OAR 340-039-0043: Requirements for Trading Ratios

(1) Water quality trades must include one or more trading ratios that apply to credits. Ratio components and underlying assumptions must be clearly documented in the trading plan. (2) Trading ratios may be used to account for variables associated with a trading project including the following: (a) Attenuation of a water quality benefit between the location where credit-generating BMPs occur and the point of use; (b) Pollutant equivalency; (c) Uncertainty of BMP performance or water quality benefit measurement or estimate; (d) Types of risk not associated with BMP performance; (e) Time lag after BMP installation before a BMP produces full water quality benefit; (f) Credit for trading projects located in priority areas; or (g) Credit retirement to ensure a net reduction in water pollution.