ASSESSMENT OF WATER QUALITY EVALUATION PERFORMANCE OF GEOSTATISTICAL TECHNIQUES

Karacaoren-II Dam Lake is a relatively deep reservoir located in Burdur, Turkey. It is one of the most important natural recreational and culture fishing area in the region. Although the lake has been constructed for irrigation and supply energy in the past, it is considered as a drinking water supply for Antalya in near future. However, it was mentioned that the lake suffers from eutrophication problem in recent scientific studies. So, the evaluation of water quality in the lake with different geostatistical techniques will facilitate the work of the managers to determine precautions and improve the water quality. In this study, water quality measurements were performed at 22 sampling locations in Karacaoren-II Dam Lake. Field works were carried out in November 2015 and August 2016. Firstly, spatial distribution maps of SD, DO and NO3-N were constituted using non-statistical Inverse Distance Weighted (IDW) and the statistical Ordinary Kriging (OK) interpolation methods within geostatistical analyst tool of ArcGIS program. Then, seasonal changes of the distributions were evaluated. Error metrics obtained from cross-validation was used to assess correctness of the interpolation methods. The results showed that both methods were effective in the identification of problematic zones. Higher SD and relatively lower DO values were clustered near outlet of the lake. DO was more sensitive to microscale variations. Although different methods were superior when different parameters, error metrics and seasons considered, most of the time OK method outperformed IDW.