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1
Ng, H. Y. F., T. Mayer e J. Marsalek. "Phosphorus Transport in Runoff from a Small Agricultural Watershed". Water Science and Technology 28, n. 3-5 (1 agosto 1993): 451–60. http://dx.doi.org/10.2166/wst.1993.0448.
Testo completoAbstract (sommario):
Impacts of phosphorus (P) discharges on receiving waters depend on the magnitude of loadings and their P bioavai lability which varies for various phosphorus forms. To advance the understanding of P transport in agricultural runoff, the main nonpoint source of P, seasonal and short-term variabilities in P forms were studied. Total phosphorus (TP), total paniculate phosphorus (TPP) and total suspended sediment (SS) concentrations were measured in runoff from the Nissouri Creek agricultural watershed. About 54% of TP in runoff was associated with sediment particles (>0.45 µm). The remaining 46% of TP was transported in the dissolved form, as soluble P (SP). Significant correlations were found between TPP and the inorganic fraction of suspended sediments (IS), and SP and the organic matter concentration in suspended sediments (OS). None of the phosphorus forms studied correlated well with runoff volumes. TP, SP and TSS concentrations varied substantially during runoff events and during the year. Higher proportion of paniculate P were typically observed at the time when runoff volumes were high, often during the early phase of runoff. Highest TP and SP concentrations were measured in spring and fall runoffs exceeding those in summer runoffs by an order of magnitude. The suspended sediments concentrations in spring and fall runoffs were, however, two orders of magnitude higher than those in the summer runoffs.
2
Fok, Hok Sum, Yutong Chen e Linghao Zhou. "Prospects for Reconstructing Daily Runoff from Individual Upstream Remotely-Sensed Climatic Variables". Remote Sensing 14, n. 4 (18 febbraio 2022): 999. http://dx.doi.org/10.3390/rs14040999.
Testo completoAbstract (sommario):
Basin water supply, planning, and its allocation requires runoff measurements near an estuary mouth. However, insufficient financial budget results in no further runoff measurements at critical in situ stations. This has recently promoted the runoff reconstruction via regression between the runoff and nearby remotely-sensed variables on a monthly scale. Nonetheless, reconstructing daily runoff from individual basin-upstream remotely-sensed climatic variables is yet to be explored. This study investigates standardized data regression approach to reconstruct daily runoff from the individual remotely-sensed climatic variables at the Mekong Basin’s upstream. Compared to simple linear regression, the daily runoff reconstructed and forecasted from the presented approach were improved by at most 5% and 10%, respectively. Reconstructed runoffs using neural network models yielded ~0.5% further improvement. The improvement was largely a function of the reduced discrepancy during dry and wet seasons. The best forecasted runoff obtained from the basin-upstream standardized precipitation index, yielded the lowest normalized root-mean-square error of 0.093.
3
Gu, Hai Yan, Yong Wang e Lei Yu. "Runoff Fractal Dimension of Songhua River Basin in Harbin Station Based on Db4 Wavelet". Advanced Materials Research 550-553 (luglio 2012): 2537–40. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2537.
Testo completoAbstract (sommario):
The wavelet analysis and fractal theory into the analysis of hydrological time series, fluctuations in hydrological runoff sequence given the complexity of the measurement methods--- fractal dimension. The real monthly runoffs of 28 years from Songhua River basin in Harbin station are selected as research target. Wavelet transform combined with spectrum method is used to calculate the fractal dimension of runoff. Moreover, the result demonstrates that the runoff in Songhua River basin has the characteristic of self-similarity, and the complexity of runoff in the Songhua River basin in Harbin station is described quantificationally.
4
Kawara, Osami, Manabu Uehara e Kanako Ibaragi. "A study on the water quality of runoff from forest". Water Science and Technology 39, n. 12 (1 giugno 1999): 93–98. http://dx.doi.org/10.2166/wst.1999.0534.
Testo completoAbstract (sommario):
The important non-point sources in Japan are urban areas, rice paddy fields and forest. The forest area in river basins occupies about 70 per cent. Furthermore, Japanese forest is usually on steep mountains. Therefore, pollutant loads from the forest cannot be ignored in Japan. In this study, we discuss the seasonal variations of water quality of runoff from forest, and of component runoffs, inter-surface runoff and groundwater runoff, based on observations and on the results separated by a numerical filter. The seasonal variations of water quality and four types of relations between water quality and flow rates of component runoffs were noted.
5
Xiao, Ziwei, Peng Shi, Peng Jiang, Jianwei Hu, Simin Qu, Xingyu Chen, Yingbing Chen, Yunqiu Dai e Jianjin Wang. "The Spatiotemporal Variations of Runoff in the Yangtze River Basin under Climate Change". Advances in Meteorology 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/5903451.
Testo completoAbstract (sommario):
A better understanding of the runoff variations contributes to a better utilization of water resources and water conservancy planning. In this paper, we analyzed the runoff changes in the Yangtze River Basin (YRB) including the spatiotemporal characteristics of intra-annual variation, the trend, the mutation point, and the period of annual runoff using various statistical methods. We also investigated how changes in the precipitation and temperature could impact on runoff. We found that the intra-annual runoff shows a decreasing trend from 1954 to 2008 and from upper stream to lower stream. On the annual runoff sequence, the upstream runoff has a high consistency and shows an increasing diversity from upper stream to lower stream. The mutation points of the annual runoff in the YRB are years 1961 and 2004. Annual runoff presents multitime scales for dry and abundance changes. Hurst values show that the runoffs at the main control stations all have Hurst phenomenon (the persistence of annual runoff). The sensitivity analyses of runoff variation to precipitation and temperature were also conducted. Our results show that the response of runoff to precipitation is more sensitive than that to temperature. The response of runoff to temperature is only one-third of the response to precipitation. A decrease in temperature may offset the impact of decreasing rainfall on runoff, while an increase in both rainfall and temperature leads to strongest runoff variations in the YRB.
6
Ren, Liliang, Xiaofan Liu, Fei Yuan, Jing Xu e Wei Liu. "Quantitative analysis of runoff reduction in the Laohahe basin". Hydrology Research 43, n. 1-2 (1 febbraio 2012): 38–47. http://dx.doi.org/10.2166/nh.2011.135.
Testo completoAbstract (sommario):
In order to determine the reason for runoff reduction, daily natural runoff series were restored using a conceptual rainfall–runoff model. The period of 1970–1979 was regarded as a base period with little human activity; model parameters for each subcatchment within the Laohahe basin were calibrated for this period. The effects of human activity and climate change on runoff were quantified by comparing the observed runoff and the natural runoff simulated by the hydrological model. The results show that the observed annual mean runoffs in the 1980s and especially in the 2000s are smaller than those of the 1970s. Although runoff reduction in the 1980s and 2000s is mainly caused by climate change, human activity also plays an important role on the runoff reduction. Taking the 2000 as an example, human activity and climate change are responsible for 45.6 and 54.4% of the runoff reduction in Laohahe basin, respectively. The effect of human activity on runoff reduction in the Laohahe basin is increasingly intensive from the 1980s to the 2000s. Human activity in the Dianzi catchment has the most drastic effect within the Laohahe basin.
7
Lv, Meizhao, Hui Lu, Kun Yang, Zhongfeng Xu, Meixia Lv e Xiaomeng Huang. "Assessment of Runoff Components Simulated by GLDAS against UNH–GRDC Dataset at Global and Hemispheric Scales". Water 10, n. 8 (24 luglio 2018): 969. http://dx.doi.org/10.3390/w10080969.
Testo completoAbstract (sommario):
The current evaluations of global land data assimilation system (GLDAS) runoff were generally limited to the observation-rich areas. At the global and hemispheric scales, we assessed different runoff components performance of GLDAS (1.0 and 2.1) using the University of New Hampshire and Global Runoff Data Centre (UNH-GRDC) dataset. The results suggest that GLDAS simulations show considerable uncertainties, particularly in partition of surface and subsurface runoffs, in snowmelt runoff modeling, and in capturing the northern peak time. GLDAS1.0-CLM (common land model) produced more surface runoff almost globally; GLDAS-Noah generated more surface runoff over the northern middle-high latitudes and more subsurface runoff in the remaining areas; while the partition in GLDAS1.0-VIC (variable infiltration capacity) is almost opposite to that in Noah. Comparing to GLDAS1.0-Noah, GLDAS2.1-Noah improved the premature snow-melting tendency, but its snowmelt-runoff peak magnitude was excessively high in June and July. The discrepancies in northern primary peak times among precipitation and runoff is partly caused by the combination of rainfall and melting-snow over high-latitude, as well as the very different temporal–spatial distributions for snowmelt runoff simulated by GLDAS models. This paper can provide valuable guidance for GLDAS users, and contribute to the further improvement of hydrological parameterized schemes.
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Kirvel, Ivan, Alexander Volchak, Sergey Parfomuk e Pavel Kirvel. "Environmental Risks of Water Resources in the Belarusian Polesie". Limnological Review 23, n. 1 (1 maggio 2023): 21–32. http://dx.doi.org/10.3390/limnolrev23010002.
Testo completoAbstract (sommario):
The article is devoted to the problems of water resources in Belarusian Polesie. Surface water resources analysis was carried out for the different types of runoffs. There was a significant decrease in maximum spring runoff and a decrease in the average annual runoff. A statistically significant increase in the minimum winter runoff is observed for the rivers of the Pripyat River basin. For the minimum summer–autumn runoff, there was no unambiguous trend in the runoff change. Quality of natural waters analysis included investigation of the annual concentrations of priority substances in the water of some rivers in Polesie for dissolved oxygen, phosphates, nitrogen, petroleum products, copper, zinc, etc. In general, there have been trends toward a pollution decrease in the Polesie Rivers. The possible consequences of changes in river runoff due to climate change are considered. The priority tasks of research on solving the Polesie water problems are outlined.
9
Adham, M. I., S. M. Shirazi, F. Othman, S. Rahman, Z. Yusop e Z. Ismail. "Runoff Potentiality of a Watershed through SCS and Functional Data Analysis Technique". Scientific World Journal 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/379763.
Testo completoAbstract (sommario):
Runoff potentiality of a watershed was assessed based on identifying curve number (CN), soil conservation service (SCS), and functional data analysis (FDA) techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling.
10
Hu, Shanshan, Yunyun Fan e Tao Zhang. "Assessing the Effect of Land Use Change on Surface Runoff in a Rapidly Urbanized City: A Case Study of the Central Area of Beijing". Land 9, n. 1 (10 gennaio 2020): 17. http://dx.doi.org/10.3390/land9010017.
Testo completoAbstract (sommario):
The change in land use during the process of urbanization affects surface runoff and increases flood risk in big cities. This study investigated the impact of land use change on surface runoff in Beijing’s central area during the period of rapid urbanization from 1984 to 2019. Land use maps of 1984, 1999, 2009, and 2019 were generated by image classification of Landsat images. Surface runoffs were calculated with the Soil Conservation Service curve number (SCS-CN) model. Correlation analysis was used to identify the dominant factor of land use change affecting surface runoff. The result showed that the variation trend of surface runoff was consistent with the trend of impervious land in Beijing’s central area, which increased during 1984~2009 and decreased during 2009~2019. Correlation analysis showed that changes in surface runoff were most strongly correlated with changes in impervious surfaces when compared with the correlation of runoff with other types of land use. The results of this study may provide a reference for city flood control and urban planning in fast growing cities worldwide, especially in developing countries.
11
You, Qiying, Hao Jiang, Yan Liu, Zhao Liu e Zilong Guan. "Probability Analysis and Control of River Runoff–sediment Characteristics based on Pair-Copula Functions: The Case of the Weihe River and Jinghe River". Water 11, n. 3 (12 marzo 2019): 510. http://dx.doi.org/10.3390/w11030510.
Testo completoAbstract (sommario):
Analyzing the encounter frequency of high–low runoff and sediment yield is important for the appropriate dispatching of runoff–sediment resources, as well as river regulation. However, there have been no reports on the utilization of the pair-copula function in analyzing the runoff–sediment characteristics from a probabilistic perspective and conducting probability control on the runoff–sediment yields of different hydrologic stations. This paper builds marginal distribution functions on the basis of kernel distribution theory. In addition, this paper builds the joint distribution functions through pair-copula functions in order to analyze the encounter probability and the compensation characteristics of high–low runoff and sediment at different stations on the Weihe River in China, as well as the origins of runoff–sediment, to conduct probability control of river runoff–sediment resource allocation. The results show that, in different periods, the synchronous probability of high–low runoff of the Weihe River’s Xianyang and Huaxian Stations, and the Jinghe River’s Zhangjiashan Station differ, while that of high–low sediment at the three stations changes little—remaining at around 54%. Therefore, the sediment and runoff of the Weihe River apparently have different origins. In years of high and low runoff, if the runoffs of the Xianyang and Zhangjiashan Stations can be kept within a certain range, then the runoff of the Huaxian Station will be in a particular range, at a certain probability. Sediment at the Huaxian Station can be controlled, in a similar way. These results are of great significance for the water and sediment management department of the Weihe river, in order to reasonably allocate water and sediment resources.
12
Xiao, Qintai, Li Zhou, Xin Xiang, Lingxue Liu, Xing Liu, Xiaodong Li e Tianqi Ao. "Integration of Hydrological Model and Time Series Model for Improving the Runoff Simulation: A Case Study on BTOP Model in Zhou River Basin, China". Applied Sciences 12, n. 14 (7 luglio 2022): 6883. http://dx.doi.org/10.3390/app12146883.
Testo completoAbstract (sommario):
Improving the accuracy of runoff simulations is a significant focus of hydrological science for multiple purposes such as water resources management, flood and drought prediction, and water environment protection. However, the simulated runoff has limitations that cannot be eliminated. This paper proposes a method that integrates the hydrological and time series models to improve the reliability and accuracy of simulated runoffs. Specifically, the block-wise use of TOPMODEL (BTOP) is integrated with three time series models to improve the simulated runoff from a hydrological model of the Zhou River Basin, China. Unlike most previous research that has not addressed the influence of runoff patterns while correcting the runoff, this study manually adds the hydrologic cycle to the machine learning-based time series model. This also incorporates scenario-specific knowledge from the researcher’s area of expertise into the prediction model. The results show that the improved Prophet model proposed in this study, that is, by adjusting its holiday function to a flow function, significantly improved the Nash–Sutcliffe efficiency (NSE) of the simulated runoff by 53.47% (highest) and 23.93% (average). The autoregressive integrated moving average (ARIMA) model and long short-term memory (LSTM) improved the runoff but performed less well than the improved Prophet model. This paper presents an effective method to improve the runoff simulation by integrating the hydrological and time series models.
13
Li, Jiaxin, Kaixuan Qian, Yuan Liu, Wei Yan, Xiuyun Yang, Geping Luo e Xiaofei Ma. "LSTM-Based Model for Predicting Inland River Runoff in Arid Region: A Case Study on Yarkant River, Northwest China". Water 14, n. 11 (29 maggio 2022): 1745. http://dx.doi.org/10.3390/w14111745.
Testo completoAbstract (sommario):
Inland river runoff variations in arid regions play a decisive role in maintaining regional ecological stability. Observation data of inland river runoff in arid regions have short time series and imperfect attributes due to limitations in the terrain environment and other factors. These shortages not only restrict the accurate simulation of inland river runoff in arid regions significantly, but also influence scientific evaluation and management of the water resources of a basin in arid regions. In recent years, research and applications of machine learning and in-depth learning technologies in the hydrological field have been developing gradually around the world. However, the simulation accuracy is low, and it often has over-fitting phenomenon in previous studies due to influences of complicated characteristics such as “unsteady runoff”. Fortunately, the circulation layer of Long-Short Term Memory (LSTM) can explore time series information of runoffs deeply to avoid long-term dependence problems. In this study, the LSTM algorithm was introduced and improved based on the in-depth learning theory of artificial intelligence and relevant meteorological factors that were monitored by coupling runoffs. The runoff data of the Yarkant River was chosen for training and test of the LSTM model. The results demonstrated that Mean Absolute Error (MAE) and Root Mean Square error (RMSE) of the LSTM model were 3.633 and 7.337, respectively. This indicates that the prediction effect and accuracy of the LSTM model were significantly better than those of the convolution neural network (CNN), Decision Tree Regressor (DTR) and Random Forest (RF). Comparison of accuracy of different models made the research reliable. Hence, time series data was converted into a problem of supervised learning through LSTM in the present study. The improved LSTM model solved prediction difficulties in runoff data to some extent and it applied to hydrological simulation in arid regions under several climate scenarios. It not only decreased runoff prediction uncertainty brought by heterogeneity of climate models and increased inland river runoff prediction accuracy in arid regions, but also provided references to basin water resource management in arid regions. In particular, the LSTM model provides an effective solution to runoff simulation in regions with limited data.
14
Xue, Yongkang, Jinjun Ji, Shufen Sun, Guoxiong Wu, K.-M. Lau, Isabelle Poccard, Hyun-Suk Kang et al. "Multiscale Variability of the River Runoff System in China and Its Long-Term Link to Precipitation and Sea Surface Temperature". Journal of Hydrometeorology 6, n. 4 (1 agosto 2005): 550–70. http://dx.doi.org/10.1175/jhm439.1.
Testo completoAbstract (sommario):
Abstract This is an exploratory study to investigate the spatial and temporal characteristics of east China’s (EC) river runoff and their relationship with precipitation and sea surface temperature (SST) at the continental scale. Monthly mean data from 72 runoff stations and 160 precipitation stations in EC, covering a period between 1951 and 1983, are used for this study. The station river runoff data have been spatially interpolated onto 1° grid boxes as runoff depth based on an extracted drainage network. Comparing runoff depth with precipitation shows that seasonal variation in runoff is consistent with the development of the summer monsoon, including the delayed response of runoff in several subregions. The dominant spatial scales and temporal patterns of summer runoff and precipitation are studied with empirical orthogonal function (EOF) analysis and wavelet analyses. The analyses show interannual, biennial, and longer-term variations in the EOF modes. South–north dipole anomaly patterns for the first two runoff EOF’s spatial distributions have been identified. The first/second runoff principal components (PCs) are highly correlated with the second/first precipitation PCs, respectively. The summer runoff’s EOF PCs also show significant correlations with the multivariate El Niño–Southern Oscillation index (MEI) of the summer and winter months, while the summer precipitation PCs do not. Statistic analysis shows that EOF1 of runoff and EOF2 of precipitation are related to El Niño, while EOF2 of runoff and EOF1 of precipitation are related to a dipole SST anomaly over the northwestern Pacific. The interdecadal relationship between summer runoff, precipitation, and SST variability is further studied by singular value decomposition (SVD) analysis. Pronounced warming (SST) and drying (runoff) trends in first SVD PCs have been identified. These SVDs are used to reconstruct a decadal anomaly pattern, which produces flooding in part of the Chang Jiang River basin and dryness in the northern EC, consistent with observations.
15
Wei, Zhang, Li Simin e Tang Fengbing. "Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases". Scientific World Journal 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/964737.
Testo completoAbstract (sommario):
To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%–30.91%, 83.29%–90.51%, and 61.54–68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff.
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Galster, Susanne, e Brigitte Helmreich. "Copper and Zinc as Roofing Materials—A Review on the Occurrence and Mitigation Measures of Runoff Pollution". Water 14, n. 3 (19 gennaio 2022): 291. http://dx.doi.org/10.3390/w14030291.
Testo completoAbstract (sommario):
Stormwater runoff from metal roofs has been a significant subject of discussion, especially when it comes to its treatment and the target concentrations that need to be achieved prior to discharge into the aquatic environment. To raise further awareness on this issue, occurrence, characterization, and also mitigation measures for metal roof runoff were analyzed using the example of copper and zinc roofs. These stormwater runoffs were found to contain metals in significant concentrations, mainly due to the wash-off of corrosion products by precipitation. Factors influencing metal corrosion and runoff concentrations were compiled. As Cu and Zn mainly occur in dissolved and thus bioavailable forms in roof runoff, harmful effects on the environment were detected. Therefore, adequate treatment of the runoff before discharge to groundwater or surface water is necessary to protect the aquatic environment. Vegetated infiltration swales as an sustainable urban drainage system enable a reduction in pollution loads. However, especially in densely built-up urban areas, stormwater quality improvement devices (SQIDs) offer an attractive alternative for pre-treating metal roof runoff, as they are mostly located underground. There is not yet a uniform legal approval system for SQIDs in Germany, but the German state of Bavaria has approved four types of SQIDs according to its own developed test criteria.
17
TRAN, HONGHI, ANDREW K. JONES e THOMAS M. GRACE. "Understanding recovery boiler smelt runoff phenomena". January 2015 14, n. 1 (1 febbraio 2015): 41–50. http://dx.doi.org/10.32964/tj14.1.41.
Testo completoAbstract (sommario):
There is considerable interest in the nature and causes of heavy smelt runoff from recovery boilers because of the role it has played in numerous dissolving tank explosions and for personnel safety around the dissolving tank. Most mills have experienced runoff problems, which can be caused by cleaning plugged spouts, burning down a large bed, low sulfidity smelt, startup with a bed in the unit, and improper firing practices. The peak smelt flow during a runoff is often 3 to 5 times normal and may be much greater in severe cases. Heavy runoffs are self-limiting and typically last less than 30 min. The geometry of the lower furnace plays a significant role in runoff events. Sloped floor units are more vulnerable to smelt pool buildup and heavy runoff when released. Decanting bottom units are inherently more tolerant of smelt pool buildup. Low sulfidity results in smelt with a high melting temperature, making the smelt easy to freeze and difficult to flow. Sulfate-rich slag/deposits falling on the hearth from the upper furnace can contribute significantly to runoff problems by causing dams and spout plugging, increasing the load of smelt pool to be removed, decreasing bed temperatures, and lowering the sulfidity of the smelt leaving the furnace.
18
Li, Shuoyang, Guiyu Yang e Hao Wang. "The Runoff Evolution and the Differences Analysis of the Causes of Runoff Change in Different Regions: A Case of the Weihe River Basin, Northern China". Sustainability 11, n. 19 (26 settembre 2019): 5295. http://dx.doi.org/10.3390/su11195295.
Testo completoAbstract (sommario):
The runoff levels of the major hydrological stations in the Weihe river basin (WRB) have been found to present decreasing trends. However, the conspicuous spatial differences in the hydro-meteorological conditions have led to variations in the rainfall–runoff pattern in each of the sub-basin areas. The aims of this research study were to reveal the main factors contributing to the runoff changes in the different regions—and it has significance in the water resources rational allocation and protection in the different regions. Three statistical methods were used to analyze the law of precipitation and runoffs of five hydrological stations. The SWAT (Soil and Water Assessment Tool) model was used to reconstruct the runoff in the impact period. The effects of climate change and human activity on runoff were separated by comparing measured runoff and reconstructed runoff. The results show that the closer the proximity to the downstream hydrological station, the more the runoff decreased. In the tributaries and upstream hydrological stations (Zhuanhtou (ZT), Zhangjiashan (ZJS), and Linjiacun (LJC)), from 1970 to 2016, the dominant factor of the runoff reduction was determined to be climate change, and accounted for 148.2%, 98.9%, and 90.5%, respectively. In the hydrological stations of middle and lower reaches (Xianyang (XY) and Huaxian (HX)), the contributions of the climate change to the runoff reduction were 49.7% and 44.3%, respectively, and the impacts of human activity accounted for 50.3% and 55.7%. The impacts of human activity on the runoff reduction were slightly greater than that of the climate change. Due to the different leading factors affecting runoff change in the basin, in response to future climate change, for tributaries and upstream areas, land use should be rationally planned to achieve the optimal balance of water volume in each part of the basin, which is of great significance to the protection and utilization of water resources. As for the middle and downstream regions, reasonable planning should also be focused on the amount of water withdraw, water resource allocations, and water conservancy project construction. According to the factors affecting runoff, corresponding strategies are proposed for different regions, which have important research significance for the protection and sustainable development of watershed water resources.
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Liu, Bojun, Xiaohui Lei, Siyu Cai, Shaoming Peng e Dawei Zhang. "Short-term Runoff Forecasting based on Hydrological Factors at Nanchang Section of Ganjiang River, China". MATEC Web of Conferences 246 (2018): 01025. http://dx.doi.org/10.1051/matecconf/201824601025.
Testo completoAbstract (sommario):
With the change of global climate and underlying surface characteristics, and increasing human activities, hydro-meteorological factors such as precipitation, evaporation, and runoff. Etc., are directly affected, therefore the assumption of stationarity may no longer exist. In a changing environment, the conventional runoff forecasting methods become invalid, which brings challenges to accurate hydrometeorological forecast. A hydrological model based on the changing environment was employed to forecast the runoff at Nanchang Section of Ganjiang River in this paper, and the rationality and validity of the built model were verified. The results shows that the built hydrological model has high accuracy in the short-term runoff forecasting, and better forecasting effect has been obtained after the parameters calibration and the real-time correction of the predicted runoffs, which can provide the strong support for the scientific water resources operation decision and also provide the boundary conditions of water level and water quality for the hydrodynamic and water-quality simulation at the Nanchang Section of the Ganjiang River.
20
Jo, Junbeom, Changjae Kwak, Jungsoo Kim e Sooyoul Kim. "Deriving Optimal Analysis Method for Road Surface Runoff with Change in Basin Geometry and Grate Inlet Installation". Water 14, n. 19 (4 ottobre 2022): 3132. http://dx.doi.org/10.3390/w14193132.
Testo completoAbstract (sommario):
Road surface-runoffs have been analyzed using various approaches, but inaccurate analysis methods lead to overestimation of the drainage capacity, causing unexpected flood damage in low-lying urban areas. Previous studies have highlighted the importance of considering various parameters for accurate road surface-runoff analysis. This study involves road surface-runoff analysis using an enhanced approach considering simplified and modified drainage basin geometries, road surface and gutter flow travel times, and inlet interception efficiency as key parameters under various road conditions. The topographical road conditions were set as follows: Width (6 m), longitudinal slope of road (2–10%), road surface slope (2%), and transverse slope of gutter (2–7%). The results show that using a modified basin considering road slope conditions for estimating actual flow path length and travel time is better for flow analysis than the simplified rectangular basin. Additionally, the runoff analysis should consider the roadside inlet installation conditions, given that the bypass discharge (i.e., rainfall runoff that is not intercepted by upstream inlets) flows downstream and affects the downstream flow characteristics. Based on these results, an optimal road surface-runoff analysis method was developed, which is expected to be useful for road design.
21
Swathi, V., K. Srinivasa Raju, Murari R. R. Varma e S. Sai Veena. "Automatic calibration of SWMM using NSGA-III and the effects of delineation scale on an urban catchment". Journal of Hydroinformatics 21, n. 5 (18 luglio 2019): 781–97. http://dx.doi.org/10.2166/hydro.2019.033.
Testo completoAbstract (sommario):
Abstract The study aims at calibration of the storm water management model (SWMM) with non-dominated sorting genetic algorithm-III (NSGA-III) for urban catchment in Hyderabad, India. The SWMM parameters calibrated were Manning's roughness coefficient (N), depression storage for pervious and impervious areas (DP and Di), sub-catchment width (W), curve number (CN), drying time (dry) of soil and percentage of imperviousness (I). The efficacy of calibration was evaluated by comparing the observed and simulated peak flows and runoff using goodness-of-fit indices. The calibration takes into consideration eight event rainfalls resulting in eight calibrated sets. Weights of goodness-of-fit indices were estimated and the best calibrated set was further validated for five continuous rainfalls/runoffs. Simulated runoff volume and peak runoff over the five continuous rainfalls deviated by 7–22% and 2–20% with respect to observed data. Results indicated that parameters calibrated for an event rainfall could be used for continuous rainfall-runoff modelling. The effect of catchment delineation scale on runoff was also studied. The study indicated that output of the model was sensitive to variation in parameter values of infiltration and imperviousness.
22
Khoirotunnisa, Safira Defiani, Gina Isna Nafisa, Chandra Setyawan, Muchammad Nu’man e Ngadisih. "Assessment of Surface Runoff Potency under Tropical Environment for Soil and Water Conservation Planning". BIO Web of Conferences 80 (2023): 03011. http://dx.doi.org/10.1051/bioconf/20238003011.
Testo completoAbstract (sommario):
Water is essential for living organisms, including crops. Its presence is a crucial factor for agriculture. Soil and water conservation is an effort to sustainably maintain the availability of water, thereby meeting the water needs of crops in the agricultural sector. This research aims to estimate the potency of surface runoff as a hydrological indicator of watershed critically for soil and water conservation purposes. A hydrological tank model was used to estimate surface runoff. The results showed a potential for surface runoff of approximately 133.82 mm/month, occurring primarily during the peak rainy season from December to April. Soil and water conservation (SWC) technology using water harvesting ponds (WHP) on farmland was proposed to store surface runoff. Data analysis indicates that the use of WHP provides significant benefits from environmental and economic aspects. Based on an average WHP storage capacity of 10 m³, approximately 40% of the total watershed area is required for constructing water harvesting structures to accommodate all surface runoff. Harvesting all surface runoffs increases the base flow during the dry season by 225.14 mm. This study serves as a valuable reference for soil and water conservation planning, particularly in tropical watersheds.
23
Wang, J., H. Y. Li e X. H. Hao. "Responses of snowmelt runoff to climatic change in an inland river basin, Northwestern China, over the past 50a". Hydrology and Earth System Sciences Discussions 7, n. 1 (21 gennaio 2010): 493–528. http://dx.doi.org/10.5194/hessd-7-493-2010.
Testo completoAbstract (sommario):
Abstract. The spatial and temporal variations of snowcover distribution, and snowmelt runoffs are considered as sensitive indicators for climatic change. The purpose of this paper is to analyze and forecast the responses of snowmelt runoff to climate change. The upstream of Heihe River Basin in Northwestern China was chose as the representative catchments, and the observation data of the meteorological and hydrological stations were utilized to analyze the status and the regularity for the climatic change from 1956 to 2008. Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to develop an optimized technology for snow mapping in the mountainous region. Snowmelt Runoff Model (SRM) was chose to simulate snowmelt runoff and scenario forecast the change trend of snowmelt runoff in catchment scale for the mountainous region in Northwestern China. The results show that climatic warming was apparent in the upstream of Heihe River Basin in the past 50a. Annual average air temperature of three different weather stations located in the basin has increased 2.1 °C, 2.6 °C and 2.9 °C, respectively. The snowmelt runoff has increased obviously from 1970 to present. With different warming climate scenarios, the results by SRM simulating showed that the first occurred time of snowmelt runoff shift ahead and discharge become larger as responses of snowmelt runoff to air temperature increasing, and the influence of temperature rising on average discharge of the whole snow season is not obvious. On the other hand, simulated discharge showed a marked increase trend with the increase of precipitation. And, the simulated results show that the increase of precipitation almost has no influence on the occurring time of snowmelt runoff.
24
Kumar, Sumant, Absar Ahmad Kazmi, Narayan Chandra Ghosh, Vinod Kumar e Ankur Rajpal. "Urban stormwater runoff treatment of Nainital Lake's catchment: an application of ballasted sand flocculation technology". Water Supply 19, n. 4 (23 agosto 2018): 1017–25. http://dx.doi.org/10.2166/ws.2018.148.
Testo completoAbstract (sommario):
Abstract Stormwater runoffs are one of the primary causes for deteriorating water quality in the Nainital Lake, India – a prominent tourist attraction and the sole drinking water source for the habitants of Nainital City. Treatment of fluctuating runoffs and contaminant influxes before mixing with the lake's water by conventional methods would require a large land footprint, which is a big constraint in the Nainital because of the hilly region. Ballasted sand flocculation (BSF) technology requires much less land footprint; a full-scale 1 MLD capacity pilot plant was applied for treatment of stormwater runoffs of the Nainital Lake. Twenty-eight storm events were monitored for runoff characterization and for evaluating the performance of BSF technology. The runoff water showed marked variation especially for total suspended solids (TSS), total phosphorus (TP), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total coliform (TC) and fecal coliform (FC) with maximum concentrations of 964 mg/l, 2.35 mg/l, 520 mg/l, 299 mg/l, 21 × 105 MPN/100 ml and 14 × 104 MPN/100 ml. The performance analyses results of the pilot plant revealed that the contaminants including trace metals in the stormwater runoff were reduced appreciably and the pollutant removal efficiencies were found to be largely unaffected by fluctuation of the influent contaminants' concentration.
25
Han, S., D. Xu e S. Wang. "Runoff formation from plot, field, to small catchment with shallow groundwater table and dense drainage system in agricultural North Huaihe River Plain, China". Hydrology and Earth System Sciences Discussions 9, n. 4 (2 aprile 2012): 4235–62. http://dx.doi.org/10.5194/hessd-9-4235-2012.
Testo completoAbstract (sommario):
Abstract. Runoff formation processes at the experimental plot (1600 m2), the field (0.06 km2), and the small catchment (1.36 km2) with shallow groundwater table and dense drainage system in North Huaihe River Plain (the northern part of the Huaihe River Basin, China) were analyzed based on observed rainfall, runoff and groundwater table depth data of 30 storm events during the flood seasons from 1997 to 2008. At the outlet of the furrow of the experimental plot, only the surface runoff was collected and measured, whereas both the surface and subsurface runoffs were collected at the drainage ditches outlets of the field and the small catchment. The present study showed that the relatively narrow range of rainfall amounts resulted in significantly different runoff amounts at all the three scales. When the ground water is close to surface, the runoff amount is a great percentage of rainfall amount. Significant linear relationships between the difference of rainfall and runoff amounts and the changes in water table or the initial water table depth were found. When the 30 events were divided into three groups with initial water table (as a parameter indicating the antecedent moisture condition) shallower than 0.5 m, deeper than 2.3 m or between 0.5 m and 2.3 m, significant rainfall-runoff relationships existed for each group. These imply that saturation-excess surface flow dominated the runoff response, especially when water table is shallow. For almost all the events, the water table rose above the bottom of drainage ditch during the event, and the total runoff amounts were larger at the field and the catchment than that at the plot with only surface flow measured, showing a great contribution of subsurface flow. Groundwater table depth, not only reflecting the antecedent moisture conditions, but also influencing the lateral sub-surface flow to the drainage ditches, would be an important parameter dominating runoff formation process in catchment like the study area with shallow water table and dense drainage system.
26
Liu, Yinge, Keke Yu, Yaqian Zhao e Jiangchuan Bao. "Impacts of Climatic Variation and Human Activity on Runoff in Western China". Sustainability 14, n. 2 (14 gennaio 2022): 942. http://dx.doi.org/10.3390/su14020942.
Testo completoAbstract (sommario):
Hydrological cycle is sensitively affected by climatic variation and human activity. Taking the upper- and middle-stream of the Weihe River in western China as an example, using multiple meteorological and hydrological elements, as well as land-use/land-cover change (LUCC) data, we constructed a sensitivity model of runoff to climatic elements and human activities based on the hydro-thermal coupling equilibrium equation, while a cumulative slope was used to establish a comprehensive estimation model for the contributions of climatic variation and human activities to the changes of runoff. The results showed that the above function model established could be well applied to quantitatively study the elasticity of runoff’s response to climatic variation and human activities. It was found that the annual average precipitation, evaporation, wind velocity, sunshine hours, relative humidity and runoff showed decreasing trends and that temperature increased. While in the hydrological cycle, precipitation and relative humidity had a non-linear positive driving effect on runoff, while temperature, evaporation, sunshine hours, wind velocity, and land-use/land-cover change (LUCC) have non-linearly negatively driven the variation of runoff. Moreover, runoff has a strong sensitive response to precipitation, evaporation and LUCC. In areas with strong human activities, the sensitivity of runoff to climatic change was decreasing, and runoff has a greater elastic response to underlying surface parameters. In addition, the analysis showed that the abrupt years of climate and runoff changes in the Weihe River Basin were 1970, 1985 and 1993. Before 1985, the contribution rate of climatic variation to runoff was 68.3%, being greater than that of human activities to runoff, and then the contribution rates of human activities to runoff reached 75.1%. The impact of natural climate on runoff was weakened, and the effect of human activities on runoff reduction increased. Under 30 hypothetical climatic scenarios, the evaluation of runoff in the future showed that the runoff in the Weihe River Basin will be greatly reduced, and the reduction will be more significant during the flood season. Comparing the geographically fragile environments and intense human activities, it was believed that climatic variation had a dramatic effect on driving the water cycle of precipitation and evaporation and affected regional water balance and water distribution, while human activities had driven the hydrological processes of the underlying surface, thus becoming the main factors in the reduction of runoff. This study provided scientific tools for regional climate change and water resources assessment.
27
Chung, N. T., J. S. Ra, K. Park, D. W. Kim e S. D. Kim. "Toxicity of artificial runoff fostered with dry deposition particulates from industrial, commercial, and highway area in Gwangju, Korea". Water Science and Technology 59, n. 11 (1 giugno 2009): 2227–35. http://dx.doi.org/10.2166/wst.2009.258.
Testo completoAbstract (sommario):
The adverse effects of rainwater and artificial urban runoff (an imitation of urban runoff during rainfall event) were investigated using a battery of bioassays employing three test species. Urban dusts were collected at three representative sites; commercial, industrial and highway areas. The water quality parameters of rainwater and artificial runoff revealed low hardness (23.4 ∼ 34.2 mg·L−1 as CaCO3) and alkalinity (7.0 ∼ 34.2 mg·L−1 as CaCO3). High toxicities were observed in the bioassays for the artificial runoffs. The average toxic units for D. magna, S. capricornutum, and O. latipes were 1.26(±0.84), 1.34(±1.10) and 2.05(±1.08), respectively. Of these species, O. latipes revealed significantly higher toxicity compared to D. magna and S. capricornutum (p<0.05). Embryo lesions were observed with 6.25% treatments, and these significantly increased at 12.5% treatments (p<0.05). The EC50 values for each artificial runoff were 22.5, 22.6 and 25.4% for commercial, industrial and highway areas, respectively. With 12.5% treatment, significant delays in hatching times were observed (p<0.05); all embryos tested did not hatched at 100% treatment. Similarly, a significant decrease in hatching success was observed at every sampling point from 25% treatment (p<0.05). The adverse effects of artificial runoff on the three test species suggests that urban surface runoff can cause significant impairment in aquatic ecosystems.
28
Vega-Garcia, Pablo, Regina Schwerd, Christian Scherer, Christoph Schwitalla e Brigitte Helmreich. "Development of a Model for Stormwater Runoff Prediction on Vertical Test Panels Coated with Plaster and Mortar". Water 12, n. 9 (16 settembre 2020): 2593. http://dx.doi.org/10.3390/w12092593.
Testo completoAbstract (sommario):
Leaching outdoor tests (LOT) are commonly used to assess the leaching of substances from construction materials. In this context, the amount of stormwater in contact with the surface material is of special interest for analyzing the runoff loads of substances from building façades. A numerical model was developed in MATLAB on the basis of previous analytical models to calculate the collected stormwater runoff volumes from the vertical test panels (VTP) during LOT. In the model, wind-driven rain (WDR) is considered to be the main mechanism for determining the amount of water impinging on the VTP, so it is a crucial factor in the modeling for the façade runoff. The new model makes it possible to simulate the runoff volumes from VTP that are covered with a wide variety of plaster and mortar. Using the new model, it was possible to relate the VTP runoff volumes obtained during an 18-month sampling period for LOTs performed at the Fraunhofer Institute for Building Physics in Valley, Germany. When comparing the simulation results with the field test accumulated runoffs, the model exhibited a difference of no more than 3.5% for each of the analyzed materials. The simulation results are satisfying, and the paper demonstrates the feasibility of the modelling approach for the runoff assessment of VTP covered with a variety of plaster and mortar.
29
Huang, Hui Ming, Hao Zhu, Yi Gang Wang e Wei Na Zhang. "Long Term Evolution Characteristics of Runoffs in the Tideway of the Changjiang River". Advanced Materials Research 1010-1012 (agosto 2014): 1095–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.1095.
Testo completoAbstract (sommario):
Abstract. Datong hydrological station is the last control station in the Changjiang River mainstream, and its runoffs have great significance on evolution of the tideway and the estuary of the Changjiang River. Therefore, this paper compiled long term series (1950~2010) of daily water discharges at Datong gauging station, and utilized the statistic methods to analyze the long term evolution characteristics of the Datong runoff. The results show that: (1) Inter-annual variability of runoffs was relatively stable, with average fluctuation range below 104m3/s, which may be caused by the location of the river basin and regulation of many large scale lakes; (2) The monthly runoffs have distinctly seasonal variation characteristics, wherein, the runoffs from June to September occupy 51% within a year, and the other months occupy the residual 49%, moreover, the runoff proportion of flood season within 2003~2010 has a slight decline of 2%, compared with that of 1995~2002.
30
Shukla, Saurabh, Tesfa Worku Meshesha, Indra S. Sen, Roland Bol, Heye Bogena e Junye Wang. "Assessing Impacts of Land Use and Land Cover (LULC) Change on Stream Flow and Runoff in Rur Basin, Germany". Sustainability 15, n. 12 (20 giugno 2023): 9811. http://dx.doi.org/10.3390/su15129811.
Testo completoAbstract (sommario):
Understanding the impact of land use/land cover (LULC) change on hydrology is the key to sustainable water resource management. In this study, we used the Soil and Water Assessment Tool (SWAT) to evaluate the impact of LULC change on the runoff in the Rur basin, Germany. The SWAT model was calibrated against the observed data of stream flow and runoff at three sites (Stah, Linnich, and Monschau) between 2000 and 2010 and validated between 2011 and 2015. The performance of the hydrological model was assessed by using statistical parameters such as the coefficient of determination (R2), p-value, r-value, and percentage bias (PBAIS). Our analysis reveals that the average R2 values for model calibration and validation were 0.68 and 0.67 (n = 3), respectively. The impacts of three change scenarios on stream runoff were assessed by replacing the partial forest with urban settlements, agricultural land, and grasslands compared to the 2006 LULC map. The SWAT model captured, overall, the spatio-temporal patterns and effects of LULC change on the stream runoffs despite the heterogeneous runoff responses related to the variable impacts of the different LULC. The results show that LULC change from deciduous forest to urban settlements, agricultural land, or grasslands increased the overall basin runoff by 43%, 14%, and 4%, respectively.
31
Zhang, Qifei, Yaning Chen, Zhi Li, Gonghuan Fang, Yanyun Xiang, Yupeng Li e Huiping Ji. "Recent Changes in Water Discharge in Snow and Glacier Melt-Dominated Rivers in the Tienshan Mountains, Central Asia". Remote Sensing 12, n. 17 (20 agosto 2020): 2704. http://dx.doi.org/10.3390/rs12172704.
Testo completoAbstract (sommario):
Global warming has generally led to changes in river runoffs fed by snow and glacier meltwater in mountain ranges. The runoff of the Aksu River, which originates in the Southern Tienshan Mountains, exhibited a positive trend during 1979–2002, but this trend reversed during 2002–2015. Through a comprehensive analysis, this study aims to estimate potential reasons for changes in the runoff of its two contrasting headwaters: the Toxkan and Kumalak Rivers, based on climatic data, the altitude of the 0 °C isotherm, glacier mass balance (GMB), snow cover area (SCA), snow depth (SD) and the sensitivity model. For the Toxkan River, the decrease in spring runoff mainly resulted from reductions in precipitation, whereas the decrease in summer runoff was mainly caused by early snowmelt in spring and a much-reduced snow meltwater supply in summer. In addition, the obvious glacier area reduction in the catchment (decreased to less than 4%) also contributed to the reduced summer runoff. For the Kumalak River, a sharp decrease rate of 10.21 × 108 m3/decade in runoff was detected due to summertime cooling of both surface and upper air temperatures. Reduced summer temperatures with a positive trend in precipitation not only inhibited glacier melting but also dropped the 0 °C layer altitude, resulting in a significant increase in summertime SCA and SD, a slowing of the glacier negative mass balance, and a lowering of the snow-line altitude.
32
Kidron, Giora J. "Sink plot for runoff measurements on semi-flat terrains: preliminary data and their potential hydrological and ecological implications". Journal of Hydrology and Hydromechanics 62, n. 4 (1 dicembre 2014): 303–8. http://dx.doi.org/10.2478/johh-2014-0032.
Testo completoAbstract (sommario):
Abstract In arid and semiarid regions where water is the main limiting factor, water redistribution is regarded as an important hydrological process of great ecological value. By providing additional water to certain loci, moist pockets of great productivity are formed, characterized by high plant biomass and biological activity. These moist pockets are often a result of runon. Yet, although runoff may take place on semi-flat undulating surfaces, runoff measurements are thus far confined to slopes, where a sufficient gradient facilitates downslope water harvesting. On undulating surfaces of mounds and depressions, such as in interdunes, no quantification of the amount of water reaching depressions is feasible due to the fact that no reliable method for measuring the runoff amounts in semi-flat terrains is available. The current paper describes specific runoff plots, designed to measure runoff in depressions (sinks). These plots, termed sink plots (SPs), were operative in the Hallamish dunefield (Negev Desert, Israel). The paper presents measurements of runoff yield that were carried out between January 2013 and January 2014 on SPs and compared them to runoff obtained from crusted slope plots and fine-grained (playa) surfaces. The potential hydrological and ecological implications of water redistribution within semi-flat terrains for this and other arid ecosystems are discussed.
33
Rahi, Khayyun A., Abdul-Sahib T. Al-Madhhachi e Safaa N. Al-Hussaini. "Assessment of Surface Water Resources of Eastern Iraq". Hydrology 6, n. 3 (26 giugno 2019): 57. http://dx.doi.org/10.3390/hydrology6030057.
Testo completoAbstract (sommario):
Large amounts of runoff is generated in western Iran and flows into eastern Iraq due to relatively intensive rainstorms along the international border line. Currently, most of this runoff is being wasted by evaporation instead of being stored and preserved for later uses. This paper is an attempt to (1) assess and harness the water resources of eastern Iraq, and (2) propose a storage scheme to use the harvested water in the water shortage times. The runoff of eight catchment areas (Mandali, Qazania, Tursaq, Mirzabad, Galal Badra, al-Chabbab, al-Teeb, and Dwaireeg) is estimated using regression equations derived for areas in the western and southern parts of the United States of America. Several models were selected from two states based on catchment area location, average terrain elevation, average annual precipitation, and slope of main stream. Observed runoffs of Tursaq, Galal Badra, and al-Chabbab streams are analyzed using normal probability plots. Statistical analysis shows that there is no a statistically significant difference between observed and predicted runoffs for different return periods. The study proposes a water reservoir to be constructed within al-Shiwiaja Marsh to accommodate runoff generated within Mandali, Qazania, Tursaq, Mirzabad, and Galal Badra streams. The capacity of the proposed reservoir is 3000 Mm3 and the expected inflow from these streams is projected to exceed the capacity of the reservoir. The proposed reservoir will contribute to the flow of the River Tigris during the non-rainy seasons. More studies are needed to propose and design a storage scheme for two remaining streams (al-Teeb and Dwaireeg).
34
Soulié, Tanguy, Francesca Vidussi, Justine Courboulès, Marie Heydon, Sébastien Mas, Florian Voron, Carolina Cantoni, Fabien Joux e Behzad Mostajir. "Simulated terrestrial runoff shifts the metabolic balance of a coastal Mediterranean plankton community towards heterotrophy". Biogeosciences 21, n. 7 (17 aprile 2024): 1887–902. http://dx.doi.org/10.5194/bg-21-1887-2024.
Testo completoAbstract (sommario):
Abstract. Climate change is projected to increase the frequency and intensity of extreme rainfall events in the Mediterranean region, increasing runoffs of terrestrial matter into coastal waters. To evaluate the consequences of terrestrial runoff for plankton key processes, an in situ mesocosm experiment was conducted for 18 d in the spring of 2021 in the coastal Mediterranean Thau Lagoon. Terrestrial runoff was simulated in replicate mesocosms by adding soil from an adjacent oak forest that had matured in water from the main tributary river of the lagoon. Automated high-frequency monitoring of dissolved oxygen, chlorophyll a fluorescence, salinity, light, and temperature was combined with manual sampling of organic and inorganic nutrient pools, pH, carbonate chemistry, and maximum quantum yield (Fv:Fm) of photosystem II (PSII). High-frequency data were used to estimate the gross primary production (GPP) of oxygen, community respiration (CR), and phytoplankton growth (μ) and loss (L) rates. During the first half of the experiment (d2–d11), the simulated runoff reduced light availability (−52 %), chlorophyll a concentrations (−70 %), and phytoplankton growth rates (−53 %). However, phytoplankton maintained a certain level of primary production by increasing its photosynthetic efficiency. Meanwhile, the runoff enhanced CR (+53 %), shifting the metabolic status (GPP : CR) of the system toward heterotrophy and increasing the partial pressure of carbon dioxide (pCO2), potentially switching the direction of the air–sea CO2 exchange. However, during the second part of the experiment (d11–d17), remineralized nutrients boosted phytoplankton growth (+299 %) in the terrestrial runoff treatment but not its loss rates, leading to phytoplankton biomass accumulation and suggesting a mismatch between phytoplankton and its predators. Our study showed that a simulated terrestrial runoff significantly affected key plankton processes, suggesting that climate-change-related increases in runoff frequency and intensity can shift the metabolic balance of Mediterranean coastal lagoons towards heterotrophy.
35
Munier, S., H. Palanisamy, P. Maisongrande, A. Cazenave e E. F. Wood. "Global runoff over 1993–2009 estimated from coupled land-ocean-atmosphere water budgets and its relation with climate variability". Hydrology and Earth System Sciences Discussions 9, n. 4 (11 aprile 2012): 4633–65. http://dx.doi.org/10.5194/hessd-9-4633-2012.
Testo completoAbstract (sommario):
Abstract. Whether the global runoff (or freshwater discharge from land to the ocean) is currently increasing and the global water cycle is intensifying is still a controversial issue. Here we compute land-atmosphere and ocean-atmosphere water budgets and derive two independent estimates of the global runoff over the period 1993–2009. Water storage variations in the land, ocean and atmosphere reservoirs are estimated from different types of datasets: atmospheric reanalyses, land surface models, satellite altimetry and in situ ocean temperature data (the difference between altimetry based global mean sea level and ocean thermal expansion providing an estimate of the ocean mass component). Results for the global runoff from the two methods show a very good correlation between both estimates. More importantly, no significant trend is observed over the whole period. Besides, the global runoff appears to be clearly impacted by large-scale climate phenomena such as major ENSO events. To infer this, we compute the zonal runoff over four latitudinal bands and set up for each band a new index (Combined Runoff Index) obtained by optimization of linear combinations of various climate indices. Results show that, in particular, the intertropical and northern mid-latitude runoffs are mainly driven by ENSO and the Atlantic Multidecadal Oscillation (AMO) with opposite behavior. Indeed, the zonal runoff in the intertropical zone decreases during major El Niño events whereas it increases in the northern mid-latitudes, suggesting that water masses over land are shifted northward/southward during El Niño/La Niña. In addition to this study, we propose an innovative method to estimate the global ocean thermal expansion. The method is based on the assumption that the difference between both runoff estimates is mainly due the thermal expansion term not accounted for in the estimation of the ocean mass. Comparison of our reconstructed thermal expansion with two existing datasets shows the relevance of this new method.
36
Daverede, I. C., A. N. Kravchenko, R. G. Hoeft, E. D. Nafziger, D. G. Bullock, J. J. Warren e L. C. Gonzini. "Phosphorus Runoff". Journal of Environment Quality 32, n. 4 (2003): 1436. http://dx.doi.org/10.2134/jeq2003.1436.
Testo completo
37
Funaki, Brian. "CTA Runoff". Seminars in Interventional Radiology 25, n. 03 (settembre 2008): 323–28. http://dx.doi.org/10.1055/s-0028-1085933.
Testo completo
38
Jeong, Dong-Guk, e Beom-Hui Lee. "Urban Watershed Runoff Analysis Using Urban Runoff Models". Journal of Korea Water Resources Association 36, n. 1 (1 febbraio 2003): 75–85. http://dx.doi.org/10.3741/jkwra.2003.36.1.075.
Testo completo
39
MATSUYAMA, Hiroshi, e Takeki IZUMI. "Snowmelt runoff analysis using SRM (Snowmelt Runoff Model)". JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES 22, n. 5 (2009): 409–18. http://dx.doi.org/10.3178/jjshwr.22.409.
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40
ARAI, Tadashi. "An Essay on Runoff Ratio and Runoff Height". Journal of Japanese Association of Hydrological Sciences 31, n. 1 (2001): 1_3–1_10. http://dx.doi.org/10.4145/jahs.31.1_3.
Testo completo
41
KADIOGLU, MIKDAT, e ZEKAI ŞEN. "Monthly precipitation-runoff polygons and mean runoff coefficients". Hydrological Sciences Journal 46, n. 1 (febbraio 2001): 3–11. http://dx.doi.org/10.1080/02626660109492796.
Testo completo
42
Southwick, L. M., G. H. Willis e R. L. Bengtson. "Runoff losses of norflurazon: Effect of runoff timing". Journal of Agricultural and Food Chemistry 41, n. 9 (settembre 1993): 1503–6. http://dx.doi.org/10.1021/jf00033a028.
Testo completo
43
Buchtele, Josef. "Runoff changes simulated using a rainfall-runoff model". Water Resources Management 7, n. 4 (1993): 273–87. http://dx.doi.org/10.1007/bf00872285.
Testo completo
44
Morassutti, M. P. "Australian runoff scenarios from A runoff-climate model". International Journal of Climatology 12, n. 8 (dicembre 1992): 797–813. http://dx.doi.org/10.1002/joc.3370120804.
Testo completo
45
Munier, S., H. Palanisamy, P. Maisongrande, A. Cazenave e E. F. Wood. "Global runoff anomalies over 1993–2009 estimated from coupled Land–Ocean–Atmosphere water budgets and its relation with climate variability". Hydrology and Earth System Sciences 16, n. 10 (16 ottobre 2012): 3647–58. http://dx.doi.org/10.5194/hess-16-3647-2012.
Testo completoAbstract (sommario):
Abstract. Whether the global runoff (or freshwater discharge from land to the ocean) is currently increasing and the global water cycle is intensifying is still a controversial issue. Here we compute land–atmosphere and ocean–atmosphere water budgets and derive two independent estimates of the global runoff over the period 1993–2009. Water storage variations in the land, ocean and atmosphere reservoirs are estimated from different types of data sets: atmospheric reanalyses, land surface models, satellite altimetry and in situ ocean temperature data (the difference between altimetry based global mean sea level and ocean thermal expansion providing an estimate of the ocean mass component). These data sets are first validated using independent data, and then the global runoff is computed from the two methods. Results for the global runoff show a very good correlation between both estimates. More importantly, no significant trend is observed over the whole period. Besides, the global runoff appears to be clearly impacted by large-scale climate phenomena such as major ENSO events. To infer this, we compute the zonal runoff over four latitudinal bands and set up for each band a new index (combined runoff index) obtained by optimization of linear combinations of various climate indices. Results show that, in particular, the intertropical and northern mid-latitude runoffs are mainly driven by ENSO and the Atlantic multidecadal oscillation (AMO) with opposite behavior. Indeed, the zonal runoff in the intertropical zone decreases during major El Niño events, whereas it increases in the northern mid-latitudes, suggesting that water masses over land are shifted northward/southward during El Niño/La Niña. In addition to this study, we propose an innovative method to estimate the global ocean thermal expansion. The method is based on the assumption that the difference between both runoff estimates is mainly due to the thermal expansion term not accounted for in the estimation of the ocean mass. We find that our reconstructed thermal expansion time series compares well with two existing data sets in terms of year-to-year fluctuations but somewhat differs on longer (multi-year) time scales. Possible explanations include non negligible steric variations from the deep ocean.
46
Wang, Shuyang, Meiping Sun, Guoyu Wang, Xiaojun Yao, Meng Wang, Jiawei Li, Hongyu Duan, Zhenyu Xie, Ruiyi Fan e Yang Yang. "Simulation and Reconstruction of Runoff in the High-Cold Mountains Area Based on Multiple Machine Learning Models". Water 15, n. 18 (10 settembre 2023): 3222. http://dx.doi.org/10.3390/w15183222.
Testo completoAbstract (sommario):
Runoff from the high-cold mountains area (HCMA) is the most important water resource in the arid zone, and its accurate forecasting is key to the scientific management of water resources downstream of the basin. Constrained by the scarcity of meteorological and hydrological stations in the HCMA and the inconsistency of the observed time series, the simulation and reconstruction of mountain runoff have always been a focus of cold region hydrological research. Based on the runoff observations of the Yurungkash and Kalakash Rivers, the upstream tributaries of the Hotan River on the northern slope of the Kunlun Mountains at different time periods, and the meteorological and atmospheric circulation indices, we used feature analysis and machine learning methods to select the input elements, train, simulate, and select the preferences of the machine learning models of the runoffs of the two watersheds, and reconstruct the missing time series runoff of the Kalakash River. The results show the following. (1) Air temperature is the most important driver of runoff variability in mountainous areas upstream of the Hotan River, and had the strongest performance in terms of the Pearson correlation coefficient (ρXY) and random forest feature importance (FI) (ρXY = 0.63, FI = 0.723), followed by soil temperature (ρXY = 0.63, FI = 0.043), precipitation, hours of sunshine, wind speed, relative humidity, and atmospheric circulation were weakly correlated. A total of 12 elements were selected as the machine learning input data. (2) Comparing the results of the Yurungkash River runoff simulated by eight machine learning methods, we found that the gradient boosting and random forest methods performed best, followed by the AdaBoost and Bagging methods, with Nash–Sutcliffe efficiency coefficients (NSE) of 0.84, 0.82, 0.78, and 0.78, while the support vector regression (NSE = 0.68), ridge (NSE = 0.53), K-nearest neighbor (NSE = 0.56), and linear regression (NSE = 0.51) were simulated poorly. (3) The application of four machine learning methods, gradient boosting, random forest, AdaBoost, and bagging, to simulate the runoff of the Kalakash River for 1978–1998 was generally outstanding, with the NSE exceeding 0.75, and the results of reconstructing the runoff data for the missing period (1999–2019) could well reflect the characteristics of the intra-annual and inter-annual changes in runoff.
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Wang, G. Q., X. L. Yan, J. Y. Zhang, C. S. Liu, J. L. Jin, Y. L. Liu e Z. X. Bao. "Detecting evolution trends in the recorded runoffs from the major rivers in China during 1950–2010". Journal of Water and Climate Change 4, n. 3 (7 maggio 2013): 252–64. http://dx.doi.org/10.2166/wcc.2013.021.
Testo completoAbstract (sommario):
Evolution trends as well as abrupt changes in recorded runoffs from the major rivers in China during 1950–2010 were investigated using the Mann–Kendall test and ordered clustering analysis. Results show that the recorded runoff series at ten key hydrometric stations on the major rivers in China are characterized by a general decreasing trend. A significant decrease has occurred at six stations: Yichang, Huayuankou, Guantai, Shixiali, Tieling and Haerbin stations, which are located on the northern major rivers. Abrupt changes in runoff series are detectable for the Yellow River (1986), the Hai River (1965 at Guantai station, 1970 at Shixiali station) and the Liao River (1965). The relationship between runoff and precipitation at these stations is different before and after the abrupt change. Intensive human activities, such as land use change, water conservation projects, water diversion projects and rapid increases in agricultural irrigation, are likely to be among the main causes of the abrupt changes in runoff. Effective strategies for water conservation and adaptation to climate change will be needed to ensure sustainable use of water resources and safeguard economic growth under China's 12th 5-year plan.
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Aoun, Joelle, Konstantinos Apostoleris, Basil Psarianos e Elias Choueiri. "Operational and Safety Performance Investigation of Skew Superelevation Runoff". Transportation Research Record: Journal of the Transportation Research Board 2638, n. 1 (gennaio 2017): 35–44. http://dx.doi.org/10.3141/2638-05.
Testo completoAbstract (sommario):
Hydroplaning and the corresponding hydroplaning speed of a vehicle are critical road safety concerns. To avoid hydroplaning, nine technical measures are available. One of the most effective is the construction of skew superelevation runoff at the critical pavement section of a highway, especially in highway rehabilitation and reconstruction projects. The concept was introduced in the German RAS-L design guide of 1984; its implementation is found mainly in central European countries. Skew superelevation runoff was adopted in recent freeway projects, some of which are reconstructions of existing two-lane highways into freeways to address identified sections with high potential for hydroplaning. Its use under normal traffic has resulted in concerns about its safety and comfort effectiveness. To investigate the operational and safety performance of the constructed skew superelevation runoffs, accurate triaxial acceleration measurements were carried out on the Korinthos-Patra freeway in Greece for a combination of vehicles and speeds along these skew superelevation runoff sections. Resulting limitational thresholds were shown to be adequate for safe operation of the skew superelevation runoff. Vehicle occupant comfort thresholds, however, are narrow and require specific additional construction improvements when design values are not observed.
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Hernández-Guzmán, Rafael, e Norma Leticia Onchi-Ramuco. "Estimating surface runoff using the curve number method in an ungauged watershed in Jalisco, Mexico evaluating its morphometric parameters". Earth Sciences Research Journal 26, n. 4 (28 febbraio 2023): 313–20. http://dx.doi.org/10.15446/esrj.v26n4.99194.
Testo completoAbstract (sommario):
The surface runoff was estimated using the curve number (CN) method for different storm events and it was associated with the morphometric parameters of an ungauged watershed in Jalisco, México. The land use and land cover map from 2019 was derived from the unsupervised classification of a Sentinel-2 image at 10 m resolution. The morphometric analysis revealed that the study area is dominated by areas of gentle slope and moderate to high permeability with dense vegetation and low relief. It is a well-drained watershed with low flood potentiality as well as a groundwater potential zone. About 69% of the study area corresponds to natural cover with tropical dry forest and evergreen forest as the most representative classes. A total of 77 storm events were identified from 2013 to 2019, with runoffs that ranged from 0.05 to 227.2 Mm3. September and October were the months with the most intense rainfall and, therefore, the months with the highest runoff volume. The average runoff was 14.52 Mm3, corresponding to an average runoff coefficient of 12.86%. Together, the methods used here provide useful results for delineating conservation strategies at the watershed level.
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Shalini Oogathoo, Shiv O. Prasher, Ramesh P. Rudra e Ramanbhai M. Patel. "Evaluation of the MIKE SHE Model in a Cold Region". Journal of Agricultural Engineering (India) 48, n. 1 (20 febbraio 2024): 26–37. http://dx.doi.org/10.52151/jae2011481.1430.
Testo completoAbstract (sommario):
Given its rapid urbanization, the Canagagigue Creek watershed, located in Grand River Basin (Ontario, Canada), is subjected to shifting hydrological patterns. Consequently, surface runoff was simulated using a watershed-scale model MIKE SHE. The model was calibrated with four years of data and validated with another four years data. Satisfactory levels of overall correlation (R2) between monitored and model-simulated monthly runoff were: 0.87 and 0.77 for the calibration and validation periods, respectively. Corresponding values of the Nash-Sutcliffe coefficient, 0.86 and 0.75, were similar. The model was also used to simulate different management scenarios, urbanization, deforestation, conversion of pastureland into agriculture, diversification of corn system into cash crops, and application of tile drainage. Urbanization showed little impact on surface runoff as increase in urbanized area was a small fraction of the watershed area. Deforestation considerably increased (11%) the total flow. Change in cropping patterns and installation of drainage system had marginal impacts on the surface runoffs. Overall, the model was able to simulate surface runoff reasonably well on monthly and annual basis, although slightly poorer on daily basis. It was concluded that the model could be used to investigate hydrological behaviour of the watersheds in cold climate.