Pub Date : 2010-12-21DOI: 10.2174/1874378101004010102
R. Huffaker, D. Rider, R. Hotchkiss
The alarming loss of water storage capacity to sedimentation in reservoirs worldwide is prompting a paradigm shift toward sustainable management. Previous research has investigated the physical capability of various technologies to control reservoir sediment, and formulated economic rules governing their optimal sustainable use. We ask the next rele- vant questions: Is sustainable reservoir management structurally stable for particular technologies, or do thresholds exist such that small perturbations in key management parameters abruptly unleash dynamics driving the reservoir toward ex- tinction? What are the dynamic properties of reservoirs in transition? We uncover a saddle-node bifurcation for the par- ticular case of a multi-purpose public reservoir manager who adopts the environmentally friendly 'hydrosuction-dredging' sediment removal technology. Beyond the bifurcation threshold, sustainable management abruptly gives way to eventual loss of storage capacity to sedimentation. Reservoirs throughout the world suffer from sedimenta- tion. Examples include estimated annual storage capacity losses of 2.3% in China (2), 0.5% in India (2), and 1% worldwide (3). Specific examples are catalogued by Batuca and Jordaan (4). These include the Cir-lurtsk Reservoir on the Sulak River (Russia) which was 95% sedimented in 7 years; the Gumati Reservoir on the Vakhs River (Georgia) which was 90% sedimented in 11 years; and the Zemo Af- char Reservoir at the confluence of the Kura and Aragi Riv- ers (Russia) which lost 44% of its initial storage capacity in the first 2 years, 32% in the next 8 years, and 3.5% up to 1967. Other examples include the Tarbela Dam on the Indus River—the most important facility of its kind in Pakistan— which lost 20% of its storage capacity after 23 years of op- eration (5); and the Matilija Dam in California whose storage capacity decreased from 7,000 acre feet in 1947 to less than 500 acre feet by 2005 (6).
{"title":"Stability and Bifurcation Analysis of Reservoir Sedimentation Management","authors":"R. Huffaker, D. Rider, R. Hotchkiss","doi":"10.2174/1874378101004010102","DOIUrl":"https://doi.org/10.2174/1874378101004010102","url":null,"abstract":"The alarming loss of water storage capacity to sedimentation in reservoirs worldwide is prompting a paradigm shift toward sustainable management. Previous research has investigated the physical capability of various technologies to control reservoir sediment, and formulated economic rules governing their optimal sustainable use. We ask the next rele- vant questions: Is sustainable reservoir management structurally stable for particular technologies, or do thresholds exist such that small perturbations in key management parameters abruptly unleash dynamics driving the reservoir toward ex- tinction? What are the dynamic properties of reservoirs in transition? We uncover a saddle-node bifurcation for the par- ticular case of a multi-purpose public reservoir manager who adopts the environmentally friendly 'hydrosuction-dredging' sediment removal technology. Beyond the bifurcation threshold, sustainable management abruptly gives way to eventual loss of storage capacity to sedimentation. Reservoirs throughout the world suffer from sedimenta- tion. Examples include estimated annual storage capacity losses of 2.3% in China (2), 0.5% in India (2), and 1% worldwide (3). Specific examples are catalogued by Batuca and Jordaan (4). These include the Cir-lurtsk Reservoir on the Sulak River (Russia) which was 95% sedimented in 7 years; the Gumati Reservoir on the Vakhs River (Georgia) which was 90% sedimented in 11 years; and the Zemo Af- char Reservoir at the confluence of the Kura and Aragi Riv- ers (Russia) which lost 44% of its initial storage capacity in the first 2 years, 32% in the next 8 years, and 3.5% up to 1967. Other examples include the Tarbela Dam on the Indus River—the most important facility of its kind in Pakistan— which lost 20% of its storage capacity after 23 years of op- eration (5); and the Matilija Dam in California whose storage capacity decreased from 7,000 acre feet in 1947 to less than 500 acre feet by 2005 (6).","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133836837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-26DOI: 10.2174/1874378101004010091
F. Bouksila, M. Persson, R. Berndtsson, A. Bahri, I. Hamba
Rapid and reliable observations of soil electrical conductivity are essential in order to maintain sustainable irri- gated agriculture. Direct measurement of the electrical conductivity of saturated soil paste (ECe), however, is tedious and time consuming. Therefore, there are needs to find efficient indirect methods to predict the soil salinity from other readily available observations. In this paper we explore the application of multiple linear regression (MLR) and artificial neural networks (ANN) to predict ECe variation from easily measured soil and groundwater properties under highly complex and heterogeneous field conditions in semiarid Tunisia. We compare two methods for dividing the data set into training and validation sub-sets; a statistical (SD) and a random data set division (RD), and their effect on model performance. The in- put variables were chosen from the plot coordinates, groundwater table properties (depth, electrical conductivity, pie- zometric level), and soil particle size at 5 depths. The results obtained with ANN and MLR indicate that the statistical properties of data in the training and validation sets need to be taken into account to ensure that optimal model perform- ance is achieved. The SD can be considered as a solution to resolve the problem of over-fitting a model when using ANN. For the SD, the determination coefficient (R 2 ) when using an ANN model varied from 0.85 to 0.88 and the root mean square error from 1.23 to 1.80 dS m -1 . Because of the complexity of the field soil salinity process and the spatial variabil- ity of the data, this clearly indicates the potential to use ANN models to predict ECe.
快速、可靠地观测土壤电导率对维持可持续灌溉农业至关重要。然而，直接测量饱和土膏体的电导率是一项繁琐且耗时的工作。因此，需要寻找有效的间接方法，从其他现成的观测数据中预测土壤盐度。本文探讨了多元线性回归(MLR)和人工神经网络(ANN)在半干旱突尼斯高度复杂和非均质野外条件下，从容易测量的土壤和地下水性质预测ECe变化的应用。我们比较了将数据集划分为训练子集和验证子集的两种方法;统计(SD)和随机数据集划分(RD)，以及它们对模型性能的影响。输入变量选择自样地坐标、地下水位特性(深度、电导率、饼状水位)和5个深度的土壤粒度。人工神经网络和MLR的结果表明，需要考虑训练集和验证集数据的统计特性，以确保获得最优的模型性能。SD可以被认为是解决使用人工神经网络时模型过拟合问题的一种方法。对于SD，使用ANN模型时的决定系数(r2)在0.85 ~ 0.88之间，均方根误差在1.23 ~ 1.80 dS m -1之间。由于田间土壤盐分过程的复杂性和数据的空间变异性，这清楚地表明了使用人工神经网络模型预测土壤盐分的潜力。
{"title":"Estimating soil salinity over a shallow saline water table in semiarid Tunisia.","authors":"F. Bouksila, M. Persson, R. Berndtsson, A. Bahri, I. Hamba","doi":"10.2174/1874378101004010091","DOIUrl":"https://doi.org/10.2174/1874378101004010091","url":null,"abstract":"Rapid and reliable observations of soil electrical conductivity are essential in order to maintain sustainable irri- gated agriculture. Direct measurement of the electrical conductivity of saturated soil paste (ECe), however, is tedious and time consuming. Therefore, there are needs to find efficient indirect methods to predict the soil salinity from other readily available observations. In this paper we explore the application of multiple linear regression (MLR) and artificial neural networks (ANN) to predict ECe variation from easily measured soil and groundwater properties under highly complex and heterogeneous field conditions in semiarid Tunisia. We compare two methods for dividing the data set into training and validation sub-sets; a statistical (SD) and a random data set division (RD), and their effect on model performance. The in- put variables were chosen from the plot coordinates, groundwater table properties (depth, electrical conductivity, pie- zometric level), and soil particle size at 5 depths. The results obtained with ANN and MLR indicate that the statistical properties of data in the training and validation sets need to be taken into account to ensure that optimal model perform- ance is achieved. The SD can be considered as a solution to resolve the problem of over-fitting a model when using ANN. For the SD, the determination coefficient (R 2 ) when using an ANN model varied from 0.85 to 0.88 and the root mean square error from 1.23 to 1.80 dS m -1 . Because of the complexity of the field soil salinity process and the spatial variabil- ity of the data, this clearly indicates the potential to use ANN models to predict ECe.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128654096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-06DOI: 10.2174/1874378101004010065
J. F. Paul, J. Kiddon, C. Strobel
Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km 2 . Parameters examined were depth, bottom temperature, bottom salinity, surface chlorophyll a, bottom dissolved oxygen, lead concentration in sediments, silt-clay content of sediments, and number of infaunal ben- thic species. Statistical methods included means, standard deviations, coefficients of variation, empirical cumulative dis- tribution functions, and contours determined by bivariate interpolation and interpolation by kriging. All of these methods were found to be appropriate depending upon the purpose of the characterization. Contouring was applied only to those systems with at least 23 discrete sample sites (7 systems). Cross-validation and randomization techniques were used to compare the two interpolation methods. Kriging was advantageous over bivariate interpolation when moderate to strong spatial correlation existed in the residuals (that is, after removal of the spatial trend with a nonparametric regression model). When kriging was conducted, the removal of the trend was necessary if the stationarity assumption was to be valid. The Delaware/Maryland coastal bays are shallow, well-mixed (horizontally and vertically) systems that exhibit little or no spatial correlation for the parameters examined. The South and Severn Rivers, subsystems of the Chesapeake Bay, exhibited moderate to strong spatial dependence for some parameters. Randomization techniques were used to evaluate the effect of decreasing the number of sites in kriged parameters. Based upon these randomizations, it was found that 23 discrete sites could be used for kriging in estuaries with characteristics similar to those in the mid-Atlantic and if the sam- ples were collected with a comparable design.
{"title":"Characterization methods for small estuarine systems in the mid-Atlantic region of the United States.","authors":"J. F. Paul, J. Kiddon, C. Strobel","doi":"10.2174/1874378101004010065","DOIUrl":"https://doi.org/10.2174/1874378101004010065","url":null,"abstract":"Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km 2 . Parameters examined were depth, bottom temperature, bottom salinity, surface chlorophyll a, bottom dissolved oxygen, lead concentration in sediments, silt-clay content of sediments, and number of infaunal ben- thic species. Statistical methods included means, standard deviations, coefficients of variation, empirical cumulative dis- tribution functions, and contours determined by bivariate interpolation and interpolation by kriging. All of these methods were found to be appropriate depending upon the purpose of the characterization. Contouring was applied only to those systems with at least 23 discrete sample sites (7 systems). Cross-validation and randomization techniques were used to compare the two interpolation methods. Kriging was advantageous over bivariate interpolation when moderate to strong spatial correlation existed in the residuals (that is, after removal of the spatial trend with a nonparametric regression model). When kriging was conducted, the removal of the trend was necessary if the stationarity assumption was to be valid. The Delaware/Maryland coastal bays are shallow, well-mixed (horizontally and vertically) systems that exhibit little or no spatial correlation for the parameters examined. The South and Severn Rivers, subsystems of the Chesapeake Bay, exhibited moderate to strong spatial dependence for some parameters. Randomization techniques were used to evaluate the effect of decreasing the number of sites in kriged parameters. Based upon these randomizations, it was found that 23 discrete sites could be used for kriging in estuaries with characteristics similar to those in the mid-Atlantic and if the sam- ples were collected with a comparable design.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132652246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-20DOI: 10.2174/1874378101004010227
F. Tracy
The purpose of this work is to test different computational algorithms for unsaturated flow for accuracy and robustness by comparing computed results in a finite element program with analytical solutions. Because real-world problems are complex, testing codes for accuracy is often difficult. This is particularly true for flow in the vadose zone where Richards' equation is highly nonlinear. Recently, however, Tracy (Tracy WRRJ 2006) [1] (Tracy JHYD 2007) [2] has derived analytical solutions for a box-shaped flow region that is initially dry until water is applied to the top of the region. Two-dimensional and three-dimensional versions of these solutions for both steady-state and transient flow are available to be used in the testing process. Numerical precision and nonlinear solver robustness were investigated for varying degrees of nonlinearity by varying the Gardner parameter. As was increased, three ways of modeling relative hydraulic conductivity inside individual finite elements and two versions of the nonlinear solver were tested using three different ways to measure the error. The results of these tests are given in this paper.
{"title":"Testing computational algorithms for unsaturated flow.","authors":"F. Tracy","doi":"10.2174/1874378101004010227","DOIUrl":"https://doi.org/10.2174/1874378101004010227","url":null,"abstract":"The purpose of this work is to test different computational algorithms for unsaturated flow for accuracy and robustness by comparing computed results in a finite element program with analytical solutions. Because real-world problems are complex, testing codes for accuracy is often difficult. This is particularly true for flow in the vadose zone where Richards' equation is highly nonlinear. Recently, however, Tracy (Tracy WRRJ 2006) [1] (Tracy JHYD 2007) [2] has derived analytical solutions for a box-shaped flow region that is initially dry until water is applied to the top of the region. Two-dimensional and three-dimensional versions of these solutions for both steady-state and transient flow are available to be used in the testing process. Numerical precision and nonlinear solver robustness were investigated for varying degrees of nonlinearity by varying the Gardner parameter. As was increased, three ways of modeling relative hydraulic conductivity inside individual finite elements and two versions of the nonlinear solver were tested using three different ways to measure the error. The results of these tests are given in this paper.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123356040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-09-18DOI: 10.2174/1874378100802010049
S. Setegn, R. Srinivasan, B. Dargahi
The SWAT2005 model was applied to the Lake Tana Basin for modeling of the hydrological water balance. The main objective of this study was to test the performance and feasibility of the SWAT model for prediction of stream- flow in the Lake Tana Basin. The model was calibrated and validated on four tributaries of Lake Tana; Gumera, GilgelA- bay, Megech and Ribb rivers using SUFI-2, GLUE and ParaSol algorithms. The sensitivity analysis of the model to sub- basin delineation and HRU definition thresholds showed that the flow is more sensitive to the HRU definition thresholds than subbasin discretization effect. SUFI-2 and GLUE gave good result. All sources of uncertainties were captured by bracketing more than 60% of the observed river discharge. Baseflow (40% - 60%) is an important component of the total discharge within the study area that contributes more than the surface runoff. The calibrated model can be used for further analysis of the effect of climate and land use change as well as other different management scenarios on streamflow and soil erosion.
应用SWAT2005模型对塔纳湖流域进行了水文水平衡模拟。本研究的主要目的是测试SWAT模型在塔纳湖流域水流预测中的性能和可行性。在塔纳湖的四条支流上对模型进行了标定和验证;Gumera, GilgelA- bay, Megech和Ribb河使用SUFI-2, GLUE和ParaSol算法。模型对子盆地圈定和HRU定义阈值的敏感性分析表明，相对于子盆地离散化效应，该模型对HRU定义阈值的敏感性更高。SUFI-2和GLUE效果良好。所有不确定因素的来源都被纳入了60%以上的观测河流流量。基流(40% ~ 60%)是研究区总流量的重要组成部分，贡献大于地表径流。校正后的模型可用于进一步分析气候和土地利用变化以及其他不同管理方案对河流和土壤侵蚀的影响。
{"title":"Hydrological Modelling in the Lake Tana Basin, Ethiopia Using SWAT Model","authors":"S. Setegn, R. Srinivasan, B. Dargahi","doi":"10.2174/1874378100802010049","DOIUrl":"https://doi.org/10.2174/1874378100802010049","url":null,"abstract":"The SWAT2005 model was applied to the Lake Tana Basin for modeling of the hydrological water balance. The main objective of this study was to test the performance and feasibility of the SWAT model for prediction of stream- flow in the Lake Tana Basin. The model was calibrated and validated on four tributaries of Lake Tana; Gumera, GilgelA- bay, Megech and Ribb rivers using SUFI-2, GLUE and ParaSol algorithms. The sensitivity analysis of the model to sub- basin delineation and HRU definition thresholds showed that the flow is more sensitive to the HRU definition thresholds than subbasin discretization effect. SUFI-2 and GLUE gave good result. All sources of uncertainties were captured by bracketing more than 60% of the observed river discharge. Baseflow (40% - 60%) is an important component of the total discharge within the study area that contributes more than the surface runoff. The calibrated model can be used for further analysis of the effect of climate and land use change as well as other different management scenarios on streamflow and soil erosion.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127712480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-05-30DOI: 10.2174/1874378100802010025
S. Jebari, R. Berndtsson, A. Bahri, M. Boufaroua
The Tunisian Dorsal area is representative of the semiarid Mediterranean region in terms of water resources availability as well as exceptional rainfall characteristics, runoff generation, and soil loss risk. In this context, soil properties, surface management practices together with highly intensive rainfall make the soils vulnerable to erosion. If the exceptional rainfall characteristics are linked to different erosion types, the erosion risk could be evaluated in a simple and straightforward way. In this regard, a short time-scale rainfall data base from the Dorsal area was analysed in the paper. The procedure used involves finding a representative duration between 1-60 min for the exceptional rainfall characteristics. Rainfall intensities of different return periods are then related to the different erosion types. The identified exceptional rainfall durations between 1-60 min were analyzed in terms of number of events, depth, average intensity and maximum intensity. Results show that the 15-min duration maximum intensity can be used to evaluate erosion risk based on soil erosion type. The developed methodology can be used to evaluate erosion risk in semiarid regions based on exceptional rainfall characteristics. In practical terms the results can be used to better manage catchments that are vulnerable to soil erosion. (Less)
{"title":"Exceptional Rainfall Characteristics Related to Erosion Risk in Semiarid Tunisia","authors":"S. Jebari, R. Berndtsson, A. Bahri, M. Boufaroua","doi":"10.2174/1874378100802010025","DOIUrl":"https://doi.org/10.2174/1874378100802010025","url":null,"abstract":"The Tunisian Dorsal area is representative of the semiarid Mediterranean region in terms of water resources availability as well as exceptional rainfall characteristics, runoff generation, and soil loss risk. In this context, soil properties, surface management practices together with highly intensive rainfall make the soils vulnerable to erosion. If the exceptional rainfall characteristics are linked to different erosion types, the erosion risk could be evaluated in a simple and straightforward way. In this regard, a short time-scale rainfall data base from the Dorsal area was analysed in the paper. The procedure used involves finding a representative duration between 1-60 min for the exceptional rainfall characteristics. Rainfall intensities of different return periods are then related to the different erosion types. The identified exceptional rainfall durations between 1-60 min were analyzed in terms of number of events, depth, average intensity and maximum intensity. Results show that the 15-min duration maximum intensity can be used to evaluate erosion risk based on soil erosion type. The developed methodology can be used to evaluate erosion risk in semiarid regions based on exceptional rainfall characteristics. In practical terms the results can be used to better manage catchments that are vulnerable to soil erosion. (Less)","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130213169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-30DOI: 10.2174/1874378100802010034
V. Chertkov
The subject of this work is the modification and specification of an approach to detail the estimation of soil crack network characteristics. The modification aims at accounting for the corrected soil crack volume based on the corrected shrinkage geometry factor compared to known estimates of crack volume and shrinkage geometry factor. The mode of the correction relies on recent results of the soil reference shrinkage curve. The main exposition follows the preliminary brief review of available approaches to dealing with the geometry of soil crack networks and gives a preliminary brief summary of the approach to be modified and specified. To validate and illustrate the modified approach the latter is used in the analysis of available data on soil cracking in a lysimeter.
{"title":"The Geometry of Soil Crack Networks","authors":"V. Chertkov","doi":"10.2174/1874378100802010034","DOIUrl":"https://doi.org/10.2174/1874378100802010034","url":null,"abstract":"The subject of this work is the modification and specification of an approach to detail the estimation of soil crack network characteristics. The modification aims at accounting for the corrected soil crack volume based on the corrected shrinkage geometry factor compared to known estimates of crack volume and shrinkage geometry factor. The mode of the correction relies on recent results of the soil reference shrinkage curve. The main exposition follows the preliminary brief review of available approaches to dealing with the geometry of soil crack networks and gives a preliminary brief summary of the approach to be modified and specified. To validate and illustrate the modified approach the latter is used in the analysis of available data on soil cracking in a lysimeter.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116009735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-24DOI: 10.2174/1874378100802010015
H. Somura, D. Nakayama, M. Aizaki, Y. Seike, M. Okumura, Kumiko Nishikata
The spatial distributions of water quality and load units were determined for each small sub basin of the Iinashi River basin as a first step in water environment management. In addition, a GIS database was established to comprehensively resolve the issue of water quality degradation. It was found the concentrations of water quality parameters in the Iinashi River basin were relatively low at almost all sampling points. The average concentrations of each parameter are 1.86 mg·L -1 of chemical oxygen demand, 0.73 mg·L -1 of dissolved organic carbon, 18.5 % of biodegradation ability, 6.58 mg·L -1 of silica, 519.8 μgN·L -1 of total nitrogen, and 27.4 μgP·L -1 of total phospho- rus. In addition, the load units discharged from the small watersheds were obtained. The load units varied greatly regardless of similar land use in the basin. Moreover, discharged loads from observation point 1-31 in the Yamasa River basin were higher than those from observation point 1-5 in the upstream of the Iinashi River basin regardless of high percentage of forest area (91.51%), low percentage of agricultural land (2.3%) and low population density (24 people·km -2 ). Finally, the discharged loads from observation point 1-3 were de- termined as 53.2 g·ha -1 ·day -1 of suspended solid, 45.4 g·ha -1 ·day -1 of chemical oxygen demand, 20.9 g·ha -1 ·day -1 of dissolved organic car- bon, 8.1 g·ha -1 ·day -1 of particulate organic carbon, 16.3 g·ha -1 ·day -1 of total nitrogen, 5.0 g·ha -1 ·day -1 of dissolved organic nitrogen, 1.3 g·ha -1 ·day -1 of particulate organic nitrogen, and 0.3 g·ha -1 ·day -1 of total phosphorus.
{"title":"Spatial Distribution of Water Quality and Load Units in the Iinashi River Basin, Shimane Prefecture, Japan","authors":"H. Somura, D. Nakayama, M. Aizaki, Y. Seike, M. Okumura, Kumiko Nishikata","doi":"10.2174/1874378100802010015","DOIUrl":"https://doi.org/10.2174/1874378100802010015","url":null,"abstract":"The spatial distributions of water quality and load units were determined for each small sub basin of the Iinashi River basin as a first step in water environment management. In addition, a GIS database was established to comprehensively resolve the issue of water quality degradation. It was found the concentrations of water quality parameters in the Iinashi River basin were relatively low at almost all sampling points. The average concentrations of each parameter are 1.86 mg·L -1 of chemical oxygen demand, 0.73 mg·L -1 of dissolved organic carbon, 18.5 % of biodegradation ability, 6.58 mg·L -1 of silica, 519.8 μgN·L -1 of total nitrogen, and 27.4 μgP·L -1 of total phospho- rus. In addition, the load units discharged from the small watersheds were obtained. The load units varied greatly regardless of similar land use in the basin. Moreover, discharged loads from observation point 1-31 in the Yamasa River basin were higher than those from observation point 1-5 in the upstream of the Iinashi River basin regardless of high percentage of forest area (91.51%), low percentage of agricultural land (2.3%) and low population density (24 people·km -2 ). Finally, the discharged loads from observation point 1-3 were de- termined as 53.2 g·ha -1 ·day -1 of suspended solid, 45.4 g·ha -1 ·day -1 of chemical oxygen demand, 20.9 g·ha -1 ·day -1 of dissolved organic car- bon, 8.1 g·ha -1 ·day -1 of particulate organic carbon, 16.3 g·ha -1 ·day -1 of total nitrogen, 5.0 g·ha -1 ·day -1 of dissolved organic nitrogen, 1.3 g·ha -1 ·day -1 of particulate organic nitrogen, and 0.3 g·ha -1 ·day -1 of total phosphorus.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128723915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-01-14DOI: 10.2174/1874378100802010001
C. George, L. León
W aterBase is a project of the United Nations University. Its aim is to advance the practice of Integrated Water Resources Management (IWRM) in developing countries, by providing (a) free, open source tools for modeling and decision support (b) a collection of IWRM resources: web sites, tools, literature, training material, etc. and (c) a community of partners who can provide advice, support, contribute to tools and resources. A first step in the project is a tool to provide Geographic Information System (GIS) support and a setup interface for the Soil and Water Assessment Tool (SWAT). This paper describes the design of this tool, called Map Window SWAT (MWSWAT).
{"title":"WaterBase: SWAT in an Open Source GIS","authors":"C. George, L. León","doi":"10.2174/1874378100802010001","DOIUrl":"https://doi.org/10.2174/1874378100802010001","url":null,"abstract":"W aterBase is a project of the United Nations University. Its aim is to advance the practice of Integrated Water Resources Management (IWRM) in developing countries, by providing (a) free, open source tools for modeling and decision support (b) a collection of IWRM resources: web sites, tools, literature, training material, etc. and (c) a community of partners who can provide advice, support, contribute to tools and resources. A first step in the project is a tool to provide Geographic Information System (GIS) support and a setup interface for the Soil and Water Assessment Tool (SWAT). This paper describes the design of this tool, called Map Window SWAT (MWSWAT).","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130154990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-06DOI: 10.2174/1874378100701010001
V. Chertkov
A recently proposed model showed how a clay shrinkage curve is transformed to the soil shrinkage curve at the soil clay content higher than a critical one. The objective of the present work was to generalize this model to the soil clay content lower a critical one. I investigated (i) the reference shrinkage curve, that is, one without cracks; (ii) the superficial layer of aggregates, with changed pore structure compared with the intraaggregate matrix; and (iii) soils with sufficiently low clay content where there are large pores inside the intraaggregate clay (so-called lacunar pores). The methodology is based on detail accounting for different contributions to the soil volume and water content during shrinkage. The key point is the calculation of the lacunar pore volume variance at shrinkage. The reference shrinkage curve is determined by eight physical soil parameters: (1) oven-dried specific volume; (2) maximum swelling water content; (3) mean solid den- sity; (4) soil clay content; (5) oven-dried structural porosity; (6) the ratio of aggregate solid mass to solid mass of intraag- gregate matrix; (7) the lacunar factor that characterizes the rate of the lacunar pore volume change with water content; and (8) oven-dried lacunar pore volume. The model was validated using available data. The model predicted value of the slope of the reference shrinkage curve in the basic shrinkage area is equal to unity minus the lacunar factor value, and is be- tween unity and zero in the agreement with observations.
{"title":"The Soil Reference Shrinkage Curve","authors":"V. Chertkov","doi":"10.2174/1874378100701010001","DOIUrl":"https://doi.org/10.2174/1874378100701010001","url":null,"abstract":"A recently proposed model showed how a clay shrinkage curve is transformed to the soil shrinkage curve at the soil clay content higher than a critical one. The objective of the present work was to generalize this model to the soil clay content lower a critical one. I investigated (i) the reference shrinkage curve, that is, one without cracks; (ii) the superficial layer of aggregates, with changed pore structure compared with the intraaggregate matrix; and (iii) soils with sufficiently low clay content where there are large pores inside the intraaggregate clay (so-called lacunar pores). The methodology is based on detail accounting for different contributions to the soil volume and water content during shrinkage. The key point is the calculation of the lacunar pore volume variance at shrinkage. The reference shrinkage curve is determined by eight physical soil parameters: (1) oven-dried specific volume; (2) maximum swelling water content; (3) mean solid den- sity; (4) soil clay content; (5) oven-dried structural porosity; (6) the ratio of aggregate solid mass to solid mass of intraag- gregate matrix; (7) the lacunar factor that characterizes the rate of the lacunar pore volume change with water content; and (8) oven-dried lacunar pore volume. The model was validated using available data. The model predicted value of the slope of the reference shrinkage curve in the basic shrinkage area is equal to unity minus the lacunar factor value, and is be- tween unity and zero in the agreement with observations.","PeriodicalId":247243,"journal":{"name":"The Open Hydrology Journal","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130350484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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