Refinement of predictive reaeration equations for a typical Indian river

Abstract

Abstract:Dissolved oxygen mass balance has been computed for different reaches of River Kali in western Uttar Pradesh (India) to obtain the reaeration coefficient K 2 . A total of 270 field data sets have been collected during the period from March 1999 to February 2000. Eleven most popular predictive equations, used for reaeration prediction and utilizing mean stream velocity, bed slope, flow depth, friction velocity and Froude number, have been tested for their applicability in the River Kali using data generated during field survey. The K 2 values computed from these predictive equations have been compared with the K 2 values observed from dissolved oxygen balance measurements in the field. The performance of predictive equations have been evaluated using error estimation, namely standard error (SE), normal mean error (NME), mean multiplicative error (MME) and correlation statistics. The equations developed by Smoot and by Cadwallader and McDonnell showed comparatively better results. Moreover, a refined predictive equation has been developed using a least-squares algorithm for the River Kali that minimizes error estimates and improves correlation between observed and computed reaeration coefficients.

Composite Goodness of Fit in Reaeration Coeffcient Modeling

“…Several k 2 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, 1967Bansal, 1973;Bennet, & Rathburn, 1972;Long, 1984;Baecheler & Lazo, 1999;Jha, Ojha, & Bhatia, 2001;Agunwamba, Maduka, & Ofosaren, 2007;Longe & Omole, 2008; 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 quantity of oxygen that would be required to break down these wastes completely was described as biochemical oxygen demand (BOD).…”

“…Therefore, the current study, which may be the first of its kind, proposes a method that combines both statistical and visual inspection of graphs of multiple models using the same data sets. The selected models for this study are Atuwara , Streeter et al (1936) (which is also known as US Geological Survey equation), O'Connor & Dobbins (1958), Owens et al (1964), Langbein and Dururn (1967), Bansal (1973), Bennet and Rathburn (1972), Long (1984), Baecheler and Lazo (1999), Jha et al, (2001) and, Agunwamba et al (2007) model which was developed in southern Nigeria using data obtained during the wet season only ( Table 1). The Streeter et al (1936) model was selected because it is the first proposed k 2 model.…”

Effects of high ammonia concentrations on three cyprinid fish: Acute and whole-ecosystem chronic tests

“…In previous studies, chronic tests have primarily been conducted in pure water, while the present study was conducted in ponds where the toxicity of the added ammonium may be modulated by various ecosystem processes. The added ammonia may in part be lost by N 2 emission through nitrification-denitrification (Admiraal and Botermans, 1989;Mulholland et al, 2000;Peterson et al, 2001) and NH 3 volatilization (Young and Huryn, 1999;Jha et al, 2001;Passell et al, 2007). Ammonia may also be taken up by phytoplankton and later, in part, transferred to the sediment when phytoplankton dies or sinks.…”

“…Thus, the toxicity of total ammonia increases as pH or temperature increases (USEPA, 2013), and pH is increasing with phytoplankton production, which, in turn, may be stimulated by higher loading of ammonia (Moss et al, 2013). However, aquatic ecosystems possess mechanisms reducing accumulation of ammonia: (1) uptake by aquatic algae and macrophytes as their nitrogen source (Mulholland et al, 2000;Peterson et al, 2001;Dodds et al, 2002), (2) transfer to sediments by adsorption on particulates (Rosenfeld, 1979;Mackin and Aller, 1984;Peterson et al, 2001), (3) emission to the atmosphere in the form of N 2 via nitrification-denitrification (Admiraal and Botermans, 1989;Chesterikoff et al, 1992;Mulholland et al, 2000;Peterson et al, 2001), and (4) NH 3 volatilization at the airwater interface (Young and Huryn, 1999;Jha et al, 2001;Hall and Tank, 2003;Passell et al, 2007). Accordingly, the organisms in natural lake ecosystems are often exposed lower ammonia concentrations than would be expected from the loading.…”

Critical appraisal of BOD and DO models applied to a highly polluted river in India

“…Another main process in the oxygen condition of streams is that of re-aeration (Moog & Jirka, 1998;Jha et al, 2001Jha et al, , 2004Jain & Jha, 2005), which is the uptake of oxygen across the water surface due to the turbulent motion of water and to molecular diffusion. This process reduces the "oxygen deficit" (D) of water, which is defined as the difference between saturation oxygen content and the actual dissolved oxygen level.…”