WAC 173-306-350   Incinerator ash siting standards for disposal facilities.  (1) Applicability. These standards apply to all new or expanded monofills. These standards do not apply to:

     (a) Existing monofills or monofills that have closed before the effective date of this chapter; or

     (b) Treatment, utilization, or processing facilities.

     (2) Siting standards.

     Owners or operators of all applicable disposal facilities shall, at the time of permit application, meet the following locational standards:

     (a) Geology. No facility may be located within two hundred feet, measured horizontally, from a fault that has had displacement in holocene times. All faults within three thousand feet of a facility must be identified and evaluated under WAC 173-306-330(1), where existing geologic information is available or can be obtained with reasonable effort. For sites for which fault information cannot reasonably be obtained, a geologic hazard assessment performed by an experienced, qualified geologist may be substituted for this siting criteria, if the study methods are reviewed and approved by the department before the investigation.

     (b) Groundwater.

     (i) No facility may be located where the depth from the lowest point of the bottom liner to the seasonal high water level of the upper most aquifer of beneficial use is less than ten feet or one hundred twenty days travel time hydraulically, whichever is greater.

     (ii) No facility may be located over a sole source aquifer.

     (iii) No facility's active area may be located closer than one thousand feet to the nearest downgradient groundwater intake for domestic water in use and existing at the time of permit application unless the owner or operator can show that the active area is no less than one hundred twenty days travel time hydraulically to the nearest downgradient groundwater intake for domestic water.

     (c) Natural soils. No facility may be located:

     (i) Where known subsidence exists within the facility boundary;

     (ii) In an area where unstable slopes may impact the active area of the facility;

     (iii) Where weak or unstable soils exist within the proposed facility boundary, unless the structural stability of the soils is mitigated through engineering practices. (The following soils or conditions are defined as weak or unstable: Organic soils, expansive soils, liquefaction sands, soft clays, sensitive clays, loess and quick conditions.)

     (d) Flooding. No facility's active area may be located within the one hundred-year flood elevation as indicated in the most current Federal Emergency Management Agency maps.

     (e) Surface water. No facility's active area may be located within five hundred feet, measured horizontally, of the ordinary high water mark of any perennial surface water body.

     (f) Sensitive areas. No facility may be located:

     (i) In an area that would result in the taking of species or the direct elimination of critical habitat for federal or state listed threatened or endangered species;

     (ii) In a wetland as defined by the United State Fish and Wildlife Service (Cowardin et al. 1979);

     (iii) In a shoreline of the state under the jurisdiction of the Shoreline Management Act;

     (iv) In an area classified as a wilderness area as defined by the Wilderness Act of 1964 (P.L. 88-577);

     (v) In a state or federally designated wildlife refuge or a game farm;

     (vi) In an area with city, county, state, or federal designation as a park or recreation area or any area provided for under chapter 79.70 RCW, natural area preserves; and

     (vii) In an area with city, county, state, or federal designation as an archaeological or historic area or a national monument.

     (g) Land use. No facility may be located so that its active area is closer than two hundred feet to the facility property line. The active area may be no closer than one thousand feet to the nearest housing unit in an existing residential development. The one thousand-foot rule may be evaluated on a case-by-case basis in rural areas and unincorporated towns.

     (h) Climatic factors. No facility may be located in an area that has a history of severe climatic factors without engineered protection to mitigate those factors. Severe climatic factors, include but are not limited to, high annual rainfall, extreme temperatures (high or low), and high winds.



[Statutory Authority: Chapter 70.138 RCW. 00-19-018 (Order 00-17), § 173-306-350, filed 9/8/00, effective 10/9/00; 90-10-047, § 173-306-350, filed 4/30/90, effective 5/31/90.]