Variations In Water Discharge Research Articles

Chimney Filter Model Wet Scrubber to Reduce Air Pollutant Emissions on the Incinerator

In general, inpatient health care facilities produce infectious and non-infectious waste 0.3 mᶟ / day. Non-infectious waste that is burned in an incinerator without a chimney filter, can cause particles, CO, SO2, NOx (air pollutants) and cause environmental pollution. This study aims to make a chimney filter design with a Scrubber model on an incinerator at the Public Health Center, Maospati District, Magetan Regency to reduce the amount of air pollutants emitted. This type of research is experimental research. This research designed a particle trapping device, gas by spraying water into the scrubber. The independent variable of this research was the variation of the water flow sprayed in the scrubber (3.2 liters / minute, 4 liters / minute, 5.6 liters / minute). The dependent variables of this study were particles, SO2, NOx, CO. Data collection using a digital gas detector method in the form of a UV spectrophotometer. Data were analyzed descriptively, in the form of frequency distribution, and percentage, presentation of data in a table based on air emission quality standards from thermal waste processing. The results illustrate that the use of a chimney scrubber filter with water spraying 3.2 liters / minute, 4 liters / minute, 5.6 liters / minute can reduce air pollutants, emission of SO2, CO to below the air quality standard. In addition, this tool can also reduce NOx gas and particles, but not yet below the quality standard. The conclusion from the results of this study is particulate emission air pollutants, gas SO2, CO, NOx. the incinerator can be lowered by modifying variations by spraying water 3.2 liters / minute, 4 liters / minute, 5.6 liters / minute on the chimney scrubber filter on the incinerator.
 
 Keywords: incinerator; scrubber; water discharge variations; particle; gas

Identifying the sources of nitrate contamination using a combined dual isotope, chemical and Bayesian model approach in a tropical agricultural river: Case study in the Mun River, Thailand

Environmental issues triggered by increasing nitrate in agricultural river has become global concern. Identifying nitrate sources and transformation are crucial for water sources protection and eliminating nitrate contamination in an agricultural watershed. In this study, chemical and dual isotopic compositions of nitrate were employed to trace the nitrate sources and transformation processes, and proportional contribution of NO3− source were estimated by SIAR based on Bayesian model. NH4+ concentrations in middle Mun and lower Mun in wet season were significantly higher than NO3−, suggesting enhanced runoff processes by flood promote agricultural fertilized NH4+ leaching into the river. Higher Cl− concentration and NO3−/Cl− indicated that manure and sewage was the dominate nitrate source in the Lam Takhong River and the upper Mun. The overall values of δ15N-NO3− and δ18O-NO3− ranged from −3.9‰ to +16.6‰ and from −5.2‰ to +40.0‰, respectively. The results of nitrate isotopes indicated that NO3− mainly originated from soil N nitrogen, chemical fertilizer, and manure and sewage wastes. Spatially, soil N and chemical fertilizer contributed the most nitrate in the mainstream of lower Mun, middle Mun, and the Lam Takhong River; whereas over 60% of nitrate was derived from manure and sewage in the upper Mun. The spatial variation of water discharge and rainfall, together with the nitrate concentration and isotopes inferred that the nitrate sources and transformations in rain-fed river in tropical zone were distinguished from other rivers. High water discharge driven by rainfall events accelerated the nitrate export and the contribution of atmospheric deposition in wet season, and enlarged the contribution of manure and sewage in dry season. This study provided an example for further researches and approaches to assess the effects of tropical climate and agriculture on nitrate accumulation in watershed.

Status of springs in mountain watershed of western Nepal

AbstractThe study, conducted in western hilly areas of Nepal, inventoried and mapped over 4,222 springs from five different watersheds. The study showed that more than 50% of the spring sources were found under natural conditions, i.e., open spring whereas 15% of them were of pond type. Similarly, the other 15% spring was recorded as a concrete structure or tank while 1% was determined to be a well. Attempts were made to identify if a change in water discharge from springs relates to rainfall patterns. The inter-annual variability analysis shows a significant fluctuation suggesting variation in water discharge across spring sources. The lowest amount of yearly rainfall received in the river basin is governed by decreasing water flow from the springs in the upper and mid-hills of Nepal. Besides, the intra-annual variation (i.e., seasonal and concentrative nature of rainfall only during monsoon) leads to shortage of drinking water and other domestic purposes (e.g., cooking, cleaning) during the dry months of the year. This study, based on the estimation of discharge flow in these springs, revealed that about 70% were decreasing and, in particular, the flow over the recent ten years decreased significantly.

Stable isotope signatures of river and lake water from Poyang Lake, China: Implications for river–lake interactions

Interactions between the Yangtze River and Poyang Lake are undergoing rapid changes due to intensive human activities and ongoing climate change. This study investigates the spatiotemporal variations of isotopic compositions (δ2H and δ18O) in river and lake water to explore the river–lake interactions in combination with water level and discharge in Poyang Lake watershed. The results showed that river and lake water isotopes (δ2H and δ18O) exhibited highly temporal heterogeneity across seasons but their spatial differences were not remarkable, which is closely related with water sources from local precipitation and groundwater, and lake hydrology. The homogeneous patterns of lake water δ2H and δ18O indicated that Poyang Lake is a well-mixed lake in spatial scales. By contrast, the river (10.7‰) and lake (10.8‰) water d-excess and lc-excess (−0.6‰) were close to precipitation d-excess and lc-excess suggesting that precipitation is the main source for the lake and river. The slope and intercept of the river water line were slightly lower than those of the local meteoric water line and lake water line, which could be attributed to a greater evaporative enrichment in river water impacted by water flow regulation in the watershed. Interactions between Poyang Lake and Yangtze River vary seasonally, as evidently shown by the variations of water discharge and isotope compositions in river and lake water. The δ2H and δ18O of the Yangtze River water become more positive in the downstream zone than those in the upstream zone, indicating that the water from Poyang Lake has a great impact on downstream river water. This result can also be demonstrated by the efflux rate from the Poyang Lake to the Yangtze River, ranging from 17.9% to 67.9% across seasons except for the outlier rate in October resulted from the backflow of water from Yangtze River to the Poyang Lake. The complex lake–river interactions between Poyang Lake and Yangtze River mainly resulted from the regulation of Three Gorges Dam and water discharge from Poyang Lake watershed. These findings of the complex lake–river interactions will help to improve understanding of the hydrological processes and transport of pollutants and solutes around the confluence zone of the Yangtze River and Poyang Lake.

Impacts of climate change and human activities on the water discharge and sediment load of the Pearl River, southern China

Global climate change and human activities have important effects on the water discharge and sediment load of the Pearl River. In this study, the water discharge and sediment load were investigated by using hydro-meteorological data from 1954 to 2018. The linear regression, Mann–Kendall abrupt test and double mass curve were employed to detect trends and abrupt change-points in water discharge and sediment load and to quantify the effects of climate change and human activities on water discharge and sediment load. The results revealed that the annual sediment load exhibited a significant decreasing trend at a rate of − 2.24 × 104 t/year, regardless of water discharge, and an abrupt change occurred in 1998. Human activities, especially dam construction contributed 96% to this change, while 4% was due to climate change. El Niño/Southern Oscillation (ENSO) events are often associated with low precipitation, resulting in low water discharge and sediment load, indicating that changes in ENSO periodicity could affect the inter-annual periodic variations of water discharge and sediment load. As population and economy boom, more dams are being built in the Pearl River basin, and special attention should be paid to the management and mitigation of the effects of dams on sediment load.

Climatic and anthropogenic impacts on water and sediment generation in the middle reach of the Jinsha River Basin

AbstractResponse of water and sediment generation to climate change and anthropogenic activities is becoming a hot topic in the middle reach of the Jinsha River Basin. In this research, coefficients of variation and concentration degree (i.e., Cv and Cd) and double mass curve (DDC) were adopted to examine the changes in water and sediment discharge and their relationships with precipitation. The contribution rates of climatic and anthropogenic factors to water and sediment discharge were assessed through comparisons between the measured and predicted values in the baseline and postbaseline periods in the basin. The main results were: (a) the water and sediment discharges of the basin showed a decreasing trend from 2006 to 2014, with peak points of Cv and Cd of sediment discharge of the basin in 2009 and 2010, respectively; (b) the precipitation had a major influence on water discharge variations, and the peak point of the DDC of the cumulative precipitation and sediment discharge was consistent with the cumulative water and sediment discharge; and (c) under annual and flooding season scales, the contribution rates of anthropogenic factors to water discharge were 63.060% and 70.457%, respectively. The contribution rates of anthropogenic factors on sediment discharge were 84.790% and 85.541%, respectively. The impacts of anthropogenic factors on water and sediment discharge were more significant than the impacts of precipitation, in which the construction and operation of cascade hydropower stations (CHS) were believed to play a crucial role.

PENGARUH LEBAR SUDUT MANGKOK TERHADAP UNJUK KERJA TURBIN KINETIK

Power and efficiency are parameters that show the performance of a kinetic turbine. Previous studies have shown various factors such as flowrate, dimensions and geometry of kinetic turbines are variables that affect the magnitude of power and efficiency. In an effort to improve the performance of kinetic turbines it takes a deep understanding of the factors that influence it. Therefore the purpose of this study was to determine the effect of width variations of bowl blades on kinetic turbine performance. The method used in this study was real experimental on a laboratory scale. Tests were carried out on vertical shaft kinetic turbines with blade width variations of 8 cm, 9 cm and 10 cm. Each turbine is tested on variations of water discharge 45 m3/h, 50 m3/h, 55 m3/h, 60 m3/h and 65 m3/h and in rotation of 80 rpm. The results showed that the width of the bowl affected the performance of the kinetic turbine where the width of the 10 cm bowl blade had a higher performance than the width of the bowl blade 8 cm and 9 cm. The highest performance of kinetic turbines in the variation of the width of the 10 cm bowl blade was obtained at discharge conditions of 65 m3/h. In these conditions the power produced by the kinetic turbine is 12.98 Watts and the efficiency is 35.72%.

Bacterial Abundance and Physicochemical Characteristics of Water and Sediment Associated with Hydroelectric Dam on the Lancang River China.

Research on bacterial abundance in water column and sediment of dammed rivers remain poorly understood, despite their importance to biogeochemical processes, benthic ecology, and bioremediation. The present study investigates the water and sediment bacteria by epifluorescence microscopy in the reservoir (above the dam site), as well as in the downstream river stretches (below-dam site) at the middle reach of Lancang River during the wet, the normal and the dry seasons. The results demonstrated that the reservoir operating regime (water discharge variations) and strong precipitation promoted significant differences in the conditions of the river below the dam, especially for the concentration of dissolved oxygen, redox potential, electric conductivity, turbidity, and total dissolved solids in water and concentration of microbial activity in sediment. The seasonal variations were also key factors influencing water quality at the below-dam sampling sites. Nutrients concentration did not induce a significant response in bacterial abundance when inorganic nutrients were sufficient. Bacterial density in sediment was regulated by hydropower-related discharge, particle size, and type of sediments, while bacterial abundances in water were strongly linked with the physicochemical characteristics of the water, such as total dissolved solids and conductivity.

Variation and Driving Factors of Water Discharge and Sediment Load in Different Regions of the Jinsha River Basin in China in the Past 50 Years

The Jinsha River is the main source of sediment in the Yangtze River Basin. The variation of water discharge and sediment load not only affects the operation of the cascade reservoirs in the basin but also change the water and sediment conditions into the Three Gorges Reservoir. The Jinsha River Basin is divided into six regions based on the measured data of hydrological stations. Herein, the variation regularity and driving factors of water discharge and sediment load in the Jinsha River Basin are analyzed in the past 50 years using the Mann–Kendall and Rank Sum Test. Results show that the source of water and sediment in the Jinsha River Basin is different, and the abrupt and trend changes of water discharge and sediment load in different regions are evident different. Changes in precipitation, water and soil conservation projects, and the construction of reservoirs are the main driving factors of sediment load variation. The average annual sediment reduction load in the Jinsha River from 1998 to 2015 is approximately 99.57 × 106 t/y, of which the contributions of water discharge change and human activities to sediment load are 18.9% and 81.1%, respectively. The reduction of sediment load in the Jinsha River Basin can result in evident decrease in the sedimentation of cascade reservoirs, erosion of the downstream channel of the river, and considerable reduction of sediment load into the Three Gorges Reservoir.

Response of Erosion and Deposition of Channel Bed, Banks and Floodplains to Water and Sediment Changes in the Lower Yellow River, China

River channel change can be very sensitive to environmental change and human activities and it has been one of the main research topics in fluvial geomorphology. In this study, repeated channel geometric measurements were used to investigate the channel adjustment to water and sediment changes of the lower Yellow River in China in the past few decades. With a high sediment concentration and large variations of water discharge, the lower Yellow River has a much active channel in its form and location, which has hindered previous research efforts to study long-term differentiated erosion/deposition of different geomorphic units in the channel. In this study, we divided each of four typical channel across-sections at hydrological stations in the lower Yellow River into different units according to the geomorphological features, and give a detailed investigation of erosion/deposition processes of these geomorphic units and the interactions between them besides the influence of incoming water and sediment conditions. The results show that with a significant decreasing trend of both the annual runoff and sediment load of the river and abrupt changes in 1985–1996, the overall siltation trend in the river channel before 1990 had been replaced by a slight erosion trend after 2006. In the earlier period, the siltation in the upstream wandering and transitional reaches mainly occurred on floodplains and that in the downstream straight reaches principally on main channel bed. In the later period, erosion occurred mainly on high and low bank slopes in the wandering reaches and on main channel bed in the transitional reaches. The erosion became weak in the wandering reaches after 2010, continued in the transitional reaches, and was still relatively minor in the straight reaches, reflecting the downstream hysteresis channel response to changes in water and sediment discharges down dams. Our results suggest that the seasonal erosion/deposition of a geomorphic unit of the river channel can be attributed to the changes in water and sediment discharges as well as to the interaction between geomorphic units. Siltation on the main channel bed could be attributed to erosion on the bank slopes in both the sections in the wandering and transitional reaches, and erosion of the main channel bed in flood seasons was negatively related with the mean water discharge at the two sections in the straight reaches. This result implies that fixing the bank slopes in the wandering and transitional reaches and raising the water discharge in the straight reach in flood seasons are favorable options for controlling the development of the two-level perching channel of the lower Yellow River.

Temporal and spatial variations in water discharge and sediment load on the Loess Plateau, China: A high-density study

Over the past 50 years, a series of soil and water conservation measures have been implemented on the Loess Plateau, including biological, engineering, and agricultural measures. As a result, water discharge and sediment load on the plateau have undergone significant changes. In this study, we compared the water discharge and sediment load at >100 hydrological stations across the Loess Plateau during the period 2008–2016 (P2) with the water discharge and sediment load during the period 1971–1987 (P1), and detected the main sources of sediment in each of the two periods. We then performed an attribution analysis to quantify the influence of different factors on the changes in sediment load. We found the following results: (1) Water discharge was reduced by 22% in P2 compared with P1, whereas the sediment load was reduced by 74%. (2) Sediment resources are mainly concentrated between Toudaoguai and Tongguan stations: this region contributed >88% of the total sediment load at the terminal station (Huayuankou station) in both P1 and P2. (3) When considering only the changes in sediment concentration on the Loess Plateau, we conclude that the contribution of human activities was >72%. This study provides a detailed description of the temporal and spatial variations in water and sediment across the Loess Plateau, providing a reliable reference for the future development of ecological soil and water conservation measures on the Loess Plateau.

Pengaruh Sudut Pengarah Aliran Pada Turbin Air Crossflow Tingkat Dua Terhadap Putaran dan Daya

The potential of hydro energy is very large both for large scale and for small scale. Until now, the need for energy continues to increase, so that energy is a very important element in the development of a country or a region. Cross-flow turbines are one type of turbine that is often used for PLTMH. In this study planning a cross-flow water turbine applied to the height and amount of water per second in the irrigation channel water flow, this water flow will rotate the turbine shaft to produce mechanical energy. With variations in the direction of the turbine flow direction, namely 30o, 35o, and 40o, and the same variation of water discharge 10,5 L / s, 21 L / s and 31,5 L / s to determine the effect on the rotation and the power produced. In this study with 12 turbine blades, 30o blade angle, 40o flow direction angle, and 31.5 L / s water discharge obtained the highest first stage turbine rotation value is 478 rpm. Whereas at the flow direction angle of 30o with the same water discharge which is 31.5 L / s so that the first stage of the turbine is obtained is 296 rpm.

Analysing the influences of ENSO and PDO on water discharge from the Yangtze River into the sea

AbstractThe El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) are two important climate oscillations that affect hydrological processes at global and regional scales. However, few studies have attempted to identify their single and combined influences on water discharge variability at multiple timescales. In this study, we examine temporal variation in water discharge from the Yangtze River into the sea and explore the influence of the ENSO and the PDO on multiscale variations in water discharge over the last century. The results of the wavelet transform analysis of the water discharge series show significant periodic variations at the interannual timescale of 2 to 8 years and the decadal timescale of 15 to 17 years. Water discharge tended to be higher during the La Niña–PDO cold phase and lower during the El Niño–PDO warm phase. The results of the cross wavelet spectrum and wavelet coherence analyses confirm the relationship between the interannual (i.e., 2 to 8 years) and decadal (i.e., 15 to 17 years) periodicities in water discharge with the ENSO and the PDO, respectively. As an important large‐scale climate background, the PDO can modulate the influence of the ENSO on water discharge variability. In general, the warm PDO enhances the influence of El Niño events, and the cold PDO enhances the influence of La Niña events. Our study is helpful in understanding the influencing mechanism of climate change on hydrological processes and provides an important scientific guideline for water resource prediction and management.

Testing behavior and effects of PRVs and RTC valves during hydrant activation scenarios

This paper provides an insight into behavior and effects of pressure reducing valves (PRVs) and of valves controlled in real time (RTC) during hydrant activation scenarios, which determine high-flow conditions in water distribution networks (WDNs). The analysis is carried out through the pressure-driven unsteady flow modeling of an Italian WDN, in which a pressure control device is assumed to be installed in the pipe outgoing from the source. Scenarios are constructed considering alternatively a PRV or an RTC valve, as pressure control device, and two different sites for hydrant activation. The results highlight that, thanks to its capability of controlling the service pressure at the critical node, the RTC valve performs better than the PRV, which is regulated based on its outlet pressure. In fact, the adoption of the RTC valve attenuates pressure deficits in the network, above all when the control time step is suitably small to attenuate pressure head oscillations at the controlled node. An additional benefit of RTC lies in increased outflows from the hydrant. The benefits of the RTC valve are smaller when the hydrant is activated in more redundant parts of the network, where pipe water discharge variations put the system to a less severe test.

Tidal waves at Mezen mouth and surge-wave formation conditions

The factors that govern the distribution and transformation of tidal waves in the macrotidal estuary of the Mezen River have been considered, including tide range in the mouth section, water discharge in the river’s lower reaches, estuary shape, and bed resistance coefficient. Data on variations of water discharge over period 1920–2008 are given. The parameters of estuary channel narrowing in horizontal and vertical sections have been considered. The effect of narrowing and bed hydraulic friction on tide wave amplitude has been evaluated. Froude number values for the tidal estuary suggest that tidal bore can form at the Mezen mouth. The conditions of the propagation of tidal waves to the mouths of different rivers and tidal bore formation in them are considered.

Dramatic variations in water discharge and sediment load from Nanliu River (China) to the Beibu Gulf during 1960s–2013

River discharge and sediment variation is vital to material transport between river and sea, which is the focus of research on river–sea interaction. This study takes Nanliu River, a typical independent river into the sea in Beibu Gulf as an example, analyzing river regimen and river bed morphology variations during 1960s–2013 in response to climate change and human activities based on wavelet analysis and Man–Kendall test methods. The results indicate that river discharge and sediment in Nanliu River have significant seasonal characters with over 70% and 90% river discharge and sediment occur in summer half year. Compared with 1960s–1980s, the time of peaked monthly river water discharge and Suspended Sediment Concentration (SSC) during 1990s–2000s had shifted from June/August to July and from April to July, respectively. Meanwhile, both river flow and SSC present 4–6 years and 11 years fluctuations. In the recent 50 years, annual river discharge and SSC present downward trends with discharge decreased by 13.9% and 22.28% respectively in upstream and downstream while SSC decreased by 33.72% and 49.05% in upstream and downstream, respectively. Rating-curve between flow and SSC turns from clockwise rotation with enveloped area during 1965–1989 to a relatively narrow appearance during 1990–2012 in upstream, but indicates relatedly mild variation in downstream. Evolution of river bed morphology is characterized by “erosion in flood season and deposition in dry season”. Moreover, the river flow entering the sea is dominated by precipitation while the sediment entering to the sea is controlled by middle and lower reaches supply. Human activities, including soil erosion, forest conservation and hydraulic engineering along the river, are responsible for the decrease of river water and sediment discharge entering the sea.

Factors responsible for temporal and spatial variations in water and sediment discharge in Ramganga River, Ganga Basin, India

The Ramganga River flows from the mountainous regions of Kumaon Himalayas, through the forests of Jim Corbett National Park and the Ganga flood plains. It is the first major tributary of the Ganga River, carrying high sediment load causing frequent floods in major cities of Uttar Pradesh. The water discharge of the river is controlled by glacial melt as well as precipitation, making it a perennial river. This study is on the temporal and spatial variation of water discharge and sediment flux of the Ramganga River and identifies the factors which control them. In this study, 84 samples were collected from different locations over the 642 km stretch of the river and its major tributaries to observe the temporal and spatial variation of suspended matter in river water. In addition, daily water flow and sediment concentration data of two locations, e.g. Bareilly and Dabri, for a duration of 10 years were used to understand the variation in those parameters over an extended time period. An attempt was also made to relate meandering to the change in water discharge and sediment flux in the Ganga flood plains. Human activities also contribute to the sediment concentration. The results of this study showed that a significant amount of water flow and sediment flux (>75 %) were attributed to the monsoon months. However, in 2009, the results were not similar to other years, probably because of low rainfall due to the occurrence of an El Nino.

Cyclicity in air temperature and water discharge variations reconstructed with tree rings for mountainous areas of Inner Asia

The study has assessed the interdecadal cyclicity in upper and lower tree-line growth variations in the tree-ring chronologies used to reconstruct the June–July air temperatures since 1715 with the Teeli meteorological station data and May–June water discharges of the Buyant River (Mongolia) since 1474. The cycle detection verification with the instrumental hydrometeorological data allowed us to come to a conclusion about the climatic causality of 21- to 45-year cyclic variations in tree-ring growth.

Quantifying the anthropogenic and climatic contributions to changes in water discharge and sediment load into the sea: A case study of the Yangtze River, China

Based on data from the Datong hydrological station and 147 meteorological stations, the influences of climate change and human activities on temporal changes in water discharge and sediment load were examined in the Yangtze River basin from 1953 to 2010. The Mann–Kendall test, abrupt change test (Mann–Kendall and cumulative anomaly test), and Morlet wavelet method were employed to analyze the water discharge and sediment load data measured at the Datong hydrological station. The results indicated that the annual mean precipitation and water discharge exhibited decreasing trends of −0.0064mm/10yr and −1.41×108m3/yr, respectively, and that the water sediment load showed a significant decreasing trend of −46.5×106t/yr. Meanwhile, an abrupt change in the water discharge occurred in 2003. The sediment load also exhibited an abrupt change in 1985. From 1970 to 2010, the climate change and human activities contributed 72% and 28%, respectively, to the water discharge reduction. The human-induced decrease in the sediment load was 914.03×106t/yr during the 1970s and 3301.79×106t/yr during the 2000s. The contribution from human activities also increased from 71% to 92%, especially in the 1990s, when the value increased to 92%. Climate change and human activities contributed 14% and 86%, respectively, to the sediment load reduction. Inter-annual variations in water discharge and sediment load were affected by climate oscillations and human activities. The effect of human activities on the sediment load was considerably greater than those on water discharge in the Yangtze River basin.

The quantitative estimation of sediment load changes entering Poyang Lake Basin induced by climate change and anthropogenic impacts

The numerical model Hydro Trend is applied to simulate the variations of water discharge and sediment fluxes into Poyang Lake during 1956- 2010 from the five tributaries of Poyang Lake Basin, namely Gan, Fu, Xin, Rao and Xiu rivers. Furthermore, the influences of climate change, vegetation cover variation and reservoirs construction on the sediment load are analyzed, and the contribution of the above three factors to the sediment load entering the Poyang Lake is quantitatively evaluated. The results show that, during the period of 1956-2010,the average annual sediment discharge into Poyang Lake under the influence of climate,vegetation cover and reservoir construction reached 15.5 Mt, 20.8 Mt, 8.5 Mt, respectively;whereas, the sediment load entering the Poyang Lake under the combined- influence of the above three factors is 12.6 Mt a- 1. In addition, during the same period, the sediment load delivered to the Poyang Lake increased by 4.2 Mt a- 1due to water and soil erosion, and decreased by 8.2 Mt a- 1attributed to reservoir interception, which accounted for 32.4% and63.2% of the observed sediment load discharged into the Poyang Lake, respectively. From 1956 to 1989, the increased sediment load caused by water and soil erosion and the decreased sediment load induced by dam emplacement, in terms of both quantity of 5.1 Mt a- 1, is equivalent; However, during 1990- 2010, the sediment load resulting from water and soil loss decreased to 2.7 Mt a- 1, and that intercepted by reservoirs increased to 13.3 Mt a- 1, suggesting that the effect of reservoirs construction on the changes of sediment load entering the Poyang Lake is 5 times of that of water and soil erosion.