Severability | Environment & Sustainability
iii. Neither buffers nor a critical area tract shall be required if the alteration meets the standards of subsection SDC 21.03.020.W.6.e.ii of this section. f. The following are exempt from the provisions of this section: i. Slopes that are 40 percent or steeper with a vertical elevation change of up to 20 feet if no adverse impact will result from the exemption based on the City’s review of and concurrence with a soils report prepared by a licensed geologist or geotechnical engineer; and ii. The approved regrading of any slope that was created through previous legal grading activities. 7. Seismic hazard areas – Development standards and permitted alterations A development proposal containing a seismic hazard area shall meet the following requirements:
injury resulting from seismically induced settlement or soil liquefaction.
X. Critical aquifer recharge areas - Development standards
1. Groundwater Quantity Protection Standards. For developments in all CARA classes, the applicant shall provide surface water infiltration as follows:
a. Seventy-five percent of on-site storm water volume generated from the proposed development shall be infiltrated; provided, that a lesser standard may apply or on-site infiltration may be waived when: i. The applicant demonstrates that infiltration is not a reasonable alternative due to site-specific soil and/ or geologic conditions; ii. It is determined that increased saturation of soils would result in an increased risk to existing facilities and/or adjacent properties; iii. Infiltration would result in significant unavoidable impacts to other critical areas or result in an excessive loss of native vegetation; or iv. The applicant proposes an addition of no more than 700 square feet of total new impervious surface compared cumulatively to 2005 levels. b. If infiltration is not feasible or required, then storm water facilities shall be constructed in accordance with City standards. c. The design and implementation of infiltration facilities shall follow the ecology infiltration guidelines specified
a. All applicable building code requirements; and
b. Alterations to seismic hazard areas may be allowed only as follows: i. The evaluation of site-specific subsurface conditions shows that the proposed development site is not located in a seismic hazard area; or ii. Mitigation based on the best available engineering and geological practices is implemented that either eliminates or minimizes the risk of damage, death, or
Effective | January 1, 2022 Errata Revisions | April 8, 2022
Title 21: Sammamish Development Code | 87
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