My research as the requirement of my graduation

Hydrograph Recession Constanta Calculation Using Semi Logarithmic Plot (A Case Study in Goseng Subwatershed)

Elly Kurniawati

Laboratory of Agricultural Resources Engineering, Agricultural Engineering Department, Faculty of Agricultural Technology, Gadjah Mada University, Yogyakarta, Indonesia

ABSTRACT

Recession curve is a spesific part of stream hygrograph after it reachs peak flow and it represents the withdrawal of groundwater from storage. Daily recession constant of surface runoff, interflow, and baseflow have been derived for 15 segments on Goseng subwatershed with area approximately 596 ha.

Semi logarithmic plot is recession analysis method which plotting stream discharge in ordinate and time in x-coordinate in semi logarithmic scale. The start of time recession is denoted by a straight line in the graphic. This method was used for separating a hydrograph into linear components of surface runoff, interflow, and baseflow.

The results of the research shows that recession segment from daily hydrograph has short time and does not have all three stream components. A short segment can only be divided into two flow components. Separation pattern for water catchment area are baseflow-interflow, baseflow-surface runoff, and interflow-surface runoff. Recession constant value differ from year to year but the differences do not have great influence in determining the average value of recession constant.

~ by errynosanctuary on August 15, 2008.