Chapter 14.60
AQUIFER RECHARGE AND WELLHEAD PROTECTION AREAS
Sections:
14.60.020 Critical aquifer recharge areas identification.
14.60.030 Critical aquifer recharge areas review procedures.
14.60.040 Critical aquifer recharge areas standards.
14.60.010 Purpose.
The purpose of this chapter is to protect critical aquifer recharge areas from degradation or depletion resulting from new or changed land use activities. Due to the exceptional susceptibility and vulnerability of groundwater underlying aquifer recharge areas to contamination and the importance of such groundwater as sources of public water supply, it is the intent of this chapter to safeguard groundwater resources and wellhead protection areas by mitigating or precluding future discharges of any contaminant from new land use activities. (Ord. 17-513 § 3 (Exh. A)).
14.60.020 Critical aquifer recharge areas identification.
A. General. Critical aquifer recharge areas are areas that have a critical recharging effect on groundwater used for potable water supplies and/or that demonstrate a high level of susceptibility or vulnerability to groundwater contamination from land use activities. These areas include the following:
1. Aquifer recharge areas, which are the boundaries of the two highest DRASTIC zones that are rated 180 and above on the DRASTIC index range, as identified in Map of Groundwater Pollution Potential, Edgewood, Washington, National Water Well Association, U.S. Environmental Protection Agency (EPA);
2. Wellhead protection areas, as defined in Chapter 14.20 EMC; and
3. Sole source aquifers, which are areas that have been designated by the EPA pursuant to the Federal Safe Drinking Water Act. As of the effective date of this title, there are no designated sole source aquifers within city limits. (Ord. 17-513 § 3 (Exh. A)).
14.60.030 Critical aquifer recharge areas review procedures.
A. General Requirements.
1. The city’s critical aquifer recharge areas map provides an indication of where critical aquifer recharge areas are located within the city and the map is updated as necessary.
2. Any proposed development located within critical aquifer recharge areas shall comply with the standards set forth in this chapter.
3. Any hazardous uses shall require the submittal of a hydrogeologic assessment, as set forth in subsection (B) of this section.
4. The department may waive critical area protective measure provisions contained in Chapter 14.10 EMC, as deemed appropriate by the director and can be shown to meet the requirements associated with best available science, if required.
B. Hydrogeologic Assessment.
1. The hydrogeologic assessment shall be prepared, signed, and dated by a state licensed geologist or hydrogeologist.
2. The hydrogeologic assessment shall be submitted in the form of a report detailing the subsurface conditions, the design of a proposed land use action, and the facilities operation which indicates the susceptibility and potential for contamination of groundwater supplies. The hydrogeologic assessment shall, at a minimum, include the general critical area report requirements of Chapter 14.10 EMC in addition to the following 15 items:
a. Information sources;
b. Geologic setting – includes well logs or borings used to identify information;
c. Background water quality;
d. Groundwater elevations;
e. Location and depth to perched water tables;
f. Recharge potential of a facility site, i.e., the permeability and transmissivity;
g. Groundwater flow direction and gradient;
h. Current available data on wells located within one-quarter mile of the site;
i. Current available data on any spring within one-quarter mile of the site;
j. Surface water location and recharge potential;
k. Water source supply to a facility, e.g., a high capacity well;
l. Any sampling schedules necessary;
m. Discussion of the effects of the proposed project on the groundwater resource;
n. Discussion of potential mitigation measures, should it be determined that the proposed project will have an adverse impact on groundwater resources; and
o. Any other information as required by the TPCHD, including information required under Washington Department of Ecology Publication No. 97-30.
C. Storage Tank Permits. In addition to the requirements set forth in this title, the following agencies also have the authority to regulate the installation, repair, replacement, or removal of any UST:
1. The Pierce County fire prevention bureau regulates and authorizes permits for all USTs, pursuant to the International Fire Code (Article 79) and this chapter.
2. The Washington Department of Ecology regulates and authorizes permits for all USTs (Chapter 173-360 WAC).
3. The TPCHD regulates and authorizes permits for the removal of any UST (Pierce County Code, Chapter 8.34). (Ord. 17-513 § 3 (Exh. A)).
14.60.040 Critical aquifer recharge areas standards.
A. General. All regulated activities that are not exempt or prohibited under the provisions of this chapter shall ensure sufficient groundwater recharge. In order to achieve sufficient groundwater recharge, the applicant shall comply with the city’s adopted stormwater manual, Chapter 13.05 EMC, and demonstrate that the total post-development infiltration rate for the project area will be equal to or better than the predevelopment rate.
B. Prohibited Uses. Landfills (other than inert and demolition landfills), Class I, III, and IV underground injection wells, metals mining, wood treatment facilities, pesticide manufacturing, petroleum refining facilities (including distilled petroleum facilities), the storage of large volumes of petroleum products, and other uses or activities determined by the department to have a significant adverse impact on groundwater are prohibited within critical aquifer recharge areas.
C. Exemptions. In addition to the general exemptions listed in EMC 14.30.030, the following uses or activities are exempt from the requirements of this chapter:
1. Sewer lines and appurtenances;
2. Biosolids and sludge land application sites; provided, that these activities comply with the requirements established in Chapters 173-200, 173-216, and 173-304 WAC; and
3. Single-family and two-family dwellings and associated accessory structures.
D. Agricultural Activities. New agricultural activities that do not involve hazardous substance handling or application are allowed within an aquifer recharge or wellhead protection area subject to the following:
1. The applicant is required to submit a farm management plan prepared by the USDA, NRCS, Pierce County Conservation District, or Washington State University Cooperative Extension Office, that certifies that water quality and quantity within the aquifer recharge area is maintained. The farm management plan shall at a minimum address the following:
a. The limits of the proposed agricultural activities.
b. The proposed scope of agricultural activities, including the use of any pesticides, fertilizers, or other chemicals.
c. The existing nitrate levels on the site and any proposed increases in nitrate levels.
2. Integrated pest management (IPM) practices for pest control and BMPs for the use of fertilizers, as described by the Washington State University Pierce County Cooperative Extension Office, shall be utilized.
3. Nitrate levels at down-gradient property line shall not exceed 2.5 mg/L or, if the background nitrate concentration exceeds 2.5 mg/L, the concentration will not be increased more than 0.1 mg/L.
4. Additional protective measures may be required if deemed necessary by the department or TPCHD to protect public health or safety.
E. Nonhazardous Uses. Subdivision of land as defined in EMC Title 16, residential structures housing three or more units, and all commercial and industrial sites or activities that do not include or involve hazardous substance processing or handling in critical aquifer recharge areas are allowed subject to the following standards:
1. Stormwater quality treatment and flow control shall be provided in conformance with the city’s adopted stormwater management manual.
2. Floor drains shall not be allowed to drain to the stormwater system and must be designed and installed to meet the Uniform Plumbing Code (UPC), as adopted in EMC Title 15.
3. If any roof venting carries a contaminant, then the portion of the roof draining from this area must go through pretreatment pursuant to the UPC, as adopted in EMC Title 15.
4. All nonresidential vehicle washing must be self-contained or be discharged to a sanitary sewer system, if approved by the sewer utility, and is subject to the UPC, as adopted in EMC Title 15.
5. Integrated pest management (IPM) practices for pest control and BMPs for the use of fertilizers, as described by the Washington State University Pierce County Cooperative Extension Office, shall be utilized.
6. For new or changes in regulated activities served by on-site sewage systems, the applicant must demonstrate to the TPCHD that nitrate levels at the down-gradient property line will not exceed 2.5 mg/L or that if the background nitrate concentration exceeds 2.5 mg/L the concentration will not be increased more than 0.1 mg/L.
7. Additional protective measures may be required if deemed necessary by the department or TPCHD to protect public health or safety.
F. Hazardous Uses – General. Hazardous substance processing or handling, hazardous waste treatment and storage facilities, animal containment areas, and solid waste facilities that require a solid waste handling permit from the TPCHD, requiring approval from the city, shall be allowed only in critical aquifer recharge areas subject to review and approval of a hydrogeologic assessment by the department and review by the TPCHD. The department has the authority to apply whatever standards deemed necessary to mitigate any negative impacts that may be associated with the proposed development and will consider comments by TPCHD.
G. Hazardous Uses – Storage Tanks. In addition to the requirement to submit a hydrogeologic assessment, the following standards apply to storage tanks in critical aquifer recharge areas:
1. Underground Tanks. All new underground storage facilities used or to be used for the underground storage of hazardous substances or hazardous wastes shall be designed and constructed so as to:
a. Prevent releases due to corrosion or structural failure for the operational life of the tank;
b. Be protected against corrosion, constructed of noncorrosive material, steel clad with a noncorrosive material, or designed to include a secondary containment system to prevent the release or threatened release of any stored substance;
c. Use material in the construction or lining of the tank which is compatible with the substance to be stored; and
d. The installation of any UST shall also be subject to other state and local permit requirements.
2. Aboveground Tanks.
a. No new aboveground storage facility or part thereof shall be fabricated, constructed, installed, used, or maintained in any manner which may allow the release of a hazardous substance to the ground, groundwater, or surface water within any critical aquifer recharge areas.
b. A new aboveground tank that will contain a hazardous substance will require both a double-walled tank and a secondary containment system separate from the tank that will hold 110 percent of the tank’s capacity. The secondary containment system or dike system must be designed and constructed to contain material stored in the tank(s). (Ord. 24-660 §§ 11 – 13 (Exh. B); Ord. 17-513 § 3 (Exh. A)).