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

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 – 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..

A bayesian hierarchical model to predict spatio-temporal variability in river water quality at 102 catchments

Our current capacity to model stream water quality is limited particularly at large spatial scales across multiple catchments. To address this, we developed a Bayesian hierarchical statistical model to simulate the spatio-temporal variability in stream water quality across the state of Victoria, Australia. The model was developed using monthly water quality monitoring data over 21 years, across 102 catchments, which span over 130,000 km2. The modelling focused on six key water quality constituents: total suspended solids (TSS), total phosphorus (TP), filterable reactive phosphorus (FRP), total Kjeldahl nitrogen (TKN), nitrate-nitrite (NOx), and electrical conductivity (EC). The model structure was informed by knowledge of the key factors driving water quality variation, which had been identified in two preceding studies using the same dataset. Apart from FRP, which is hardly explainable (19.9%), the model explains 38.2% (NOx) to 88.6% (EC) of total spatio-temporal variability in water quality. Across constituents, the model generally captures over half of the observed spatial variability; temporal variability remains largely unexplained across all catchments, while long-term trends are well captured. The model is best used to predict proportional changes in water quality in a Box-Cox transformed scale, but can have substantial bias if used to predict absolute values for high concentrations. This model can assist catchment management by (1) identifying hot-spots and hot moments for waterway pollution; (2) predicting effects of catchment changes on water quality e.g. urbanization or forestation; and (3) identifying and explaining major water quality trends and changes. Further model improvements should focus on: (1) alternative statistical model structures to improve fitting for truncated data, for constituents where a large amount of data below the detection-limit; and (2) better representation of non-conservative constituents (e.g. FRP) by accounting for important biogeochemical processes