Aşağı Gediz Havzası Nehir Sularının Kalitesinin Değerlendirilmesi ve Fizikokimyasal Parametrelerin Makroomurgasız Üzerine Etkilerinin İncelenmesi

Abstract

The aim of this study is to (1) investigate the quality of river waters in the Aşağı Gediz sub basin, which is an important subbasin of the Gediz basin, for current and future improvements scenarios applied situation with a model, and (2) to investigate the effects of improvements in chemical and physicochemical parameters of watershed quality on the macroinvertebrate ecological quality ratios. For this purpose, a water quality model based on Biological Oxygen Demand (BOD5), Dissolved Oxygen (DO), Organic Nitrogen, Ammonium Nitrogen (NH4-N) and Nitrate and Nitrite Nitrogen (NO3-N & NO2-N) parameters was established. The modeling study was carried out with QUAL2K water quality model published in 2004 by the United States Environmental Protection Agency (USEPA). The relationship between the macroinvertebrate biological quality component, which is an important component for the rivers, and Biological Oxygen Demand (BOD5), Dissolved Oxygen (DO), Ammonium Nitrogen (NH4-N) and Nitrate Nitrite Nitrogen (NO3-N & NO2-N), temperature and conductivity parameters were determined by correlation analyses. v Mathematical equations for calculation of Ecological Quality Ratio (EQR) were determined with regression analyses. Three Ecological Quality Ratios available for the study site were included in the scope of the study that include BMWP, Shannon Wiener and National Index. The results of the analysis showed that the structural equation created with National Index EQR gives a higher R2. By developing scenario models, the improvements in chemical and physicochemical parameters in each scenario and the effect of these improvements on the ecological quality ratios of macroinvertebrate were determined. Within the scope of this study, 7 different scenario situation models have been established and water quality improvements were at the highest level in the case of Scenario 7. Scenario 7 included assumptions of establishment of domestic wastewater treatment plants are established, higher efficiency industrial wastewater treatment plants are operated with and 50% reduction in diffuse pollution load. Based on annual average values, for DO parameter 40.91% III. Class water quality decreases to a ratio of 31.82% in the case of Scenario 7. While I. Class water quality does not exist for the current situation on the basis of the BOD parameter, I. Class water quality may be achieved with the Scenario models. On the basis of TN parameter, II. Class water quality ratio may increase from 7.73% to 70.45% with Scenario 7. When the other scenario situations are examined, it is seen that the closest improvements to Scenario 7 may be achieved with Scenarios 5 and 1. The common assumption of these scenarios is the establishment of domestic wastewater treatment plants. Therefore, it was concluded that the most important pollutant problem in the basin is domestic direct discharges. In the cases of Scenario 5, Scenario 6 and Scenario 7, macroinvertebrate EQRs have been estimated and despite the increase in physicochemical parameters, the ecological quality still showed a poor ecological status for the macroinvertebrate component. In this study, to what degree the variance in macroinvertebrates EQRs which is an important biological quality component may be explained by physicochemical parameters were investigated.