1. (1) Groundwater.

   1. (a) Sole source aquifers. New MSWLF units and lateral expansions may not be located over a designated sole source aquifer unless the owner or operator can demonstrate during the permit process of WAC 173-351-700 or through the permit modification process of WAC 173-351-720(6) that the sole source aquifer is not vulnerable to potential groundwater contamination from the active area. Vulnerability is defined as the propensity or likelihood of a sole source aquifer to become contaminated should the integrity of the engineering control (including liners) fail; it is a measure of the propensity to deteriorate the water quality of a sole source aquifer, and takes into account an assessment of the physical barriers, the physical movement of contaminants, the hydraulic properties of the subsurface lithology; the rate of a contaminant plume movement; the physical and chemical characteristics of contaminants; and it also includes an assessment of the likelihood and ease for contaminant removal or clean-up, or the arrest of contamination, so as to not impact any further portion of the designated sole source aquifer. The owner or operator must place the demonstration in the application for a permit under WAC 173-351-700 or through the permit modification process of WAC 173-351-720(6). Such a vulnerability demonstration must include the submission of a hydrogeologic report as required in WAC 173-351-490 and additionally must meet the following performance criteria:

      1. (i) Demonstrates the presence of confining units or other lithology that will prevent the migration of groundwater contamination;
      2. (ii) Addresses the fate and transport of contaminants, including interactions in the lithologic framework, hydrogeochemical facies, contaminant travel times;
      3. (iii) Defines and summarizes the groundwater budgets for the active area and the sole source aquifer including recharge and discharge areas and includes flow net diagrams;
      4. (iv) Provides a contingency and groundwater assessment plan for the immediate arrest of any groundwater contamination and steps to assess the extent of contamination;
      5. (v) Design specifications for the proposed ground and surface water monitoring systems;
      6. (vi) Is prepared by a geologist or other licensed professional in accordance with the requirements of chapter 18.220 RCW, Geologists; and
      7. (vii) "Sole source aquifer" means an aquifer designated by the Environmental Protection Agency pursuant to Section 1424e of the Safe Drinking Water Act (PL 93-523).

   2. (b) Drinking water supply wells. New MSWLF units and lateral expansions active area may not be located closer than one thousand feet (three hundred meters) to any drinking water supply well, in use and existing at the time of the purchase of the property containing the active area unless the owner or operator can demonstrate during the permit process of WAC 173-351-700 or through the permit modification process of WAC 173-351-720(6) that the active area is no less than a ninety-day hydraulic travel time to the nearest down-gradient drinking water supply well in the first useable aquifer. The owner or operator must place the demonstration in the application for a permit under WAC 173-351-700 or through the permit modification process of WAC 173-351-720(6). Such a demonstration must be prepared by a geologist or other licensed professional in accordance with the requirements of chapter 18.220 RCW, Geologists, and include:

      1. (i) A hydrogeologic report required in WAC 173-351-490; and the necessary calculations for showing compliance with the ninety-day travel time; the ninety-day travel time must be based on the peak or full pumping capacity of installed nearby wells and include potentiometric surface maps showing well capture zones and radius of influence;
      2. (ii) Any available ground/surface water quality data for aquifers, springs, or streams in direct hydrologic contact with landfill's active area;
      3. (iii) The waste management unit boundaries at facility closure; and
      4. (iv) Design specifications for the proposed ground and surface water monitoring systems.

2. (2) Surface water. New MSWLF units and lateral expansions active area may not be located in a channel migration zone or within two hundred feet (sixty-one meters) measured horizontally from the ordinary high water mark, of a shoreline of the state as defined in RCW 90.58.030 (which includes some wetlands associated with waters of the state), nor any public land that is being used by a public water system for watershed control for municipal drinking water purposes in accordance with WAC 246-290-450.

   See also wetlands in WAC 173-351-130(4). Local wetlands protection ordinances should be consulted to determine if greater setbacks are required.

3. (3) Land use. New MSWLF units and lateral expansions may not be located:

   1. (a) In areas designated by the United States Fish and Wildlife Service or the department of wildlife as critical habitat for endangered or threatened species of plants, fish, or wildlife;
   2. (b) So that the active area is closer than one hundred feet (thirty meters) to the facility property line for land zoned as nonresidential or unzoned lands, or closer than two hundred fifty feet (seventy-six meters) to the property line of adjacent land zoned as residential, existing at the time of the purchase of the property containing the active area;
   3. (c) So as to be at variance with any locally-adopted land use plan or zoning requirement unless otherwise provided by local law or ordinance; or
   4. (d) So that the active area is any closer than one thousand feet (three hundred meters) to any state or national park.
4. (4) All landfill facilities must comply with the location restrictions specified in RCW 70.95.060.

[Statutory Authority: RCW 70.95.020(3), 70.95.060(1), and 70.95.260 (1), (6). WSR 12-23-009 (Order 07-15), § 173-351-140, filed 11/8/12, effective 12/9/12. Statutory Authority: Chapter 70.95 RCW and 40 C.F.R. 258. WSR 93-22-016, § 173-351-140, filed 10/26/93, effective 11/26/93.]