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"Soil loss and its transport processes were coupled with an existing distributed hydrological modelto assess the effects of land use change on stream flow and suspended sediment load in the ChaoPhraya River basin, Thailand. The simulation period spanned from 2001 to 2010. The resultsindicate that the Nash-Sutcliffe efficiency of upper sub-basins fluctuated in the range 0.51- 0.72,indicating the applicability of the model for longterm simulation at the monthly scale. Land usechange during 200l-2010 caused a 1.6% increase in suspended sediment load based on the presenttrend. The changes were particularly pronounced in the Wang River basin, where the delivery ratiowas highest. Moreover, the urbanization and conversion of farm land from paddy fields exertednegative effects on sediment runoff in Chao Phraya River basin. The proposed model has theability to quantitatively evaluate the heterogeneity of sediment runoff in the basin, demonstratingthe benefits and trade-offs of each land use change class. The results of this study can support basinand local land development policy to control sediment losses during development."

"Preceding monitoring reports indicated that di (2-ethylhexyl) phthalate (DEHP), a commonplasticizer, was found in the samples of suspended sediment and water collected from the lowerpart of Chao Phraya River. In this continuing study, the suspended sediment and water samplesfrom the Chao Phraya Delta were collected twice a year in January and July during January 201 1 -July 2013. The analyses were performed for both DEHP and Diethyl Phthalate (DEP). Overallresults showed that concentrations of both DEHP and DEP in the water samples were relativelyhigher than those in the suspended sediment samples. The concentrations of DEHP and DEP fromall sampling periods in the water samples ranged from 1.58 - 27.55 pg/L and from 0.64 - 2.59ug/L, respectively, whereas the concentrations of DEHP and DEP from all sampling periods in thesuspended sediment samples ranged from 0.01 - 26.82 mg/g and from 0.01 - 1.93 mg/g,respectively. The concentrations of both DEHP and DEP in both suspended sediment and watersamples were relatively higher in the samples collected during lower discharge period of the ChaoPhraya River in July. The results indicated that sediment transport system could play an importantrole in the dispersion of both DEHP and DEP. The ecological risk assessment indicated that for thecurrent level of contaminations the risk did not exceed the acceptable level."

"Heavy metals in suspended sediments (SS) were investigated in the lower Chao Phraya River,Thailand, and Main particulate metals. The particulate fractions accounted mostly for 60-100% of total concentrations of Cr, Mn, Ni, Cu, Zn, and Pb in both dry and rainy seasons. The comparison of metal contents of the sampled SS and upper continental crust (UCC) implied some anthropogenic inputs of Cr, Ni,Cu, and Zn as well as the dilution process for those metals in the rainy season in Chao Phraya River. Enrichment factor in both rivers also indicated anthropogenic effects on metal content in SS,reflecting the distinctive seasonal process in Chao Phraya River and the spatial variation withinMaxil."

"Alih fungsi lahan memiliki kaitan yang erat dengan pertumbuhan penduduk dan ekonomi. Perubahan ini memiliki dampak positif dan tidak sedikit dampak negatifnya. Salah satu hal yang disebabkan oleh adanya alih fungsi lahan adalah meningkatnya lahan kedap air dan berkurangnya baseflow. Perubahan fungsi lahan ini berujung kepada meningkatnya aliran permukaan dan bencana banjir. Melihat hal ini, dibutuhkan studi lebih lanjut mengenai hubungan perubahan fungsi lahan dan banjir yang terjadi pada suatu kawasan. Penelitian ini berfokus pada DAS Martapura yang merupakan bagian DAS Barito, salah satu DAS terbesar di Indonesia. Penelitian ini menggunakan pendekatan spasial terhadap hasil tangkapan Citra Landsat pada tahun 1990, 2000, 2010, dan 2020. Menggunakan fitur maximum likelihood classification, penelitian ini mendeteksi tutupan lahan pada setiap data Citra Landsat yang digunakan. Penelitian ini juga menggunakan bantuan HEC-HMS dalam menghasilkan hidrograf banjir untuk setiap sub-DAS, reach, dan junction. Data ini yang bervariasi menurut tutupan lahan setiap tahunnya dan menjadi input ke dalam HEC-RAS. Penelitian ini menggunakan fitur analisis hidrolika HEC-RAS 2D untuk menghasilkan peta genangan. Berdasarkan simulasi yang telah dilakukan, perubahan tutupan lahan menjadi kedap air semakin meningkat. Hal ini juga meningkatkan limpasan permukaan dan puncak debit banjir yang terlihat pada hasil hidrograf. Menurut analisis genangan banjir yang terjadi, didapatkan peningkatan luas genangan banjir seiring bertambahnya tahun Sebagai upaya pengendalian banjir di lokasi ini, diperlukan perencanaan tata ruang dan penataan kawasan dengan lebih baik. Hal ini perlu dilakukan untuk mengendalikan laju perubahan tutupan lahan dan mengendalikan dampak bencana banjir.

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Land conversion has a very close relation with population and economic growth. This change has had both positive and negative impacts. One of the things caused by land use change is the increase in impermeable land and reduced baseflow. This land use change leads to an increase in surface runoff and flooding. In regards to this problem, further studies are needed to determine the relation between land use change and flooding that occur in an area. This study focuses on the Martapura Watershed which is a part of the Barito Watershed, one of the largest watershed in Indonesia. This study uses a spatial approach to Landsat Image capture in 1990, 2000, 2010 and 2020. Using the maximum likelihood classification feature, this study detects land cover in each Landsat Image data used. This study also uses HEC-HMS assistance in generating flood hydrographs for each sub-watershed, reach, and junction. This data, which varies by land cover each year, is the input to the HEC-RAS. This study uses the HEC-RAS 2D hydraulics analysis feature to generate inundation maps. Based on the simulations that have been carried out, land cover changes to a more impermeable cover are increasing. This also increase surface runoff and peak flood discharge as seen in the hydrograph results. According to the analysis of the flood inundation that occurred, it was found that there was an increase in the area of ​​​​the flood inundation in every year modelled. As an effort to control flooding in this location, better spatial planning and regional arrangement are needed. This needs to be done in order to control the rate of land cover change and the impact of floods."

"In 2011, massive flooding and inundation in the Chao Phraya River basin, in Thailand, causedserious damage to various activities for a prolonged period of time. Although snapshot images ofthe inundated area are available, detailed information including temporal changes of the inundatedareas and the relationship with meteorological and hydrological conditions are not welldocumented, particularly for the middle and upper sections of the basin. Therefore, we conductedan analysis using two types of satellite data, HJ-1A and Envisat, to better understand behavior ofthe large-scale inundation occurred in 2011, focusing on the middle section of the Chao PhrayaRiver basin. In the analysis, water surface in selected domains was extracted using the NDWI valuecalculated from HJ-1A data. The threshold value of the Envisat ASAR image was then adjusted sothat the inundated area estimated from Envisat gives the closest possible match with that estimatedfrom HJ-1A. Finally, the inundated area was estimated for the whole study domain based on thesame threshold value from the Envisat data. Results indicated that the inundated area began toextend along the Yom and Nan rivers in early August and continued to spread down to the NakhonSawan city area until October. A significant increase in inundated areas occurred between Sep. 2and Sep. l3, during which higher rainfall intensity was observed. Even after the water level inrivers receded below the bank-full elevation, large areas were left inundated along rivers,particularly over lowlying marsh and paddy fields. In addition, several areas located far fromrivers were also inundated, which was likely a consequence of water ponding in paddy fields."

"[Lapangan ARA yang terletak di lepas pantai Delta Mahakam modern merupakan lapangan penghasil gas yang berproduksi sejak 2008 hingga sekarang. Sesar Utama yang merupakan sesar normal berorientasi NNE-SSW dengan kemiringan relatif ke arah Timur memisahkan Lapangan ARA menjadi dua panel: Panel Barat dan Panel Tengah. Studi konklusif mengenai sifat sekatan sesar utama inidiperlukan dalam optimisasi pemodelan geologi dan kelanjutan pengembangan lapangan. Studi internal telah menggunakan interpretasi horizon dan sesar dari seismik 3D beserta data log sumur sebagai dasar utama pembuatan model struktur, fasies, dan petrofisik Lapangan ARA. Prediksi SGR (shale gouge ratio), permeabilitas batuan zona sesar (Kf), dan fault-rock capillary pressure (FRPc) adalah parameter-parameter utama yang digunakan dalam analisis sifat sekatan sesar. Parameter-parameter tersebut di kalibrasi menggunakan analisis reservoir statik dan dinamik berdasarkan data pengukuran tekanan reservoir. Analisis sekatan Sesar Utama Lapangan ARA menghasilkan batas nilai parameter sekatan untuk zona sesar bersifat tersekat, yaitu SGR > 0.39, Kf < 0.025 mD, dan FRPc > 3.3 bar / 47.8 psi. Variasi kapasitas sekatan sesar dikontrol lebih dominan oleh faktor penyebaran reservoir juxtaposition dibandingkan faktor penyebaranatribut fault throw. Peningkatan perbedaan tekanan reservoir saling kontak antar panel hingga melebihi kapasitas sekatan sesar akibat produksi intensif, menjadi penyebab kebocoran sesar;ARA Field, which is located in offshore area of modern Mahakam Delta, is producing gas since 2008. Main normal fault in the middle of the field separatesthe field into two panels: West panel and Central Panel. Conclusive study about the sealing behavior of this main fault is needed in order to optimize geology model and future field development. Internal study has used 3D seismic faults and horizons interpretation with its welllogs as main input to made structural, facies, and petrophysic model of ARA Field. Shale gouge ratio prediction, fault-rock permeability (Kf), and fault-rock capillary pressure (FRPc) are main analyzed parameters used in this research. Those parameters are then validated with static and dynamic reservoir analysis based on available reservoir pressure data. ARA Field Main Fault seal analysis results cutoff value for each analyzed parameters: SGR > 0.39, Kf < 0.025 mD, and FRPc > 3.3 bar / 47.8 psi. Fault sealing capacity distribution is controlled more dominantly by the reservoir juxtaposition distribution than fault throw attribute. Increase of across fault differential pressure in juxtaposed reservoirs that exceeds the maximum fault seal threshold capability is interpreted as the main cause of fault leak., ARA Field, which is located in offshore area of modern Mahakam Delta, isproducing gas since 2008. Main normal fault in the middle of the field separatesthe field into two panels: West panel and Central Panel. Conclusive study aboutthe sealing behavior of this main fault is needed in order to optimize geologymodel and future field development.Internal study has used 3D seismic faults and horizons interpretation with its welllogs as main input to made structural, facies, and petrophysic model of ARAField. Shale gouge ratio prediction, fault-rock permeability (Kf), and fault-rockcapillary pressure (FRPc) are main analyzed parameters used in this research.Those parameters are then validated with static and dynamic reservoir analysisbased on available reservoir pressure data.ARA Field Main Fault seal analysis results cutoff value for each analyzedparameters: SGR > 0.39, Kf < 0.025 mD, and FRPc > 3.3 bar / 47.8 psi. Faultsealing capacity distribution is controlled more dominantly by the reservoirjuxtaposition distribution than fault throw attribute. Increase of across faultdifferential pressure in juxtaposed reservoirs that exceeds the maximum fault sealthreshold capability is interpreted as the main cause of fault leak.]"

"Nowadays, severe flooding frequently occurs in various parts of Thailand resulted from changesin climatic condition and land use patterns. The flooding has caused great damages to propertiesand lives and affects country economy. Experience from the most severe flooding in the northernand central regions of Thailand in the year 2011 reveals that reliable flood warning system is stilllagging. For flood warning purpose, it is necessary to have an accurate flood routing system. Thisstudy is aimed at developing mathematical models for flood routing so as to provide data for floodwarning. Two different models are developed, i.e., kinematic overland flow model and kinematicstream flow model. The finite element method with Galerkin’s weighted residual technique is usedin model development. The second order Runge-Kutta method is applied to solve the set ofdifferential equations obtained from finite element formulation. The developed models are appliedto simulate flows in the Wang river basin in the northern region of Thailand during July 1 -October 31, 2011 when severe flooding occurred in this region. Model calibration is made byadjusting some parameters in the models and comparing the obtained results with measured datarecorded by RID at 5 stream flow gauge stations along the Wang river. For correlation analysis.three statistical indices are determined, these include coefficient of determination, R2, Nash-Sutcliffe model efficiency coefficient, NSE, and coefficient of variation of the root mean squareerror, CV(RMSE). It is found that the model results at the upstream portion of the riversatisfactorily agree with the observed data, with the values of R2 greater than 0.55 and CV(RMSE)less than 0.57. For the downstream portion of the river, there are remarkable differences betweenthe model results and the observed data. The values of R2 are less than 0.35, CV(RMSE) greaterthan 0.76, and the NSE values are less than 0.16. This might be due to some errors in the inputdata, including rainfall pattern, topography, land use, river cross-sectional area, and water seepagealong the river. More detailed field investigation and model calibration are still needed."

"ABSTRAKThe retention basin is a tub or pond that can accommodate or absorb water while it is contained in it. retention basin is the most effective and efficient system in handling floods that occur in an area. an environmentally flood control effort needs to be done such as retention basin. this study aims to plan the dimensions of retention basins from the central region of the Deli river. planning the volumje of retention basins made around Deli river is calculated using maximum daily rainfall data of Deli river area. maximum rainfall data can be obtained from Climatology Meteorology and Geophysies Agency (BMKG) Medan City or Dinas PSDA Medan. The maximum daily rainfall is calculated first then the volume, the retention basin construction can accommodate the excessive water discharge of the Deli River. from the results of 25 years rainfall period data processing with Nakayashu method obtained Qplan of 229 m3/s is used to design drainage channel plan. The obtained the capacity of retention basin at the center of 6462288 m3. Then the retention basin dimension planned with area of 2154096 m2 and depth of 3 m. "

"Northeast Java Basin is known as mature cenozic basin, yet this understanding override possibility of sediment older than cenozic. This thoughthas brought current exploration strategy of this basin concerning within only cenozic sediments."