Abstract
Determination of reaeration coefficient is an important factor in surface water quality modeling as it determines the efficiency of the Streeter-Phelps model used for predicting dissolved oxygen deficit of any stream. This study compared the efficiency of Atuwara model with ten other reaeration coefficients models by making use of three data sets obtained from river Atuwara during the prevalent wet and dry seasons using composite goodness of fit test which was developed by quantitatively combining statistical and graphical goodness of fit. The eleven tested models were ranked in order of performance. Results show that the four top ranking models were developed through a process that utilized data from multiple streams while models that were developed from data obtained from the test subject alone performed less competitively. The outcome of the study also suggests that the usual practice of selecting the best model based on statistical analysis alone does not necessarily yield the best result and therefore recommended the incorporation of quantitatively analyzed graphs. The paper concludes that selection of the best performing model among existing reaeration coefficient models using the composite goodness of fit may present a cheaper and better alternative to conventional model development approach.
Highlights
Computation of reaeration coefficient (k2) is an integral part of the process of modeling the dissolved oxygen of any surface water body (Chapman, 1996; Lin & Lee, 2007; Omole, Adewumi, Longe, & Ogbiye, 2012)
Several k2 models have been proposed and their distinguishing factor has been their capacity to predict measured data with minimum error. This has been demonstrated through several publications on reaeration coefficient modeling (Streeter, Wright, & Kehr, 1936; O’Connor & Dobbins, 1958; Owens, Edwards, & Gibbs, 1964, Langbein & Dururn, 1967; Bansal, 1973; Bennet, & Rathburn, 1972; Long, 1984; Baecheler & Lazo, 1999; Jha, Ojha, & Bhatia, 2001; Agunwamba, Maduka, & Ofosaren, 2007; Longe & Omole, 2008; Omole & Longe, 2012) beginning with the pioneering work of Streeter and Phelps (1925) where it was established that dissolved oxygen (DO) content of surface water bodies is used up in breaking down biological and chemical wastes
The ranking was done for each data set and combined to find an average score which was converted to percentages in the last row of Table 2
Summary
Computation of reaeration coefficient (k2) is an integral part of the process of modeling the dissolved oxygen of any surface water body (Chapman, 1996; Lin & Lee, 2007; Omole, Adewumi, Longe, & Ogbiye, 2012). Several k2 models have been proposed and their distinguishing factor has been their capacity to predict measured data with minimum error This has been demonstrated through several publications on reaeration coefficient modeling (Streeter, Wright, & Kehr, 1936; O’Connor & Dobbins, 1958; Owens, Edwards, & Gibbs, 1964, Langbein & Dururn, 1967; Bansal, 1973; Bennet, & Rathburn, 1972; Long, 1984; Baecheler & Lazo, 1999; Jha, Ojha, & Bhatia, 2001; Agunwamba, Maduka, & Ofosaren, 2007; Longe & Omole, 2008; Omole & Longe, 2012) beginning with the pioneering work of Streeter and Phelps (1925) where it was established that dissolved oxygen (DO) content of surface water bodies is used up in breaking down biological and chemical wastes.
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