The simulation showing transformation of rainfall into streamflow, and routing the generated flows through the streams in a basin, is widely used in many fields of water resources analysis, including understandSimulacao Hidrologica de Grandes Bacias 118 ing the earth surface phase processes of the hydrologic cycle. The early mathematical models developed to simulate this transformation were based on empirical relations between hydrological variables. The newgeneration hydrological models are physically based and distributed, and are adequate to represent small basins. There are few models able to simulate the hydrological processes in large basins, with an adequate physical base. In this paper we present a physically-based large-scale hydrological model, that takes into account the distributed nature of the basin’s characteristics such as land use, vegetation and stream network. The model was applied to two basins, almost 27.000 km2, with very distinct physical characteristics, and with many rainfall and streamflow gauging stations. The model performance, estimated by the fit between measured and calculated daily river discharges at different gauging stations, was very good. Applying the model enabled a preliminary analysis of land use changes in one of the basins, improving the understanding and comparison of the hydrological behavior of both basins. All results show that a large-scale hydrological model is a very useful tool in water resources analysis, even considering the data availability conditions in countries like Brazil. Key-words: simulation; rainfall-streamflow; large basins.

Integração de modelos hidrológicos e sistemas de informações geográficas: fundamentos

Simulação Hidrológica de Grandes Bacias

A new methodology is proposed to capture the seasonal behavior of evapotranspiration from precipitation and streamflow data and to develop hydrometeorological evapotranspiration models tailored for each basin. The water budget method for determining evapotranspiration is downscaled to periods between 15 and 160 days that occur between well-marked hydrological recessions. Using these uneven time periods, the error associated with the unknown soil moisture storage is minimized, whereas groundwater storage changes are estimated by means of a classical linear groundwater reservoir whose time constant is obtained by recession analysis. This seasonal water budget (SWB) method is able to reproduce the seasonal signal of evapotranspiration even when it is absent from the precipitation and streamflow records. The estimates are also compatible with calculated monthly net radiation. By selecting short enough water budget periods it is possible to check the relationship between SWB evapotranspiration estimates and net radiation, Penman and Priestley-Taylor potential evaporation, precipitation minus outflow, water vapor deficit, and basin storage. The ratio of SWB evapotranspiration to an upper limit value represented by either net radiation or potential evaporation is well correlated with precipitation minus outflow, water vapor deficit, or both but is very poorly related to basin storage. The calculated regressions lead to a family of hydrometeorological evapotranspiration monthly (HEM) models fitted to the basins in question, in a way analogous to the calibration of rainfall-runoff models. In the two watersheds where the methodology was applied the HEM models were able to preserve mass, with total accumulated differences no larger than 0.25 mm d−1 and root-mean-square errors of the order of 0.7 mm d−1.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999WR900230

A hydrometeorological model for basin-wide seasonal evapotranspiration

Universidade estadual paulista "julio de mesquita filho" faculdade de ciências agronômicas campus de botucatu simulação da produção de sedimentos na bacia hidrográfica do rio pardo - botucatu / sp, por modelagem hidrológica

This paper describes the integration of the QUAL2E model for water quality simulation in the GIS/DBMS environment of the "Integrated Monitoring System of the Cuiaba River Watershed" (SIBAC). Programmed database modules prepare data tables for an interactive QUAL2E data entry, executed by the SIBAC GIS-Environment. Modified ArcView/Avenue (ESRI) scripts, partially based on the BASINS application (USEPA 1998), allow the automated model calibration and visualization of modeling results in the GIS environment. Database and GIS tools created for evaluation of the Cuiaba watershed in Mato Grosso, Central Brazil, are appropriated for application in other river basins.

Um ambiente sig para modelagem integrada da qualidade da ã?gua utilizando qual2e

This study presents the application of the distributed hydrological model based on GIS – ACUMOD to estimate the water discharges and potentialities of Pirapama river sub-basins, to be used by the Pirapama River Basin Committee (COBH-Pirapama). The model application included several steps, such as: precipitation data selection, basin discretization into cells, and model parameter calibration using try-and-error technique. The model was calibrated and validated with monthly precipitation data for the period 1987–2001. It was noted that the following parameters were the most important ones during the calibration process: infiltration function, soil minimum water capacity to generate runoff, and soil mean water storage capacity, which directly affect the computed runoff volume. The difference between observed and computed runoff during the calibration and validation processes were respectively -12.65% and 18.87%. The results of the simulated discharges by ACUMOD, compared to observed ones, showed that the model satisfactorily represents the water basin

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Integração de modelos hidrológicos e sistemas de informações geográficas: fundamentos

Citations

Simulação Hidrológica de Grandes Bacias

A hydrometeorological model for basin-wide seasonal evapotranspiration

Universidade estadual paulista "julio de mesquita filho" faculdade de ciências agronômicas campus de botucatu simulação da produção de sedimentos na bacia hidrográfica do rio pardo - botucatu / sp, por modelagem hidrológica

Um ambiente sig para modelagem integrada da qualidade da ã?gua utilizando qual2e

Aplicação do modelo hidrológico AÇUMOD baseado em SIG para a gestão de recursos hídricos do rio Pirapama, Pernambuco, Brasil