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Wisconsin Administrative Codes [PDF]

Protecting Wisconsin’s Best: Outstanding and Exceptional Resource Waters

O/ERW Designations

Wisconsin has designated many of the state’s highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an “antidegradation” policy that is designed to prevent any lowering of water quality – especially in those waters having significant ecological or cultural value.

What is the difference between ORWs and ERWs?

ORWs receive the state’s highest protection standards, with ERWs a close second. ORWs and ERWs share many of the same environmental and ecological characteristics. They differ in the types of discharges each receives, and the level of protection established for the waterway after it is designated.

  • ORWs: ORWs typically do not have any point sources discharging pollutants directly to the water (for instance, no industrial sources or municipal sewage treatment plants), though they may receive runoff from nonpoint sources. New discharges may be permitted only if their effluent quality is equal to or better than the background water quality of that waterway at all times—no increases of pollutant levels are allowed.

    • Number of ORW/ERW Waterbodies
  • ERWs: If a waterbody has existing point sources at the time of designation, it is more likely to be designated as an ERW. Like ORWs, dischargers to ERW waters are required to maintain background water quality levels; however, exceptions can be made for certain situations when an increase of pollutant loading to an ERW is warranted because human health would otherwise be compromised.

How many waters in Wisconsin are ORW/ERW?

Of Wisconsin’s 15,000 lakes and impoundments, 103 are designated as ORW—fewer than 1%. Of Wisconsin’s 53,413 streams and rivers, 254 are designated as ORW, and 1,544 are designated as ERW. However, it can be more useful to consider stream statistics in terms of the number of stream miles rather than number of streams, since streams can be of widely varying lengths. Wisconsin has a total of ~42,000 stream/river miles in the state. Based on the current ORW/ERW list, a total of 3,179 stream miles (7.6%) have been designated as ORW, and 4,668 stream miles (11%) have been designated as ERW.

Find O/ERW Waters

To look up specific waterbodies, you can use several sources:

Wisconsin Administrative Code NR 102
Waters currently designated as ORWs and ERWs are listed in Wisconsin’s Administrative Code in chapters NR 102.10 (ORWs) and NR 102.11 (ERWs). The code is the legally authoritative source, though it can be complex to interpret. If you would like assistance in determining whether a specific water you are interested in is an ORW/ERW, contact the ORW/ERW Coordinator, Kristi Minahan, at 608-266-7055 or kristi.minahan@wisconsin.gov.

Maps of ORW/ERW

Lists of ORW/ERW
NOTE: In using the documents below, be sure to use both those from before 2006 and those from the 2006 addition, in conjunction with one another.

Listing Process

How is a decision made to designate waters as ORW or ERW?

History of ORW/ERW Listings

Streams that are designated as ORWs or ERWs are typically identified by water quality biologists as having one or more of the characteristics named in Wisconsin Administrative Code NR 102. By assessing the qualities of the stream, or by evaluating existing data, biologists recommended specific waters for ORW/ERW designation. These recommendations are eventually brought before the Natural Resources Board and the Wisconsin Legislature for approval. To be formally recognized as an ORW/ERW, waters must be added to the ORW/ERW lists found in NR 102.10 and NR 102.11.

History of Wisconsin’s ORW/ERW

Of Wisconsin’s 15,000 lakes and impoundments, 103 are designated as ORW—less than 1%. Of Wisconsin’s 53,413 streams and rivers, 254 are designated as ORW, and 1,544 are designated as ERW. However, it can be more useful to consider stream statistics in terms of the number of stream miles rather than number of streams, since streams can be of widely varying lengths. Wisconsin has a total of ~42,000 stream/river miles in the state. Based on the current ORW/ERW list, a total of 3,179 stream miles (7.6%) have been designated as ORW, and 4,668 stream miles (11%) have been designated as ERW. It can also be helpful to consider these statistics in terms of the number of stream miles rather than number of stream segments, since segments can be of widely varying lengths. Based on the current list, a total of 3,179 stream miles have been designated as ORW, or 7.6% of the ~42,000 perennial stream/river miles in the state. A total of 4,668 stream miles have been designated as ERW, or 11% of the perennial stream/river miles in the state.

Listing Implications

What are the permitting implications of an ORW/ERW decision?

Designation as an ORW or ERW has implications for permitting, in order to protect the quality of the waterway. For instance:

  • Point source discharges must meet background water quality, except in specific cases on ERW.
  • A general or individual permit is required for various waterway alteration activities.
  • Increased environmental review is required for high capacity wells near ORW/ERW.

See the attached document for more information:
What does an ORW/ERW designation mean for permittees? [PDF 95.7KB]

What are the legal impacts and socioeconomic implications?

A detailed study was conducted in 1995 documenting legal and socioeconomic impacts of ORW/ERW decisions in Marinette County. See full report: Outstanding and Exceptional Resource Waters: Analysis of Effects on Marinette County, WI [PDF 7.3MB].

Last Revised: Wednesday November 02 2011