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

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.

2019 ◽  
Vol 7 (2) ◽  
pp. 100-111
Author(s):  
Miskar Maini ◽  
Junita Eka Susanti

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.


2019 ◽  
Vol 7 (2) ◽  
pp. 70-84
Author(s):  
Bayu Oktasandi ◽  
Endang Setyawati Hisyam ◽  
Indra Gunawan

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.


RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Carina Barbosa Colman ◽  
Karina Mendes Pinheiro Garcia ◽  
Rodrigo Bahia Pereira ◽  
Enio Arriero Shinma ◽  
Fernanda Ely Lima ◽  
...  

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.


2019 ◽  
Vol 11 (7) ◽  
pp. 1840 ◽  
Author(s):  
Valter Marques ◽  
Marcos Ceddia ◽  
Mauro Antunes ◽  
Daniel Carvalho ◽  
Jamil Anache ◽  
...  

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.


2014 ◽  
Vol 70 (3) ◽  
pp. 495-501 ◽  
Author(s):  
S. E. Lee ◽  
S. H. Kang

Spatially distributed sediment delivery (SEDD) models are of great interest in estimating the expected effect of changes on soil erosion and sediment yield. However, they can only be applied if the model can be calibrated using observed data. This paper presents a geographic information system (GIS)-based method to calculate the sediment discharge from basins to coastal areas. For this, an SEDD model, with a sediment rating curve method based on observed data, is proposed and validated. The model proposed here has been developed using the combined application of the revised universal soil loss equation (RUSLE) and a spatially distributed sediment delivery ratio, within Model Builder of ArcGIS's software. The model focuses on spatial variability and is useful for estimating the spatial patterns of soil loss and sediment discharge. The model consists of two modules, a soil erosion prediction component and a sediment delivery model. The integrated approach allows for relatively practical and cost-effective estimation of spatially distributed soil erosion and sediment delivery, for gauged or ungauged basins. This paper provides the first attempt at estimating sediment delivery ratio based on observed data in the monsoon region of Korea.


2013 ◽  
Vol 68 (1) ◽  
pp. 124-133 ◽  
Author(s):  
S. E. Lee ◽  
S. H. Kang

This paper describes a sediment delivery ratio (SDR) using the Geographic Information System (GIS)-based Revised Universal Soil Loss Equation (RUSLE), to calculate the soil loss and sediment rating curve (SRC) basis of measured data in the six basins of Four Rivers, South Korea. The data set for calculating SDR was prepared during 3 years from 2008 to 2010. Mean soil loss in the six basins of Four Rivers was 515–869 t km−2 yr−1 and mean specific sediment yield (SSY) was 20–208 t km−2 yr−1 with basin size. The SDR ranged from 0.03 to 0.33 in the six rivers. Most sediment flows in the monsoon period from June to September (mean Max.: >97%; mean Min.: >84%), but SDR is lower than those of similar continental river basins. This is due to environmental factors, for example rainfall characteristics and associated run-off, soil characteristics and cultivated patterns with increasing basin size. This research provides the first application of SDR based on the observed field data in South Korea.


Author(s):  
A. Rymszewicz ◽  
E. Mockler ◽  
J. O'Sullivan ◽  
M. Bruen ◽  
J. Turner ◽  
...  

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.


2020 ◽  
Vol 31 (3) ◽  
pp. 113-114
Author(s):  
Nelson Laville ◽  
Kenrick Witty ◽  
Ulises Garcia

The Beyond Compliance Global team held an interview by video link with Dr Eric Jang, United States Department of Agriculture, Agricultural Research Service (USDA/ARS), now retired. His lab was based in Hawaii, where he continues to reside. Eric was an early advocate and one of the originators of the concepts for Systems Approach.


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