Wisconsin Administrative Code › Department of Natural Resources › NR 100-199 - Environmental Protection General › Chapter NR 151 - Runoff Management › Subchapter IV - Transportation Facility Performance Standards › Section NR 151.242 - Total suspended solids performance standard

Current through June 24, 2024
(1) REQUIREMENT.
				  Except as provided in sub. (3), BMPs shall be designed, installed, and
				  maintained to control total suspended solids carried in runoff from the
				  transportation facility post-construction site. BMPs shall be designed in
				  accordance with Table 1., or to the maximum extent practicable as provided in
				  sub. (4). The design shall be based on an average annual rainfall, as compared
				  to no runoff management controls.
Table 1. TSS Reduction
								  Standards
Development Type
TSS Reduction
New Transportation Facilities
80 percent
Highway Reconstruction
40 percent
Non-highway transportation facility
								  redevelopment
40 percent of load from parking areas and
								  roads
(2)
				  NON-HIGHWAY TRANSPORTATION REDEVELOPMENT AND HIGHWAY RECONSTRUCTION. Except as
				  provided in s.
				  NR
				  151.241(4), the non-highway
				  transportation facility redevelopment and highway reconstruction total
				  suspended solids reduction standard of Table 1. applies to non-highway
				  transportation facility redevelopment and highway reconstruction.
(3) DELAYED IMPLEMENTATION. For
				  municipalities that are regulated under subch. I of ch. NR 216 and for
				  transportation facilities under the jurisdiction of the department of
				  transportation for maintenance purposes that are located within municipalities
				  regulated under subch. I of ch. NR 216, the highway reconstruction total
				  suspended solids performance standard first applies January 1, 2017.
(4) MAXIMUM EXTENT PRACTICABLE. If the design
				  cannot meet a total suspended solids reduction performance standard of sub.
				  (1), Table 1., the storm water management plan shall include a written,
				  site-specific explanation of why the total suspended solids reduction
				  performance standard cannot be met and why the total suspended solids load will
				  be reduced only to the maximum extent practicable. The department may not
				  require any person to exceed the applicable total suspended solids reduction
				  performance standard to meet the requirements of maximum extent practicable.
Note:
Pollutant loading models such as
					 DETPOND, SLAMM, P8, or equivalent methodology may be used to evaluate the
					 efficiency of the design in reducing total suspended solids. Information on how
					 to access these models is available from the department's storm water
					 management program at dnr.wi.gov. Use the most recent version of the model and
					 the rainfall files and other parameter files identified for Wisconsin users
					 unless directed otherwise by the regulatory authority.
(5) OFF-SITE DRAINAGE. When designing BMPs,
				  runoff draining to the BMP from off-site shall be taken into account in
				  determining the treatment efficiency of the practice. Any impact on the
				  efficiency shall be compensated for by increasing the size of the BMP
				  accordingly.