i. The activity will not increase surface water discharge or sedimentation to adjacent properties beyond pre-development conditions;

ii. The activity will not decrease slope stability on adjacent properties;

iii. Such alteration will not adversely impact other critical areas or pose a potential threat risk to life, health, and safety.

i. The proposed alteration must not decrease the slope stability. The factor of safety against landslide occurrences for residential and commercial developments must be one and one-half for static conditions and one and two-tenths for dynamic conditions, unless approved by the decision-maker. Analysis of dynamic conditions must be based on a minimum horizontal acceleration as established by the current version of the International Building Code;

ii. Structures and improvements must be clustered to avoid geologically hazardous areas and other critical areas;

iii. Structures and improvements must minimize alterations to the natural contour of the slope, and foundations must be tiered where possible to conform to existing topography;

iv. Structures and improvements must be located to preserve the most critical portion of the site and its natural landforms and vegetation;

v. The proposed development must not result in greater risk or a need for increased buffers on neighboring properties;

vi. Development must be designed to minimize impervious lot coverage;

vii. The decision-maker may accept an alternative design that deviates from one or more of these standards if a report by a qualified professional demonstrates that greater long-term slope stability can be achieved while meeting all other provisions of this title. The requirement for long-term slope stability must exclude designs that require regular and periodic maintenance to maintain their level of function.

i. Acknowledges and accepts the risks of development in the landslide hazard area;

ii. Waives any rights to claims against the city;

iii. Indemnifies and holds harmless the city against claims, losses, and damages; and

iv. Informs subsequent owners of the property of the risks and the covenant.

i. Stormwater may be discharged at flow durations matching predeveloped conditions, with adequate energy dissipation, into existing channels that previously conveyed stormwater runoff in the predeveloped state;

ii. Stormwater may be dispersed upslope of the landslide hazard area onto a low-gradient undisturbed buffer demonstrated to be adequate to infiltrate all surface and stormwater runoff, if the critical area report determines such facilities or systems will not adversely affect slope stability;

iii. If demonstrated that no other practical alternative is available, stormwater may be discharged from the hazard area into adjacent waters, provided it is collected above the hazard and directed to the water by a tight line drain (constructed of high-density polyethylene pipe with fuse-welded joints, or similar product that is technically equal or superior) and provided with an energy dissipating device at the point of discharge.

i. Land that is located wholly within a landslide hazard area or its buffer may not be subdivided. Land that is located partially within a landslide hazard area or its buffer may be divided; provided, that each resulting lot has sufficient buildable area outside of, and will not affect, the landslide hazard or its buffer;

ii. Access roads and utilities may be permitted within the landslide hazard area and associated buffers if the decision-maker determines that no other feasible alternative exists, and if the critical area report determines such development will not adversely affect slope stability.

i. Except as otherwise provided in this section, existing vegetation must be retained on all lots until building permits are approved for development on individual lots;

ii. If any vegetation on the lots is damaged or removed during construction of the subdivision infrastructure, the applicant must implement a revegetation plan in those areas that have been impacted prior to final inspection of the site development permit or the issuance of any building permit for the subject property;

iii. Clearing of vegetation on individual lots may be allowed prior to building permit approval if the decision-maker determines that:

i. All alterations are permitted within a mine hazard area with a low potential for subsidence,

ii. Within a mine hazard area with a moderate potential for subsidence and at coal mine byproduct stockpiles, all alterations are permitted subject to a mitigation plan to minimize risk of structural damage using appropriate criteria to evaluate the proposed use, as recommended in the hazard analysis, and

iii. Within a mine hazard area with a severe potential for subsidence only those activities allowed in AMC 19.70.040, Exempt activities, will be allowed.

i. Land that is located within 200 feet of a mine hazard area with a severe potential for subsidence may not be subdivided. Land that is located partially within a mine hazard area may be divided; provided, that each resulting lot has sufficient buildable area that is 200 feet away from the mine hazard area with a severe potential for subsidence. Land that is located within a mine hazard area with a low or moderate potential for subsidence may be subdivided;

ii. Access roads and utilities may be permitted within 200 feet of a mine hazard area with a moderate or severe potential for subsidence if the city determines that no other feasible alternative exists.