Judul: Aplikasi Model Tangki untuk Pendugaan Neraca Air dan Laju Sedimentasi menggunakan Metode MUSLE di Sub DAS Lahar Kabupaten Blitar
Abstrak: Lahar Sub-Watershed has the elongated shape of the river with a narrow width whereas the main river has 16.86 km length. Under these conditions affect the distribution of water flow to the downstream. Tank Model is one of the hydrologic models that is able to estimate the distribution of water flow either vertically or horizontally. To estimate the sedimentation rate using MUSLE method, which the erosivity parameter in this method is run off data from Tank Model. In order to know distribution of water flow at Lahar Sub-Watershed so used Tank Model. Application of this model is an attempt in a better management of Watershed. The purpose of this researches is to estimate the characteristics of water balance in Lahar Sub-Watershed and to estimate the sedimentation rate using Tank Model application and MUSLE method. This research is located in Lahar Sub-Watershed, Blitar, East Java that has an area of 1418.80 ha. Land cover in Lahar Sub-Watershed consist of 261.58 ha natural forest, 905.46 ha farm field, 54.96 ha agricultural field, 63.76 ha rice field, and 133.04 ha residential area. Soil types in Lahar Sub-Watershed is consist of grey andosol and grey regosol association, grey regosol and brown latosol association, reddish brown mediteran and brown regosol with undulated until mountainous topography and the elevation between 291 ̶ 1093 mdpl. The average temperature in this area between 23.3°C with the highes temperature is 34.7°C and the lowest is 19,2°C, it was a B3 and C3 climate type. Result of the calibration data obtained correlation between water level and water flow, y=6.238TMA1.495 with R2=0.918 and correlation between water flow and sedimentation rate y=43.56Q2.118 with R2=0.853. Total of rainfall in 2009 is 1702 mm/yr and in 2010 is 3304 mm/yr. Total of observation sedimentation rate in 2009 is 12366 ton/yr or 8.7 ton/ha/yr and in 2010 is 20180 ton/yr or 14 ton/ha/yr. Result of Tank Model optimation obtained R=0.65 and water balance, the rainfall is 2590 mm/yr, the evapotranspiration is 797 mm/yr, and the outflow calculation is 1308 mm/yr that distributed through surface 203.5 mm (15.56%), intermediate flow 324.5 mm/yr (24.82%), sub-base flow 520.8 mm/yr (39.83%), and base flow 258.7 mm/yr (19.79%), so the value of storage is 479 mm/yr. Result of the MUSLE method obtained formula R2=0.631. It is shown that MUSLE model could estimate sedimentation rate well. Total of sedimentation rate from June 1st until May 31th 2010 is 26899 ton/yr (19 ton/ha/yr or 1.6 mm/yr). This indicates that sedimentation rate in Lahar Sub-Watershed included to medium category.
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Judul: Pendugaan neraca air, erosi, dan sedimentasi menggunakan aplikasi Tank Model dan metode musle di Sub Das Cilebak kabupaten Bandung
Abstrak: Berbagai metode telah banyak dikembangkan untuk menduga besarnya erosi, salah satunya adalah metode MUSLE (Modified Universal Soil Loss Equation). Di Indonesia metode MUSLE masih jarang digunakan karena tidak semua lokasi mempunyai data limpasan, sedangkan metode MUSLE membutuhkan data limpasan sebagai faktor penduga besarnya erosi. Dalam penelitian ini metode MUSLE dikombinasikan dengan Tank Model, dimana Tank Model digunakan untuk mengetahui besarnya limpasan yang nantinya digunakan sebagai input metode MUSLE. Penelitian dilaksanakan di Sub-DAS Cilebak, Desa Nagrak, Kecamatan Pacet, Kabupaten Bandung, Provinsi Jawa Barat. Tujuan penelitian ini adalah : 1) Mengkaji laju sedimen dan erosi, 2) Mengaplikasikan Tank model dan metode MUSLE berbasis data SPAS. Tahap penelitian meliputi : 1) Analisis hubungan debit aliran sungai dengan tinggi muka air, 2) Analisis input Tank Model, 3) Analisis hidrograf, 4) Analisis output Tank Model , 5) Analisis laju sedimen dan erosi dengan metode MUSLE ,6) Analisis neraca air. Luas Sub-DAS Cilebak sebesar 413,57 ha, dengan penutupan lahan sebagai berikut : semak 139,64 ha (33,76%), hutan 46,42 ha (11,22%), Kebun 1,39 ha (0,34%), pemukiman 37,59 ha (9,09%), sawah irigasi 28,86 ha (6,98%), dan tegalan atau ladang 159,67 ha (38,61%). Jenis tanah di Sub-DAS Cilebak di dominasi oleh tanah regosol dengan luas 221,89 ha (53,7%) dan tanah aluvial seluas 191,68 ha (46,3%). Berdasarkan hasil kalibrasi data diperoleh hubungan tinggi muka air dengan debit aliran, yaitu Q = 153,5 TMA3,353 dengan R2 = 0,955, dimana ; TMA adalah tinggi muka air (m) dan Q adalah debit (m3s-1), dan hubungan debit aliran dengan laju sedimen, yaitu Qs = 7,618 Q2,267 dengan R2 = 0,921, dimana ; Qs adalah sedimentasi (ton hari-1) dan Q adalah debit (m3s-1). Jumlah curah hujan tahun 2009 sebesar 1.166,2 mm tahun-1 dan jumlah curah hujan pada tahun 2010 sebesar 1.147,3 mm 7bulan-1. Total laju sedimen observasi pada tahun 2009 sebesar 276,678 ton tahun-1 dan pada tahun 2010 sebesar 105,635 ton 7bulan-1. Total laju sedimen MUSLE pada tahun 2009 sebesar 134,197 ton tahun-1 dan pada tahun 2010 sebesar 185,449 ton 7bulan-1. Hubungan laju sedimen observasi dengan laju sedimen kalkulasi model MUSLE menunjukkan korelasi yang kuat dengan persamaan regresi Qsm = 3,080 Qs - 0,002 dan R2 = 0,792, dimana ; Qsm adalah sedimentasi MUSLE (ton hari-1) dan Qs adalah sedimentasi hasil observasi (ton hari-1).
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Judul: Prenilasi Senyawa β-Diketon sebagai Prekursor 3-Prenilflavon
Abstrak: One group of flavonoids that has not been commonly synthesized is 3- prenylflavone. The main objective of this experiment was to synthesize precursor of 3-prenylflavone. Firstly, β-diketone was synthesized via 4 steps from phenol as starting compound with total yield of 24%. Prenylation of β-diketone with prenyl bromide and K2CO3 base produced 4 fractions which were separated by using preparative thin layer chromatography (PTLC) with n-hexane:EtOAc (8:2) as the eluent. Fraction with Rf = 0.80 was further separated by using preparative PTLC with n-hexane:EtOAc (99:1) as the eluent. Two fractions were obtained with Rf = 0.38 and 0.42. The first fraction has been characterized as diprenylated β-diketone with 49% yield. Application of protecting group on the phenolic OH group in β- diketone are needed to obtain monoprenylated β-diketone which can be further cyclized into 3-prenylflavone
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