The Wisconsin DNR has proposed changes to its runoff regulation, NR 151 (and related rules), designed to reduce nonpoint source water pollution from agricultural and municipal sources and construction sites. 

Nonpoint source runoff continues to be the major cause of water pollution in the Midwest and around the country.  Nutrients,  sediment, and bacteria from agricultural lands; bacteria, toxic chemicals, oil and grease, and heavy metals from urban stormwater; and sediment from construction sites lead to the majority of water quality impairments in Wisconsin.

Federal laws like the Clean Water Act do an incomplete job of addressing diffuse nonpoint source pollution; state programs implemented by the DNR, therefore, are the primary tool for abating runoff.  DNR’s chief regulatory mechanism is NR 151, a regulation that sets runoff performance standards for agricultural sources (including cropland and livestock facilities), developed urban areas, construction sites, and transportation facilities.

DNR has proposed to strengthen these rules in several important ways:

Proposed changes to the agricultural performance standards:

• Requires a rolling 8-year average Phosphorus Index of 6 with a 1-year maximum of 10.  The Wisconsin “Phosphorus Index” is a modeling tool used to predict the amount of phosphorus that will run off agricultural land into the nearest body of water.  The calculation takes cropping practices, fertilizer application, soil characteristics, and other relevant factors into account using a computer program called SNAP-Plus. 

It is important for DNR to use the Phosphorus Index as an indicator of nutrient runoff, but the Index of 6 is far too high.  UW-Extension interprets a Phosphorus Index of 4-6 to mean a “high to excessive” potential for phosphorus delivery to nearby surface waters.  To further reduce nutrient pollution and harmful algae blooms in Wisconsin waters, DNR should lower the required PI to a at least a rolling average of 4, with an annual maximum of 6.

• Requires a Tillage Setback of 20 feet.  Driven in part by research performed through the Wisconsin Buffer Initiative, DNR is proposing a Tillage Setback of 20 feet, meaning that farmers and landowners would not be able to till the soil within 20 feet of the top of channel of a waterbody.  This important step protects the integrity of the streambank, reducing erosion and the delivery of pollutants directly to the water.

Farmland is valuable, and the temptation is great to use every square foot of it – especially when prices for corn and soybeans are high.  But occasionally crops are planted right up to the edge of a river or stream, weakening the protective streambank and leading to a surge in nutrient and sediment delivery to the water.  Under DNR’s proposal, the land can still be used but it can’t be tilled.  This important setback is a small price to pay for clean water.

• Strengthening Total Maximum Daily Load (TMDL) requirements for nonpoint sources.  Under the Clean Water Act, a TMDL represents the total amount of a pollutant that a waterbody can assimilate and still meet water quality goals.  DNR proposes to modify the rule to ensure that nonpoint sources design pollution-reducing practices to meet the requirements of the TMDL, if one exists for that waterbody.

When a TMDL is prepared by the DNR, each source of pollution in a watershed is assigned a pollutant load; in theory, when all sources of pollution meet their allocated loads, the water will meet water quality goals.  For point sources of pollution (like factories and sewerage treatment plants); the pollution loads are converted into binding limits in their pollution discharge permits (WPDES permits), ensuring transparency and enforceability.  But no concrete mechanism exists yet to ensure that nonpoint sources can and will meet their allocated pollution loads.  DNR’s proposal is a step in the right direction, and the agency needs new tools to make the TMDL process more meaningful for nonpoint sources.

Some organizations and industries, most notably the mainstream agricultural organizations like the Farm Bureau, are expected to oppose these important and much-needed improvements in NR 151. MEA supports the strengthening of NR 151 and related standards, and urges you to voice your support for clean water to the DNR at an upcoming public hearing.

Proposed changes to non-agriculture performance standards:

• The proposed construction site performance standards (NR 151.11) do not incorporate regulations recently promulgated by the United States Environmental Protection Agency concerning effluent limitations guidelines and standards for construction sites.  Effective February 1, 2010, EPA has set effluent limitations guidelines for construction sites (40 C.F.R. Part 450).  Non-numeric effluent limitations are required for all construction sites, whereas a numeric effluent limitation for turbidity is set for construction sites that disturb greater than 20 acres at a time.

DNR’s proposed revisions to chapter 151 were drafted before the EPA’s effluent limitations guidelines were published and went into effect.  Under the Clean Water Act, Wisconsin is a delegated state that has authority to issue point source pollution discharge permits (WPDES permits).  Within an issued WPDES permit, DNR must incorporate applicable federal guidelines and limitations.  Therefore, DNR should revise the construction site performance standard (NR 151.11) to reflect EPA’s construction site effluent limitations guidelines. 

• Proposed rule NR 151.11(3) requires that construction site performance standards apply to any construction site with land disturbing construction activity.  Currently, NR 151.11(2)(b) applies only to construction sites that have at least one acre of land disturbing activity.

DNR has taken the positive step of requiring that all construction sites with land disturbing activities, regardless of size, comply with the construction site performance standard.   The proposed rule will ensure that small sites employ best management practices to reduce the amount of sediment that is allowed to runoff into the state’s water. 

• Proposed rule NR 151.11(6)(a) requires that construction sites utilize best management practices designed to limit sediment runoff to no more than 5 tons per acre per year.  The current standard requires best management practices that achieve an 80% reduction of sediment runoff as compared to no controls. 

DNR’s proposed rule is an unacceptable change from a relative (80% reduction as compared to no controls) to an absolute (5 tons per acre per year) standard for controlling sediment runoff from construction sites.  A relative standard ensures that every applicable construction site installs best management practices to reduce sediment load carried in runoff, including sites that only generate a small or moderate amount of sediment runoff.  An absolute standard is good for reducing sediment runoff from construction sites that create a large amount of sediment, but has no effect on sites that discharge less than 5 tons of sediment runoff per acre per year.  Five tons of sediment is a lot of sediment.  The Occupational Safety & Health Administration estimates that one cubic foot of soil weighs between 110 and 140 pounds.  Assuming that soil and sediment have similar characteristics, five tons of sediment would fill a volume of approximately 80 cubic feet.  DNR should combine the current relative standard with the proposed absolute standard and require that construction sites use best management practices to reduce the sediment load carried in runoff by 80% with a maximum allowed discharge of 5 tons per acre per year.

• Within the proposed runoff rules, DNR has created a protective areas performance standard that requires impervious surfaces to be kept out of protective areas.  Protective areas are defined in the proposed rule as distances away from an outstanding resource water and exceptional waters (75 feet), perennial and intermittent streams identified on a U.S. geological survey map or county soil survey map (50 feet), lakes (50 feet), wetlands (50 feet), or highly susceptible wetlands (75 feet).  Proposed rule NR 151.125 requires that non-transportation and transportation surfaces that do not allow water to pass through must be kept out or not constructed within in protective areas.  Furthermore, if construction has disturbed a protective area, then sod or self-sustaining vegetation must be established on at least 70 percent of the land where no impervious surface exists.   

The proposed protective areas performance standard is important for the health of the state’s water and wetland resources.  Land disturbing construction activity and impervious services are major causes of runoff that eventually harm the state’s water resources.    

• Proposed rule 151.13(2)(e) states that municipalities implementing best management practices to comply with the developed urban area performance standard are not required to spend more than $0.37 per thousand dollars of reported equalized value annually.  This provision places an explicit cap on the amount of money a municipality must spend in order to meet proposed rule NR 151.13(2)’s requirement that permitted municipalities (NR 216: Storm Water Discharge Permits) achieve a 40 percent reduction in total suspended solids or a reduction to the maximum extent practicable by March 31, 2013.

The developed urban area performance standard for municipalities is an important tool for reducing total suspended solids in runoff.  By placing a cap on the amount of money a municipality is required to spend on complying with the standard, DNR is potentially reducing the number of municipalities that will fully comply with the 40 percent reduction.  Instead, municipalities will only have to reduce total suspended solids to the maximum extent practicable using $0.37 per thousand dollars of equalized value.  DNR should remove the explicit cap on the amount of money a municipality must spend on best management practices to comply with the developed urban area performance standard.        

Public Hearing Dates and Locations

Public hearings are concluded.

Written comments may be submitted through March 12, 2010, to the following address:

Carol Holden,
DNR - WT/3,
P.O. Box 7921,
Madison, WI 53707-7921
carol.holden@wisconsin.gov