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The Use of Asymptotic Functions for Determining Empirical Values of CN Parameter in Selected Catchments of Variable Land Cover

–101. [28] S oulis K.X., V aliantzas J.D., Identification of the SCS-CN Parameter Spatial Distribution Using Rainfall-Runoff Data in Heterogeneous Watersheds , Water Resour Manage, 2012, 27, 1737–1749. [29] USDA Natural Resources Conservation Service. Hydrology , [in:] National Engineering Handbook; USDA Soil Conservation Service: Washington, DC, USA, 2004, Chapter 9. [30] W ałęga A., R utkowska A., Usefulness of the Modified NRCS-CN Method for the Assessment of Direct Runoff in a Mountain Catchment , Acta Geophysica, 2015, 63(5), 1423–1446. [31

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DETERMINING THE CHARACTERISTICS OF DIRECT RUNOFF FROM REAL RAIN USING GIS ENVIRONMENT / STANOVENIE CHARAKTERISTÍK PRIAMEHO ODTOKU Z REÁLNEHO DAŽĎA S VYUŽITÍM PROSTREDIA GIS

Abstract

The selected SCS-CN method is used worldwide and adapted to the conditions of Slovakia. GIS environment provides an opportunity to simulate changes in land use, and then to calculate the total volume of water from the river and peak water flow in the river bed of the stream. The simulation was done for two rainfall events, 72 mm and 42.6 mm, which were measured in precipitation station in Jelenec (a village situated next to the area of interest). The calculation was made for 4 possible scenarios - current land use, forest, arable land and grassland and pasture. Culmination discharge and time of outflow from rainfall 72 mm for current land use were calculated using the NRCS method. The calculation of water runoff volume showed that similar values were measured for the rainfall of 72 mm and rainfall 42.6 mm in case of AMC-III. The highest values of water runoff volume were marked in the case of arable land in all calculations, the lowest one for forest. Comparison of designed stream cross section and calculated culmination discharge allowed us to determine the point of outflow from the river bed of the Drevenica stream.

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Land use changes in the last half century and their impact on water retention in the Šumava mountains and foothills (Czech Republic)

Abstract

Changes in land use and runoff characteristics in Otava river basin and its two subcatchment (Volšovka and Vydra) were examined. The goal was to find out how water retention have responded to changes in landscape management in Šumava mountains and foothills since the year 1970. There were two basic levels of changing land use - (a) conversion of arable land with varying intensity at different management of intensive and extensive grassland, (b) deforestation of large areas of indigenous mostly spruce monocultures and their transfer to the shrub and herbaceous vegetation covering the surface with a discontinuous vegetation. Water retention in Šumava mountains is locally reduced due to vulnerability of monoculture spruce forests by natural disasters (windstorms), diseases and pests. A positive effect of current agricultural management in the Šumava foothills on the reduction of direct runoff during intense rainfall was confirmed.

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Episodic runoff generation at Central European headwater catchments studied using water isotope concentration signals

Abstract

Hydrological monitoring in small headwater catchments provides the basis for examining complex interrelating hydraulic processes that govern the runoff generation. Contributions of different subsurface runoff mechanisms to the catchment discharge formation at two small forested headwater catchments are studied with the help of their natural isotopic signatures. The Uhlirska catchment (Jizera Mts., Czech Republic) is situated in headwater area of the Lusatian Neisse River. The catchment includes wetlands at the valley bottom developed over deluviofluvial granitic sediments surrounded by gentle hillslopes with shallow soils underlain by weathered granite. The Liz catchment (Bohemian Forest, Czech Republic) is situated in headwater area of the Otava River. It belongs to hillslope-type catchments with narrow riparian zones. The soil at Liz is developed on biotite paragneiss bedrock. The basic comparison of hydrological time series reveals that the event-related stream discharge variations at the Uhlirska catchment are bigger and significantly more frequent than at Liz. The analysis of isotope concentration data revealed different behavior of the two catchments during the major rainfall-runoff events. At Uhlirska, the percentage of the direct runoff formed by the event water reaches its maximum on the falling limb of the hydrograph. At Liz, the event water related fraction of the direct outflow is maximal on the rising limb of the hydrograph and then lowers. The hydraulic functioning of the Uhlirska catchment is determined by communication between hillslope and riparian zone compartments.

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Comparing Methods for Computing the Time of Concentration in a Medium-Sized Hungarian Catchment

Abstract

One of the most often-used parameters that describes morphology and runoff from a watershed is the time of concentration (Tc). At gauged watersheds, Tc can be determined using rainfall and a runoff hydrograph, while for ungauged watersheds, empirical equations are used. A good initial estimate of Tc greatly improves the accuracy of runoff predictions. In our study, we applied 14 empirical equations to determine Tc. Tarján Creek, which is located in northeastern Hungary, was selected as the trial gauged watershed. It is located in a mountainous region with an area of 72 km2. The input parameters for the empirical equations were determined using geoinformatical tools. To evaluate the accuracy of the empirical equations, HEC-HMS was used to model the runoff. Using the measured runoff data, both continuous and event-based models were calibrated. For direct runoff, Clark’s unit hydrograph was selected. Tc is one of the input parameters for this model. After the calibration, the estimates from the empirical equations for Tc were compared to the HEC-HMS calibrated values for each subwatershed. The empirical estimates varied greatly. The Wisnovszky-equation, which is most often used in Hungary, underestimated Tc.

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Gis-Based Flow Routing with the Distributed Hydrological Wetspa Model in the Ziarat River Basin - Gorgan, Iran

Abstract

The GIS-based distributed hydrological model, WetSpa, whose flow routing method is described in this paper is suitable for flood prediction and watershed management on catchment scale. The model predicts outflow hydrographs at the basin outlet or at any converging point in the watershed, and it does so at a user-specified time step. The model is physically based, spatially distributed and timecontinuous. This paper focuses on the GISbased diffusive transport approach for the determination of rainfall runoff response and flood routing through a catchment. The watershed is represented as a grid cell mesh, and routing of runoff from each cell to the basin outlet is accomplished using the first passage time response function based on the mean and variance of the flow time distribution, which is derived from the advection-dispersion transport equation.The flow velocity is location dependent and calculated in each cell by the Manning equation based on the local slope, roughness coefficient and hydraulic radius. The hydraulic radius is determined according to the geophysical properties of the catchment and the flood frequency. The total direct runoff at the basin outlet is obtained by superimposing all contributions from every grid cell. The model is tested on the Ziarat _Gorgan watershed with 4 years of observed hourly rainfall and discharge data, and the results are in excellent agreement with the measured hydrograph at the basin outlet

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Stakeholder group consensus based on multi-aspect hydrology decision making / Skupinový konsensus zainteresovaných subjektů založený na multikriteriální metodě rozhodování. j. hydrol. hydromech., 60, 2012, 4; 22 lit, 6 obr., 8 tab.

environmental modelling process - A framework and guidance. Environmental Modelling and Software, 22 , 11, 1543-1556. SINGH V. P., 1996: Kinematic Wave Modelling in Water Resources. John Wiley & Sons, Inc., New York. SOULIS K. X., VALIANTZAS J. D., DERCAS N., LONDRA P. A., 2009: Investigation of the direct runoff generation mechanism for the analysis of the SCS-CN method applicability to a partial area experimental watershed. Hydrol. Earth Syst. Sci., 13 , 605-615. ŠRAJ M., DIRNBEK L., BRILLY M., 2010: The influence of

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Parameter recalculation for a rainfall-runoff model with a focus on runoff curve numbers

monthly, hosted on ArcGIS online). < http://services7.arcgis.com/xQldfwn7vL7z10wM/arcgis/rest/services/BPEJ/FeatureServer > National Engineering Handbook (1972) Estimation of direct runoff from storm rainfall. Section 4 Hydrology, Chapter 10, Soil Conservation Service, Washington. National Engineering Handbook (2004) Hydrologic Soil-Cover Complexes. Part 630 Hydrology, Chapter 9, United States Department of Agriculture, Washington. Novotný I, Vopravil J, Kohoutová L ... Žížala D (2013) Metodika mapování a aktualizace bonitovaných půdně ekologických jed

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Assessment of Regional Variation of Flood Runoff in the Republic of Moldova

://earthexplorer.usgs.gov/ (accessed on 3.04.2017); 27. ***(1956), Soil Conservation Service (SCS): Hydrology, National Engineering Handbook, Supplement A, Sect. 4, Chapt. 10, USDA, Washington, D.C., 70p; 28. ***(1972), Soil Conservation Service (SCS): National Engineering Handbook, Supplement A, Sect. 4, Hydrology, Chapt. 10, Estimation of direct runoff from storm rainfall, USDA, Washington, D.C., 77p; 29. ***STATGRAPHICS http://www.statgraphics.com/ (accessed on 3.04.2017).

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Implementation of conceptual linear storage model of runoff with diurnal fluctuation in rainless periods / Aplikace konceptuálního lineárního modelu základního odtoku s denní variabilitou v bezesrážkovém období, Česká republika. J. Hydrol. Hydromech., 60, 2012, 4; 27 lit., 8 obr., 3 tab.

Press, Wallingford, pp. 367-388. KOVÁŘ P., DVOŘÁKOVÁ Š., KUBÁTOVÁ E., 2006: Possibilities of Using the Direct Runoff Model KINFIL for a Road Network Design. Soil and Water Research, 1 , 2, pp. 49-56. LOHEIDE S. P., BUTLER J. R. J., J., GORELICK S. M., 2005: Estimation of groundwater consumption by phreatophytes using doutnal water table fluctuations: A saturatedunsaturated flow assessment. Wat. Resour. Res., vol. 41 , W07030. NASH J. E., SUTCLIFFE J. V., 1970: River flow forecasting through conceptual models part I - A

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