16.20.530 Critical aquifer recharge area.
(1) Classification.
(a) Critical Potential. Wellhead protection areas, streams, wetlands, and any other lands that have been specifically identified as critical recharge areas based on reliable scientific data.
(b) High Potential. Areas in which soils show permeability ratings of more than 20 inches per hour.
(2) Development Standards.
(a) Development activities within an aquifer recharge area shall be designed, developed and operated in a manner that will not potentially degrade groundwater resources nor adversely affect the recharging of the aquifer.
(b) All new development shall comply with the following requirements:
(i) Applicable water source protection regulations set forth by the United States Environmental Protection Agency, the Washington State Department of Ecology, the Washington State Department of Health, or the Grant County health district.
(ii) Applicable ground water management area (GWMA) regulations.
(iii) Applicable regulations set forth by any irrigation districts regulated by the United States Department of the Interior, Bureau of Reclamation (BOR).
(iv) State requirements regarding protection of upper aquifer zones and ground water quality (Chapters 173-154 and 173-200 WAC, respectively).
(v) The Stormwater Management Manual for Eastern Washington (Washington Department of Ecology Publication No. 04-10-076, or as revised) shall provide the preferred guidance for stormwater best management practices.
(c) A hydrogeologic study and/or ongoing monitoring may be required to assess impacts of development activities on groundwater resources.
(d) All proposed activities within aquifer recharge areas must comply with the water source protection requirements of the federal Environmental Protection Agency, state Department of Health and the Grant County health district.
(e) On-site stormwater facilities shall be designed and installed in all aquifer recharge areas, so as to provide both detention and treatment of all runoff associated with the development.
(f) All development occurring within aquifer recharge areas shall be required to connect to city sewer and water, and on-site sewage disposal shall be prohibited.
(g) Landfills, junkyards/salvage yards, mining, wood treatment facilities, or any other activity that could impair the recharge of critical aquifer recharge areas. Such activities may be permitted in areas with high or moderate recharge potential in accord with applicable zoning regulations, providing the applicant can satisfactorily demonstrate that potential negative impacts to groundwater can be prevented.
(h) All storage tanks, whether above- or underground, shall be required to be constructed so as to protect against corrosion for the operational life of the tank, to prevent any release of hazardous substances to the ground, ground waters, or surface waters, and to utilize appropriate containment methods.
(i) Any agricultural activities conducted within aquifer recharge areas shall incorporate best management practices concerning waste disposal, fertilizer/pesticide/herbicide use, and stream corridor management. If necessary, applicants shall seek technical assistance from the Grant County conservation district or the WSU cooperative extension office.
(j) Application of pesticides, herbicides and fertilizers within aquifer recharge areas shall comply with timing and rates specified on product packaging.
(k) Vehicle repair and servicing activities must be conducted over impermeable pads and within a covered structure capable of withstanding normally expected weather conditions. Chemicals used in the process of vehicle repair and servicing must be stored in a manner that protects them from weather and provides containment should leaks occur.
(3) Critical Area Report Requirements.
(a) In addition to the general requirements for critical areas reports, a critical areas report for development activities within or adjacent to an aquifer recharge area shall contain the following:
(i) A scaled development plan showing the recharge areas;
(ii) Detailed information on the following items:
(A) Hydrogeological susceptibility to contamination and contaminant loading potential;
(B) Depth to ground water;
(C) Hydraulic conductivity and gradient;
(D) Soil texture, permeability, and contaminant attenuation potential;
(iii) Vadose zone analysis, including implications of permeability and attenuation properties;
(iv) An analysis of the recharge area’s toleration for impervious surfaces in terms both of aquifer recharge and the effect on water quality; and
(v) A summary of the proposed development’s effect on the recharge area.
(b) When a proposed use presents a high risk of drinking water contamination, a hydrogeologic assessment shall be required.
(i) A hydrogeologic assessment shall be required for the following land uses:
(A) Hazardous substance processing and handling.
(B) Hazardous waste treatment and storage facility.
(C) Wastewater treatment plant sludge disposal.
(D) Solid waste disposal facility.
(ii) A required hydrogeologic assessment shall be submitted by a hydrogeologist licensed by the state of Washington. The hydrogeologic assessment shall use scientifically valid methods and studies to establish existing (baseline) water quality and shall be used to develop conditions of approval to ensure that the proposed development will not contribute contaminants or facilitate degradation of recharge areas. In addition to the information required in all critical areas reports, the assessment shall include, at a minimum:
(A) Pertinent well log and geologic data.
(B) Ambient groundwater quality.
(C) Groundwater elevation.
(D) Recharge potential of facility site.
(E) Current data on wells and any springs located within 1,000 feet of the facility.
(F) Surface water location and potential recharge.
(G) Water supply source for the facility.
(H) Analysis and discussion of the effects of the proposed project on the groundwater resource.
(iii) A required hydrogeologic assessment must demonstrate that the proposed use does not present a threat of contamination to the aquifer system. Successful demonstration of those findings warrants approval under this section.
(iv) Ongoing monitoring of uses that present high risk of drinking water contamination may be required to assess impacts of development activities on groundwater resources. (Ord. 484 § 2, 2014)