Determining of Total Maximum Daily Load on Abdal River Basin of the Mid-Black Sea

Abstract

Total maximum daily load is a tool that used to organize water quality standards and it bases on relationship between water quality conditions and pollutant sources. In this study, to apply WARMF (Watershed Analysis Risk Management) Model to Abdal river basin which is located at the Mid-Black Sea Coast, to calculate the total maximum daily loads over point and nonpoint specific parameters in the river basin area. Abdal river basin is an important area because of Cakmak Dam which provides drinking and irrigation water in Samsun city constructed above the river basin area. WARMF model was chosen because of it is a tool designed to support the watershed approach, to evaluate alternatives the river basin water quality management to achieve results over many parameters for stakeholders and especially calculating total maximum daily load that to propose for the reasons. In order to obtain the most accurate and precise results in model, calibration studies were carried on according to 2008-2009 seasonal change results in study site and relative errors were calculated between measurements and model calculations. After then WARMF model calibration and run, TMDL calculated for regional loading and source contributions along the river basin. According to this results, it was calculated that for the present situation nitrate TMDL the highest value WLA 730 kg/day on the sub-basin 2 and the lowest value LA 380 kg/day on the sub basin 3, total phosphorus TMDL, the highest value WLA 72 kg/day on the sub-basin 2 and the lowest value LA 37 kg/day on the sub- basin 1. In addition to running WARMF model of the river basin, it was determined that nitrate nitrogen TMDL resulted from 22% distributed sources, 33% agricultural sources, 45% other usage sources and total phosphorus TMDL resulted from 42% distributed sources, 26% agricultural sources, 32% other usage sources.