Integration of habitat quality index with physicochemical and ecological models oriented to the Ecosystem recovery in the Meléndez River, Cali-Colombia

The ecological quality of the water of the Meléndez River at the medium and low basin was evaluated through the application of quality and pollution indices in the ecosystem by using physicochemical parameters and its... [ view full abstract ]

The ecological quality of the water of the Meléndez River at the medium and low basin was evaluated through the application of quality and pollution indices in the ecosystem by using physicochemical parameters and its association with aquatic macroinvertebrates. In addition, a pollution control scenario was evaluated by the application of a simplified dissolved oxygen model of Streeter Phelps, in the most critical loads into the river. This study was performed in a period of high precipitation of the last quarter of the year 2016. The aim of this project was find the actual ecological situation at the river in order to create a baseline study necessary for the future environmental improvement of the city. In general the ecological quality index showed a significant alteration of the riverside forest in the middle basin and an extreme degradation in the low part. On the other hand the physicochemical parameters results showed high dissolved oxygen levels (7.21 mg / L in the middle basin and 6.63 mg / L in the low basin), pH very close to neutrality in all stations, BOD₅ and COD with values that did not exceed 12 mg/L, whereas fecal coliforms presented high levels in the low basin (up to 66000 CFU) showing a certain degree of contamination in the lower river basin. A total of 22041 individuals of macroinvertebrates of 7 different families were obtained by the catching methods which indicates according to the BMWP-Col index that the river presents very polluted waters due to the discharges of domestic wastewaters. The measured physicochemical parameters and the species of macroinvertebrates present good correlations according to the analysis of canonical correspondence where there are strong associations in the X axis with pH (0.940) and OD (0.919), while in the Y axis a strong correlation With the BOD (0.819). This project contributes to explore new issues to discuss about our ecosystem resources and how our environmental authorities can improve their care through the use of ecological indices, models and its correlation with the aquatic macroinvertebrates providing a frequently tracing spatial and temporal in our Rivers.

Key words: aquatic macroinvertebrates, ecological quality, sustainability indicators, Streeter Phelps model, Meléndez River.