Impervious surface standards shall apply to the construction,
reconstruction, expansion, replacement, or relocation of any impervious
surface on a riparian lot or parcel and any nonriparian lot or parcel
that is located entirely within 300 feet of the OHWM of any navigable
waterway.
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 OHWM by the total surface area of that lot or parcel, and multiplied by 100. Impervious surfaces described in §
242-35 shall be excluded from the calculation of impervious surface on the lot or parcel. If an outlot lies between the OHWM 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.
Each lot is allowed up to 15% of impervious surface.
For properties where the general impervious surface standard applies under §
242-33, a property owner may exceed 15% of impervious surface but shall not exceed 30% of impervious surface, provided that the following is met:
A. Properties exceeding 15% of impervious surface but not 30% of impervious surface can be issued a permit for development with an approved mitigation plan that meets the standards found in Article
XII.
For existing impervious surfaces that were lawfully placed when constructed but that do not comply with the impervious surface standard in §
242-33 or the maximum impervious surface standard in §
242-34, 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 existing building envelope;
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 Ordinance, and impervious surface meets the applicable setback requirements of §
242-23 or
242-24.