Evaluation of Sefidroud River’S Reaeration-Rate Coefficient, Iran

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Mehdi Mohammadi Ghaleni, Kumars Ebrahimi, Mohammad Hosein Omid

Wednesday 1 july 2015

12:48 - 12:51h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment, Poster pitches

Parallel session: Poster pitches: 9G. Environment - Impact

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Accurate estimation of the reaeration rate coefficient is very important for the purposes of dissolved oxygen and self-purification modelling in rivers. The main target of this paper is to evaluate 19 commonly used reaeration rate coefficient prediction equations, in Sefidroud River, North of IRAN. In this paper the river’s dissolved oxygen has been modelled involving Streeter- Phelps Equation. Then the predicted reaeration rate coefficient results have been compared with four series of collected and recorded data of the river. The studied reach has a length of 110km, including 12 water quality sampling stations along the river and it is extended from downstream of Sefidroud dam to the south coast of Caspian Sea. According to the results, among all equations Parkhurst-Pomeroy equation has shown the most accurate prediction of the reaeration rate coefficient values, with the statistical criteria of Standard Error (SE), Mean Multiplicative Error (MME) and Sum of Square of Residuals (SSR) equal to 0.51, 1.05 and 2.35, respectively. Moreover, results indicate that the river has a high Biochemical Oxygen Demand (BOD) and as well a low Self-Purification capacity, during September, which is simultaneous with the seepage of non-point agricultural pollutants.