STORM WATER MANAGEMENT AND EROSION CONTROL 

General Background                                            

Over the last 4 decades, 3 to 5 square miles of Waukesha County's landscape was converted each year to urban uses. With this land use change also comes a change in the way rainfall and snowmelt behaves - which in turn affects our lakes, streams and groundwater.

Runoff from the urban landscape is now the biggest threat to the water resources in Waukesha County. It is the largest source of water pollution is most areas, including sediment from construction sites and a smorgasbord of pollutants coming off our streets, parking lots and lawns. It is the root cause for chronic local flooding problems. Where farming continues, fields are often washed out due to runoff from next-door developments - as if the land use conflicts weren't enough. 

Addressing all of the negative impacts of urban runoff is the number one priority for the conservation staff in the Land Resource Division. We do this through a combination of educational programs, technical assistance and regulation.

If you would like to learn more about the impacts of urbanization on our water resources and what can be done about it, click  here  (EPA site video) or read this  fact sheet: "Suffering Waters on the Urban Landscape".  They both describe in more detail the phenomena behind what has just been described.

Waukesha County Storm Water Management and Erosion Control Ordinance
Waukesha County Code - Chapter 14, Article VIII

As a major component of Waukesha County's efforts to control water pollution from urban runoff, the county adopted a construction site erosion control ordinance, which became effective on May 5, 1992. This ordinance requires a county permit for land disturbing construction activity in order to reduce the amount of sediment originating from construction sites. Construction site erosion is estimated to account for over 70% of the sediment that flows into many of the streams and lakes in Waukesha County each year.

The ordinance became more comprehensive on May 28, 1998 when post-development storm water management requirements were added to the permit conditions. This means that the permit not only covers erosion control during the construction phase, but also covers storm water runoff from the development afterwards. This expanded the scope of the ordinance to address other types of water pollution from urban runoff besides sediment. It also deals with flooding related issues that usually occur when additional impervious surfaces, such as rooftops and pavement, are added to the landscape.

Following the publication of non-agricultural nonpoint performance standards in Administrative Rule NR 151 in 2002, and the subsequent update to storm water discharge permit requirements under Administrative Rule NR 216 in 2004, it became necessary to update the Waukesha County ordinance.  This is because three of the towns covered by the county ordinance were subject to enforcing the new performance standards as a condition of a municipal permit under NR 216.

A summary of the urban performance standards for new construction sites include:

• Control 80% of sediment from construction sites. 
• Control 80% of post-construction total suspended solids (TSS) from new developments and 40% from redevelopments. 
• Maintain pre-development peak discharge rates for the 2-year, 24 hour design storm for new developments. 
• Infiltrate 90% of pre-development runoff volumes for new residential developments and 60% for non-residential. 
• Maintain protective areas (50-75 feet) between new impervious surfaces and lakes, streams, and wetlands. 
• Control petroleum runoff (visible sheen) from fueling and vehicle maintenance areas. 

Starting in August 2004, the LRD worked with the Waukesha County Storm Water Advisory Committee over the period of seven months to rewrite the county ordinance to reflect the new performance standards and address a number of other implementation issues identified by the LRD.  In March of 2005, the Waukesha County Board adopted the new Waukesha County Storm Water Management and Erosion Control Ordinance.  Enforcement of this ordinance currently represents the largest workload for the LRD, resulting in an average of 100 permits per year. It should be noted that local erosion control ordinances do not apply to single-family home construction as these are regulated under COM 21 Wisconsin Administrative Code.  By state statute, COM 21 supercedes all local ordinances.

Both construction site erosion and storm water management are combined into a single permit in the county ordinance to simplify the process. A permit summary is available, which explains the applicability of the ordinance and what is required to obtain a permit. A flow chart shows the time lines and steps involved in the permit process. Together, these two pages will give the reader a general understanding of what triggers the need for a permit and how to get one. A complete copy of the ordinance is contained in Waukesha County Code - Chapter 14, Article VIII. The jurisdiction of the ordinance includes all unincorporated areas of the county and newly annexed lands where the local community has not adopted similar ordinance provisions. A map is available to see where these areas are in the county.

Development Review Team
Proposed developments often require the review and approval of several agencies in county government. To help coordinate these reviews, Waukesha County has established a Development Review Team, consisting of staff from the Department of Parks and Land Use and the Department of Public Works.

The Development Review Team convenes on an as-needed basis to review proposed residential, commercial and industrial development projects. The process provides the developer with a single point of contact and compiles comments from the various county reviewers. Issues reviewed include erosion control and storm water management, highway access, compliance with the county development plan, suitability for private waste disposal systems, and the protection of environmental corridors and other sensitive natural resources.

The goal of the team is to enhance the quality of land use decisions under county jurisdiction. The team encourages the submittal of proposed developments early in the planning phase to improve communication, better define expectations, and expedite the development review process. For meeting information, contact the Department of Parks and Land Use - Planning and Zoning Division at (262) 548-7790.