Conclusion

     Using STELLA as a predictive model, an increase in water temperature and/or respiration of organisms causes a decrease in dissolved oxygen levels in fresh water streams.  Conversely,  an increase in photosynthesis and turbulence causes an increase in dissolved oxygen levels.  An extension of this model could be used to explore the effect of global warming on cold water fish species and their relation to dissolved oxygen.

    It should be noted that the model constructed here appears to agree with presently accepted theories concerning the effects of the environment on levels of dissolved oxygen in freshwater streams.  This STELLA model, however, has not been validated.  The quantity of data used here to develop these relationships is also inadequate.  The equations used in the model's construction are for the most part standard.  Some of the values were adjusted to give the model a constant base line.  Any conclusion drawn using this model to determine effects of the environment on dissolved oxygen would at best be tentative.
 

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