GÖLPAZARI HAVZASI’NIN (BİLECİK) MIKE SHE PROGRAMI İLE BÜTÜNLEŞİK HİDROLOJİK MODELİ

Abstract

Gölpazarı Basin, located in the middle part of the Sakarya Basin, is spread over an area of 170 km2 within the borders of Bilecik province. The middle part of the basin is a plain with an area of 35 km2. Water requirement for drinking, use and irrigation for the settlements in the basin, especially in Gölpazarı district, are provided from the wells drilled in different levels in the plain and also Akçay Irrigation Dam that is located on the Akçay stream. The available data set of regional geology, hydrology, surface flow records and hydrometeorological data were evaluated. In addition to the existing data set provided by 3rd Regional Directorate of State Hydraulic Works, retention, evapotranspiration and infiltration parameters controlling the rainfall runoff relation were generated and tested using remote sensing data sets. Overland and channel flow, surface and canopy retention, evaporanspiration and unsaturated flow and storage processes were conceptualized and modeled for the entire basin for the period from 2013 to 2017. The model was calibrated by the merely available gauging station representing only a small part of the basin. As a result of the integrated hydrological model of the Gölpazarı Basin, Infiltration and storage in the vadose zone are estimated as 18 % of the precipitation, whereas evapotranspiration correspond to 78 % of precipitation. In the conditions of soil characteristics created by using the remote sensing data set, the infiltration rate in the plain area was calculated relatively higher than the upper elevations of the basin.