Can a permit require chemical and biological sampling at points other than the discharge outfall?
This question is not entirely specific to nutrients, and therefore, is answered the same as for any other water quality criteria. Biological sampling may be appropriate to effectively monitor the discharge status and ensure compliance. One practice for collecting ambient monitoring is described in EPA’s Interim Guidance for Performance-based Reductions of NPDES Permit Monitoring Frequencies [PDF – 87 KB – 23 pp], which states that the permit authority can grant reductions in effluent monitoring for a permittee with a history of good compliance and permitting performance in exchange for ambient monitoring. In an attempt to test some of the ideas in the 1996 Interim Guidance, performance track facilities have been piloting programs to strike a balance between ambient monitoring and end-of-pipe monitoring. Specifically, Kodak Colorado Division and other dischargers near Kodak on the Cache la Poudre River have formed an ambient water quality monitoring group. This group was formed in coope
