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Pierre Hayek - One of the best experts on this subject based on the ideXlab platform.
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Micro-Catchment water harvesting potential of an arid environment
Agricultural Water Management, 2010Co-Authors: Akhtar Ali, Atef Abdul Aal, T. Y. Oweis, Attila Yazar, Pierre HayekAbstract:Micro-Catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-Catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-Catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158mm in year 2004/2005, 45mm in year 2005/2006 and 127mm in year 2006/2007. About 5000 MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-Catchments with Catchment areas between 13 and 50m\n 2 was measured. Also the runoff was indirectly assessed for another 40 micro-Catchments by using soil water balance in the micro-Catchments and the plant basins. Results show that runoff yield varied between 5 and 187m\n 3ha\n -1 for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%. The rainfall threshold for runoff generation was estimated about 4mm. Overall; the soil water balance approach predicted 38-57% less water than micro-Catchment runoff approach. This difference was due to the reason that the micro-Catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-Catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning. ?? 2010 Elsevier B.V.
Lawrence E. Band - One of the best experts on this subject based on the ideXlab platform.
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Leveraging Big Data Towards Functionally-Based, Catchment Scale Restoration Prioritization
Environmental Management, 2018Co-Authors: John P. Lovette, Jonathan M. Duncan, Lindsey S. Smart, Lydia P. Olander, Dean L. Urban, Nancy Daly, Jamie Blackwell, Anne B. Hoos, Ana María García, Lawrence E. BandAbstract:The persistence of freshwater degradation has necessitated the growth of an expansive stream and wetland restoration industry, yet restoration prioritization at broad spatial extents is still limited and ad-hoc restoration prevails. The River Basin Restoration Prioritization tool has been developed to incorporate vetted, distributed data models into a Catchment scale restoration prioritization framework. Catchment baseline condition and potential improvement with restoration activity is calculated for all National Hydrography Dataset stream reaches and Catchments in North Carolina and compared to other Catchments within the river subbasin to assess where restoration efforts may best be focused. Hydrologic, water quality, and aquatic habitat quality conditions are assessed with peak flood flow, nitrogen and phosphorus loading, and aquatic species distribution models. The modular nature of the tool leaves ample opportunity for future incorporation of novel and improved datasets to better represent the holistic health of a watershed, and the nature of the datasets used herein allow this framework to be applied at much broader scales than North Carolina.
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Exploring functional similarity in the export of Nitrate‐N from forested Catchments: A mechanistic modeling approach
Water Resources Research, 1998Co-Authors: I. F. Creed, Lawrence E. BandAbstract:Functional similarity of Catchments implies that we are able to identify the combination of processes that creates a similar response of a specific characteristic of a Catchment. We applied the concept of functional similarity to the export of NO3−-N from Catchments situated within the Turkey Lakes Watershed, a temperate forest in central Ontario, Canada. Despite the homogeneous nature of the forest, these Catchments exhibit substantial variability in the concentrations of NO3−-N in discharge waters, over both time and space. We hypothesized that functional similarity in the export of NO3−-N can be expressed as a function of topographic complexity as topography regulates both the formation and flushing of NO3−-N within the Catchment. We tested this hypothesis by exploring whether topographically based similarity indices of the formation and flushing of NO3−-N capture the observed export of NO3−-N over a set of topographically diverse Catchments. For Catchments with no elevated base concentrations of NO3−-N the similarity indices explained up to 58% of the variance in the export of NO3−-N. For Catchments with elevated base concentrations of NO3−-N, prediction of the export of NO3−-N may have been complicated by the fact that hydrology was governed by a two-component till, with an ablation till overlying a basal till. While the similarity indices captured peak NO3−-N concentrations exported from shallow flow paths emanating from the ablation till, they did not capture base NO3−-N concentrations exported from deep flow paths emanating from the basal till, emphasizing the importance of including shallow and deep flow paths in future similarity indices. The strength of the similarity indices is their potential ability to enable us to discriminate Catchments that have visually similar surface characteristics but show distinct NO3−-N export responses and, conversely, to group Catchments that have visually dissimilar surface characteristics but are functionally similar. Furthermore, the similarity indices provide a potentially powerful method to scale and generalize NO3−-N export responses to other regions.
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Exploring functional similarity in the export of nitrate-N from forested Catchments: A mechanistic modeling approach
Water Resources Research, 1998Co-Authors: I. F. Creed, Lawrence E. BandAbstract:Functional similarity of Catchments implies that we are able to identify the combination of processes that creates a similar response of a specific characteristic of a Catchment. We applied the concept of functional similarity to the export of NO 3 / - -N from Catchments situated within the Turkey Lakes Watershed, a temperate forest in central Ontario, Canada. Despite the homogeneous nature of the forest, these Catchments exhibit substantial variability in the concentrations of NO 3 / - -N in discharge waters, over both time and space. We hypothesized that functional similarity in the export of NO 3 / - -N can be expressed as a function of topographic complexity as topography regulates both the formation and flushing of NO 3 / - -N within the Catchment. We tested this hypothesis by exploring whether topographically based similarity indices of the formation and flushing of NO 3 / - -N capture the observed export of NO 3 / - -N over a set of topographically diverse Catchments. For Catchments with no elevated base concentrations of NO 3 / - -N the similarity indices explained up to 58% of the variance in the export of NO 3 / - -N. For Catchments with elevated base concentrations of NO 3 / - -N, prediction of the export of NO 3 / - -N may have been complicated by the fact that hydrology was governed by a two-component till, with an ablation till overlying a basal till. While the similarity indices captured peak NO 3 / - -N concentrations exported from shallow flow paths emanating from the ablation till, they did not capture base NO 3 / - -N concentrations exported from deep flow paths emanating from the basal till, emphasizing the importance of including shallow and deep flow paths in future similarity indices. The strength of the similarity indices is their potential ability to enable us to discriminate Catchments that have visually similar surface characteristics but show distinct NO 3 / - -N export responses and, conversely, to group Catchments that have visually dissimilar surface characteristics but are functionally similar. Furthermore, the similarity indices provide a potentially powerful method to scale and generalize NO 3 / - -N export responses to other regions.
Andras Bardossy - One of the best experts on this subject based on the ideXlab platform.
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calibration of hydrological model parameters for ungauged Catchments
Hydrology and Earth System Sciences, 2006Co-Authors: Andras BardossyAbstract:The parameters of hydrological models for Catchments with few or no discharge records can be estimated using regional information. One can assume that Catchments with similar characteristics show a similar hydrological behaviour and thus can be modeled using similar model parameters. Therefore a regionalisation of the hydrological model parameters on the basis of Catchment characteristics is plausible. However, due to the non-uniqueness of the rainfall-runoff model parameters (equifinality), a workflow of regional parameter estimation by model calibration and a subsequent fit of a regional function is not appropriate. In this paper a different approach for the transfer of entire parameter sets from one Catchment to another is discussed. Parameter sets are considered as tranferable if the corresponding model performance (defined as the Nash-Sutclife efficiency) on the donor Catchment is good and the regional statistics: means and variances of annual discharges estimated from Catchment properties and annual climate statistics for the recipient Catchment are well reproduced by the model. The methodology is applied to a set of 16 Catchments in the German part of the Rhine Catchments. Results show that the parameters transfered according to the above criteria perform well on the target Catchments.
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modeling of the effect of land use changes on the runoff generation of a river basin through parameter regionalization of a watershed model
Journal of Hydrology, 2004Co-Authors: Yeshewatesfa Hundecha, Andras BardossyAbstract:A conceptual rainfall-runoff model was applied to 95 Catchments in the Rhine basin for the purpose of modeling of the effect of land use change on the runoff. An approach to calibrate the model by associating the model parameters with the physical Catchment characteristics was implemented. Land use, soil type, Catchment size, and topographic structure were used as the bases for regionalization of the model parameters. Parameter values were initially associated with these Catchment characteristics and were finally transferred into their Catchment scale values using a transfer function, whose form was assumed a priori. A simultaneous model calibration was performed for a number of Catchments with contrasting Catchment characteristics. An optimization algorithm was used for the calibration with an objective function defined as the normalized sum of the squared differences between the modeled and the observed runoff. The regionalized model thus obtained was then used to model the resulting runoff for different land use scenarios generated in the model area. The results obtained suggest that increased urbanization leads to an increase in the lower peak runoff resulting from summer storm, while the increase in the higher peaks resulting from winter rainfall is very little. On the other hand, a considerable reduction of both the peak runoff and the total runoff volume resulted from intensified afforestation.
Akhtar Ali - One of the best experts on this subject based on the ideXlab platform.
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Micro-Catchment water harvesting potential of an arid environment
Agricultural Water Management, 2010Co-Authors: Akhtar Ali, Atef Abdul Aal, T. Y. Oweis, Attila Yazar, Pierre HayekAbstract:Micro-Catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-Catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-Catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158mm in year 2004/2005, 45mm in year 2005/2006 and 127mm in year 2006/2007. About 5000 MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-Catchments with Catchment areas between 13 and 50m\n 2 was measured. Also the runoff was indirectly assessed for another 40 micro-Catchments by using soil water balance in the micro-Catchments and the plant basins. Results show that runoff yield varied between 5 and 187m\n 3ha\n -1 for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%. The rainfall threshold for runoff generation was estimated about 4mm. Overall; the soil water balance approach predicted 38-57% less water than micro-Catchment runoff approach. This difference was due to the reason that the micro-Catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-Catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning. ?? 2010 Elsevier B.V.
Martyn P Clark - One of the best experts on this subject based on the ideXlab platform.
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the camels data set Catchment attributes and meteorology for large sample studies
Hydrology and Earth System Sciences, 2017Co-Authors: Nans Addor, Andrew J Newman, Naoki Mizukami, Martyn P ClarkAbstract:We present a new data set of attributes for 671 Catchments in the contiguous United States (CONUS) minimally impacted by human activities. This complements the daily time series of meteorological forcing and streamflow provided by Newman et al. (2015b). To produce this extension, we synthesized diverse and complementary data sets to describe six main classes of attributes at the Catchment scale: Topography, climate, streamflow, land cover, soil, and geology. The spatial variations among basins over the CONUS are discussed and compared using a series of maps. The large number of Catchments, combined with the diversity of the attributes we extracted, makes this new data set well suited for large-sample studies and comparative hydrology. In comparison to the similar Model Parameter Estimation Experiment (MOPEX) data set, this data set relies on more recent data, it covers a wider range of attributes, and its Catchments are more evenly distributed across the CONUS. This study also involves assessments of the limitations of the source data sets used to compute Catchment attributes, as well as detailed descriptions of how the attributes were computed. The hydrometeorological time series provided by Newman et al.
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Catchment properties, function, and conceptual model representation: Is there a correspondence?
Hydrological Processes, 2014Co-Authors: Fabrizio Fenicia, Gerrit Schoups, Dmitri Kavetski, H. H.g. Savenije, Laurent Pfister, Martyn P Clark, Jim FreerAbstract:This study investigates the possible correspondence between Catchment structure, as represented by perceptual hydrological models developed from fieldwork investigations, and mathematical model structures, selected on the basis of reproducing observed Catchment hydrographs. Three Luxembourgish headwater Catchments are considered, where previous fieldwork suggested distinct flow-generating mechanisms and hydrological dynamics. A set of lumped conceptual model structures are hypothesised and implemented using the SUPERFLEX framework. Following parameter calibration, the model performance is examined in terms of predictive accuracy, quantification of uncertainty and the ability to reproduce the flow-duration curve signature. Our key research question is whether differences in the performance of the conceptual model structures can be interpreted based on the dominant Catchment processes suggested from fieldwork investigations. For example, we propose that the permeable bedrock and the presence of multiple aquifers in the Huewelerbach Catchment may explain the superior performance of model structures with storage elements connected in parallel. Conversely, model structures with serial connections perform better in the Weierbach and Wollefsbach Catchments, which are characterised by impermeable bedrock and dominated by lateral flow. The presence of threshold dynamics in the Weierbach and Wollefsbach Catchments may favour non-linear models, while the smoother dynamics of the larger Huewelerbach Catchment were suitably reproduce by linear models. It is also shown how hydrologically distinct processes can be effectively described by the same mathematical model components. Major research questions are reviewed, including the correspondence between hydrological processes at different levels of scale and how best to synthesise the experimentalist's and modeller's perspectives. Copyright © 2013 John Wiley & Sons, Ltd.
