Section NR 151.20 - Purpose and applicability(1) This subchapter establishes performance standards, as authorized by s. 281.16(2) (a), Stats., for transportation facilities that cause or may cause runoff pollution. These performance standards are intended to limit runoff pollution in order to achieve water quality standards. Design guidance and the process for developing technical standards to implement this subchapter are set forth in subch. V.(2) Transportation facilities that are directed and supervised by the department of transportation and that are regulated by an administrative rule administered by the department of transportation, where the department determines in writing that the rule meets or exceeds the performance standards of this subchapter and is implemented in accordance with the administrative rule provisions, shall be deemed to meet the requirements of the portions of this subchapter determined by the department.(3) In s. NR 151.23, soil loss is calculated using the appropriate rainfall or runoff factor, also referred to as the R factor, or an equivalent design storm using a type II distribution, with consideration given to the geographic location of the site and the period of disturbance.Wis. Admin. Code Department of Natural Resources NR 151.20
CR 00-027: cr. Register September 2002 No. 561, eff. 10-1-02; CR 09-112: am. Register December 2010 No. 660, eff. 1-1-11.The universal soil loss equation and its successors, revised universal soil loss equation and revised universal soil loss equation 2, utilize an R factor which has been developed to estimate soil erosion, averaged over extended time periods. The R factor can be modified to estimate monthly and single-storm erosion.