Water balance estimation in Anthemountas river basin and correlation with underground water level

Abstract

Estimation of annual water balance is critical for water management and developmental planning in the area of Anthemountas river basin. In the framework of LIFE04/ENV/GR/000099 project and in continuance to prior projects in the area, the average annual water balance was estimated using the annual precipitation and water consumption. The statistic relationship between elevation and precipitation measured at different stations in the greater area, was applied to the Digital Elevation Model (DEM) (accuracy 20X20m) and the spatial distribution of annual precipitation is calculated for the Anthemountas river basin. Consumption of underground water was analytically calculated based on the different types of agricultural activities as annually reported by the Ministry of Agriculture. The Domestic water consumption was also calculated. Evaportranspiration is estimated analytically using two different methods (Thorthwaite’s and Turk’s). Both methods gave similar results. Moreover the spatial distribution of infiltration and runoff coefficients were calculated taking into consideration the different geological features, since they determine the maximum value of the infiltration coefficient, and the CORINE land coverage classification assuming no infiltration at builded areas. All the above were calculated and presented in raster format using the ESRI ArcGIS 9 environment. The correlation between the negative water balance and the drop of the underground water level, as this was pictured through underground water level measurements in the past decade, was discussed and evaluated. To further understand the relationship between the negative water balance and the spatial distribution of the underground water level drop, the most consuming wells in the Anthemountas river basin are distributed and categorized based on consumption estimates. Future work should assess more precise land coverage dataset in order to produce spatial distribution of evaportranspiration. At the same time, precise precipitation datasets, that will be produced by the meteorological monitoring network, that is to be established in the LIFE04/ENV/GR/000099 project framework, will provide more accurate estimates of precipitation distribution. This will lead to the determination of more accurate estimates for both infiltration and runoff in the basin. Data monitoring, assessment and water balance estimation are valuable tools in a step-by-step procedure towards the achievement of sustainable use of water in the river basin of Anthemountas.