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IWRA World Water Congress 2008 Montpellier France
1. Water availability, use and management
Author(s): Anda Bakute
Ansis Z.
Elga A.
(1)Faculty of Geographical and Earth Sciences, University of Latvia, Raina bulv. 19, Riga LV-1586, Latvia, Fax:+371 67332704,Phone: +371 67332627 E-mail: abakute@gmail.com, E-mail: elga.apsite@lu.lv

Keyword(s): river basins, hydrological modelling, calibration
Article: Poster:

AbstractThe river basins of Latvia are characterized with different natural conditions – the uneven relief, humid climate and geological development. These natural conditions are important aspects in hydrological regime of rivers. However, not always all parameters of hydrological regime or river basins have been observed. One of the explanations is that hydrological monitoring is rather expensive and there have been financial problems during last fifteen years. Therefore, mathematical model as one of more accepted tools in hydrology could be use (Bergström 1991; Bergström 1992; Brandt and Arheimer 1998; Podstchine et al. 1999; Ziverts and Jauja 1999). In this paper are presented the results of the new one version of the model METQ for the six different pilot river basins in Latvia: Iecava, Malta, Pērse, Vienziemīte, Malmutīte and Vircava. The aim of this study is to test the conceptual model METQ2007BDOPT for the unmonitored rivers basins under different natural conditions. As previous versions of the model METQ the METQ2007BDOPT is applied for the simulation of the daily runoff for the rivers with different catchment areas. The METQ2007BDOPT has 23 parameters. Most of the parameters are physically based and the rest of parameters could be estimated by the calibration. In present study the model METQ2007BDOPT is tested for the simulation of the daily runoff for the River Iecava at Dupši, the River Malta at Viļāni, the River Pērse at Pērse, the River Mālmute at Kažava, the River Vienziemīte at the Vienziemīte and the River Vircava at the Vircava. Theses pilot river basins characterise with different natural conditions – sandy lowlands, lakes, forested areas, swamps, agricultural lowlands and hilly agricultural lands. Input data for the model are daily mean meteorological data from eight meteorological stations – Zilupe, Rēzekne, Skrīveri, Gulbene, Bauska, Zosēni, Jelgava and Vienziemīte. The calibration of the model was done for the period from 1956 to 1995. To consider the runoff heterogeneity in runoff processes the each studied river basin have divided in hydrological response units (HRU) characterised by a relative homogeneity with respect to the most important parameters, which include slope, vegetation and soil characteristics. To analyses the results of model calibration a statistical criterion R2 (Nash and Sutcliffe 1970) and a correlation coefficient r are used. The numerical values of the model parameters for each pilot basin reflect the geomorphologic conditions of studied drainage areas. Sufficient or even good coincidence between the observed and simulated daily discharges has obtained. The efficiency criterion R2 differs from 0.66 to 0.78 but the correlation coefficient r is from 0.82 to 0.88. The obtained results of model calibration show that the model METQ2007BDOPT for these pilot basins are widely applicable.
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