Chapter 18E.50
AQUIFER RECHARGE AND WELLHEAD PROTECTION AREAS

Sections:

18E.50.010    Purpose.

18E.50.020    Aquifer Recharge and Wellhead Protection Areas.

18E.50.030    Aquifer Recharge and Wellhead Protection Area Review Procedures.

18E.50.040    Aquifer Recharge and Wellhead Protection Area Standards.

18E.50.010 Purpose.

The purpose of this Chapter is to protect critical aquifer recharge and wellhead protection areas from degradation or depletion resulting from new or changed land use activities. Due to the exceptional susceptibility and/or 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 contaminants from new land use activities. (Ord. 2004-57s § 2 (part), 2004)

18E.50.020 Aquifer Recharge and Wellhead Protection Areas.

A.    General. Aquifer recharge and wellhead protection 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.

B.    Aquifer Recharge Areas.

1.    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, Pierce County, Washington, National Water Well Association, U.S. Environmental Protection Agency; and

2.    The Clover/Chambers Creek Aquifer Basin boundary as identified in the Clover/Chambers Creek Basin Groundwater Management Program (TPCHD 1991).

C.    Wellhead Protection Areas. Wellhead protection areas that lie within the ten-year time-of-travel zone boundary of a group A public water system well, as delineated by the water system purveyor or its designee, pursuant to WAC 246-290-135.

(Ord. 2004-57s § 2 (part), 2004)

18E.50.030 Aquifer Recharge and Wellhead Protection Area Review Procedures.

A.    General Requirements.

1.    The Pierce County Critical Areas Atlas-Aquifer Recharge and Wellhead Protection Area Map provides an indication of where aquifer recharge and wellhead protection areas are located within the County.

2.    The Department will complete a review of the Aquifer Recharge Area Map for any development proposal to determine whether the proposed project area for a regulated activity falls within an aquifer recharge or wellhead protection area.

3.    When the Department's maps or sources indicate that the proposed project area for a regulated activity is located within an aquifer recharge or wellhead protection area, the Department shall require aquifer recharge and wellhead protection area review as set forth in this Chapter.

4.    Any regulated activity located within an aquifer recharge or wellhead protection area shall comply with the standards set forth in PCC 18E.50.040.

5.    Any hazardous uses, as defined in PCC 18E.50.040, shall require the submittal of a hydrogeologic assessment, as set forth in PCC 18E.50.030 B. below.

6.    The Department may waive some of the critical area protective measure provisions contained in PCC 18E.10.080.

B.    Hydrogeologic Assessment.

1.    The hydrogeologic assessment shall be prepared under the responsible charge of an appropriately licensed geotechnical professional, and signed, sealed, and dated by an appropriately licensed geotechnical professional.

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 following:

a.    Information sources;

b.    Geologic setting – Include well logs or borings used to identify information;

c.    Background water quality;

d.    Groundwater elevations;

e.    Location/depth to perched water tables;

f.    Recharge potential of facility site (permeability/transmissivity);

g.    Groundwater flow direction and gradient;

h.    Currently available data on wells located within 1/4 mile of the site;

i.    Currently available data on any spring within 1/4 mile of the site;

j.    Surface water location and recharge potential;

k.    Water source supply to facility (e.g., 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 97-30.

3.    The TPCHD shall provide written notice to all Group A water systems in whose wellhead protection area the proposed regulated activity lies. The TPCHD shall consider comments received from the water system(s) when reviewing the hydrogeologic assessment.

4.    Uses requiring a hydrogeologic assessment may be conditioned or denied based upon the TPCHD's evaluation of the hydrogeologic assessment. Any project denied a permit based upon the TPCHD's evaluation of the hydrogeologic assessment shall receive a written explanation of the reason(s) for denial and an explanation of standards required, if any, to comply with these regulations.

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 underground storage tanks:

1.    The Pierce County Fire Prevention Bureau regulates and authorizes permits for underground storage tanks, pursuant to the Uniform Fire Code (Article 79) and this Chapter.

2.    The Washington Department of Ecology regulates and authorizes permits for underground storage tanks (WAC 173-360).

3.    The TPCHD regulates and authorizes permits for the removal of underground storage tanks (Chapter 8.34 PCC).

(Ord. 2004-57s § 2 (part), 2004)

18E.50.040 Aquifer Recharge and Wellhead Protection Area Standards.

A.    General. All regulated activities that are not exempt, prohibited, or otherwise excluded in the following standards under the provisions of this Chapter shall ensure sufficient groundwater recharge. In order to achieve sufficient groundwater recharge the applicant shall either comply with the impervious surface limitations set forth in Table 18E.50.040 A or demonstrate that the volume of water infiltrated at the proposed project area will be the same or greater amount for post-development as the pre-development volume. Also see Title 18J PCC, Development Regulations – Design Standards and Guidelines, Chapter 18J.30 PCC, for additional impervious surface standards.

Table 18E.50.040-A. Aquifer Recharge Area

Impervious Surface Limitations

Comprehensive Plan Land Use Designation

Maximum Impervious Surface Coverage (1)

Urban Land Use Designations

Employment Center

60%

Major Urban Center

75%

Activity Center

50%

Community Center

50%

Neighborhood Center

50%

Mixed Use District

75%

High Density Residential District

50%

High Density Single Family

50%

Moderate Density Single Family

35%

Public Institution

60%

Urban Military Land

Not Applicable

Urban Village

75%

Master Planned Community

20%

Employment Based Planned Community

20%

Rural Land Use Designations

Essential Public Facility Rural Airport North

PUD

Essential Public Facility Rural Airport South

PUD

Rural Activity Center

60%

Rural Neighborhood Center

50%

Gateway Community

50%

Rural Separator

10%

Rural Sensitive Resource

10%

Rural Farm

10%

Rural 10

10%

Rural 20

10%

Rural 40

10%

Reserve 5

10%

Master Planned Resort

10%

Rural Military Land

Not Applicable

Natural Resource Land Designations

Designated Forest Land

Not Applicable

Agricultural Resource Land

Not Applicable

(1)    The maximum impervious surface coverage is calculated for the total amount of impervious surface per each individual site. The percentage for maximum total impervious surface per lot or site may be exceeded if the applicant can demonstrate that the effective impervious surface on the site is less than or equal to what is allowed for the total impervious surface.

B.    Prohibited Uses. Landfills (other than inert and demolition landfills), underground injection wells (Class I, III, and IV), metals mining, wood treatment facilities, pesticide manufacturing, petroleum refining facilities (including distilled petroleum facilities), and the storage of more than 70,000 gallons of liquid petroleum or other hazardous products are prohibited within aquifer recharge and wellhead protection areas.

C.    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 Best Management Practices (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, that 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.

D.    Non-Hazardous Uses. Subdivision of land as defined in Title 18F PCC, 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 an aquifer recharge and/or wellhead protection area are allowed subject to the following standards:

1.    Stormwater treatment and control shall be provided in conformance with the Pierce County Stormwater Management and Site Development 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) Section 303.

3.    If any roof venting carries contaminants, then the portion of the roof draining this area must go through pretreatment pursuant to UPC Section 304(b).

4.    All vehicle washing done somewhere other than at a residence must be self-contained or be discharged to a sanitary sewer system, if approved by the sewer utility, and is subject to UPC Sections 708 and 711.

5.    Integrated Pest Management (IPM) practices for pest control and Best Management Practices (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 TPCHD to protect public health or safety.

E.    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 shall be allowed only in an aquifer recharge and/or wellhead protection area subject to review and approval of a hydrogeologic assessment by the TPCHD. For this Chapter, natural gas distribution systems are exempted. The TPCHD has the authority to apply whatever standards deemed necessary to mitigate any negative impacts that may be associated with the proposed development. At a minimum, the activity must employee AKART (all known, available, and reasonable treatment) to protect ground water quality.

F.    Hazardous Uses – Storage Tanks. In addition to the requirement to submit a hydrogeologic assessment, the following standards apply to storage tanks in an aquifer recharge and/or wellhead protection area:

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 non-corrosive 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; and

c.    Use material in the construction or lining of the tank which is compatible with the substance to be stored.

d.    The installation of underground storage tanks 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 waters of Pierce County within an aquifer recharge area.

b.    A new above 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. 2014-42 § 4, 2014; Ord. 2009-18s3 § 4 (part), 2009; Ord. 2006-103s § 2 (part), 2006; Ord. 2006-53s § 4, 2006; Ord. 2004-57s § 2 (part), 2004)