Storm Drainage Report
Some building and utilities permits issued by the City of Bellevue require a storm drainage report to be submitted for plan review. Prepare your report using the requirements outlined in the most current City of Bellevue Surface Water Engineering Standards (SWES), Section D2 - D6. For assistance in submitting your report online, refer to Electronic Plan Requirements and Electronic Review Efficiency. For questions regarding your submittal, contact the Utilities Review desk.
- All plan sheets must be a minimum of 18 x 24 inches.
- Storm drainage reports must be on 8 ½ x 11 inches and should be separate from the geotechnical report.
Project Information
- Project address
- Name, address and stamp of preparer (if a licensed individual)
- Vicinity map
Report Requirements
- Table of contents.
- Utility standards and Department of Ecology codes pertinent to the project.
- Project overview - existing and proposed conditions.
- One quarter mile downstream analysis.
- Off-site capacity analysis (if applicable).
- Site Assessment and Planning Packet
- Pre-developed and post-developed chart showing square footage of hard surfaces and pervious surfaces.
- Figure 1.4 or 1.5 highlighting the flow path used to determine stormwater minimum requirements for the project.
- Highlight flow path Reference SWES, Figure 5.1, for infiltration feasibility.
- Details of infiltration testing, if required (test hole must be a minimum of six feet deep per SWES Appendix D-10).
- Discussion of how each minimum requirement is being met.
- Thorough discussion of List #1, List #2 or LID performance standard (SWES D104.2(e)). Include infeasibility criteria per SWES Table D-9.1 and D-9.2.
- Sizing calculations for Best Management Practices (BMPs) proposed.
- When required per SWES D4-03, provide hydrologic/hydraulic calculation methodologies, inputs, assumptions and results for analysis of off-site conveyance capacity.