David Rozman

Prague, July 2019

Infiltration of precipitation and recharge was assessed by hydrologic model BILAN.

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developed by T.G. Masaryk Water Research Institute

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described in Tallaksen and van Lannen (2004)

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further developed during the last decade and it has proven to be a reliable tool in local

conditions (Vizina et al. 2015, Hanel et al. 2012, Horáček et al. 2008)

Structure of the model is constructed by a system of equations

describing basic principles of water balance. It simulates the

process on the surface, in the soil aeration zone including the effect

of vegetation and in the saturated zone. Air temperature is used as

an indicator of energy conditions, which significantly affect the

water balance components.

The BILAN model simulates water fluxes and amounts of water

stored in the snow pack, in the unsaturated zone and in the aquifer.

The simulated flow of water is dependent on six free parameters:

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capacity of soil moisture storage

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snow melting factor

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parameter controlling outflow from direct runoff storage

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parameter controlling distribution of percolation into direct runoff and

groundwater recharge under summer conditions

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parameter controlling distribution of percolation into direct runoff and

groundwater recharge under snow melting conditions

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parameter controlling outflow from groundwater storage

The parameters are calibrated using an optimization algorithm. The optimization

process employs MAPE criterion to find the best fit between the observed and

simulated runoff at the outlet from the catchment.

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delineation of model catchments

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measurement of catchment area

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interpolation od meteorological data

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transformation to mm/month

The parameters are calibrated using an optimization

algorithm with MAPE (mean absolute percentage

error) criterion to find the best fit between the

observed and simulated runoff at the outlet from the

catchment.

The gained results are water balance components including potential

and actual evapotranspiration, soil infiltration and recharge of the aquifer.

The gained results are water balance components including potential

and actual evapotranspiration, soil infiltration and recharge of the aquifer.

Uncertainties:

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shorter calibration period for Cunnersdorferbach and Kamenice

(input data quality?)

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in case of Kamenice, the baseflow for calibration was set by classic

hydrograph separation (groundwater flows)

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In case of Křinice we are not able to quantify the effect of the part of the

catchment North of the Lausitz thrust

Groundwater model input:

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outputs are valid for the model

catchments

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time series relevant for the

entire hydraulic model area

are calculated as weighted

average