alur pelayaran di perairan Pulau Karimunjawa dan Kemujan. Kata kunci: Ekosistem alami, ekologi lanskap, pemodelan spasial berbasis sel.  This article is focused to landscape ecology approach and cell based modeling for the natural ecosystem zonation in Karimunjawa and Kemujan. Natural Ecosystem zonation on this research is focused on five natural ecosystems, such as coral reef, sea weed, mangrove, coastal forest and low land tropical forest. Karimunjawa and Kemujan are two populated small island neighbors in Karimunjawa National Park, Central Java. Landscape ecology is an integrated concept of ecology and spatial aspect that can be used to design natural ecosystem zonation. A complex landscape condition in these islands can be simplified and represent as thematic layers, integrate and manage them using spatial modeling. Cell based modeling is spatial modeling data processing base on raster, cells or pixel that represent an area with specific object. Landscape ecology condition of Karimunjawa and Kemujan Islands is represent to 10m x 10m resolution of cell  and analyst them using modeling techniques, such as topography, hydrology and weighted to design zonation. Landscape ecology of natural ecosystem spatial data are extracted from Terra/ASTER remote sensing satellite system, thematic map and survey. The result is conservation zone that consist of sub zones include  preservation, protected areas (river and beach green belt and water spring), rehabilitation, historical/religious site areas, traditional use and sea lenes in Karimunjawa and Kemujan coastal area. Key words: Natural ecosystem, landscape ecology, cell based modeling
Analisis Respon Spektral dan Ekstraksi Nilai Spektral Terumbu Karang Pada Citra Digital Multispektral Satelit ALOS-AVNIR di Perairan Gugus Pulau Pari, Kepulauan Seribu, Jakarta. Helmi, Muhammad; Hartoko, Agus; S, Herkiki; Munasik, Munasik; Wouthuyzen, S
BULETIN OSEANOGRAFI MARINA Vol 1, No 1 (2011): Vol 1, No.1, Oktober 2011
Publisher : BULETIN OSEANOGRAFI MARINA

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Abstract Coral reef and other coastal ecosystem map are very important spatial data to provide for many coastal management and planning purposes in Indonesia. Pari Islets of Thousand Islands in the northern coast of Jakarta has great variation on complex coastal ecosystem, such as beach forest, mangrove, coral reefs and seagrass. These rather large shallow and clear water islets could be ideal for satellite image spectral-respond study. The study aimed to asses spectral respond and spectral value of coral reef extraction on ALOS-AVNIR multispectral-satellite image in Pari Islets of Thousand Islands, Jakarta. THSI 4-band multispectral satellite image dated 30 April 2008 (JAXA, 2008) with 10 m spatial resolution. Ground survey was conducted in 85 sampling points between June-July 2009. A set of image processing method including geometric correction, atmospheric calibration (enhanced dark pixel correction), water column correction, Lyzenga transform, Hue Saturation Intensity (HSI) transform, Principle Component 1, scattergram analysis, spectral comparison, was applied for the multispectral image analysis, accompanied by   a Line Intercept Transect (LIT) and Manta-taw field survey for the coral reef study. The result showed that coral reef covers area in Pari islets were 249.9 ha (26.5%), seagrass 313.6 ha (33.3%) and shallow water sand 378.9 ha (40.2%).  Spectral characteristic of green and red band were much better on differentiating between coral reef and other shallow water substrate compared to the other bands. Visually coral reef identification on HSI transformed image much easier compared to on Lyzenga transformed image. The map accuracy on HSI (88.1%) also higher than Lyzenga (77.3%). Spectral values of coral reef on scattergram were clumped only on specific location and easily differentiated from other shallow water substrates, and so coral reef patch on ALOS-AVNIR satellite image could be extracted directly from the scattergram.   Key Word: Spectral respond, Coral reef, ALOS-AVNIR, Multispectral      
ANALISA SPASIAL DINAMIKA MORFOMETRI WADUK MENGGUNAKAN DATA SATELIT MULTI TEMPORAL DI WADUK RAWA PENING PROVINSI JAWA TENGAH Hardini, Adiasti Rizqi; Helmi, Muhammad; Sasmito, Bandi
Jurnal Geodesi Undip Volume 1, Nomor 1, Tahun 2012
Publisher : Jurnal Geodesi Undip

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Waduk Rawa Pening berada di antara jalan negara Semarang – Salatiga - Surakarta dan jalan Kabupaten antara Salatiga – Ambarawa yang terletak diantara jalan negara Semarang – Magelang – Yogyakarta, 32 km ke arah selatan dari kota Semarang dan 10 km ke arah utara dari kota Salatiga. Waduk Rawa Pening mempunyai peranan yang cukup penting sebagai pembangkit listrik tenaga air, bertani eceng gondok dan beternak ikan. Pertumbuhan eceng gondok yang semakin meningkat dari tahun ke tahun mengakibatkan perubahan morfometri waduk dan perubahan tutupan lahan disekitar Waduk Rawa Pening. Penelitian ini menggunakan Peta Topografi skala 1:50.000 lembar Ambarawa no helai 47/XL-D, data citra satelit landsat TM 5 tahun 1990, landsat 7 ETM+ tahun 2000, ALOS AVNIR-2 tahun 2009 dan dilakukan dengan metode penginderaan jauh yaitu interpretasi manual untuk memperoleh peta tutupan lahan. Tujuan penelitian ini adalah mengkaji dinamika morfometri Waduk Rawa Pening Provinsi Jawa Tengah dalam periode ±10 tahun dimulai dari tahun 1982 sampai dengan tahun 2009 dan mengkaji dinamika perubahan pola tutupan lahan di area sekitar Waduk Rawa Pening Provinsi Jawa Tengah. Hasil penelitian menunjukan bahwa tahun 1982-1990 perubahan luas waduk sebesar 1051,85 Ha dan pola perubahn tutupan lahan yang terjadi yaitu perubahan sawah irigasi menjadi sawah dan permukiman menjadi air, pada tahun 1990-2000 perubahan luas waduk sebesar 305,24 Ha dan pola perubahan tutupan lahan yang terjadi yaitu perubahan air waduk menjadi sawah irigasi.serta tahun 2000-2009 perubahan luas waduk sebesar 392,97 Ha dan pola perubahan tutupan lahan yang terjadi yaitu perubahan air waduk menjadi sawah irigasi.
PEMODELAN SPASIAL ALIRAN PERMUKAAN MENGGUNAKAN DATA SATELIT TERRA ASTER-GDEM DI DAERAH TANGKAPAN HUJAN WADUK RAWA PENING PROVINSI JAWA TENGAH Asih, Tika Murni; Helmi, Muhammad; Sasmito, Bandi
Jurnal Geodesi Undip Volume 1, Nomor 1, Tahun 2012
Publisher : Jurnal Geodesi Undip

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Waduk Rawa Pening merupakan salah satu kawasan prioritas di Jawa Tengah dan memiliki keunggulan komparatif yang tidak dimiliki oleh kawasan lainnya,sehingga perlu didayagunakan secara optimal dan berkelanjutan. Kondisi Waduk Rawa Pening saat ini mengalami penurunan dalam hal daya dukung dan fungsi utama sebagai akibat sedimentasi dan pendangkalan. Penelitian ini bertujuan untuk mengetahui pola aliran permukaan dan pengaruh penggunaan lahan di daerah tangkapan hujan yang aliran airnya masuk ke dalam Waduk Rawa Pening. Penelitian ini dilakukan dengan metode penginderaan jauh yaitu dengan interpretasi citra satelit ALOS AVNIR-2 dan citra satelit Landsat 7 ETM+  untuk memperoleh peta penggunaan lahan tahun 2009. Pemetaan daerah tangkapan hujan dalam penelitian ini diperoleh dari hasil pengolahan data ASTER-GDEM produk satelit Terra. Berdasarkan daerah tangkapan hujan tersebut kemudian dilakukan analisa komposisi penggunaan lahan yang ada di dalamnya. Hasil penelitian menunjukkan bahwa pola aliran yang terbentuk di daerah tangkapan hujan Waduk Rawa Pening adalah pola aliran yang menyerupai percabangan pohon (dendritic). Berdasarkan analisa penggunaan lahan yang telah dilakukan pada 25 daerah tangkapan hujan, ada 4 daerah tangkapan hujan yang mengalami kerusakan, yaitu Gajahbarang, Panjang Timur, Parat Kidul dan Tranah. Empat daerah tangkapan hujan ini memiliki persentase hutan kurang dari 30%, sehingga dikatakan kondisi lahannya sangat buruk. Kata kunci : ASTER-GDEM, Aliran Permukaan, Daerah Tangkapan Hujan
STUDI KESESUAIAN DAN DAYA DUKUNG KAWASAN UNTUK REKREASI PANTAI DI PANTAI PANJANG KOTA BENGKULU Nugraha, Himavan Prathista; Indarjo, Agus; Helmi, Muhammad
Journal of Marine Research Vol 2, No 2 (2013) : Journal of Marine Research
Publisher : Journal of Marine Research

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resort in the Panjang Beach area. One form of the beach tourism is the beach recreation activities. However, in its efforts to the development of tourism in Panjang Beach needed to be identified and approaches the problems first. The most fundamental and the goal of this research is to conduct a study on the level of suitability and carrying capacity of the Panjang Beach coast primarily for recreational activities. Research carried out by field observations (collecting primary data and secondary data) for 2 months in July 2012 until August 2012 at the Panjang Beach city of Bengkulu, which is divided into seven-point sampling locations from the south up to the north shore. Collecting primary data consist of physics and chemistry sea water data and suitability parameters of beach recreation, such as type of beach, width of the beach, slope of the beach, brightness of sea water, current velocity, water depth, water base material, beach land cover, presence of harmful organism and availability of fresh water. The method used to analyze the results of the research is descriptive method with the help of Tourism Suitability Index analysis and the carrying capacity of Regions that generate value and suitability of the tourist carrying capacity. Based on the results obtained from the calculation of tourism suitability index for coastal recreation activities are mostly above 80%. This indicates that the coastal areas of Bengkulu City, Panjang Beach classified in the category of Highly Suitable (S1) for coastal recreation activities. While the value Capability Area of the Panjang Beach approximately 42.045 people per day.
Kajian Kerentanan Tsunami Menggunakan Metode Sistem Informasi Geografi di Kabupaten Bantul, Daerah Istimewa Yogyakarta Mardiyanto, Bangun; Rochaddi, Baskoro; Helmi, Muhammad
Journal of Marine Research Vol 2, No 1 (2013): Journal of Marine Research
Publisher : Journal of Marine Research

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Indonesian archipelago directly opposite to the subduction zone between the Indo-Australian plate with the Eurasian plate. Based on plate movements, earthquakes are common in the Indian Ocean. As a result, the southern part of Java Island is very prone to earthquakes. If earthquakes occur beneath the sea and vertical fracture occurs, it will cause a tsunami. The purpose of this research is to create a map of vulnerability to tsunamis in the region peisir Bantul, Yogyakarta using Geographic Information Systems technology (GIS) and identify any areas that are highly vulnerable The research was conducted in March 2012 until August 2012. The method of analysis in this research is qualitative and quantitative. The methodology used in this study include data gathering both primary and secondary data include satellite imagery, DEM, scale 1:25,000 Topographic maps, demographic data, seismic positioning data, bathymetry data, and earthquake data fault. Processing parameters data that represent each variable vulnerability, ie environmental vulnerability, physical, social and economic was weight and then given a vulnerability score of each variable, vulnerability areas data processing to tsunami to get the vulnerability of the region to the tsunami map and field surveys. Villages in coastal areas that have a high level of tsunami vulnerability is Poncosari Village, Gadingsari Village, Gadingharjo Village, Srigading Village, Tirtoharo Village, Donotirto Village and Parangtritis village. Land use in Bantul related to human activities that weredamage threatened by the tsunami are residential, gardens, fields, ponds, moor and forest.
ANALISIS PERUBAHAN LUAS MANGROVE BERDASARKAN CITRA SATELIT IKONOS TAHUN 2004 DAN 2010 DI KECAMATAN MLONGGO, TAHUNAN DAN KEDUNG KABUPATEN JEPARA JAWA TENGAH Karyono, Afirman; Pribadi, Rudhi; Helmi, Muhammad
Journal of Marine Research Vol 2, No 3 (2013) : Journal of Marine Research
Publisher : Journal of Marine Research

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Mangrove as one of coastal ecosystem has plenty of role on coastal stability, but the current condition even though of mangroves ecosystem is Java, including Jepara destructed by many reasons mostly human activities such as. Conversion of mangrove forests to ponds, settlements and illegal logging. Rehabilitation was conducted in some places. therefore, there is a need of review the changes. The purpose of this study to determine the mangrove area changes based on IKONOS satellite imagery of 2004 and 2010 in the District Mlonggo, Tahunan and Kedung, Jepara. Descriptive method is used to describe the state of research areas by comparing the field data and interpretation process. Satellite images have been digitized in overlay to know the changes at mangrove area. Ground check was conducted the field using the quadratic sampling plots of 10m x 10m to for tree, 5m x 5m for sapling and 1m x 1m for seedling. The results were increate that the between period of 2004 to 2010. However, the mangrove area increased 5,959 ha and reduced 5,294 ha and so there was in general 0.665 ha increased. The total area at mangrove in 2004 38,098 ha and in 2010 was variously 37,444. There were at least 20 species in the research area and Rhizophora sp was the most dominant species.
Analisa Sel Sedimen Sebagai Pendekatan Studi Erosi Di Teluk Lampung, Kota Bandar Lampung Provinsi Lampung Dianpurnama, Dianpurnama; Helmi, Muhammad; Yusuf, Muhammad
Journal of Marine Research Vol 2, No 1 (2013): Journal of Marine Research
Publisher : Journal of Marine Research

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Shoreline deformation is a result from sediment transport process with an intervention of current. Concept of sediment cell used to facilitate the analysis and it can be seen on satellite images Landsat. The purpose of this research is to identify sediment cell limit and dominant direction of sediment transport along shore, erosion and sedimentation analysis using sediment cell approachment based satellite images analysis and wave modeling. This research used remote sensing method to determine sediment cell limit and ground check method to identify the source, direction and limits of sediments movement. The landmass that got erosion and accretion was obtained from satellite images overlay. Satellite images which used in this research is Landsat 1990, 2000 and 2010. According to the result of overlay, seashore deformation for 20 years was dominated by accretion (167,71 ha wider than erosion). The result of overlay showed that average accretion rate was 8,3855 ha/year and average erosion rate was 1,1745 ha/year. Results of overlay processing based on erosion and accretion showed that seashore in Bandar Lampung divided into 6 sub sediment cell with 5 limit of static sub cell and 1 dynamic sub cell appropriate for cell sediment concept.
ANALISIS FINANSIAL PADA PERSEMAIAN KARET (Hevea Brasiliensis) PT. PERKEBUNAN NUSANTARA XIII DANAU SALAK I KECAMATAN MATARAMAN KABUPATEN BANJAR KALIMANTAN SELATAN Helmi, Muhammad
Jurnal Hutan Tropis Vol 7, No 18 (2006)
Publisher : Jurnal Hutan Tropis

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Rubber represent one of effort sector owning important role in yielding state´s stock exchange of because rubber have come to especial exporting commodity of Indonesia. Rubber crop also give very important contribution in continuation of environment. Strive the continuation of environment latterly become important issue remember condition of most experienced forest more and more to concern. At Rubber crop, energi yielded like oxygen, wood, and biomassa applicable to support environmental repair function like rehabilitating the farm, floods and erosion prevention, arrangement arrange to utilize water for other dissimilar crop, and create free and healthy climate of pollution. At critical area, leaf of rubber which be fall able to fertilize land. Therefore, existence of rubber crop very strategic for continuity of life, because personating of depositor able to and source energi. Keywords : rubber crop, financial analyse