A. Applicability. 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. In accordance with WAC 365-190-100, the entirety of Bainbridge Island is classified as an aquifer recharge area to preserve the volume of recharge available to the aquifer system and to protect groundwater from contamination.

B. Permit Review and Procedures

1. Any development, use or activity described in subsection B.3.b or c of this section shall require a critical area permit.

2. Critical area permits shall be reviewed pursuant to the criteria in BIMC 16.20.070.

3. Applications for critical area permits for aquifer recharge areas shall include:

a. City of Bainbridge Island master land use application (http://www.bainbridgewa.gov/161/Documents-Forms-Applications); and

b. Proposals for any development, use or activity not associated with permitted principal and accessory residential uses pursuant to BIMC 18.09.020 that has the potential to generate a pollutant identified as a potential source of drinking water contamination (either in Appendix A of the Washington State Critical Aquifer Recharge Area Guidance Document or on the North American Industry Classification System as used by the city’s department of public works) or known to be deleterious to the environment or human health shall require submittal of a hydrogeologic assessment, as set forth in BIMC 16.20.180.A. If the applicant has completed a site assessment review (SAR) in accordance with Chapter 15.19 BIMC that includes sufficient information to address the elements listed in BIMC 16.20.180.A, the SAR will suffice to fulfill this requirement. Additional in-depth site assessment elements as detailed in BIMC 16.20.180.A may be required by the city or if requested by affected public water purveyors (Group A and B), affected tribes, or the Kitsap Public Health District upon review of the SAR.

c. Proposals requiring designation of an aquifer recharge protection area pursuant to subsection E.1 of this section shall require submittal of a site assessment review application.

C. Prohibited Activities and Uses. The following activities and uses are prohibited within critical aquifer recharge areas due to the probability or potential magnitude of their adverse effects on groundwater:

1. Landfills. Landfills, including hazardous or dangerous waste, municipal solid waste, special waste, wood waste, and inert and demolition waste landfills;

2. Underground Injection Wells. Class I, III, and IV wells and subclasses 5F01, 5D03, 5F04, 5W09, 5W10, 5W11, 5W31, 5X13, 5X14, 5X15, 5W20, 5X28, and 5N24 of Class V wells;

3. Chemical wood preservation and/or treatment facilities;

4. Storage, Processing, or Disposal of Radioactive Substances. Facilities that store (other than minor sources such as medicinal uses or industrial testing devices), process, or dispose of radioactive substances;

5. Hazardous liquid transmission pipelines;

6. Commercial mining and chemical washing of metals, hard rock, sand, and gravel;

7. Hydrocarbon extraction, reprocessing, refinement, and storage;

8. Electroplating/metal finishing;

9. Facilities that treat, store, process, or dispose of hazardous waste; and

10. Other Prohibited Uses or Activities.

a. Activities that would significantly reduce the recharge to aquifers currently or potentially used as a potable water source; and

b. Activities that would significantly reduce the recharge to aquifers that are a source of significant baseflow to a stream.

D. Development Standards – General.

1. No development, use or activity may exceed water quality standards or otherwise violate the antidegradation requirements specified in Chapter 173-200 WAC.

2. Any development or activity that is not exempt or excluded by subsection E.1 of this section shall ensure sufficient groundwater recharge, defined as maintaining 100 percent of the annual average pre-construction groundwater recharge volume for the site. The primary means to ensure sufficient groundwater recharge shall be through the designation of an aquifer recharge protection area in accordance with subsection E of this section.

E. Development Standards – Aquifer Recharge Protection Area (ARPA).

1. Any proposed development or activity requiring a site assessment review (SAR) pursuant to Chapters 15.19 and 15.20 BIMC located within the R-0.4, R-1 or R-2 zoning designations requires designation of an ARPA; except, designation of an ARPA is not required for the following:

a. Removal of invasive species;

b. Construction of public trails provided the standards set forth in BIMC 16.20.110.G.5.a through 16.20.110.G.5.e are met;

c. Replacement of hard surfaces;

d. Development and activities located on properties protected in perpetuity by a legal instrument acceptable to the city attorney wherein at least 65 percent of the site meets the development standards for aquifer recharge protection areas of this section; and

e. Activities related to the installation, upgrade, and maintenance of primary utility facilities, when located on property not owned in fee by the utility, provided the applicant submits a vegetation restoration plan for approval by the city arborist unless the vegetation management and mitigation provisions within Chapters 16.12 and/or 16.20 BIMC provide greater net functions and values within the shoreline or for a critical area. A proposed vegetation restoration plan shall include:

i. Tree inventory showing all trees to be removed within the project area including location, number, and size of proposed trees to be removed. Size shall be provided in both diameter at breast height (DBH) in inches and estimated canopy square footage.

ii. A minimum of the following ratios for each tree removed: 2:1 for trees removed that are up to 24 inches at diameter breast height (DBH), 3:1 for trees between 25 inches and 47 inches DBH, and 4:1 for trees 48 inches DBH and larger, or demonstrate equal canopy coverage replacement within 30 years. Replacement trees may be planted at a nearby location. Additional tree planting may be required based on site specific conditions, to the satisfaction of the city arborist.

iii. Shrubs and other vegetation may be substituted for trees in locations where trees are infeasible or inappropriate due to compatibility with utility use, pending review and approval by the city arborist.

iv. Replacement vegetation shall demonstrate an emphasis on the use of native and/or climate resilient species.

2. ARPA General Requirements.

a. The location and configuration of the ARPA shall be determined through completion of a site assessment review (SAR) in accordance with Chapter 15.19 BIMC. The city may require a professional forester, ISA-certified arborist or landscape architect to determine the location and configuration of the ARPA if needed to ensure the ARPA design standards set forth in subsections E.3.a through c of this section are met;

b. The ARPA shall include all existing native vegetation on a site, up to a maximum of 65 percent of the total site area. A lower percentage is allowed if necessary to achieve a development area of at least 12,500 square feet on a parcel;

c. The maximum area of the required ARPA may be reduced to 50 percent for public schools and public parks allowed in the underlying zoning district;

d. The location and configuration of the ARPA may change over time; however, the total area required pursuant to subsection E.2.b of this section shall be retained once established. Any alteration to the location or configuration of the ARPA shall be approved by the director and documented on a site plan included with a notice to title in accordance with BIMC 16.20.070.G. The city may require an ARPA stewardship plan prior to approving a change to the location and configuration of the ARPA.

3. ARPA Design Standards.

a. Healthy, existing trees and vegetation should be retained to the maximum extent possible. Healthy significant trees shall be priority trees for retention. Trees shall be retained in one or more stands or clusters.

b. The ARPA shall be delineated to include:

i. A low perimeter-to-area ratio;

ii. A minimum width of 12 feet; and

iii. The critical root zone of all significant trees.

c. The ARPA shall be contiguous with abutting, off-site areas of other ARPAs, open space or critical areas to the extent feasible.

d. The ARPA may include landscaping or open space requirements pursuant to BIMC 18.15.010.D and E and Chapter 17.12 BIMC, respectively, and other critical areas and their buffers or setbacks pursuant to other sections of this chapter.

4. ARPA Use Standards. The following developments and activities are allowed within a designated ARPA:

a. Any structure or activity as long as the new structure or activity is shown to not negatively impact the amount of groundwater recharge on the site. Specifically, any structure or activity is allowed as long as the structure or activity (including mitigation measures, if any are needed) maintains 100 percent of the annual average groundwater recharge volume that existed on the site prior to the structure or activity as demonstrated by the 2012 Western Washington Hydrology Model (WWHM2012) recharge module, as amended.

b. Tree and vegetation activities specified in BIMC 16.20.090.

c. Installation of native plants.

d. Removal of invasive plant species.

e. Passive recreation, including pervious trails.

f. Potable water wells and well houses.

g. Low impact fencing or signs marking the ARPA boundary.

h. On-site sewage drainfield facilities, if construction of the system will not require the use of heavy equipment or removal of significant trees.

i. Storm drainage facilities if the applicant can demonstrate that (i) the system meets the low impact design (LID) standards of Chapter 15.20 BIMC, and (ii) construction of the system will not require the use of heavy equipment or removal of significant trees.

j. Accessory solar panels, small wind energy generators, composting bins, rainwater harvesting barrels, and cisterns, as defined in Chapter 18.36 BIMC.

k. Other structures or hard surfaces with a total footprint of no greater than 200 square feet.

l. Driveways may be allowed to pass through the ARPA if (i) siting of the driveway within the ARPA is determined by the director to be necessary to achieve greater native vegetation retention and use of nonstructural low impact design practices, (ii) site utilities are installed within the footprint of the driveway, (iii) siting of the driveway avoids removal of significant trees to the maximum extent feasible and (iv) the total area required pursuant to subsection E.1 of this section is achieved, which may require replanting of areas comprised of nonnative vegetation.

m. Removal of any significant tree, other than hazard tree removal, with city review and preapproval of an aquifer recharge protection area stewardship plan prepared in accordance with BIMC 16.20.180.H.

5. ARPA Protection.

a. The ARPA, including the critical root zone of significant trees, shall be protected during construction as provided in BIMC 18.15.010.C.4 or as specified by an ISA-certified arborist.

b. The ARPA shall be documented on a site plan included with a notice to title in accordance with BIMC 16.20.070.G. (Ord. 2024-04 § 1, 2024; Ord. 2018-01 § 2 (Exh. A), 2018)