Chapter 20.32 CRITICAL AQUIFER RECHARGE AREAS

Chapter 20.32
CRITICAL AQUIFER RECHARGE AREAS

Sections:

20.32.010 Designation of critical aquifer recharge areas.

The goal of designating critical aquifer recharge areas (CARAs) is to protect the functions and values of Oak Harbor’s drinking water by preventing pollution and maintaining supply.

(1) CARAs are those areas with a critical recharging effect on aquifers used for potable water. CARAs have prevailing geologic conditions associated with infiltration rates that create a high potential for contamination of ground water resources or contribute significantly to the replenishment of ground water. These include aquifer recharge areas moderately or highly susceptible to degradation, as identified by the Island County aquifer recharge area map or other study using criteria established by the Washington State Department of Ecology for soil permeability, geologic matrix, infiltration and depth to water.

(2) The approximate location and extent of CARAs are shown on the city’s adopted critical areas maps. These maps are to be used as a reference for the city, project applicants and property owners and may be superseded by new data. (Ord. 1801 §§ 46, 47, 2018; Ord. 1440 § 6, 2005).

20.32.020 Regulated activities.

The following permitted activities or land uses are subject to the requirements of this chapter, when conducted within 200 feet of a CARA moderately or highly susceptible to degradation:

(1) Above or below ground storage tanks for hazardous substances or hazardous wastes.

(2) Commercial, industrial, institutional or other facilities that include: automobile washers, chemical treatment storage and disposal facilities, dry cleaners, hazardous waste generators, junk yards and salvage yards, oil and gas drilling, on-site sewage systems, pesticide storage and use, petroleum transmission facilities and/or storage tanks, solid waste handling and recycling facilities, vehicle repair and services, wastewater application to land surfaces, and other activities that create a significant risk of contaminating CARAs.

(3) Residential sewage disposal systems that serve two or more residences or that have a density greater than one system per acre.

(4) Stormwater management facilities that infiltrate the majority of water they manage. (Ord. 1801 § 48, 2018; Ord. 1440 § 6, 2005).

20.32.030 Critical areas report.

(1) For all regulated activities, the applicant shall submit a report describing the best management practices to be used to minimize the risk of aquifer contamination. At a minimum, these practices shall include those recommended by the Stormwater Management Manual for Western Washington: Volume IV, Source Control BMPs (Publication No. 14-10-055) or future updated publications, as applicable, and shall comply with requirements in the Washington Administrative Code for the proposed activity.

(2) The following general development standards shall apply to all regulated activities:

(a) Floor drains shall be connected to an approved sanitary sewer system;

(b) Vehicle washing facilities must be self-contained and connected to an approved sanitary sewer system;

(d) Vehicle repair and service areas shall be conducted over impermeable pads and located within an enclosed structure;

(e) Chemicals shall be stored in a manner that is protected from the weather and located within containment areas; and

(f) Additional protective measures may be required if deemed necessary by the city of Oak Harbor.

(3) The applicant shall also submit a spill prevention plan that identifies equipment being used or any structures that could fail and contaminate CARAs. The plan shall include provisions for regular inspection, repair, replacement, clean-up methods to be used, and methods to dispose of all spilled materials.

(4) If the director determines that additional precautions may be necessary to protect against ground water contamination, a hydrogeologic site evaluation prepared by a qualified professional who has training and experience in hydrogeology per WAC 308-15-057 may be required. The city may engage an independent qualified professional to review the evaluation, at the applicant’s expense. The evaluation shall address some or all of the following, as specified by the director:

(a) Hydrogeologic Setting.

(i) Description of the geologic setting of the site, illustrated with geologic and soil maps;

(ii) Discussion of geologic features which may influence ground water movement, such as faults, landforms, etc.;

(iii) Description of the occurrence and movement of groundwater in the area, including a general discussion of aquifer recharge and discharge, depth of groundwater and groundwater flow patterns; and

(iv) General discussion of groundwater quality in the area.

(b) Site-Specific Hydrogeologic Data.

(i) Scaled map showing the location of wells (in use or inactive) and springs within 1,000 feet of the site or as required by the director;

(ii) Depth to groundwater layer in the immediate vicinity;

(iii) Hydrogeological cross-sections through the site and immediate vicinity with references to information used to prepare the cross-sections;

(iv) Description of groundwater movement beneath the site with considerations for the following:

(A) Areal distribution, stratification and hydraulic conductivity of the water-bearing formations;

(B) Probable migration pathways for contaminants;

(C) An estimate of the probable times of travel through the soil horizontally and vertically from a potential contaminant source;

(v) Description of how the contaminants of concern will be attenuated within the saturated zone; and

(vi) Estimate of the quantity and/or quality of water recharged to the saturated zone under anticipated operation.

(5) A mitigation plan shall be required to address groundwater impacts identified in the hydrogeologic site evaluation, consistent with OHMC 20.12.090 and 20.12.100. The director may require that the plan include monitoring, process controls, remediation and discussion of alternatives. (Ord. 1801 §§ 49, 50, 2018; Ord. 1784 § 80, 2016; Ord. 1440 § 6, 2005).