DNR Proposes New Impervious Surface Standards Near Waterways
By Tom Larson
The Wisconsin Department of Natural Resources (DNR) is proposing several new changes to the state’s shoreland zoning regulations (NR 115), which were revised in 2009 and will go into effect on January 1, 2014 unless the effective date is extended. For commercial development purposes, the most significant of these changes relate to the regulation of impervious surfaces, which developers and county zoning administrators alike have warned will be harmful to economic development efforts in Wisconsin unless modified.
Since 1966, Wisconsin has imposed minimum shoreland zoning standards that requires counties to regulate the use of property near lakes, rivers, streams and other navigable waterways. These regulations apply all forms of development (commercial, industrial and residential) and to all land within 1,000 feet of a lake, pond or flowage, and land within 300 feet of a stream or river. Because the state standards are only minimum standards, counties are permitted to create standards that are more restrictive.
In 2009, the DNR revised NR 115 due to increased development pressure along our waterways and numerous complaints about the prior regulations. However, after having more time to analyze the impacts on existing property owners and future development, many county zoning administrators believe that several of the new regulations are overly restrictive and will create hardships for new development and for property owners wishing to expand their existing homes.
In response, the DNR has introduced several new modifications to the impervious surface regulations in NR 115, including the following:
+ Higher impervious surface standard for already highly-developed areas
The current regulations limit the amount of impervious surfaces (concrete, blacktop, footprint of structure, etc.) for new construction and expansions of existing homes and buildings within 300 feet of the water to no more than 15% of the lot area. The impervious surface standard is increased to 30% if the property owner agrees to perform mitigation measures established by the county.
For more urban areas with higher densities and smaller lots, these impervious surface standards would place significant restrictions on the size of the home that can be built on the lot and, in some cases, could make the lots unbuildable. For example, in a sample study performed on several lakes in Waukesha County, over 50% of the existing homes exceeded the 30% impervious surface standard and, thus, would not have been allowed to be built in the same manner if the impervious surface limits were in place when the homes were constructed.
Under the proposed changes, the impervious surface standards would be increased in areas with highly developed shorelines. These areas include areas that are located with an urbanized area or an urbanized cluster, according to the 2010 U.S. Census, or areas with a commercial, industrial or business zoning classification. In these areas, the impervious surface standards for residential development would be increased to 30% without mitigation and up to 40% if mitigation was performed. For commercial and industrial development, the impervious surface standard would be increased to 40% without mitigation and up to 60% with mitigation. Please remember that these impervious surface standards would only apply to new construction. Existing homes and buildings would be able to maintain their current percentages of impervious surfaces.
+ Applying impervious surface regulations to only riparian lots and non-riparian lots located entirely within 300 feet of the OHWM
In addition to increasing the impervious surface standards in highly developed areas, the proposed changes would limit the application of the impervious surface standard to only:
+ riparian lots (adjacent to a navigable waterway), and
+ non-riparian lots located entirely within 300 feet of the ordinary high water mark (OHWM)
If any portion of the lot is more than 300 feet away from the OHWM, the impervious surface standards would not apply.
+ Exempting lots that do not drain directly into the lake or river
One of the other significant changes is new definition of “impervious surface.” Under this definition, any surfaces that do not drain directly into a lake or river are not considered impervious. In other words, if a surface drains into an off-site stormwater pond, constructed wetlands, or other engineered system, or a surface that drains into an internally drained area, the surface will not be considered “impervious” for purposes of calculating the impervious surface limits.
The Next Steps in the Rulemaking Process
Before going into effect, the proposed rule changes must satisfy a series of procedural requirements including public hearings, approvals by the Governor, Natural Resources Board, and review by the legislature. At any point in the process, the proposed changes could be modified. While it is somewhat unclear how long this process will take, the DNR is hoping to complete the rulemaking process by early 2014.
The NAIOP-WI Public Affairs Committee has not yet had an opportunity to take a position on the proposed changes, but they will likely consider them to positive changes. If you have questions about the proposed changes to the shoreland zoning regulations, please contact Tom Larson (firstname.lastname@example.org).