Sediment Delivery Ratio Values Research Articles

GIS-Based RUSLE Reservoir Sedimentation Estimates: Temporally Variable C-Factors, Sediment Delivery Ratio, and Adjustment for Stream Channel and Bank Sediment Sources

The empirical Revised Universal Soil Loss Equation (RUSLE) has been adapted to geographical information system (GIS) frameworks to study the spatial variability of soil erosion across landscapes and has also been used to estimate reservoir sedimentation. The literature presents contradictory results about the efficacy of using RUSLE in a GIS context for quantifying reservoir sedimentation, requiring further evaluation and validation of its estimates relative to measured reservoir sedimentation. Our primary objective was to determine if these contradictory results may be a function of the RUSLE’s inability to account for sediments derived from gullies, stream channels, or stream banks; the temporal variability of some of RUSLE’s empirically based factors such as the land cover/land management (C-) factor; and in some model renditions, the choice of value for the sediment delivery ratio (SDR). The usefulness of adjusting these estimates using a regional representative value of gully/stream bank sediment contributions was also assessed. High-spatial horizontal resolution (2 m) digital elevation models (DEMs) for 12 watersheds were used together with C-factor data for five representative years in a GIS-based RUSLE model that incorporates SDR within a sediment routing routine to study the impacts of choice of C-factor and SDR on reservoir sedimentation estimates. Choice of image date for developing C-factors was found to impact reservoir estimates. We also found that the value of SDR for some of the study watersheds would have to be unrealistically small to produce sedimentation estimates comparable to measured values. Estimates of reservoir sedimentation were comparable to measured data for 5 of the 12 watersheds, when the regionally based adjustment for gully/stream bank contributions was applied. However, differences remained large for the remaining seven watersheds. Statistical analysis revealed that certain combinations of geomorphic, pedologic, or topographic variables could be used to predict the degree of sediment underestimation with a significant and high level of correlation (0.72 < R2 ≤ 0.99; p-value < 0.05). Our findings indicate that the level of agreement between GIS-based RUSLE estimates of reservoir sedimentation and measured values is a function of watershed characteristics; for example, the area-weighted soil erodibility (K-) factor of the soils within the watershed and stream channels, the stream entrenchment ratio and bank full depth, the percentage of the stream corridor having slopes ≥ 21°, and the width of the stream flood way as a percentage of the watershed area. Within the context of GIS, these metrics are easily obtained from digital elevation models and publicly available soils data and may be useful in prioritizing reservoirs’ assessments for function and safety.

Characteristics of watershed dynamic sediment delivery based on improved RUSLE model

Soil loss is a worldwide environmental problem involving slope erosion and sediment delivery. The soil erosion is simulated universally and efficiently by Revised Universal Soil Loss Equation (RUSLE) model. Still, there are certain errors in the rainfall-runoff erosivity (R) factor in RUSLE model owing to rainfall inhomogeneity. The sediment delivery progress is generalized by the sediment delivery ratio (SDR), meanwhile, its key influencing factors and changing laws remain unclear under intense human interference. In this study, we improved the performance of the RUSLE model by introducing the precipitation concentration degree of different rainfall intensities into the R factor. Then, we get the monthly SDR of Mahuyu watershed during 2006–2016 is range from 0 to 7.94 according to the erosion amount simulated by the improved RUSLE model and the measured sediment yield. Furthermore, there is a logarithmic function relationship between the monthly SDR and the maximum daily streamflow at a certain range. Results showed that (i) it is reasonable and necessary to consider the influence of precipitation concentration in the simulation of soil erosion under the probable condition of more concentrated rainfall in the future, (ii) Streamflow become the dominant factor determining the value of SDR. The findings could be used as a reference for the calculation of R factor in watersheds with extreme rainfall events, and also as a guidance for soil conservation.

Analysis of Erosion and Sediment Movement at the Confluence of Two Rivers (A Case Study of Tawaeli River, Central Sulawesi, Indonesia)

The research was conducted at the confluence of two rivers on Tawaeli River, Nupabomba Village, Tanantovea District, Central Sulawesi, Indonesia. This research intends to determine the rate of erosion in the watershed as part of the source of sediment transport at the confluence of the Tawaeli River. The research method applied to collect primary data and secondary data. In determining the rate of erosion, researchers used the Universal Soil Loss Equation (USLE) method. By calculating the value of the erosion rate using the USLE method using ArcGIS, the total value of the erosion rate that occurs in the Upper Tawaeli watershed area is 13506,865 tons/year where each hectare of the watershed is able to produce sediment from the erosion process of 4,3977 tons/ha/year included in the very low classification based on the criteria for the value of the erosion hazard level, and based on the erosion hazard level class, most of the watershed area, which is an area of 3053,572 ha or equivalent to 99.42% of the total area of the Upper Tawaeli watershed, is included in the area category with a very low level of erosion hazard. The results of the analysis through the sediment delivery ratio (SDR) using the Auserwald equation obtained an SDR value of 0.223 which indicates that not all sediment from the erosion process is transported or enters the river, therefore the sediment produced at the river outlet (STA. 3.4). is smaller than the erosion rate result of 261,278 tons/year. In addition, the results of this research also reveals that the configuration of the riverbed at the meeting point of the tributary has changed from the previous one which had a base elevation of 175,143 m, after an aggradation phenomenon occurred which was marked by an increase in the elevation of the riverbed as high as 0.348 meters.

The Study of Sedimentation at Jongkong Reservoir in District Central of Bangka through Erosion of Catchment Area

Jongkong reservoir creates a reservoir of water that is used for the purposes of raw water as fundamental media for improvement of drinking water production especially at dry season for the District of Koba. The advantage of being able to hold water in wet season and releasing it in dry season will be detained if the life storage of the reservoir can be utilized effectively, but sedimentation problem will decrease its volume which can influence the life time of reservoir. Finally the reservoir becomes less effective, so it is very important to study. The method which is used to predict an average erosion rate in the catchment area considers factors of rain erosivity, soil erodibility, ground inclination of slope or slope length, management of crop and land, soil conservation. Calculation was done by using the USLE equation (Universal Soil Loss Equation) which was developed by Wischmeier and Smith (1965, 1978). From this research result, the prediction of surface erosion rate in the basin catchment area in the year 2019 is equal to 53.20 mm/year or equivalent with 62,491.92 m3/year, and the value of Sediment Delivery Ratio (SDR) is equal to 32,28 %. The number of material which eroded is equal to 957.59 Ton/Ha/year so it is classified into the medium erosion class category. The dead storage of 5% of the the volume of the reservoir cage will be fully charged in the year 2022 or for 3 The next year and the total volume of the reservoir Ridge will be full of sediment in the year 2062 or 43 years.

Exploring the potential of using 7Be measurements to estimate soil redistribution rates in semi-arid areas: results from Western Iran and Southern Italy

The need for further research to investigate the possibility of using 7Be as a soil erosion tracer under a range of climatic conditions, specifically in arid and semi-arid agro-environments, has been emphasised in the literature. In this context, this paper reports research conducted in two semi-arid areas located in Western Iran and Southern Italy in order to assess the potential of using 7Be measurements for estimating soil erosion over short timescales. The two study sites differ in terms of land use. More specifically, the area in Western Iran, under cultivation, is cropped mostly under wheat, barley and pea rotation. The area in Southern Italy has never been cultivated, has few eucalyptus trees, resulting from re-afforestation conducted in 1966 and retains a sparse grass cover. Soil sampling required two field campaigns undertaken in April 2011 and April 2016 in Western Iran and Southern Italy, respectively. In Western Iran, the 7Be reference inventory was estimated at 326 ± 40 Bq m−2 and the corresponding value of the shape factor was equal to 3.57 kg m−2. The soil loss was calculated to be 6.8 Mg ha−1, resulting in a Sediment Delivery Ratio (SDR) of ca. 80%. In Southern Italy, the 7Be reference inventory was equal to 180 ± 20 Bq m−2, emphasising a lower penetration of 7Be into the soil that is documented by a lower value of the shape factor (2.45 kg m−2). The overall results provided a net soil loss of ca. 20.7 Mg ha−1. In this case, no deposition was documented and a SDR value of ca. 100% was calculated. The magnitude of soil erosion reflects, for both sites, the steep topography, the different management system and the heavy rainfall occurring during a period that coincides with the absence of vegetative cover. The results obtained in this study are in line with similar studies carried out in other countries and suggest that, in cultivated areas, care must be taken when traditional cultivation systems are applied; in re-afforested areas, the presence of a uniform vegetative cover is crucial in protecting soil from erosion. However, there still is a need for further work to assess the feasibility of using 7Be in different areas and under different land uses or vegetation covers. Also, further refining of the conversion model, which is based here on the simple exponential function, are still possible.

KAJIAN EROSI DAN POTENSI SEDIMENTASI DI DAS KAHAYAN PROVINSI KALIMANTAN TENGAH

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.

Evaluation of the sediment delivery ratio of small watersheds in the forest-steppe and steppe regions of the Russian plain

Dependence between sediment delivery ratio (SDR) and morphometric parameters of a set of 27 previously studied small watersheds located in the central and southern parts of the Russian plain in various geomorphological conditions in the areas of active agricultural development is established. The SDR of small riversheds were determined using field methods. When comparing the SDR with individual terrain characteristics, there is no direct linear relationship between each of the parameters and SDR. The highest value of the correlation coefficient between the SDR and relief indicators of the small rivershed was obtained for the average steepness of the watershed area (r = 0.52). As one of the verified morphometric characteristics, the parameter of the planimetric form of the rivershed area (the circularity coefficient) was used. The resulting equation includes several morphometric parameters: the ratio of area and perimeter (derived from the circularity coefficient) and the amplitude of absolute heights. These parameters allow taking into account the watershed planimetric form and the landform energy potential. About half the SDR values, obtained by the equation, deviate within ±10% of the initial values. For watersheds with SDR > 50%, the calculated values are significantly different from the initial values due to the spread of data in this area. The obtained equation of SDR can be used together with land-use remote sensing data to study the dynamics of sediments redistribution in river basins.

Prediction of Land Erosion by USLE Method in Dibawah Lake Catchment Areas, Solok Regency

The Government of West Sumatra functioned Dibawah Lake as a tourist area. Besides that, it is also used as an irrigation water source. Location of the Dibawah Lake, which is in the highlands with slope levels between 28% - 40% gives rise to the potential for land erosion in the lake catchment area, which is quite high. This study aims to predict the magnitude of land erosion, sediment delivery ratio and sedimentation rate in lake bodies using topographic spatial analysis and the USLE (Universal Soil Loss Equation) method. From the results of the analysis, it was found that the Dibawah Lake Catchment Area reached 2881.7 ha, which was divided into 27 sub-catchments. The rainfall erosivity value (R) of the Dibawah Lake catchment area is 8219.46 mm. The types of soils in the Dibawah Lake catchment area are cambisols and Andosols with soil erodibility values (K) 0.22 and 0.20. The slope average of the Dibawah lake catchment area is 28% - 40%. The total land erosion in the Dibawah Lake catchment area is 1061.36 tons/ year. The Sediment Delivery Ratio (SDR) of the Dibawah Lake catchment area is 31.08%. With an SDR value of 31.08%, the sedimentation rate in the Dibawah Lake body is 329.85 tons/ year.

Using the comprehensive governance degree to calibrate a piecewise sediment delivery ratio algorithm for dynamic sediment predictions: A case study in an ecological restoration watershed of northwest China

The sediment delivery ratio (SDR) is a bond of slope erosion and channel sediment transport but exhibits poor dynamic applicability, which makes it difficult to accurately identify the spatio-temporal evolutions of sediment yield in an ecological restoration watershed with different governance degrees. i) An innovative piecewise SDR algorithm considering the multi-stage effects of the comprehensive governance degree from 1991 to 2013 was embedded in a dynamic sediment yield model to solve the complex dynamic applicability problem of the SDR in sediment yield predictions. ii) The main advantages of the improved SDR algorithm over the existing models are small data requirements, dynamic mechanism, wide application range, reduced complexity, ease of use and better accuracy. iii) The erosion intensities of sloping farmland and orchards in the Yangou River watershed were both intensive at the early stage of governance in 1997. The trends in erosion and sediment yield were closely related to the watershed management measures. The soil erosion modulus in this watershed decreased from 5657 t/km2 in 1997 to 906.2 t/km2 in 2012, a total decrease rate of 84%. The sediment yield modulus decreased from 4500 t/km2 in 1997 to 51.9 t/km2 in 2012, a total reduction rate of 98.8%. iv) The annual dynamics of the SDR values were not completely affected by the random fluctuations in rainfall erosivity but showed an obvious decreasing trend from 0.932 in 1992 to 0.057 in 2012 due to the soil conservation measures. The annual average SDR in 1991–2013 was approximately 0.38, indicating that the average sediment yield after ecological restoration was significantly less than the average soil erosion in the Yangou River watershed. The results of this study may provide a better understanding of dynamic SDR studies and reveal the profound insights needed to guide watershed soil conservation planning.

MODELLING RESERVOIR SEDIMENTATION AT BIN EL OUIDANE DAM, MOROCCO

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.

Assessment of soil erosion in a monsoon-dominated mountain river basin in India using RUSLE-SDR and AHP

ABSTRACTThe long-term average annual soil loss (A) and sediment yield (SY) in a tropical monsoon-dominated river basin in the southern Western Ghats, India (Muthirapuzha River Basin, MRB; area: 271.75 km2), were predicted by coupling the Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratio (SDR) models. Moreover, the study also delineated soil erosion risk zones based on the soil erosion potential index (SEPI) using the analytic hierarchy process (AHP) technique. Mean A of the basin is 14.36 t ha−1 year−1, while mean SY is only 3.65 t ha−1 year−1. Although the land use/land cover types with human interference show relatively lower A compared to natural vegetation, their higher SDR values reflect the significance of anthropogenic activities in accelerated soil erosion. The soil erosion risk in the MRB is strongly controlled by slope, land use/land cover and relative relief, compared to geomorphology, drainage density, stream frequency and lineament frequency.

Kajian Erosi Dan Hasil Sedimen Untuk Konservasi Lahan DAS Kreo Hulu

Watershed as rainwater catchment are is susceptible with erosion and sedimentaion problems. The calculation of erosion and sediment yield can be calculated with USLE and SDR (Sediment Delivery Ratio) method at each area unit. This research intends to find out the erosion value, distribution and prediction of sediment yield contained in Kreo Hulu Watershed in 2009-2014. Data accumulation methods for the research are observation, documentation, and field measurement. The erosion forecast result in this research obtained based on overlay few maps, that is rain erosivity map, soil erodibility map, length of slope map, management and conservation soil map. This research was construct with using rainfall data from 2009 until 2014. Based on the calculations model of erosion is known that the erosion in the watershed upstream Kreo fluctuation occurring annually. With the result of erosion from 2009 until 2014 are respectively 17.45 tons; 18.78 tons; 17.83 tons; 25.70 tons; 31.62 tons; 26.17 tons. Sediment yield estimates obtained by the relationship between the unit value erosion (based mapping unit), as well as the erosion area of the unit value of Sediment Delivery Ratio in watershed. By calculation of these factors, the value of watershed sediment Kreo Hulu forecast results for 2009-2014 are respectively 2,78 tons, 2.93 tons; 2,78 tons; 4.01 tons; 4.93 tons; 4,08 tons. Spatial distribution of erosion prediction Kreo upstream watershed of very high value erosion is largely rural area/village Gunungpati, Banjarejo, Karangmalang, Lebak and Cepoko. Weight and middle erosion are covering parts of Pasigitan, Branjang, Kalisidi, and Tinjomoyo. Then need to increase conservation of alternative methods land mechanically and vegetative at upstream Kreo watershed.

Catchment Erosion and Sediment Delivery in a Limno-Reservoir Basin Using a Simple Methodology

Accelerated soil erosion is a threat for the societies due to the loss of ecosystems services. Soil erosion and sediment delivery have been assessed in a small catchment of Central Spain with a new water body, the Pareja Limno-reservoir, located in its outlet. This limno-reservoir was created in 2006 with environmental and recreational purposes in the riverine zone of a large reservoir. Sedimentation risk is an issue of concern regarding limno-reservoirs environmental feasibility. Thus, the study of the soil erosion in the Pareja Limno-reservoir catchment and its sediment delivery seemed of the utmost importance. In this paper we establish an affordable and simple methodology to address it. A soil erosion and deposition monitoring network was installed in the Ompolveda River basin (≈88 km2), which flows into the Pareja Limno-reservoir. Results obtained were related with those from a sedimentation study previously carried out in the limno-reservoir. Gross hillslope erosion in the catchment was 6.0 Mg ha−1 year−1, which is in agreement with values reported for Mediterranean areas. After subtraction of the deposition measured, a soil loss of 1.2 Mg ha−1 year−1 was found in the catchment. Sediment delivery ratio (SDR) was estimated to be 3.8 %. SDR is low as a result of the low connectivity between the stream network and the limno-reservoir. Some local characteristics may also have a secondary influence in the low SDR value. Results obtained support the environmental feasibility of the Pareja Limno-reservoir from the sedimentation risk perspective. They also demonstrate that the methodology followed allows the assessment of soil loss and sediment delivery at a catchment scale, and the identification of areas where the erosion problems are most severe.

Distributed empirical algorithms to estimate catchment scale sediment connectivity and yield in a subtropical region

AbstractThe intensity of soil loss and sediment delivery, representing hydrologic and geomorphic processes within a catchment, accelerates with rapid changes in land cover and rainfall events. An underlying component of sustainable management of water resources is an understanding of spatial and temporal variability and the adverse influences of regional parameters involved in generating sediment following widespread changes in land cover. A calibrated algorithm of soil loss coupled with a sediment delivery ratio (SDR) was applied in raster data layers to improve the capability of a combined model to estimate annual variability in sediment yields related to changes in vegetation cover identified by analyses of SPOT imagery. Four catchments in Kangaroo River State forest were assessed for annual changes in sediment yields. Two catchments were selectively logged in 2007, while the two other sites remained undisturbed. Results of SDR estimates indicated that only a small proportion of total eroded sediment from hillslopes is transported to catchment outlets. Larger SDR values were estimated in regions close to catchment outlets, and the SDR reduced sharply on hillslopes further than 200–300 m from these areas. Estimated sediment yield increased by up to 30% two years after land cover change (logging) in 2009 when more storm events were recorded, despite the moderate density of vegetation cover in 2009 having almost recovered to its initial pre‐logging (2005) condition. Rainfall had the most significant influence on streamflow and sediment delivery in all catchments, with steeply sloping areas contributing large amounts of sediment during moderate and high rainfall years in 2007 and 2009. It is concluded that the current scenario of single‐tree selection logging utilized in the study area is an acceptable and environmentally sound land management strategy for preservation of soil and water resources. Copyright © 2013 John Wiley & Sons, Ltd.

Modeling the spatial distribution of water erosion within a Spanish olive orchard microcatchment using the SEDD model

Olive orchards located in mountainous or hilly landscapes in Southern Spain have been identified as one of the major sources of sediments for streams in the region. This paper presents a modeling study of the magnitude and spatial distribution of sources of sediment within a small 6.1 ha olive orchard forming a microcatchment in a mountainous area. The model used was SEDD, which was calibrated using rainfall, runoff and soil erosion patterns monitored over a 3-year period. Although the data series are incomplete, 46 events were observed. SEDD permitted an analysis of the erosive behavior and the sediment delivery ratio ( SDR) in the catchment on an event scale. High variability in catchment responses was observed, due to differences in the characteristics of storms and the seasonal ground cover. A small group of two or three erosive events, occurring mainly in autumn, were responsible for most annual runoff and sediment loads, while the impact of spontaneous grass cover was apparent in events occurring in spring, where, despite high runoff depth, the sediment loss was low. This bimodal tendency justified the calibration of the SEDD model through the medians of β-values in both the periods September–January and February–June. The results of the calibration ( E = 0.97 and RMSE = 0.03 t ha − 1 ) confirmed the applicability of SEDD to predict soil loss in the microcatchment and to allow us to complete the data series. Although the annual mean of SDR in the catchment for the study period was 3.8%, high spatial variability was found in the geomorphological units identified, with SDR values between 0.3% and 21.7%. On the event scale, probabilities of 50% for surpassing an SDR value of 10% were calculated for only 6% of the catchment area. The location of these most significant sources of sediment will permit the design of more efficient management plans in order to reduce sediment discharge into streams.

Utilizing Geographic Information System for Prediction of Soil Erosion in Sono Sragen Catchment Area

Problem statement: Embung is a small dam created by manmade lakes and used to catch water during rainy season for an irrigation source. In Sragen area, Embung Sono is one of around twenty embung that used to catch rain water for irrigation. Soil erosions in catchment area are potential to reduce water capacity of the embung. Although many embung have been constructed in Sragen areas, the numbers of soil erosion in catchment area of embung are not well considered. Approach: Soil erosion in the Sono catchment area was analyzed using Geographic Information System (GIS) and Universal Soil Loss Equation (USLE) method. Results: The result showed that total number of soil erosion in the Sono catchment area is 63.50 ton/ha-year and categorized in moderate classified. Value of Sediment Delivery Ratio (SDR) for catchment was 0.34. Empirical equation proposed by Renfro, Vanoni and USDA were also used to analyze the SDR value. Conclusion: It was found that USDA is the best method that can be used to predict soil erosion in Sragen area. It means the crop management and environmental conservation in Sono catchment need to be improved.

Assessment of soil erosion and sediment yield in Liao watershed, Jiangxi Province, China, Using USLE, GIS, and RS

Soil erosion by water is a serious problem all over the world. In China, about 1 790 000 km2 of land suffers from water erosion, which accounts for 18.3% of China’s total area. This study was conducted in the Liao (潦) watershed in Jiangxi (江西) Province to assess annual soil erosion and sediment yield using the Universal Soil Loss Equation (USLE). A geographic information system (GIS) was used to generate maps of the USLE factors, which include rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover (C), and conservation practice (P) factors. By integrating these factors in a GIS, a spatial distribution of soil erosion over the Liao watershed was obtained. The soil erosion was found to vary from nil for flat and well-covered areas to more than 500 t/ha/a in mountainous places with sparse vegetation. The average soil erosion is 18.2 t/ha/a with a standard deviation of 109.3 t/ha/a. The spatial distribution of erosion classes was estimated. About 39.5% of the watershed is under the tolerant erosion rate, and 60.5% of the study area experienced erosion to different extents. A spatially distributed sediment delivery ratio (SDR) module was developed to account for soil erosion and deposition. It was found that the SDR value at the outlet of the Liao watershed was 0.206, and the sediment yield was 1.32 million t/a, which was 20% higher than the measured sediment. The results can be used to identify the soil erosion hot spots and develop the best soil erosion management practices and help estimate the quantity of soil that was transported into the downstream Poyang (鄱阳) Lake.