Establish impervious surface standards to protect water quality
and fish and wildlife habitat and to protect against pollution of
navigable waters. Impervious surface standards of this chapter shall
apply to the construction, reconstruction, expansion, replacement,
or relocation of any impervious surface on a riparian lot or parcel
and any non-riparian lot or parcel that is located entirely within
300 feet of the ordinary high-water mark of any navigable waterway.
A.
Percentage of impervious surface shall be calculated by dividing the surface area of the existing and proposed impervious surfaces on the portion of a lot or parcel that is within 300 feet of the ordinary high-water mark by the total surface area of that lot or parcel, and multiplied by 100. Impervious surfaces described in § 338-49 shall be excluded from the calculation of impervious surface on the lot or parcel. If an outlot lies between the ordinary high-water mark and the developable lot or parcel and both are in common ownership, the lot or parcel and the outlot shall be considered one lot or parcel for the purposes of calculating the percentage of impervious surface.
B.
Note: § NR 115.05(1)(e)1m, Wis. Adm. Code, clarifies that,
if an outlot lies between the OHWM and the developed lot or parcel
and both are in common ownership, then the lot or parcel should be
considered one property for the purposes of calculating the percentage
of impervious surfaces. If there is an outlot, parcel or road that
is owned by some other entity, for example a hydroelectric facility,
town, or County, then the County should determine what level of control
the property owner has over that portion of the lot. Can the property
owner place structures, such as shoreline protection, piers, stairs,
boathouses etc. on that portion of the lot, or does some other entity
have control over development? If a property owner has no or little
say over construction on that portion of the lot, then impervious
surfaces on that portion of the lot should be calculated separately.
For properties that have condominium ownership, the impervious surface
calculations apply to the entire property. The property is still under
one legal description and the proposed expansion to a unit is not
the only impervious surface calculated since the regulation states
lot or parcel and not a unit. It will be important to remember also
that mitigation applies to the property as a whole and not just to
the portion of the frontage that might be in front of the unit impacted.
[Amended 4-18-2017 by Ord. No. 8-2017]
[Amended 4-18-2017 by Ord. No. 8-2017]
A property may exceed the impervious surface standard under § 338-47, provided the following standards are met:
A.
Impervious surfaces that can be documented to show they meet either of the following standards shall be excluded from the impervious surface calculations under § 338-46.
(1)
The impervious surface is treated by devices such as stormwater ponds,
constructed wetlands, infiltration basins, rain gardens, bioswales,
or other engineered systems.
(2)
The runoff from the impervious surface discharges to an internally
drained pervious area that retains the runoff on or off the parcel
and allows infiltration into the soil.
B.
Note: The provisions in § 338-49 are an exemption from the impervious surface standards and, as such, should be construed narrowly. As such, a property owner is entitled to this exemption only when the runoff from the impervious surface is being treated by a sufficient (appropriately sized) treatment system, treatment device, or internally drained. Property owners that can demonstrate that the runoff from an impervious surface is being treated consistent with § 338-49 will be considered pervious for the purposes of implementing the impervious surface standards in this ordinance. If a property owner or subsequent property owner fails to maintain the treatment system, treatment device, or internally drained area, the impervious surface is no longer exempt under § 338-49.
[Amended 11-12-2019 by Ord. No. 18-2019]
C.
To qualify for the statutory exemption, property owners shall submit
a complete land use permit application that is reviewed and approved
by the Land Use Planning and Zoning Department. The application shall
include the following:
(1)
Calculations showing how much runoff is coming from the impervious
surface area.
(2)
Documentation that the runoff from the impervious surface is being
treated by a proposed treatment system, treatment device, or internally
drained area.
(3)
An implementation schedule and enforceable obligation on the property
owner to establish and maintain the treatment system, treatment devices,
or internally drained area.
(a)
The enforceable obligations shall be evidenced by an instrument
recorded in the office of the Register of Deeds prior to the issuance
of the land use permit.
D.
Where
reference is made to a rain garden, the rain garden shall be designed,
installed, and maintained in accordance with Wisconsin DNR Publication,
PUB-WT-776-2018, "Rain Gardens: A Guide for Homeowners and Landscapers."
[Added 12-21-2021 by Ord. No. 38-2021]
For existing impervious surfaces that were lawfully placed when constructed but do not comply with the impervious surface standard in § 338-47 or the maximum impervious surface standard in § 338-48, the property owner may do any of the following:
A.
Maintain and repair the existing impervious surfaces;
B.
Replace existing impervious surfaces with similar surfaces within
the three-dimensional space of the structure;
[Amended 12-21-2021 by Ord. No. 38-2021]
C.
Relocate or modify an existing impervious surface with similar or
different impervious surface, provided that the relocation or modification
does not result in an increase in the percentage of impervious surface
that existed on the effective date of the County Shoreland Zoning
Ordinance, and the impervious surface meets the applicable setback
requirements in this chapter.
[Amended 11-12-2019 by Ord. No. 18-2019]
D.
Note: The impervious surface standards in this section (changed to
reflect Ch. NR 115, Wis. Adm. Code) shall not be construed to supersede
other provisions in the County Shoreland Zoning Ordinance.
[Amended 11-12-2019 by Ord. No. 18-2019]
(1)
All of the provisions of the County Shoreland Zoning Ordinance still
apply to new or existing development.
