Development and application of the modelling system J2000-S for the EU-water framework directive

The scientific sound definition of measures to achieve the goals of the EU water framework directive (WFD) acquires spatially distributed analyses of the water and substance dynamics in meso- to macro-scale catchments. For this purpose, modelling tools or systems are needed which are robust and fast enough to be applied on such scales, but which are also able to simulate the impact of changes on single fields or small areas of a specific land use in the catchment. <br><br> To face these challenges, we combined the fully-distributed hydrological model J2000 with the nitrogen transport routines of the Soil Water Assessment Tool SWAT model, which are normally applied in a semi-distributive approach. With this combination, we could extend the quantitative focus of J2000 with qualitative processes and could overcome the semi-distributed limitation of SWAT. For the implementation and combination of the components, we used the Jena Adaptable Modelling System JAMS (Kralisch and Krause, 2006) which helped tremendously in the relatively rapid and easy development of the new resultant model J2000-S (J2000-Substance). <br><br> The modelling system was applied in the upper Gera watershed, located in Thuringia, Germany. The catchment has an area of 844 km<sup>2</sup> and includes three of the typical landscape forms of Thuringia. The application showed, that the new modelling system was able to reproduce the daily hydrological as well as the nitrogen dynamics with a sufficient quality. The paper will describe the results of the new model and compare them with the results obtained with the original semi-distributed application of SWAT

Multiscale investigations in a mesoscale catchment ? hydrological modelling in the Gera catchment

International audienceThe application of the hydrological process-oriented model J2000 (J2K) is part of a cooperation project between the Thuringian Environmental Agency (Thüringer Landesanstalt für Umwelt und Geologie ? TLUG) and the Department of Geoinformatics of the Friedrich-Schiller-University Jena focussing on the implementation of the EU water framework directive (WFD). In the first project phase J2K was parametrised and calibrated for a mesoscale catchment to quantify if it can be used as hydrological part of a multi-objective tool-box needed for the implementation of the WFD. The main objectives for that pilot study were: The development and application of a suitable distribution concept which provide the spatial data basis for various tasks and which reflects the specific physiogeographical variability and heterogeneity of river basins adequately. This distribution concept should consider the following constraints: The absolute number of spatial entities, which forms the basis for any distributive modelling should be as small as possible, but the spatial distributed factors, which controls quantitative and qualitative hydrological processes should not be generalised to much. The distribution concept of hydrological response units HRUs (Flügel, 1995) was selected and enhanced by a topological routing scheme (Staudenrausch, 2001) for the simulation of lateral flow processes. J2K should be calibrated for one subbasin of the pilot watershed only. Then the parameter set should be used on the other subbasins (referred as transfer basins) to investigate and quantify the transferability of a calibrated model and potential spatial dependencies of its parameter set. In addition, potential structural problems in the process description should be identified by the transfer to basins which show a different process dominance as the one which was used for calibration does. Model calibration and selection of efficiency criteria for the quantification of the model quality should be based on a comprehensive sensitivity and uncertainty analysis (Bäse, 2005) and multi-response validations with independent data sets (Krause and Flügel, 2005) carried out in advance in the headwater part of the calibration basin. To obtain good results in the transfer basins the calibrated parameter set could be adjusted slightly. This step was considered as necessary because of specific constraints which were not of significant importance in the calibration basin. This readjustment should be carried out on parameters which show a sensitive reaction on the identified differences in the environmental setup. Potential scaling problems of the process description, distribution concept or model structure should be identified by the comparison of the modelling results obtained in a small headwater region of the calibration basin with observed streamflow to find out if the selected efficiency measures show a significant change

Continental-scale bias-corrected climate and hydrological projections for Australia

The Australian Bureau of Meteorology has developed a national hydrological projections (NHP) service for Australia. The NHP aimed to provide nationally consistent hydrological projections across jurisdictional boundaries to support planning of water-dependent industries. NHP is complementary to those previously produced by federal and state governments, universities, and other organisations for limited geographical domains. The projections comprise an ensemble of application-ready bias-corrected climate model data, derived hydrological projections at daily temporal and 0.05° × 0.05° spatial resolution for the period 1960–2099, and two emission scenarios (Representative Concentration Pathway (RCP) 4.5 and RCP8.5). The spatial resolution of the projections matches that of gridded historical reference data used to perform the bias correction and the Bureau of Meteorology's operational gridded hydrological model. Three bias correction techniques were applied to four CMIP5 global climate models (GCMs), and one method was applied to a regional climate model (RCM) forced by the same four GCMs, resulting in a 16-member ensemble of bias-corrected GCM data for each emission scenario. The bias correction was applied to fields of precipitation, minimum and maximum temperature, downwelling shortwave radiation, and surface winds. These variables are required inputs to the Bureau of Meteorology's landscape water balance hydrological model (AWRA-L), which was forced using the bias-corrected GCM and RCM data to produce a 16-member ensemble of hydrological output. The hydrological output variables include root zone soil moisture (moisture in the top 1 m soil layer), potential evapotranspiration, and runoff. Here we present an overview of the production of the hydrological projections, including GCM selection, bias correction methods and their evaluation, technical aspects of their implementation, and examples of analysis performed to construct the NHP service. The data are publicly available on the National Computing Infrastructure (https://doi.org/10.25914/6130680dc5a51, Bureau of Meteorology, 2021), and a user interface is accessible at https://awo.bom.gov.au/products/projection/ (last access: 24 November 2023).</p

Modelling electrical conductivity variation using a travel time distribution approach in the Duck River catchment, Australia

Abstract Solute dynamics depend strongly on hydrologic flow paths and transit times within catchments. In this paper, we use a travel time tracking method to simulate stream salinity (as measured by electrical conductivity) in the Duck River catchment, NW Tasmania, Australia. The study couples storage selection function transit time modelling with two alternate approaches to model electrical conductivity (EC). The first approach assumes the catchment has a cyclic salt balance (i.e., rainfall source, stream flow sink) that is in dynamic equilibrium and evapoconcentration of salt is the only process changing concentration. The second approach assumes that the salinity of water in catchment storages is a function of water age in those stores, without explicitly simulating salt mass balance processes. The paper compares these alternate approaches in terms of EC simulation performance, simulated stream water age distributions, and simulated storage age distributions. A split sample calibration‐validation analysis was conducted using the 2008 and 2009 water years. Both EC simulation approaches reproduced stream EC variations very well under both calibration and validation. The simulations using the age‐related EC simulation approach produced less biased results and, consequently, higher model coefficient of efficiency for validation periods. This approach also produced more consistent model parameter estimates between periods. There were systematic differences in the resultant age distributions between models, particularly for the solute balance‐based simulations where parameters (catchment storage size) changed more between the two calibration periods. The effect of time varying versus static storage selection functions were compared, with clear evidence that time varying storage selection functions with parameters linked to catchment conditions (flow) are essential for adequate simulation of EC dynamics during flow events

Complementary water quality modelling to support natural resource management decision making in Australia

Identifying sources and pathways of pollutants moving through catchments is a prerequisite for effectively targeting on-ground works to improve water quality. Simulation models are an important tool in this regard to: (i) Understand current catchment conditions including locating critical pollutant source areas, quantifying nutrient and sediment loads, determining delivery mechanism and elucidating causeeffect relationships. (ii) Summarise current knowledge into conceptual models of catchment function and system responses. (iii) Identify priority areas for intervention and assessing their likely impacts and cost-effectiveness. A large number of hydrologic, nutrient and sediment models exist for research and natural resource management support. In terms of complexity, the choice of the model determines the demand for input data and calibration parameters and the spatio-temporal resolution of the simulation. All these factors influence the extent to which models provide useful information to support decision makers. Model comparisons often lead to debates about which model is better, rather than the more constructive approach of applying different models for different purposes to improve understanding or predictive capacity. In this paper we investigate how three different water quality models, WaterCAST, CatchMODS and JAMS, could potentially complement one another to inform water quality management. The strengths, weaknesses and suitability of each model is discussed in the context of regional environmental investment planning within the Cradle Coast Natural Resource Management (NRM) region of north western Tasmania, a process typical of that being applied within Australia's 56 NRM regions. We suggest that the models potentially compliment one another in the following ways: (i) WaterCAST and CatchMODS are appropriate for carrying out rapid estimations of sediment and nutrient loads at subcatchment and catchment scales, (ii) JAMS is most appropriate for developing a conceptual understanding of hydrologic and solute processes and mapping critical pollutant source areas in space and time, (iii) JAMS is the most appropriate for developing and evaluating nutrient-based management interventions (iv) CatchMODS and JAMS together can be used to plan management interventions and evaluate the costeffectiveness of different scenarios. Further work will demonstrate the practicability of this approach for a selected case study in North West Tasmania

Monitoring strategies and scale-appropriate hydrologic and biogeochemical modelling for natural resource management

This short communication paper presents recommendations for developing scale-appropriate monitoring and modelling strategies to assist decision making in natural resource management (NRM). These ideas presented here were discussed in the session (S5) ‘Monitoring strategies and scale-appropriate hydrologic and biogeochemical modelling for natural resource management’ session at the 2008 International Environmental Modelling and Simulation Society conference, Barcelona, Spain. The outcomes of the session and recent international studies exemplify the need for a stronger collaboration and communication between researcher and model developer on the one side, and natural resource managers and the model users on the other side to increase knowledge in: 1) the limitations and uncertainties of current monitoring and modelling strategies, 2) scale-dependent linkages between monitoring and modelling techniques, and 3) representation of hydrologic and biogeochemical phenomena in model development and practical application for natural resource management

Multiscale investigations in a mesoscale catchment &ndash; hydrological modelling in the Gera catchment

The application of the hydrological process-oriented model J2000 (J2K) is part of a cooperation project between the Thuringian Environmental Agency (Thüringer Landesanstalt für Umwelt und Geologie &ndash; TLUG) and the Department of Geoinformatics of the Friedrich-Schiller-University Jena focussing on the implementation of the EU water framework directive (WFD). In the first project phase J2K was parametrised and calibrated for a mesoscale catchment to quantify if it can be used as hydrological part of a multi-objective tool-box needed for the implementation of the WFD. The main objectives for that pilot study were: The development and application of a suitable distribution concept which provide the spatial data basis for various tasks and which reflects the specific physiogeographical variability and heterogeneity of river basins adequately. This distribution concept should consider the following constraints: The absolute number of spatial entities, which forms the basis for any distributive modelling should be as small as possible, but the spatial distributed factors, which controls quantitative and qualitative hydrological processes should not be generalised to much. The distribution concept of hydrological response units HRUs (Flügel, 1995) was selected and enhanced by a topological routing scheme (Staudenrausch, 2001) for the simulation of lateral flow processes. J2K should be calibrated for one subbasin of the pilot watershed only. Then the parameter set should be used on the other subbasins (referred as transfer basins) to investigate and quantify the transferability of a calibrated model and potential spatial dependencies of its parameter set. In addition, potential structural problems in the process description should be identified by the transfer to basins which show a different process dominance as the one which was used for calibration does. Model calibration and selection of efficiency criteria for the quantification of the model quality should be based on a comprehensive sensitivity and uncertainty analysis (Bäse, 2005) and multi-response validations with independent data sets (Krause and Flügel, 2005) carried out in advance in the headwater part of the calibration basin. To obtain good results in the transfer basins the calibrated parameter set could be adjusted slightly. This step was considered as necessary because of specific constraints which were not of significant importance in the calibration basin. This readjustment should be carried out on parameters which show a sensitive reaction on the identified differences in the environmental setup. Potential scaling problems of the process description, distribution concept or model structure should be identified by the comparison of the modelling results obtained in a small headwater region of the calibration basin with observed streamflow to find out if the selected efficiency measures show a significant change. </ol

Multiscale investigations in a mesoscale catchment &ndash; hydrological modelling in the Gera catchment

O número 13/14 (Outono 2008/Primavera 2009) da revista Trajectos tem como tema de capa a escola. A revista é dirigida por José Rebelo e pertence ao ISCTE.Publicação de grande regularidade e de uma linha editorial muito bem identificada, é uma das revistas científicas de ciências sociais e humanas de maior interesse, pela inovação das suas temáticas e pelas suas colaborações variadas.Deste número, e para além do dossiê do tema de capa, destaco os textos de Isabel Babo-Lança, Isabel Férin Cunha..

Contrasting sediment and nutrient export patterns across different hydrological regimes:A case study in the Great Barrier Reef catchments

Stream water quality is highly variable in both space and time. A sound understanding of spatial and temporal changes in stream water quality is of great importance for the effective prioritisation of funding for pollution mitigation measures adopted in different agricultural sectors. Concentration-discharge (C-Q) relationship is a useful tool to characterise and identify solute and particulate export patterns, which provides critical information on processes that control constituent source, mobilisation, transformation and delivery at the catchment scale. Previous studies revealed that this relationship is not only varying across different catchments due to heterogeneity in climate and landscapes, but also varying within each catchment across different temporal scales. For example, changes in hydrological regimes, e.g., baseflow-dominated seasonal flow vs. quick flow-dominated storm event flow, would result in contrasting export patterns for solutes and sediments. However, routinely available water quality monitoring records (e.g., monthly) might not be capable of capturing the detailed response of concentration to changes in discharge over storm events. To overcome this, in this study, we used event-based water quality monitoring data set collected as part of the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program in the Great Barrier Reef (GBR) catchments. This study focuses on Total Suspended Solids (TSS) and dissolved Oxidized Nitrogen (NOX) from 12 GBR catchments. We used a Bayesian modelling framework to investigate the difference in sediment and nitrate export patterns at various temporal scales, i.e., seasonal and event scales. Our main findings are: • The export patterns at event scale are more consistent than those at seasonal scale. During storm events, TSS and NOX in most of the catchments demonstrate a mobilisation pattern. In contrast, non-significant concentration-discharge relationship (C-Q slope) at seasonal scale, suggesting that the response of C is invariant to the temporal change in Q during baseflow periods. • Catchment topography and land use are the two most influential groups of characteristics that control the export patterns for both TSS and NOX, which are relevant to temporal changes in sources and transport pathways across different hydrological regimes. The presented modelling results demonstrate that the export behaviours for solute and sediment are varying at different temporal scales, determined by heterogeneity in catchment landscape characteristics. These site-specific export patterns should be considered when prioritising future management strategies for the purpose of reducing loads of different constituents.</p