Wisconsin Administrative Code › Department of Natural Resources › NR 200-299 - Environmental Protection - Wisconsin Pollutant Discharge Elimination System › Chapter NR 217 - Effluent Standards And Limitations For Phosphorus › Subchapter III - Waterbody Assessments and Reporting › Section NR 217.15 - Determination of necessity for water quality based effluent limitations for phosphorus

Current through June 24, 2024
(1)
(a)
General.
The department shall include a water quality based
				  effluent limitation for phosphorus in a permit whenever the discharge or
				  discharges from a point source or point sources contain phosphorus at
				  concentrations or loadings which will cause, has the reasonable potential to
				  cause or contribute to, an exceedance of the water quality standards in s.
				  NR
				  102.06 in either the receiving water or downstream
				  waters. The department shall use the procedures in this section to make this
				  determination.
(b)
Permittees with existing phosphorus limitations.
If a
				  permittee has a technology based phosphorus limitation in a permit that is less
				  restrictive than a water quality based effluent limitation for phosphorus
				  calculated pursuant to s.
				  NR
				  217.13, then the department shall include the water
				  quality based effluent limitation in the permit.
(c)
Permittees without existing
				  phosphorus limitations.
If a permittee discharges phosphorus, but does
				  not have a technology based limitation for phosphorus in its permit, the
				  department shall use the procedures in this paragraph to determine whether a
				  discharge will cause, has the reasonable potential to cause or contribute to an
				  exceedance of the phosphorus water quality criterion in s.
				  NR
				  102.06 in the receiving or downstream waters, and
				  whether to include a water quality based effluent limit for phosphorus in the
				  WPDES permit.
1. Using at least 11 daily
				  discharge concentrations of phosphorus, if the upper 99th percentile of the 30
				  day average discharge concentration of phosphorus exceeds the potential
				  phosphorus limitation calculated under s.
				  NR
				  217.13, then the water quality based effluent
				  limitation for phosphorus shall be included in the WPDES permit. If the upper
				  99th percentile of the 30 day average discharge concentration of phosphorus is
				  less than the potential phosphorus limitation calculated under s.
				  NR
				  217.13, then a water quality based effluent limitation
				  for phosphorus is not required in the WPDES permit. The upper 99th percentile
				  of available discharge concentrations shall be calculated pursuant to s.
				  NR
				  106.05(5).
2. If 11 daily discharge concentrations of
				  phosphorus are not available for a permittee, then a water quality based
				  effluent limitation for phosphorus shall be included in the permit when the
				  mean of available effluent concentrations is greater than one-fifth of the
				  limit.
3. If no phosphorus effluent
				  data is available for an existing permittee, the department may require
				  phosphorus sampling as part of a permit application for reissuance to determine
				  whether a water quality based effluent limit is necessary in the WPDES permit
				  under par. (a), or the department may use effluent data information from
				  similar point sources to make the determination under par. (a).
Note: The department will develop guidance regarding the
					 administration of this section to ensure that permitted discharges with a
					 reasonable potential to cause or contribute to exceedances of the applicable
					 phosphorus water quality criterion in s.
					 NR
					 102.06 are identified.
(d)
Sampling.
Prior to
				  permit reissuance, a permittee discharging any phosphorus shall collect
				  effluent samples of phosphorus at a frequency specified by the department in
				  the permit application for reissuance.
(e)
New dischargers.
The
				  department shall include a water quality based phosphorus limitation in a
				  permit for a new discharger if the department determines the new discharger
				  will discharge phosphorus at concentrations or loadings which may cause or
				  contribute to exceedances of the water quality criteria in s.
				  NR
				  102.06 in either the receiving water or downstream
				  waters. To estimate the amount of phosphorus discharged by a new discharger,
				  the department may consider projected discharge information from the permit
				  applicant and phosphorus discharge information from similar sources.