Hydrograph analysis of Inountas River Basin (Lakonia, Greece)

Abstract

Three approaches have been used to analyze the hydrograph of Inountas River basin in two reaches. Flow in each reach was estimated by combining the water level records with monthly field flow measurements. Base-flow separation has been accomplished by using the SWAT (Soil and Water Assessment Tool) baseflow filter program. The fraction of water yield contributed by baseflow was estimated between 0.76-0.62 for Kladas reach and 0.79-0.70 for Vassaras reach respectively. Flow duration curve for each reach was constructed from daily flow data. The flow-probability relationship, Q50 for Vassaras reach had a value of 0.164 and for Kladas 0.198. The ratio Q90/Q50 for Vassaras reach was 0.689 indicating that 68.9% of Vassaras stream flow was contributed from groundwater storage. The calculated recession factors were for Kladas reach 0.024 (10/04/2010- 04/06/2010) and for Vassaras reach 0.009 (20/03/2010-27/05/2010) and 0.005 (09/07/2010-11/10/2010).