Using the object modeling system for hydrological model development and application

State of the art challenges in sustainable management of water resources have created demand for integrated, flexible and easy to use hydrological models which are able to simulate the quantitative and qualitative aspects of the hydrological cycle with a sufficient degree of certainty. Existing models which have been de-veloped to fit these needs are often constrained to specific scales or purposes and thus can not be easily adapted to meet different challenges. As a solution for flexible and modularised model development and application, the Object Modeling System (OMS) has been developed in a joint approach by the USDA-ARS, GPSRU (Fort Collins, CO, USA), USGS (Denver, CO, USA), and the FSU (Jena, Germany). The OMS provides a modern modelling framework which allows the implementation of single process components to be compiled and applied as custom tailored model assemblies. This paper describes basic principles of the OMS and its main components and explains in more detail how the problems during coupling of models or model components are solved inside the system. It highlights the integration of different spatial and temporal scales by their representation as spatial modelling entities embedded into time compound components. As an exam-ple the implementation of the hydrological model J2000 is discussed

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

Analysis of the Hydrological Budget using the J2000 Model in the Pendjari River Basin, West Africa

In a semi - arid region where water scarcity is a major problem, quantify the water balance variables is very essential for sustainable water management. In a condition where meteorological input data are often not available in a sufficient spatial and temporal resolution, simulating the water balance variables is a big challenge. This research assesses the water balance for the Pendjari River basin, a 23208 km² sub-basin of the Volta basin in West Africa. The main purpose of this study is to assess how much water is available in the Pendjari River basin in terms of blue water and green water. To assess the water balance variables the distributed hydrological model J2000 has been used. The model has been manually and automatically calibrated for the period 1982 – 1990 using 24 parameters and validated for the period 1998 – 2008. 17 of the parameters have been selected for regional sensitivity analysis. The performance of the model has been measured using objective functions: Root Mean Square Error, Percent Bias, Nash-Sutcliffe efficiency, Relative Nash-Sutcliffe efficiency and Coefficient of Determination. The findings of this study have indicated that 58.67% of annual rainfall represents the evapotranspiration, which is considered as the amount of green water used to support natural vegetation productivity and agricultural system. The total actual evapotranspiration is estimated at 87% of annual rainfall. 12.53 % of annual rainfall end up as surface runoff and 9.92% of annual rainfall represents the groundwater recharge rate. Approximately 21% of annual rainfall represents the water yield, which is devoted to blue water source in the Pendjari River basin. The meteorological simulations are globally acceptable and the hydro-meteorological component simulation has shown very good model performances in comparison with the observed discharge data, indicating the potential of J2000 model to reproduce the geographical environment of the Pendjari River basin. Keywords: J2000; Green water; Blue water; Hydrological budget; Pendjari Rive

Investigating the impact of two decades of urbanization on the water balance of the Yzeron peri-urban catchment, France

International audienceThis paper addresses the impact of 18 years of urbanization (1990-2008) on the Yzeron meso-scale peri-urban catchment (150 km²), located close to Lyon, France. A simplified version of the distributed hydrological model J2000 was used to perform long term simulations at a daily time step for several land use scenarios. These scenarios were derived from satellite SPOT images from years 1990, 1999 and 2008. The corresponding land use maps were classified into 5 classes depending on the percentage of impervious surfaces and the dominant non-impervious land use (agriculture or forest). The paper presents the methodology for the model setup and the simulation results for the main water balance components of the catchment: total runoff, runoff components, evapotranspiration and soil moisture. The results highlight the change of the catchment seasonal response from 1990 to 2008, mainly due to a change of the respective contributions of groundwater flow / surface runoff (+ 92% / - 28%, respectively). Monthly mean summer discharge unexpectedly appears to be higher in summer. It is provided by intermittent surface runoff generated by summer storm events. As surface runoff generated on urban surfaces is likely to carry a wide range of contaminants, this has a potential large impact on water quality

Flow intermittence prediction using a hybrid hydrological modelling approach: influence of observed intermittence data on the training of a random forest model

Rivers are rich in biodiversity and act as ecological corridors for plant and animal species. With climate change and increasing anthropogenic water demand, more frequent and prolonged periods of drying in river systems are expected, endangering biodiversity and river ecosystems. However, understanding and predicting the hydrological mechanisms that control periodic drying and rewetting in rivers is challenging due to a lack of studies and hydrological observations, particularly in non-perennial rivers. Within the framework of the Horizon 2020 DRYvER (Drying River Networks and Climate Change) project, a hydrological modelling study of flow intermittence in rivers is being carried out in three European catchments (Spain, Finland, France) characterised by different climate, geology, and anthropogenic use. The objective of this study is to represent the spatio-temporal dynamics of flow intermittence at the reach level in mesoscale river networks (between 120 and 350 km2). The daily and spatially distributed flow condition (flowing or dry) is predicted using the J2000 distributed hydrological model coupled with a random forest classification model. Observed flow condition data from different sources (water level measurements, photo traps, citizen science applications) are used to build the predictive model. This study aims to evaluate the impact of the observed flow condition dataset (sample size, spatial and temporal representativity) on the performance of the predictive model. Results show that the hybrid modelling approach developed in this study allows the spatio-temporal patterns of drying to be accurately predicted in the three catchments, with a sensitivity criterion above 0.9 for the prediction of dry events in the Finnish and French case studies and 0.65 in the Spanish case study. This study shows the value of combining different data sources of observed flow condition to reduce the uncertainty in predicting flow intermittence.</p

Modelagem de processos hidrológicos em bacias de mesoescala escassamente monitoradas na Mata Atlântica, RJ, Brasil.

A Bacia Hidrográfica do Guapi-Macacu (BHGM), situada na região metropolitana do Rio de Janeiro, é responsável pelo abastecimento de mais de dois milhões de pessoas. A região é sujeita a inundações e deslizamentos no período chuvoso, e escassez hídrica na estação seca, com riscos para o abastecimento doméstico e agrícola nos anos de menor precipitação. Ferramentas de modelagem podem colaborar para a gestão integrado de recursos hídricos e apoiar a tomada de decisão. Este estudo utilizou o modelo hidrológico J2K, desenvolvido na plataforma Jena Adaptable Modeling System (JAMS), para representar o comportamento hidrológico da BHGM. Os procedimentos de parametrização e calibração do modelo foram baseados em dados de campo e de séries temporais meteorológicas e de vazão. O modelo parametrizado para a BHGM foi aplicado numa bacia adjacente, a Bacia Dois Rios (BHDR). Os indicadores de desempenho do modelo foram satisfatórios a bons para ambas as bacias e mostraram a viabilidade de aplicar conjuntos de parâmetros obtidos a partir de bacias instrumentadas em âmbito regional, i.e., em bacias semelhantes quanto às características geomorfológicas e climatológicas

Proposing environmental flows based on physical habitat simulation for five fish species in the Lower Duero River Basin, Mexico

The concept of “environmental flow” is defined as hydrologic regimes that are required to sustain ecosystem health and functions in rivers. In Mexico, it has become an important topic, not least because a 2012 legal standard (NMX-AA-159-SCFI-2012), establishes procedures for determining instream flow requirements. Goals. The aim of this paper is to propose an acceptable environmental flow requirement for a regulated river segment in the Duero River Basin in, Michoacan, Mexico. Methods. Of the many methods of establishing environmental flows in rivers, this article is concerned with the habitat simulation method. This is based on the IFIM theoretical framework and the PHABSIM mathematical model, by which the WUA-Q curves were obtained for five species of fish. Results. From these curves, we determined that the Goodea atripinnis species has the greater habitat area and reached a maximum of 4338 m2/km for a flow of 5 m3/s; Alloophorus robustus maintained a constant habitat of 2000 m2/km between flow rates of 5 to 15 m3/s. With smaller area, Menidia jordani had a maximum habitat of 1323 m2/km for 4.5 m3/s; and with WUA less than 500 m2/km the curves of the species Algansea tincella and Aztecula sallaei were obtained. Conclusions. The average regulation in March and April was 3.61 and 3.44 m3/s and with the EFR proposal it was 5.11 and 5.00 m3/s for March and April, respectively. In general, the monthly environmental regime is to maintain 80% of the natural flow regime, generating an increase in habitat during the dry season of 24% for A. robustus and 23% for A. sallaei