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THE POTENTIAL OF RAINFALL AND ITS IMPACT TO GROUNDWATER STORAGE IN JAVA ISLAND

Indonesian Journal of Geography Vol 40, No 2 (2008): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

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Abstract

The objectives of the study are to map the distribution of rainfall in Java, toanalyze its potential and the impact to groundwater storage. To achieve thosegoals, rainfall distribution is mapped using isohyet method. From the averagedistribution of monthly rainfall, the annual potential of rainwater on everywatershed was calculated. Afterwards, the groundwater storage was analyzed andcounted by applying the water balance concept. The results of the study show thatthe mean of the highest annual rainfall is 4082 mm which occurs on Cisadane-Ciliwung watershed and the lowest one is 1421 mm on Citarum Hilir watershed.From the rainfall potential, Cisadeg-Cikuningan watershed has the highest rainfallpotential at the amount of 25342 million m31month and Grindulu Panggulwatershed has the lowest potential at the amount of 3678 million m3lmonth.Meteorologically, Cisadeg-Cikuningan watershed has the highest groundwaterstorage at the amount of 6088 million m31yearand the lowest amount of it occurson Madura watershed at 78 million m3lyear.

KAJIAN PENGARUH LIMBAH INDUSTRI SOUN TERHADAP KUALITAS AIRTANAH DI DESA MANJUNG KECAMATAN NGAWEN KABUPATEN KLATEN

Jurnal Bumi Indonesia Volume 1, Nomor 1, Tahun 2012
Publisher : Fakultas Geografi UGM

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Abstract

Pembuangan limbah cair soun belum optimal, karena masih banyak industri yangmembuang langsung tanpa diolah melalui IPAL terpadu. Sehingga berdampakpada kondisi airtanah yang keruh dan berbau. Metode penelitian dengan surveidilakukan untuk memperoleh data tinggi muka airtanah dan data kualitas airtanah.Pengambilan sampel airtanah dilakukan dengan metode purposive sampling,dengan mempertimbangkan arah aliran airtanah dan jarak dengan industri soun.Analisis grafis dipilih karena dengan adanya grafik dapat menunjukkan gambaranbesar kecilnya parameter yang diuji. Dari delapan sampel airtanah, dua sampeldiantaranya kurang layak untuk dikonsumsi, karena kandungan COD dan BODyang melebihi baku mutu air minum. Hasil tersebut membuktikan bahwa tingginyaindikator pencemar dalam limbah soun telah berpengaruh pada kondisi kualitasairtanah.Kata kunci: industri soun, limbah soun, kualitas airtanah

Dinamika Kedudukan Interface di Pesisir Kabupaten Kebumen, Jawa Tengah

Majalah Geografi Indonesia Vol 31, No 2 (2017): September 2017
Publisher : Fakultas Geografi, Universitas Gadjah Mada

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Abstract

Abstrak Interface adalah mintakat pertemuan antara air laut yang bersifat asin dan airtanah di daratan yang bersifat tawar. Interface tidak ditemukan dalam wilayah yang tegas, namun merupakan wilayah percampuran antara air tawar dan air asin, sehingga keberadaan interface tidak bersifat statis melainkan dinamis. Penelitian ini bertujuan untuk (1) mengetahui dan menganalisis kedudukan interface di Pesisir Kabupaten Kebumen dan (2) menganalisis dinamika kedudukan interface selama kurun waktu 21 tahun yaitu tahun 1993 dan 2014. Kedudukan interface diketahui berdasarkan pendugaan geolistrik rangkaian Schlumberger. Pendugaan dilakukan pada lokasi dan jalur yang sesuai dengan penelitian yang dilakukan oleh Simoen dkk. (1993), yaitu pada (1) jalur Salak-Petanahan-Munggu-Gadung-Pantai Petanahan, (2) jalur Tambakrejo-Jeblok-Prajuritan-Adikarto-Pantai Kebumen dan (3) jalur Sinungrejo-Sidoluhur-Bener-Kaibon-Ambal dan Pantai Kutowinangun. Perbandingan hasil pendugaan interface di kedua waktu tersebut akan diketahui perbedaan dan persamaan kedalaman interface pada masing-masing titik pengukuran dalam selang waktu 21 tahun dan selanjutnya dapat dianalisis faktor-faktor yang mempengaruhinya. Hasil penelitian  menemukan adanya lapisan airtanah tawar mulai kedalaman 2 hingga 10 meter dari permukaan tanah. Berbeda dengan di tahun 1993, hasil pendugaan di tahun 2014 tidak mendeteksi adanya interface di semua jalur pengukuran. Tidak terdeteksinya interface disebabkan kedudukan interface semakin dalam akibat desakan airtanah tawar yang semakin kuat. AbstractAn interface is a zone where seawater (salt) and inland groundwater (fresh) meet. It has no distinct boundaries because it is formed by a mixture of fresh and saltwater. Therefore, the presence of interface is not static or somewhat dynamic. This research aimed to (1) identify and analyze the position of salt-freshwater interface in the Coast of Kebuman Regency and (2) analyze the dynamics of the said interface at a timespan of 21 years, i.e., in 1993 and 2014. The position was estimated using geoelectrical sounding with Schlumberger arrangement. The estimation was conducted in the locations and along the lines that were determined based on the research performed by Simoen et al. (1993). The lines traversed the following areas (1) Salak-Petanahan-Munggu-Gadung-Petanahan Coast, (2) Tambakrejo-Jeblok-Prajuritan-Adikarto-Kebumen Coast, and (3) the Sinungrejo-Sidoluhur-Bener-Kaibon-Ambal-Kutowinangun Coast. The comparison of the estimated interfaces in two observation years yielded depth differences and similarities at every measurement point. This information, then, provided the underlying factors of the dynamic interface. The research found a freshwater layer at a depth of 2 to 10 m from the soil surface. Unlike the estimation results in 1993, the ones in 2014 did not detect any presence of interface in all of the measurement lines. The interface was undetected because it lowered as the pressure of fresh groundwater became stronger.   

Quality and Type of Chemical of Groundwater at Coastal Areas of Semarang

Forum Geografi Vol 18, No 2 (2004)
Publisher : Forum Geografi

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Abstract

There are two objectives of this researh. First, to identify and analyze the condition of ground water quality in the research area, and second to determined the chemial types of groundwater. To ahieve these objectives 59 groundwater samples were taken stratifiedly, base on the different of electrical conductance value. As a result, it is identified that most groundwater in the research area is not suitable for drinking water sources, because has high concentration of electrical conductance, turbidity, hardness, chloride, manganese, and salinity. Thiis conclusion is also supported by stiff diagram analysis. The result of Stuyfzand analysis shhows that the chemical types of groundwater is very variative. Groundwater in coastal areas has higher suply of saline water than fresh water.

Hasil Aman Penurapan Airtanah untuk Kebutuhan Non Pertanian di Kabupaten Bantul

Forum Geografi Vol 26, No 1 (2012): July 2012
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

There are three objectives of this research. First, to calculate the potency of groundwater in Bantul District, second, to calculate the utilization for non agricultural usage and third, to analyze the safe yield of groundwater exploitation for non agricultural usage. To achieve these objectives, groundwater potency is calculated by static method, i.e. by multiplying area width, aquifer thickness and specific yield. Non Agricultural usage is determined by calculating the water utilization for domestic, industry, hotel and livestock. Safe yield is calculated base on area width, groundwater fluctuation and its specific yield. The groundwater resources potency of research area that has area width 506,85 km², amounted 10.059.393.198 m³/year, whereas the safe yield is 260.365.868 m³/year. Water utilization for domestic, industry, hotel and livestock is 21.658.541 m³/year. Reviewed number of potency and utilization, the potency of groundwater in the research area is still able to meet its water needs for non agricultural because the usage have not exceeded its safe yield. Although the groundwater potency is high, the agricultural sector in Bantul District does not use groundwater resources significantly.

Sistem Akuifer dan Potensi Airtanah Daerah Aliran Sungai (DAS) Opak

Forum Geografi Vol 21, No 2 (2007): December 2007
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

Opak River Basin is an area with high concentration of settlement. Generally, the settlement use groundwater as a water source. Variation of groundwater condition cause differentiation of water usage in some regions. There are two objectives of this research. First, to determine aquifer system in the research area and second, to calculate the groundwater potential in each aquifer system. To achieve these objectives, aquifer system is determined base on its geology and geomorphology, whereas groundwater potency is calculated by static and dynamic approach. As a result, show that the aquifer system in Opak River Basin can be distinguished into seven aquifer system. There are The Upper Merapi Aquifer System, The Middle Merapi Aquifer System, The Lower Merapi Aquifer System, Baturagung Range Aquifer System, The Aquifer System of Baturagung Range Foot Slope, Sentolo Hill Aquifer System and Sanddune Aquifer System. Among the seventh aquifer system, The Middle Merapi Aquifer System, The Lower Merapi Aquifer System and The Sanddune Aquifer System have high productivity. Sentolo Hill Aquifer System and The Aquifer System of Baturagung Range Foot Slope Aquifer have low productivity, whereas The Baturagung Range is categorized as non akuifer.

Groundwater Conservation Model in Coastal Plain of Semarang City

Forum Geografi Vol 20, No 2 (2006): December 2006
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

There are three objectives of this research. First, to build the model of groundwater usage and conservation in the research area. Second, to identify the behaviour of model in various usages and conservations. Third, to formulate the policy of groundwater resources management that suitable with the region caracteristic. As a result, show that the programme Powersim 2.5c can be used dan applied in hydrologis, especially in building groundwater conservation model. The conservation model that significantly suitable are to decrease the usage of water in domestic and industrial sector. Relationship by the third objectives, the some policies that can be carried out to conservations, namely decreasing water usage, restricting industrial growth, restricting settlement growth (especially in recharge area) and increasing the capacity of PDAM production.

DISTRIBUSI AIRTANAH ASIN DI DATARAN PANTAI KOTA SEMARANG DAN KESEDIAAN MEMBAYAR PENDUDUK DALAM PERBAIKAN KONDISI SUMBER AIR

Majalah Geografi Indonesia Vol 19, No 1 (2005): Maret 2005
Publisher : Fakultas Geografi, Universitas Gadjah Mada

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Abstract

ABSTRAK Penelitian ini rnempunyai empat sujuan. Pertama, mengidentifikasi dan menganalisis kondisi kualitas airtanah. Kedua, menganalisis faktor faktoryang menyebabkan terdapatnya airtanah asin di daerah penelitian. Ketiga, mengidentifikasi dan mengana-lisis daerah-daerah yang masih mempunyai kandungan air tawar dan keempat, menghitung dan menganalisis besarnya kesediaan membayar (WTP) penduduk di daerah penelitian dalam perbaikan kondisi sumber air. Untuk mencapai tujuan tersebut dilakukan pengambilan 59 sampel airtanah dan empal sampel air sungai. Disamping flu, juga dilakukan pengukuran geofisika permukaan di 30 titik dan wawancara terhadap 118 responden. Penentuan sampel airtanah dilakukan secara stratified random sampling, sedangkan penentuan sampel air sungai, titik pengukuran geofisika permukaan dan pemilihan responden dilakukan secara purposive sampling.Untuk mengidentifikasi dan menganalisis kondisi kualitas airtanah digunakan analisis spasial dan analisis statistik. Untuk menganalisis distribusi air asin digunakan metode Revelle dengan menghitung rasio 1C11/(11-1CO3-j-F [C01]), sedangkan metode Kloosterman dengan diagram Piper segiempat digunakan untuk menganalisis faktor penyebabnya. Untuk mengidentifikasi keberadaan air tawar dilakukan pendugaan geolistrik yang kemudian dianalisis menggunakan program Schlumberger ONeil. Selanjutnya, untuk menghitung dan menganalisis besarnya kesediaan membayar (WTP) digunakan analisis CVM. Hasil penelitian menunjukkan bahwa airtanah di daerah pantai mengandung DHL, kesadahan, kalsium, magnesium, nairium, kalium, klorida, sulfa! dan salinitas dalam konsentrasi tinggi. Kesimpulan ini juga didukung oleh hasil analisis statistik. Diketahuijuga bahwa sebagian besar airtanah di daerah penelitian telah tercemar air asin dengan tingkat keterpengaruhan yang bervariasi. Pencemaran air asin tersebut terutama disebabkan oleh air evaporit. Hasil analisis geolistrik menunjukkan bahwa di bawah lapisan air asin, dapat ditemukan lapisan air tawar dengan kedalaman dan produktivitas yang bervariasi. Selanjutnya, hasil analisis CYM menunjukkan bahwa penduduk daerah penelitian bersedia membayar perbaikan kondisi sumber air lebih tinggi daripada harga air dari PDAM yang berlaku pada saat ini.

PEMANFAATAN TEKNIK GEOLISTRIK UNTUK MENDETEKSI PERSEBARAN AIRTANAH ASIN PADA AKUIFER BEBAS DI KOTA SURABAYA

Majalah Geografi Indonesia Vol 20, No 1 (2006): Maret 2006
Publisher : Fakultas Geografi, Universitas Gadjah Mada

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Abstract

ujuan penelitian ini adalah untuk mengetahui persebaran airtanah asin di Kota Surabaya, menganalisis faktor penyebabnya dan mencari kemungkinan ditemukannya airtanah tawar pada akuifer tertekan. Untuk rnencapai tujuan tersebut dilakukan pendugaan geolistrik pada tujuh penampang dengan masingmasing penampang terdiri atas dua hingga tiga titik pendugaan. Untuk menganalisis hash pendugaan, data tahanan jenis hash pendugaan lapangan diinterpretasi dengan Program Schlumberger 0 Weil. Hasil interpretasi dapat ditentukan kedalaman dan ketebalan lapisan airtanah beserta sifat-sifatnya. Hasil penelitian menunjukkan bahwa di Kota Surabaya telah terdeteksi adanya airtanah asin dan airtanah payau, dengan jarak dari garis pantai dan ketebalan lapisan yang beniariasi. Faktor penyebab adanya airtanah asin dan airtanah payau tersebut adalah air fosil (connate water) Hasil lain dari penelitian ini adalah bahwa hingga kedalaman 150 meter dari permukaan tanah, tidak ditemukan akuifer tertekan yang mengandung airtanah tawar.

Kajian Kualitas Air Sungai Code Propinsi Daerah Istimewa Yogyakarta

Majalah Geografi Indonesia Vol 28, No 1 (2014): Maret 2014
Publisher : Fakultas Geografi, Universitas Gadjah Mada

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Abstract

ABSTRAK Status pencemaran dan beban daya tampung Sungai Code yang besar menunjukkan besarnya bahan pencemar yang masuk ke sungai, selain itu Sungai Code juga merupakan salah satu sungai yang terkena dampak aliran lahar din-gin Erupsi Gunungapi Merapi tahun 2010. Erupsi meningkatkan input sedimen dan debit air Sungai Code, serta men-gubah substrat dasar perairan. Tujuan penelitian ini : (1) Menganalisis kualitas air Sungai Code secara fisik dan kimia; (2). Membandingkan kualitas air Sungai Code pasca erupsi Merapi 2010 berdasarkan paramater pH, sulfida, dan besi total, dengan kondisi sebelum erupsi; (3). Menganalisis kondisi makrozoobentos pasca erupsi Gunungapi Merapi 2010, serta menganalisis pengaruh kualitas air sungai terhadap makrozoobentos; dan (4). Menganalisis kerugian ekonomi dan mengetahui persepsi terhadap sungai dari sebagian masyarakat yang memanfaatkan air sungai untuk irigasi pertanian dan perikanan keramba.Pengumpulan data dengan metode survei. Lokasi pengambilan sampel ditentukan secara pur-posive sampling yang mewakili kawasan bagian tengah Sungai Code (sebelum kota dan tengah kota), dan bagian hilir Sungai Code kawasan (setelah kota), meliputi setengah panjang Sungai Code. Sampel air dianalisis secara fisika kimia di Laboratorium. Sampel makrozoobentos diidentifikasi kemudian dianalisis dengan pendekatan kemelimpahan, dom-inansi, dan keragaman, serta regresi. Hasil wawancara untuk menilai persepsi masyarakat dan kerugian ekonomi akibat banjir lahar dingin dianalisis dengan crosstab. Hasil penelitian menunjukkan bahwa parameter DO, BOD, COD, dan ni-trat, tidak memenuhi baku mutu air kelas I di beberapa lokasi. Adapun kekeruhan, fosfat, dan sulfida, hampir di seluruh lokasi tidak memenuhi baku mutu. Menurunnya kualitas DO, BOD, COD, nitrat, dan fosfat disebabkan oleh limbah yang masuk ke sungai, sedangkan menurunnya kualitas sulfida dan kekeruhan, selain dari limbah juga disebabkan oleh erupsi Merapi. Makrozoobentos yang ditemukan di Sungai Code ada 5 genus yaitu Chironomous, Simulium, Ephemer-optera, Lymnaea, dan Tubifex. Suhu, kecepatan arus dan DO berpengaruh pada menurunnya keragaman dan dominansi bentos. Status Sungai Code pasca erupsi tercemar ringan berdasarkan indeks keragaman bentos = 1,69. Pendapatan masyarakat dari sawah dan perikanan keramba sungai pasca banjir lahar dingin menurun antara Rp.500.000,00-Rp. 2.000.000,00/ responden/ panen. ABSTRACT Pollution status and load capacity of Code River which great shows total of pollutants entering the river, beside of the Code River also one of the affected rivers of lava Merapi Volcano Eruption at 2010. Eruption increase input of sediment and water discharge Code River and change the base substrate waters. The aim of this study: (1) Analyze the Code River water quality of physical and chemical; (2) Compare the Code River water quality after the eruption of Merapi in 2010 based on the parameters pH, sulfide, and total iron, with condition before the eruption; (3) Analyze the conditions of macrozoobenthos after eruption of Merapi Volcano in 2010, and to analyze the effect of water quality on macrozoobenthos; and; (4) Analyze the economic loss and know  perception of most people on the river water for agriculture irrigation and fishpond. Location of sampling is determined by purposive sampling to represent the central part of the Code River (before town and downtown), and the lower of the Code River (after city), include a half the length of the Code River. The water sampling were analyzed in the laboratory to examine quality water of chemical and physics. Macrozoobenthos sampling were identified and analyzed with the approach of abundance, dominant, and diversity, and regression. Results of interview to assess public perceptions and economic loss due to lava flood were analyzed by crosstab. The results show parameters of DO, BOD, COD, and nitrat. Results of interview to assess public perceptions and economic loss due to lava flood were analyzed by crosstab. The results show parameters of DO, BOD, COD, and nitrat, not comply with water quality standard of class I in some locations. Also, turbidity, phosphates and sulfides, nearly all locations not comply quality standards. Decrease of quality of DO, BOD, COD, nitrates, and phosphates were caused by waste into the river, while the declining quality of sulphide and turbidity, besides from waste also caused by eruption of Merapi. Macrozoobenthos were found in the River Code as genus as Chironomous, Simulium, Ephemer-optera, Lymnaea, and Tubifex. Temperature, current speed and DO effect on decreasing the diversity and dominance benthos. Status of Code River after eruption has polluted with the diversity index of benthic = 1.69. Income of farmer and fisherman of river after lava flood has descreasing between in IDR 500.000,00 until IDR 2,000,000.00 / respondent / harvest.