scholarly journals Different approaches to estimate the sediment yield in a tropical watershed

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Carina Barbosa Colman ◽  
Karina Mendes Pinheiro Garcia ◽  
Rodrigo Bahia Pereira ◽  
Enio Arriero Shinma ◽  
Fernanda Ely Lima ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Delivery Ratio ◽  
Ungauged Basins ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Yield Values ◽  
Sdr Model ◽  
Tropical Watershed ◽  
Soil Loss Equation

ABSTRACT Several Sediment Delivery Ratio (SDR) models have been used to estimate Sediment Yield (SY), mainly in data-scarce and ungauged basins, such as in many regions of Brazil. However, it is difficult to choose the most suitable SDR model, mainly because of the lack of investigations of this approach using observed data. Here, we investigated the performance of five widely used SDR models (SDREST) to estimate sediment yield values (SYEST ) based on observed data in a tropical watershed. We used observed sediment yield values (SY OBS) during September 2011 to July 2017 in three sub-basins of the Guariroba Basin, Midwestern Brazil. To estimate the average annual soil loss, we used the Revised Universal Soil Loss Equation. The SDROBS and SYOBS ranged from 5.56 to 10.54% and 940.76 to 5,400.32 t yr-1, respectively. The Williams and Berndt (1972) method presented the best performance, with a percent bias ranging from -2.34 to 3.30% in SRD estimation. Therefore, this model provided suitable SDR and SY estimates, and may be useful to estimate SY in other tropical data-scarce and ungauged basins.

KAJIAN EROSI LAHAN DI KAWASAN AIR STRIP RUNWAY 2600 BANDARA DEPATI AMIR (PGK) BERDASARKAN TATA GUNA LAHAN MASTERPLAN ULTIMATE

2019 ◽  
Vol 7 (2) ◽  
pp. 100-111
Author(s):  
Miskar Maini ◽  
Junita Eka Susanti
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Soil Loss Equation

Standar permintaan engineering pesawat agar desain bangunan infrastruktur di area Air Strip Runway 2600 yang ada dapat mempunyai fungsi lain. Sedangkan kondisi lain sangat menentukan keselamatan karena lahan di sekitar Air Strip Runway 2600 Bandara Depati Amir (PGK) jika tidak ditutupi vegetasi seperti rumput, kondisi lain lahan yang belum ditutupi vegetasi di sekitar Air Strip Runway 2600 berpotensi akan mengalami erosi lahan, kemudian hasil erosi lahan ini akan terbawa oleh aliran air sehingga akan masuk ke saluran drainase yang akan menyebabkan sedimentasi pada saluran drainase tersebut, akhirnya akan berkurang efektifitas kinerja saluran drainase tersebut. Metode yang digunakan untuk memprediksi laju rata-rata erosi di area Air Strip Runway 2600 dengan memperhitungkan faktor erosivitas hujan, erodibilitas tanah, kemiringan lereng atau panjang lereng, pengelolaan tanaman dan konservasi tanah, yang masing masing tata guna lahan tersebut mengacu pada Masterplan Ultimate Bandara Depati Amir (PGK). Perhitungan dilakukan menggunakan persamaan USLE (Universal Soil Loss Equation) yang dikembangkan oleh Wischmeier dan Smith (1965, 1978), kemudian Sediment Delivery Ratio (SDR) dan Sediment Yield.Hasil penelitian ini, prediksi laju erosi permukaan pada area Air Strip Runway 2600 Bandara Depati Amir (PGK) tahun pertama yang mencapai 5,60 mm/tahun atau 100,76 Ton/Ha/tahun, laju erosi tahun kedua mencapai 3,38 mm/tahun atau 60,84 Ton/Ha/tahun dapat diklasifikasikan ke dalam kelas bahaya erosi sedang (kelas III) dan nilai SDR adalah sebesar 56,3%, nilai sediment yield (SR) pada tahun pertama sebesar 5.887,59 Ton/Tahun, pada tahun kedua ketika rumput pada area Air Strip telah tumbuh dengan sempurna terjadi penurunan hasil sediment yield yaitu nilai SR sebesar 3.554,85 Ton/Tahun.

scholarly journals USLE K-Factor Method Selection for a Tropical Catchment

2019 ◽  
Vol 11 (7) ◽  
pp. 1840 ◽  
Author(s):  
Valter Marques ◽  
Marcos Ceddia ◽  
Mauro Antunes ◽  
Daniel Carvalho ◽  
Jamil Anache ◽  
...  
Keyword(s):  
Soil Loss ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Annual Average ◽  
Sediment Delivery ◽  
Rainfall Simulator ◽  
K Factor ◽  
Selection For ◽  
Tropical Watershed ◽  
Soil Loss Equation

The use of the Universal Soil Loss Equation (USLE) and the Sediment Delivery Ratio (SDR) facilitates sediment yield (SY) estimates in watersheds. However, the soil loss predictions are frequently unrealistic because of the methods used to estimate the USLE’s factors. Here, we evaluated the performance of methods to estimate the soil erodibility (K-factor) and the influence of its estimation in the SY predictions. K-factor values were obtained from three widely used equations and using a portable rainfall simulator. These values were used to compute annual average soil loss and SY in a tropical watershed. We compared SY estimates with a 15-month observed sediment discharge dataset sampled in the catchment outlet. The most reliable method for the K-factor estimating was the USLE nomograph. Furthermore, our results indicate that the use of a portable rainfall simulator to estimate the K-factor tends to underestimate soil loss and sediment delivery.

scholarly journals Assessing the applicability of the Revised Universal Soil Loss Equation (RUSLE) to Irish Catchments

2015 ◽  
Vol 367 ◽  
pp. 99-105 ◽  
Author(s):  
A. Rymszewicz ◽  
E. Mockler ◽  
J. O'Sullivan ◽  
M. Bruen ◽  
J. Turner ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Overland Flow ◽  
Universal Soil Loss Equation ◽  
Initial Assessment ◽  
Delivery Ratio ◽  
National Scale ◽  
Sediment Delivery ◽  
Yield Values ◽  
Soil Loss Equation

Abstract. Elevated suspended sediment concentrations in fluvial environments have important implications for system ecology and even small concentrations may have serious consequences for sensitive ecosystems or organisms, such as freshwater pearl mussels (Margaritifera margaritifera). Informed decision making is therefore required for land managers to understand and control soil erosion and sediment delivery to the river network. However, given that monitoring of sediment fluxes requires financial and human resources which are often limited at a national scale, sediment mobilisation and delivery models are commonly used for sediment yield estimation and management. The Revised Universal Soil Loss Equation (RUSLE) is the most widely used model for overland flow erosion and can, when combined with a sediment delivery ratio (SDR), provide reasonable sediment load estimations for a catchment. This paper presents RUSLE factors established from extant GIS and rainfall datasets that are incorporated into a flexible catchment modelling approach. We believe that this is the first time that results from a RUSLE application at a national scale are tested against measured sediment yield values available from Ireland. An initial assessment of RUSLE applied to Irish conditions indicates an overestimation of modelled sediment yield values for most of the selected catchments. Improved methods for model and SDR factors estimation are needed to account for Irish conditions and catchment characteristics. Nonetheless, validation and testing of the model in this study using observed values is an important step towards more effective sediment yield modelling tools for nationwide applications.

ANALISIS EROSI PADA DAERAH ALIRAN SUNGAI (DAS) POMPONG KABUPATEN BANGKA

2019 ◽  
Vol 7 (2) ◽  
pp. 70-84
Author(s):  
Bayu Oktasandi ◽  
Endang Setyawati Hisyam ◽  
Indra Gunawan
Keyword(s):  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Soil Loss Equation

DAS Pompong merupakan salah satu DAS yang termasuk dalam klasifikasi DAS yang dipulihkan di Provinsi Kepulauan Bangka Belitung dengan luas 7.701,192 Ha. Kerusakan DAS Pompong diakibatkan oleh perubahan tataguna lahan serta kurangnya kesadaran masyarakat terhadap pelestarian DAS serta aktifitas pertanian dan penambangan yang semakin tak terkendali yang menimbulkan dampak sangat besar terhadap tanah diatasnya, berupa pengikisan (erosi) dan pengendapan (sedimentasi). Penelitian ini bertujuan untuk mengetahui besar erosi dan hasil sedimentasi serta memberikan rekomendasi upaya konservasi lahan pada DAS Pompong. Pada penelitian ini menggunakan Metode USLE (Universal Soil Loss Equation) untuk menghitung besarnya erosi yang terjadi, dan Metode SDR (Sediment Delivery Ratio) untuk menghitung besarnya sedimentasi. Berdasarkan hasil analisis yang dilakukan diperoleh besarnya erosi total pada DAS Pompong sebesar 260,038 ton/ha/thn atau 2.002.603,816 ton/thn, dan jumlah sedimentasi sebesar 278.361,930 ton/thn. Hasil analisis menunjukkan bahwa besar erosi yang terjadi pada DAS Pompong masuk klasifikasi bahaya erosi  Kelas IV (Berat). Arahan konservasi lahan yang dapat direkomendasikan adalah dengan melakukan tidakan konservasi tanah secara vegetatif dan mekanik.

scholarly journals KAJIAN EROSI DAN POTENSI SEDIMENTASI DI DAS KAHAYAN PROVINSI KALIMANTAN TENGAH

2019 ◽  
Vol 8 (02) ◽  
pp. 29-36
Author(s):  
Raden Haryo Saputra
Keyword(s):  
Soil Conservation ◽  
Soil Loss ◽  
Delivery Ratio ◽  
Soil Conservation Service ◽  
United States Department ◽  
Sediment Delivery Ratio ◽  
Department Of Agriculture ◽  
Sediment Delivery ◽  
States Department ◽  
Soil Loss Equation

Pengelolaan daerah rawa tidak terlepas dari pengelolaan Daerah Aliran Sungai (DAS). Erosi dan sedimentasi pada DAS mempengaruhi kualitas maupun kuantitas air sungai yang masuk ke daerah rawa. Salah satu indikator adanya erosi terlihat dari keruhnya air Sungai Kahayan sedangkan sampai saat ini belum diketahui berapa besar erosi dan potensi sedimentasi yang terjadi pada DAS Kahayan sehingga kajiannya sangat diperlukan bagi pengelolaan DAS Kahayan yang terintegrasi. Penelitian ini bertujuan untuk menyelidiki besarnya erosi, menganalisis tingkat bahaya erosi (TBE) dan besarnya hasil sedimen yang terjadi pada DAS Kahayan. Analisis luasan lahan dan unit lahan berbasis Sistim Informasi Geografis. Perhitungan perkiraan besarnya erosi menggunakan metode Universal Soil Loss Equation (USLE), dan hasil sedimen menggunakan metode Soil Conservation Service-United States Department of Agriculture (SCS-USDA) dengan mempertimbangkan bobot luasan unit lahan terhadap luas totalnya.  Perkiraan besarnya erosi yang terjadi pada DAS Kahayan sebesar 13,19 ton/ha/tahun dengan TBE terdiri dari kategori sangat ringan 47,65%, ringan 50,99%; sedang 0,25%; berat 1,12% dan sangat berat 0%. Khusus areal dengan TBE kategori berat, skor total ketiga faktor karakter fisik DAS (kemiringan lereng, jenis tanah menurut kepekaannya terhadap erosi, dan intensitas curah hujan) diperoleh sebesar 184 dengan arahan penggunaan lahan adalah kawasan lindung. Berdasarkan nilai Sediment Delivery Ratio (SDR), hasil sedimen pada DAS Kahayan adalah sebesar 169.115 ton/tahun dan menurut Peraturan Dirjen Rehabilitasi Lahan dan Perhutanan Sosial, hasil sedimen pada DAS Kahayan termasuk dalam kategori baik.

Soil Sediment Loading and Related Environmental Impacts from Farms

2017 ◽  
Author(s):  
Vito Ferro
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Soil Erosion ◽  
Sediment Yield ◽  
Water Storage ◽  
Sediment Deposition ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Soil Particles

Beyond damage to rainfed agricultural and forestry ecosystems, soil erosion due to water affects surrounding environments. Large amounts of eroded soil are deposited in streams, lakes, and other ecosystems. The most costly off-site damages occur when eroded particles, transported along the hillslopes of a basin, arrive at the river network or are deposited in lakes. The negative effects of soil erosion include water pollution and siltation, organic matter loss, nutrient loss, and reduction in water storage capacity. Sediment deposition raises the bottom of waterways, making them more prone to overflowing and flooding. Sediments contaminate water ecosystems with soil particles and the fertilizer and pesticide chemicals they contain. Siltation of reservoirs and dams reduces water storage, increases the maintenance cost of dams, and shortens the lifetime of reservoirs. Sediment yield is the quantity of transported sediments, in a given time interval, from eroding sources through the hillslopes and river network to a basin outlet. Chemicals can also be transported together with the eroded sediments. Sediment deposition inside a reservoir reduces the water storage of a dam. The prediction of sediment yield can be carried out by coupling an erosion model with a mathematical operator which expresses the sediment transport efficiency of the hillslopes and the channel network. The sediment lag between sediment yield and erosion can be simply represented by the sediment delivery ratio, which can be calculated at the outlet of the considered basin, or by using a distributed approach. The former procedure couples the evaluation of basin soil loss with an estimate of the sediment delivery ratio SDRW for the whole watershed. The latter procedure requires that the watershed be discretized into morphological units, areas having a constant steepness and a clearly defined length, for which the corresponding sediment delivery ratio is calculated. When rainfall reaches the surface horizon of the soil, some pollutants are desorbed and go into solution while others remain adsorbed and move with soil particles. The spatial distribution of the loading of nitrogen, phosphorous, and total organic carbon can be deduced using the spatial distribution of sediment yield and the pollutant content measured on soil samples. The enrichment concept is applied to clay, organic matter, and all pollutants adsorbed by soil particles, such as nitrogen and phosphorous. Knowledge of both the rate and pattern of sediment deposition in a reservoir is required to establish the remedial strategies which may be practicable. Repeated reservoir capacity surveys are used to determine the total volume occupied by sediment, the sedimentation pattern, and the shift in the stage-area and stage-storage curves. By converting the sedimentation volume to sediment mass, on the basis of estimated or measured bulk density, and correcting for trap efficiency, the sediment yield from the basin can be computed.

scholarly journals Assessment of uncertainties in soil erosion and sediment yield estiamtes at ungauged basins: an application to the Garra River basin, India

2017 ◽  
Author(s):  
Somil Swarnkar ◽  
Anshu Malini ◽  
Shivam Tripathi ◽  
Rajiv Sinha
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Uncertainty Propagation ◽  
River Basins ◽  
Large River ◽  
Delivery Ratio ◽  
Mountainous Region ◽  
Ungauged Basins ◽  
Sediment Delivery

Abstract. High soil erosion and excessive sediment load are serious problems in several Himalayan River basins. To apply mitigation procedures, precise estimation of soil erosion and sediment yield with associated uncertainties are needed. Here, Revised Universal Soil Loss Equation (RUSLE) and Sediment Delivery Ratio (SDR) equations are used to estimate the spatial pattern of soil erosion (SE) and sediment yield (SY) in the Garra River basin, a small Himalayan tributary of River Ganga. A methodology is proposed for quantifying and propagating uncertainties in SE, SDR and SY estimates. Expressions for uncertainty propagation are derived by first-order uncertainty analysis, making the method viable even for large river basins. The methodology is applied to investigate the relative importance of different RUSLE factors in estimating the magnitude and uncertainties of SE over two distinct morpho-climatic regimes of the Garra River basin, namely, upper mountainous region & lower alluvial plains. The results suggest that average SE in the basin falls in very high category (20.4 ± 4.1 t/ha/y) with higher values in the upper mountainous region (84.4 ± 13.9 t/ha/y) than in the lower alluvial plains (17.7 ± 3.6 t/ha/y). Furthermore, the topographic steepness (LS) and crop practice (CP) factors exhibit higher uncertainties than other RUSLE factors. The annual average SY is estimated at two locations in the basin – Nanak Sagar dam (NSD) for the period 1962–2008 and Husepur gauging station (HGS) for 1987–2002. The SY at NSD and HGS are estimated to be 8.0 ± 1.4 × 105 t/y and 7.9 ± 1.7 ×106 t/y, respectively, and the estimated 90 % confidence interval contains the observed values 6.4 × 105 t/y and 7.2 × 106 t/y. The study demonstrated the usefulness of the proposed methodology for quantifying uncertainty in SE and SY estimates at ungauged basins.

scholarly journals MODELLING RESERVOIR SEDIMENTATION AT BIN EL OUIDANE DAM, MOROCCO

AGROFOR ◽  
2018 ◽  
Vol 2 (1) ◽  
Author(s):  
El Mouatassime SABRI ◽  
Ahmed BOUKDIR ◽  
Rachid El MASLOUHI ◽  
Mustapha MABROUKI ◽  
Abdellah EL MAHBOUL ◽  
...  
Keyword(s):  
Information System ◽  
Soil Erosion ◽  
Sediment Yield ◽  
Delivery Ratio ◽  
Reservoir Sedimentation ◽  
Mountainous Areas ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Sparse Vegetation ◽  
Bin El Ouidane

This study was conducted in the Oued El Abid watershed upstream of the Bin ElOuidane dam, in Tadla-Azilal province (Morocco) to quantify the dam siltationrates. To assess the annual soil erosion and the sediment yield the universal soilloss equation (USLE) was used. A geographic information system (GIS) was usedto generate and integrate maps of the USLE factors. A spatial distribution of soilerosion in the Oued El Abid watershed was obtained. The soil erosion wasdetermined for each rural commune in order to identify the soil erosion hotspot andestimate the amount of soil that has been transported downstream (Bin El OuidaneDam). Soil erosion ranged from very limited values for flat and well covered areasto over 2100 t /ha/y in mountainous areas with sparse vegetation. The total annualsoil loss within the watershed is estimated at 19. 6 million tons per year. Anequation of sediment delivery ratio (SDR) based on river gradient was calculated.It was found that the value of SDR at the outlet of the watershed Oued El Abid was0. 65 with a sediment yield of 12. 74 million tons per year which affect thedurability of the dam.

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