Erosion Control & Stormwater Management

Since 1998 most construction/development sites in all 12 townships in Washington County are required to have a county-approved Runoff Control Permit. Through inter-governmental agreements, the county’s model ordinance sets standards to control soil erosion during construction, reduce the chance of sediment leaving development and manage stormwater discharges to protect downstream water resources and property during and after development. The exception with having to receive county approval is the Townships of Jackson, Kewaskum and Wayne; they administer this permit through their engineering firms.

The Erosion Control & Stormwater Management Ordinance covers two main phases of a project site; land disturbing constructions active and post development to control and quantity and quality of stormwater runoff. A permit is oftentimes required when a proposed project will meet or exceed any of the following activities:

1. Land Disturbance (Erosion Control)
• Disturbs 4,000 square feet of total land surface
• Involves 400 cu. yd. of excavation, filling or any combination thereof
• Disturbs 300 lineal feet of road ditch, grass waterway or other drainage  flows
• Other land disturbing activities, having a high risk of polluting water

2. Land Development (Erosion Control & Stormwater Management)
• A subdivision plat that meets the definition criteria under §236.02(12), Wis. Stats.
• The construction of roads or driveways (serving 2 or more houses)
• The addition of 20,000 sq ft of impervious surfaces or more in total area
• Land disturbing construction activity of One Acre or More
• Other land development activities, having a high risk of polluting water

Stormwater runoff is water from rain storms or snow melt that flows over the land rather than evaporating or soaking into the ground. Urban areas generate more stormwater runoff than rural areas because buildings and pavement cover much of the land. These impervious surfaces will prevent water from percolating down into the ground, cause runoff to accumulate and funnel into storm drains at high speeds. When quickly flowing runoff empties into receiving waters, it can severely erode streambanks. Paved surfaces also transfer heat to runoff, thereby increasing the temperature of receiving waters. As development alters the natural landscape, the percentage of the land covered by impervious surfaces increases, initiating a chain of events that culminates in degraded water resources.

Erosion Control & Stormwater Management - Permit & Ordinance Page