Section 378.301  Die-off Equation

a)         The permittee shall model the die-off of fecal coliform from its discharge using the first-order die-off equation provided in Appendix A of this Part.  Appendix B of this Part provides step-by-step guidance for the application of this equation.  Appendices C through E of this Part provide further assistance in the application of the equation.

b)         The die-off equation predicts levels of fecal coliform at points downstream from the fecal coliform source.  The equation includes variables to reflect upstream levels of fecal coliform, changes in dilution and travel time, and other stream-specific parameters.

c)         In modeling the effects of its discharge, the permittee shall collect additional stream-specific information as necessary to demonstrate compliance with fecal coliform water quality standards.  The amount of field data necessary to utilize the equation as specified in Appendix B of this Part will depend on the proximity of the source to protected waters and the nature of the receiving waters. Additional field data collected will produce more accurate prediction of downstream levels of fecal coliform.