The effect of reaeration and benthic algae on the oxygen balance of an artificial ditch

In an artificial ditch, receiving a low nutrient input, processes affecting DO (dissolved oxygen) were measured. Estimated process parameters were implemented in a dynamic model to simulate continuously measured DO. The processes modelled were primary production, respiration, sediment oxygen demand and reaeration. y production by a benthic layer of algae was found to dominate the oxygen balance. The contribution of reaeration was also large, even at the observed oxygen concentrations which were close to equilibrium. tion to ambient light conditions was introduced in the description of benthic primary production. The reaeration coefficient was related to the continuously measured wind velocity. This resulted in a good agreement between simulated and measured DO concentrations, with a model efficiency of 89%.