A. The applicant must demonstrate that the development or hydraulic alteration will not cause an indirect wetland impact unless one of the following exceptions applies:
1. The wetlands occur at or below the OHWM of a waterway on which the hydraulics will not be changed; or
2. The development is a stream bank stabilization project; or
3. The director or administrator concurs that there is no potential for adverse impact.
B. A development or hydraulic alteration is considered to have an indirect impact if one of the following limitations is exceeded:
1. An increase or decrease in the high water level of more than three inches (3") in the 2.03 inch, 2.51 inch, and 3.04 inch, 24-hour rainfall events; or
2. Changes in the wetland's draw down time resulting in an increase or decrease of greater than forty eight (48) hours from the peak elevation to the normal water level. The draw down times must be calculated for the 2.03 inch, 2.51 inch, and 3.04 inch, 24-hour rainfall event for both the existing and proposed conditions; or
3. An increase in the duration of inundation of more than twenty percent (20%) from existing to proposed conditions for the 5.51 and 7.58 inch, 24-hour rainfall event. A minimum increase of forty eight (48) hours is allowed for these storm events.
The director or administrator can, based on a review of the submitted information, determine that proposed impacts outside of the above limits will not affect the existing plant communities, and therefore, would be allowable.
C. Under certain circumstances, the director or administrator, may allow minor variations to the normal water level if it can be demonstrated by an environmental scientist to be an ecological benefit to the wetland system.
D. When the dominant plant community or wetland type is known to be sensitive to relatively small changes in depth and duration of inundation (e.g., sedge meadow, vernal pool), then the thresholds as outlined in subsection B of this section may be reduced by the director or administrator. (Ord. G-1003, 6-11-2013)