TY - JOUR A1 - Bronstert, Axel A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Güntner, Andreas A1 - Hauschild, M. A1 - Döll, P. T1 - Integrated modelling of water availability an management in the semi-arid Notheast of Brazil Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Güntner, Andreas T1 - A large-scale hydrological model for the semi-arid environment of north-eastern Brazil Y1 - 2000 ER - TY - JOUR A1 - Güntner, Andreas A1 - Olsson, J. A1 - Calver, Ann A1 - Gannon, B. T1 - Cascade-based disaggregation of continuous rainfall time series : the influence of climate Y1 - 2001 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - WAVES - Water availability, vulnerability of ecosystems and society in the northeast of Brazil : sub-project large-scale hydrological modelling Y1 - 2001 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Modelling the effects of climate change on water availability in the semi-arid of North-East Brazil Y1 - 2001 ER - TY - JOUR A1 - Bronstert, Axel A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Güntner, Andreas T1 - Integrated modelling of climate, water, soil, agricultural and socio-economic processes : a general introduction to the methodology and some exemplary results from the semi-arid Northeast of Brazil Y1 - 2002 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Process-based modelling of large-scale water availability in a semi-arid environment : process representation and scaling issues Y1 - 2002 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Representation of landscape variability and lateral redistribution processes for large-scale hydrological modelling in semi-arid areas N2 - The spatial variability of landscape features such as topography, soils and vegetation defines the spatial pattern of hydrological state variables like soil moisture. Spatial variability thereby controls the functional behaviour of the landscape in terms of its runoff response. A consequence of spatial variability is that exchange processes between landscape patches can occur at various spatial scales ranging from the plot to the basin scale. In semi-arid areas, the lateral redistribution of surface runoff between adjacent landscape patches is an important process. For applications to large river basins of 10(4)-10(5) km(2) in size, a multi-scale landscape discretization scheme is presented in this paper. The landscape is sub-divided into modelling units within a hierarchy of spatial scale levels. By delineating areas characterized by a typical toposequence, organised and random variability of landscape characteristics is captured in the model. Using runoff-runon relationships with transition frequencies based on areal fractions of modelling units, lateral surface and subsurface water fluxes between modelling units at the hillslope scale are represented. Thus, the new approach allows for a manageable description of interactions between fine-scale landscape features for inclusion in coarse-scale models. Model applications for the State of Ceara (148,000 km(2)) in the north- east of Brazil demonstrate the importance of taking into account landscape variability and interactions between landscape patches in a semi-arid environment. Using mean landscape characteristics leads to a considerable underestimation of infiltration-excess surface runoff and total simulated runoff. Re-infiltration of surface runoff and lateral redistribution processes between landscape patches cause a reduction of runoff volumes at the basin scale and contribute to the amplification of variations in runoff volumes relative to variations in rainfall volumes for semi-arid areas. (C) 2004 Elsevier B.V. All rights reserved Y1 - 2004 SN - 0022-1694 ER - TY - JOUR A1 - Güntner, Andreas A1 - Krol, Marten S. A1 - de Arajo, José Carlos A1 - Bronstert, Axel T1 - Simple water balance modelling of surface reservoir systems in a large data-scarce semiarid region N2 - Water resources in dryland areas are often provided by numerous surface reservoirs. As a basis for securing future water supply, the dynamics of reservoir systems need to be simulated for large river basins, accounting for environmental change and an increasing water demand. For the State of Ceara in semiarid Northeast Brazil, with several thousands of reservoirs, a simple deterministic water balance model is presented. Within a cascade-type approach, the reservoirs are grouped into six classes according to storage capacity, rules for flow routing between reservoirs of different size are defined, and water withdrawal and return flow due to human water use is accounted for. While large uncertainties in model applications exist, particularly in terms of reservoir operation rules, model validation against observed reservoir storage volumes shows that the approach is a reasonable simplification to assess surface water availability in large river basins. The results demonstrate the large impact of reservoir storage on downstream flow and stress the need for a coupled simulation of runoff generation, network redistribution and water use Y1 - 2004 SN - 0262-6667 ER - TY - JOUR A1 - De Araujo, Josè Carlos A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Loss of reservoir volume by sediment deposition and its impact on water availability in semiarid Brazil N2 - A methodology is presented to assess the impact of reservoir silting oil water availability for semiarid environments, applied to seven representative watersheds in the state of Ceara, Brazil. Water yield is computed using stochastic modelling for several reliability levels and water yield reduction is quantified for the focus areas. The yield-volume elasticity concept, which indicates the relative yield reduction in terms of relative storage capacity of the reservoirs, is presented and applied. Results chow that storage capacity was reduced by 0.2% year(-1) due to silting, that the risk of water shortage almost doubled in less than 50 years for the most critical reservoir, and that reduction of storage capacity had three times more impact oil yield reduction than the increase in evaporation. Average 90% reliable yield-volume elasticity was 0.8, which means that the global water yield (Q(90)) in Ceara is expected to diminish yearly by 388 L s(-1) due to reservoir silting Y1 - 2006 UR - http://www.atypon-link.com/IAHS/loi/hysj U6 - https://doi.org/10.1623/hysj.51.1.157 SN - 0262-6667 ER -