Wisconsin Department of Natural Resources


Storm water management Definitions

Best management practices

"BMPs" means schedules of activities, prohibitions of practices, maintenance procedures, structural controls, source area controls, treatment requirements, operating procedures, outdoor storage containment and other management practices to prevent or reduce pollutants in runoff entering waters of the state.

Construction erosion control plan

Required by certain commerial and industrial businesses that disturb land for new business creation or expansion. The plan details how to control erosion, short-term and long term. The plan must cover methods to control erosion before, during and after land-disturbing activities. (Examples include installing silt fencing and using erosion blankets to stop sediment). A guidance document is available through the Wisconsin DNR (ordering information found in the Storm water runoff permits web page)

clock icon NOTE: You must complete this plan prior to applying for the Construction Site Storm Water Management Permit and prior to any land-disturbing activities.

Construction site

means a site upon which land disturbing activities affecting one or more acres of land are occurring, including areas that are part of a larger common plan of development or sale where multiple separate and distinct construction activities may be taking place at different times on different schedules but under one plan such that the total disturbed area is one or more acres.

Contaminated storm water

means storm water that comes into contact with material handling equipment or activities, raw materials, intermediate products, final products, waste materials, byproducts, or industrial machinery.


means the detachment and movement of soil, sediment or rock fragments by water, wind, ice or gravity.

Event mean concentration

means the flow-weighted concentration over the duration of a single runoff event.

Final stabilization

means that all soil disturbing activities at the site have been completed and that a uniform perennial vegetative cover has been established with a density of 70% of the cover for the unpaved areas and areas not covered by permanent structures or that employ equivalent permanent stabilization measures.

One acre or greater

includes not only land disturbed at one time, but also any land that will be disturbed in the future that is part of a larger common plan for your site.

General WPDES permit

means a permit for the discharge of pollutants issued by the department under s. 283.35, Stats.

Illicit discharge

means any discharge to a municipal separate storm sewer that is not composed entirely of storm water except discharges with a WPDES permit or other discharges allowed locally.

Infiltration system

means a device or practice that encourages surface water to percolate or penetrate into underlying soil, including but not limited to infiltration trenches, grassed waterways and infiltration basins.

Land disturbing construction activity

means any man-made change of the land surface resulting in a change in the topography, existing vegetative and non-vegetative soil cover or the existing soil topography which may result in storm water runoff and lead to increased soil erosion and movement of sediment into waters of the state. Land disturbing construction activities include, but are not limited to clearing and grubbing, demolition, excavating, pit trench dewatering, filling and grading activities, but does not include agricultural land uses.


means any person holding fee title, an easement or other interest in property which allows the person to undertake land disturbing construction activity on the property.

Long-term storm water management plan

A plan describing what long-term storm water practices (managing flow over long periods) will be installed prior to your business start-up.

clock icon NOTE: You must complete this plan prior to applying for the Construction Storm Water Management Permit and prior to any land-disturbing activities.

Notice of intent (NOI)

Forms to apply for permits required to help decrease the amount of sediment caused from land-disturbing activities or permits required by certain commerical and industrial facilities if they have outdoor materials or operations that could contaminate storm water. Good housekeeping practices at your small business may prevent the need for this permit.


replacing previously developed commercial, residential or industrial land (not building on what was previously agricultural land).

Storm water pollution prevention plan (SWPPP)

Details what good housekeeping practices will be in place at your business. An example is storing raw materials inside so no exposure to storm water occurs. For new facilities your plan must be developed and implemented upon to start-up.

clock icon NOTE: You must complete this plan prior to applying for either the Construction or Industrial Storm Water Permits and prior to any land-disturbing activities.

Waters of the state

includes those portions of Lake Michigan and Lake Superior within the boundaries of Wisconsin, and all lakes, bays, rivers, streams, springs, ponds, wells, impounding reservoirs, marshes, watercourses, drainage systems and other surface water or groundwater, natural or artificial, public or private, within Wisconsin or its jurisdiction.