Irrigation Pond Stratification Structure Determination and Temperature - Dissolved Oxygen Modeling Using Ce-Qual-W2

Abstract

Thermal stratification experienced in irrigation ponds leads to intensification of agricultural pollution events due to hypolimnetic oxygen depletion. In this study, stratification in a small pond in western Turkey was investigated. Pond bathymetry was determined with a combination of an Acoustic Doppler Current Profiler (ADCP) equipment measurement and field study using Real Time Kinematic GPS (RTK GPS) equipment. The Relative Thermal Resistance to Mixing (RTRM) index and 2-dimensional hydrologic model CE-QUAL-W2 was utilized to characterize the stratification structure. Based on these monitoring results, the temperature profile was constructed. The pond volume was found to be occupied by 60% with the epilimnion, 20% metalimnion and 20% hypolimnion. The model was calibrated with monitoring data from 2013 and validated with data from 2014. It was determined that the pond was monomictic. The pond was modeled with CE-QUAL-W2 and the dates of stratification, the temperature and dissolved oxygen profiles were simulated with absolute mean errors of 0.77 degrees C for temperature and 1.09 mgO(2)/L for dissolved oxygen. Different irrigation and meteorological scenarios were examined to predict pond volumes and temperatures till 2020. As a result of scenario implementations, drip irrigation practices were found to be the best management application for the sustainable management of the pond.