A. City-Specific Standards. The city amends the standards adopted as part of the stormwater manual as follows:

1. Instead of following the Better Site Design BMP (BMP T5.41) in Volume V, Section V-2 of the stormwater manual, conduct a site assessment following the guidance in the LID manual adopted in BIMC 15.20.050. Comply with the city of Bainbridge Island design and construction standards for streets and roadways unless an exception is granted in writing by the administrator.

2. The hard surface threshold for triggering Minimum Requirements No. 1 through 5 for new development and redevelopment (Volume I, Section I-3.3) is reduced from 2,000 square feet to 800 square feet or greater of new plus replaced hard surface area.

3. Volume I, Section 3.5.2, Additional Protective Measure (“APM”) 1, Financial Liability, is not adopted.

4. Volume I, Section 3.5.1, APM No. 2, Off-Site Analysis and Mitigation, and Volume III, Section 3.2.3, Perform an Off-Site Analysis, is required for new development and redevelopment projects creating 5,000 square feet or more of hard surface area.

5. Volume I, Section 3.6.1, Adjustments to the MRs, is not adopted.

6. Volume V, BMP D.1, Detention Ponds, Signage section under Design Criteria, is amended to include the following language:

City of Bainbridge Island specific signage for constructed ponds is required to be provided by the developer as a part of the project. Contact the City Stormwater Management Program Coordinator to obtain approved sign specifications for a permanent surface water control pond, which will include the pond name, pond number, and telephone number to include on the sign.

7. Volume V, Section 1.2, Setbacks, Slopes, and Embankments, is amended to add the following language after the first paragraph in the Setbacks section:

Chapter 16.20 BIMC defines “Zone of Influence” as it relates to moderate and steep slopes. A Geotechnical Engineer is required to evaluate a project stormwater site plan that proposes land disturbance, changes in land use, or changes in site hydrology within the zone of influence of any geologically hazardous area as defined in Chapter 16.20 BIMC.

8. The city utilizes the Rain Garden Handbook for Western Washington: A Guide for Design, Installation and Maintenance (Hinman et al., 2013). Volume V, Section V-11 of the stormwater manual, BMP T5.14, Rain Gardens, is modified to add the following text to the end of the first paragraph of the Design Guidelines section:

Use the “Good (80%)” performance level for Rainfall Region 3 in the Rain Garden Sizing Chart at a minimum. “Better (95%)” performance level is preferred.

(Ord. 2022-11 § 4, 2022; Ord. 2017-03 § 3, 2017; Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 5, 2009: Ord. 2005-10 § 5, 2005: Ord. 2001-49 § 2, 2001; Ord. 98-31 § 1, 1999)