TECHNICAL NOTE: TECHNICAL NOTE: DETERMINATION OF THE SCS DETERMINATION OF THE SCS INITIAL ABSTRACTION RATIO INITIAL ABSTRACTION RATIO

IN AN EXPERIMENTAL IN AN EXPERIMENTAL WATERSHED IN GREECEWATERSHED IN GREECE

Helin SemilarskiHelin Semilarski

Estonian University of Life SciencesEstonian University of Life Sciences

Hydrobiology , 2011Hydrobiology , 2011

INTRODUCTIONINTRODUCTION

The experimental watershed is located on The experimental watershed is located on the Pentali Mountain in Greecethe Pentali Mountain in Greece

Study objective is to find the initial Study objective is to find the initial abstraction ratio (la/S)abstraction ratio (la/S)

MATERIALMATERIAL

The total area of the The total area of the watershed is 15,18 watershed is 15,18 kmkm22

The mean, minimum The mean, minimum and maximum and maximum altitudes were 430, altitudes were 430, 146 and 950 m146 and 950 m

METHODMETHOD

18 storm events were selected, analyzing 18 storm events were selected, analyzing measured rainfallmeasured rainfall

The analysis step was 30 minutesThe analysis step was 30 minutes

NATURAL RESOURCES NATURAL RESOURCES CONSERVATION SERVICE – CONSERVATION SERVICE – CURVE NUMBER (SCS-CN)CURVE NUMBER (SCS-CN)

SCS is based on the areas hydrologic soil SCS is based on the areas hydrologic soil group, land use, treatment and hydrologic group, land use, treatment and hydrologic conditioncondition

In order to study land covers properties a In order to study land covers properties a description research was carried outdescription research was carried out

CN is used in hydrology for predicting CN is used in hydrology for predicting direct runoff from rainfall excessdirect runoff from rainfall excess

RESULTSRESULTS

The average initial abstraction ratio of the The average initial abstraction ratio of the watershed is equal to 0,014 watershed is equal to 0,014

The human being intervention, in the form The human being intervention, in the form of urban development found in the of urban development found in the southern partsouthern part

CONCLUSIONCONCLUSION

The determined values of the initial ratio The determined values of the initial ratio are close to suggested index of 0,05are close to suggested index of 0,05

Runoff from these areas reaches the outlet Runoff from these areas reaches the outlet at the early stages of the storm and thus at the early stages of the storm and thus leads to low initial abstractionleads to low initial abstraction

REFERENCESREFERENCES

Baltas, E.A., Dervos, N.A, 2007, Vol. 11: Baltas, E.A., Dervos, N.A, 2007, Vol. 11: 1825-1829 “ Technical Note: 1825-1829 “ Technical Note: Determination of the SCS initial Determination of the SCS initial abstraction ratio in an experimental abstraction ratio in an experimental watershed in Greece” Available at watershed in Greece” Available at http://www.hydrol-earth-syst-sci.net/11/182http://www.hydrol-earth-syst-sci.net/11/1825/2007/hess-11-1825-2007.pdf5/2007/hess-11-1825-2007.pdf

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