VOLUME IV – Permanent Stormwater Site Management

Chapter 1 – Introduction

1.1 Purpose of this Volume

This volume provides guidance in the preparation of permanent Stormwater Site Management Plans for sites and facilities required to meet Core Requirement #3 – Source Control of Pollution and Core Requirement #9 – Operation and Maintenance. Stormwater Site Management Plans are composed of Best Management Practices (BMPs) and operation and maintenance guidance for facility owners/program operators to ensure the long-term functionality and protection of engineered stormwater facilities and environmental resources.

1.2 Content and Organization of this Volume

Volume IV of this stormwater manual contains four chapters and associated appendices.

Chapter 1 serves as an introduction and provides guidance on using this Volume.

Chapter 2 describes the responsibility to maintain stormwater facilities and BMPs through development and implementation of permanent Stormwater Site Management Plans. This chapter describes the content and preparation of such plans.

Chapter 3 is focused on Pollution Source Control and contains descriptions of operational and structural source control BMPs. It distinguishes between applicable (mandatory) BMPs, and recommended BMPs. It describes the relationship between the source control BMPs in this volume and regulatory requirements.

Chapter 3 Section 3.6 describes the content and procedures for creating a site-specific Pollution Source Control Program. In Chapter 3, Section 3.6.3, operational and structural BMPs designed to address specific types of pollutant sources are listed for use in preparing plans.

Chapter 4 addresses the long-range maintenance of stormwater facilities and structural BMPs, collection and conveyance systems, and low impact development controls. Information contained in Chapter 4 and the referenced appendices are intended to be used for maintenance program creation and for public education.

The appendices in this volume contain additional information on selected topics. Most notably, examples and templates used for completing both Pollution Source Control Programs and Stormwater Facility Maintenance Programs are included in the appendices.

1.3 How to Use this Volume

Stormwater Site Management Plans

Chapter 2 of this Volume outlines the structure and content necessary for preparing Stormwater Site Management Plans for projects and management areas. Preparation of a Stormwater Site Management Plan is only necessary when required to meet both Core Requirement #3 – Source Control of Pollution and Core Requirement #9 – Operation and Maintenance. Projects subject to both Core Requirement #3 and #9 will start preparation of Stormwater Site Management Plans by consulting Chapter 2.

Pollution Source Control

Use Chapter 3 and associated appendices of this Volume in preparing Pollution Source Control Programs as required by Core Requirement #3 of Volume I.

Within this volume, the reader should interpret the term “applicable” when referring to specific operational or structural source controls as meaning “mandatory” or “required”.

Users should consult Appendix IV-A regarding their specific businesses and activities to identify their common pollutant sources. Then refer to the appropriate worksheets contained in the templates of Appendix IV-B to identify proper source control BMPs for a given type of pollutant source. Chapter 3 also contains design criteria for source control BMPs. Some users will wish to refer to additional appendices for specific information on regulatory requirements affecting their projects.

Chapter 3 identifies pollution source control BMPs that apply to specific types of pollutant sources. For a more complete discussion of treatment BMP design information, refer to Volume V.

Operators under Ecology’s Industrial Stormwater General Permit, Boatyard General Permit, or Sand and Gravel General Permit should use Volume IV of Ecology’s Stormwater Management Manual for Western Washington to identify applicable (mandatory) and recommended operational and structural source control BMPs for inclusion in their Stormwater Pollution Prevention Plans (SWPPPs).

Operators of commercial, industrial, and multifamily properties not under an Ecology permit should use Chapter 3 of this volume in developing their SWPPPs and should check with the City of Olympia regarding local requirements related to source control BMPs and SWPPPs.

Stormwater Facility Maintenance and Inspection

Chapter 4 and associated appendices of this Volume shall be used in preparing Stormwater Facility Maintenance Programs as required by Core Requirement #9 – Operation and Maintenance, of Volume I.

Chapter 4, Section 4.2 covers the preparation of Stormwater Facility Maintenance Programs and the content of those documents. See Chapter 4, Section 4.2.1 for the necessary components of a complete Stormwater Facility Maintenance Program.

Appendix IV-H, Appendix IV-J, and Appendix IV-K contain maintenance agreements, stormwater facility checklists, descriptions, and inspection reporting materials to be used when preparing a Stormwater Facility Maintenance Program.