Steady-state dissolved oxygen model for the Rideau River

1977 ◽  
Vol 4 (4) ◽  
pp. 471-481 ◽  
Author(s):  
K. Adamowski ◽  
A. C. Middleton
Keyword(s):  
Steady State ◽  
Dissolved Oxygen ◽  
Oxygen Demand ◽  
River Channel ◽  
Sediment Oxygen Demand ◽  
Model Parameters ◽  
Marginal Effect ◽  
One Dimensional ◽  
Source Sink ◽  
Rideau River

A steady-state, one dimensional dissolved oxygen (DO) model was developed for summer conditions for the Rideau River near Ottawa, Ontario. Model parameters were estimated for July 1975 conditions, and model acceptance was based on June 1975 conditions. Results of the model indicated that the tributaries in this section had only a marginal effect on DO concentrations. The major factor affecting DO concentrations was the distributed source–sink processes, which include photosynthesis, respiration, and sediment oxygen demand. River channel reaeration and aeration at dams had a minimal effect on DO.

Controlling mechanisms of sediment-driven dissolved oxygen dynamics in New Bedford Outer Harbour

1995 ◽  
Vol 46 (1) ◽  
pp. 69 ◽  
Author(s):  
BH Kolb ◽  
MC Heineman
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Municipal Sewage ◽  
Strongly Correlated ◽  
Storm Events ◽  
One Dimensional ◽  
Air Temperatures ◽  
Bottom Waters ◽  
Oxygen Dynamics

A summer-long monitoring programme investigated mechanisms controlling near-bottom dissolved oxygen (DO) concentrations in New Bedford Outer Harbor, a shallow embayment on the southern Massachusetts coast that receives discharge from a 1.3 m3 s-1 municipal sewage outfall. Continuously recording meters and hydrographic cruises measured DO, temperature, salinity, meteorology, waves and/or currents. The programme quantified the magnitude, spatial extent and duration of oxygen undersaturation in the bottom waters. Summer stratification of New Bedford Outer Harbor reduced reaeration of the bottom waters. Depletion of near-bottom DO was strongly correlated with the presence and duration (though not intensity) of stratification. Stratification is typically thermal, a result of seasonal warming of the water surface, although it can become enhanced (and somewhat salinity driven) owing to the influx of cold saline bottom water following major storm events. Destratification is caused by high wind speed or a drop in 24-h average air temperatures below the water temperature. The decrease in DO concentrations when the water column is stratified is directly related to local sediment oxygen demand. In general, DO dynamics were found to be local and fundamentally one dimensional.

Considering the impact of intermittent discharges when modelling overflows

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Preliminary Investigation ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Combined Sewer Overflows ◽  
River Hydraulics ◽  
Combined Sewer ◽  
The Impact ◽  
Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

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