City of Lemon Grove - Best Management Practices (BMP) Design Manual - December 2024

Oct 22, 2026

Uploaded by adawds

City of Lemon Grove Best Management Practices (BMP) Design Manual (December 2024) establishes updated onsite post-construction stormwater requirements under the MS4 Permit, translating permit performance standards into local planning, preliminary design, and BMP selection and design procedures. It supports Standard Projects and Priority Development Projects by clarifying local practices, referencing the adopted Post-Construction BMP Design Standards Ordinance, and detailing key changes such as PDP thresholds, LID applicability, treatment control retention criteria, biofiltration standards, and revised hydromodification management requirements. The manual also explains when applicants may pursue alternative compliance.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages476

Reading Time20 h 0 min

AccessFree to download

Summary

What this Manual is intended to address

What this manual does not address

City of Lemon Grove Best Management Practices (BMP) Design Manual December 2024 Intentionally Left Blank Summary In May 2013, the California Regional Water Quality Control Board, San Diego Region (RWQCB) reissued a municipal stormwater National Pollutant Discharge Elimination System permit (Municipal Separate Storm Sewer System [MS4] Permit) that covered its region. The jurisdictions subject to the MS4 Permit include municipal agencies in San Diego, Orange, and Riverside counties, including the City of Lemon Grove (collectively,“Copermittees”) . The MS4 Permit reissuance to the San Diego County Copermittees went into effect in 2013 (Order No. R9-2013-0001) . The reissued MS4 Permit updates and expands stormwater requirements for new developments andredevelopments. In February 2015, the MS4 Permit was amended by Order R9-2015-0001, and again in November 2015 by Order R9-2015-0100 As required by the reissued MS4 Permit, the Copermittees prepared the Model Best Management Practices (BMP) Design Manual (Model BMP Design Manual)(from hereafter referred to as “Model BMP Design Manual”) to replace the current Countywide Model Standard Urban Stormwater Mitigation Plan (SUSMP), dated March 25, 2011, which was based on the requirements of the 2007 MS4 Permit. The Model BMP Design Manual was submitted to the RWQCB on behalf of the Copermittees, including the City of Lemon Grove (City), in June 2015. The effective date of the Model BMP Design Manual was February 16, 2016. This City of Lemon Grove BMP Design Manual (from hereafter referred to as “BMP Design Manual”or “manual”) is based on the Model BMP Design Manual, with edits to clarify local practices and procedures that apply in the City. The City has also adopted an updated Post-Construction BMP Design Standards Ordinance, Chapter 8.52 of the Lemon Grove Municipal Code, to provide legal authority for the implementation of the requirements described in the Lemon Grove BMP Design Manual. Throughout this manual, new or revised text present in the Lemon Grove BMP Design Manual not present in the Model BMP Design Manual is identified via gray highlight. Longer discussions of local practices and procedures are shown in gray-highlighted boxes like the one below. Gray boxes, like this one, contain extended discussions of local practices and procedures or other City of Lemon Grove-specific guidance. What this Manual is intended to address: This Manual addresses updated onsite post-construction stormwater requirements for Standard Projects and Priority Development Projects (PDPs), and provides updated procedures for planning, preliminary design, selection, and design of permanent stormwater BMPs based on the performance standards presented in the MS4 Permit. The intended users of the BMP Design Manual include project applicants, for both private and public developments, their representatives responsible for preparation of Stormwater Quality Management Plans (SWQMPs) and City personnel responsible for review of these plans. The following are significant updates to stormwater requirements ofthe MS4 Permit compared to the 2007 MS4 Permit and 2011 Countywide Model SUSMP: • PDP categories have been updated, and the minimum threshold of impervious area to qualify as a PDP has been reduced. • Many of the low impact development (LID) requirements for site design that were applicable only to PDPs under the 2007 MS4 Permit are applicable to all projects (Standard Projects and PDPs) under the MS4 Permit. • The standard for stormwater pollutant control (also known as treatment control) is retention of the 24-hour 85th percentile storm volume, defined as the event that has a precipitation total greater than or equal to 85 percent of all daily storm events larger than 0.01 inches over a given period of record in a specific area or location. • For situations where onsite retention of the 85th percentile storm volume is technically not feasible, biofiltration must be provided

FAQs

What kinds of projects does the Lemon Grove BMP Design Manual apply to?

It addresses updated onsite post-construction stormwater requirements for Standard Projects and Priority Development Projects (PDPs), including procedures for planning and designing permanent stormwater BMPs.

What user groups are intended to use this manual?

Project applicants for both private and public developments, representatives preparing Stormwater Quality Management Plans (SWQMPs), and City personnel responsible for reviewing those plans.

What topics does the manual explicitly not address regarding alternative compliance?

It provides guidance on when alternative compliance may be sought, but it notes that regional crediting systems and available in-lieu fees or alternative compliance projects implemented after development completion are not yet available.

Oct 22, 2026

Uploaded by adawds