(Amended by Ord. No. 181,899, Eff. 11/14/11, Oper. 5/12/12.)
(A) Objective. (Amended by Ord. No. 183,833, Eff. 10/3/15.) The provisions of this section contain requirements for construction activities and facility operations of Development and Redevelopment projects to comply with the Land Development requirements of the MS4 permit though integrating LID practices and standards for stormwater pollution mitigation, and maximize open, green and pervious space on all Developments and Redevelopments consistent with the City's landscape ordinance and other related requirements in the Development Best Management Practices Handbook.
(B) Scope. (Amended by Ord. No. 183,833, Eff. 10/3/15.) This section contains requirements for stormwater pollution control measures in Development and Redevelopment projects and authorizes the Board to further define and adopt stormwater pollution control measures, develop LID principles and requirements, including, but not limited to, the objectives and specifications for integration of LID strategies, collect Best Management Practices compliance plan check fees, collect funds for projects that are granted waivers, conduct inspections, cite violators for infractions and impose fines. Except as otherwise provided herein, the Board shall administer, implement and enforce the provisions of this section.
(C) LID Requirements. (Amended by Ord. No. 183,833, Eff. 10/3/15.) All Developments and Redevelopments shall comply with the following:
1. Development or Redevelopment involving four or fewer units intended for residential use shall implement LID BMP alternatives identified in the Development Best Management Practices Handbook.
2. Development or Redevelopment Involving Nonresidential Use or Five or More Units Intended for Residential Use.
a. Development or Redevelopment resulting in an alteration of at least 50% or more of the impervious surfaces on an existing developed Site, the entire Site must comply with the standards and requirements of this article and with the Development Best Management Practices Handbook; and
b. Development or Redevelopment resulting in an alteration of less than 50% of the impervious surfaces of an existing developed Site, only such incremental Development shall comply with the standards and requirements of this article and with the Development Best Management Practices Handbook.
3. A Development or Redevelopment of any size that would create 2,500 square feet or more of impervious surface area and is located partly or wholly within an ESA shall comply with the standards and requirements of this article and with the Development Best Management Practices Handbook.
4. A Development or Redevelopment of any size that would create more than 10,000 square feet or more of impervious surface area and total one acre or more of disturbed area shall comply with the standards and requirements of this article and with the Development Best Management Practices Handbook.
5. Street and road construction of 10,000 square feet or more of impervious surface area shall comply with the standards and requirements of the Development Best Management Practices Handbook.
6. The Site for every Development or Redevelopment shall be designed to manage and capture stormwater runoff, to the maximum extent feasible, in priority order: infiltration, evapotranspiration, capture and use, treated through high removal efficiency biofiltration/biotreatment system of all of the runoff on site. High removal efficiency biofiltration/biotreatment systems shall comply with the standards and requirements of the Development Best Management Practices Handbook. A LID Plan shall be prepared to comply with the following:
a. Stormwater runoff will be infiltrated, evapotranspired, captured and used, treated through high removal efficiency Best Management Practices, onsite, through stormwater management techniques that comply with the provisions of the Development Best Management Practices Handbook. To the maximum extent feasible, onsite stormwater management techniques must be properly sized, at a minimum, to infiltrate, evapotranspire, store for use, treat through high removal efficiency biofiltration/biotreatment system, without any storm water runoff leaving the Site for at least the volume of water produced by the Stormwater Quality Design Volume (SWQDv) that results from the greater of:
(i) The volume of runoff produced from a 0.75-inch storm event; or
(ii) The 85th percentile, 24-hour runoff event, as determined from the Los Angeles County 85th percentile precipitation isohyetal map.
For purposes of compliance with the LID requirements, and without changing the priority order of design preferences identified in this section, all runoff from the SWQDv, as identified in Paragraph (a) of this subdivision, that has been treated through an onsite high removal efficiency biofiltration/biotreatment system shall be deemed to have achieved 100% infiltration regardless of the runoff leaving the Site from an onsite high removal efficiency biofiltration/biotreatment system, and thus any runoff volume shall not be subject to the offsite mitigation requirement of this article.
b. Pollutants shall be prevented from leaving the Site for a SWQDv as defined in Paragraph (a) of this subdivision unless it has been treated through an onsite high removal efficiency biofiltration/biotreatment system.
c. Hydromodification impacts shall be minimized to natural drainage systems as defined in the MS4 Permit.
7. When, as determined by the Director, the onsite LID requirements are technically infeasible, partially or fully, as defined in the Development Best Management Handbook, the infeasibility shall be demonstrated in the submitted LID Plan, shall be consistent with other City requirements and shall be reviewed in consultation with the Department of Building and Safety. The technical infeasibility may result from conditions that may include, but are not limited to:
a. Locations where seasonal high groundwater is within ten feet of surface grade;
b. Locations within 100 feet of a groundwater well used for drinking water;
c. Brownfield Development sites or other locations where pollutant mobilization is a documented concern;
d. Locations with potential geotechnical hazards;
e. Locations with impermeable soil type as indicated in applicable soils and geotechnical reports; and
f. Other site or implementation constraints identified in the Development Best Management Practices Handbook.
8. If partial or complete onsite compliance of any type is technically infeasible, the project Site and LID Plan shall be required to manage the flow from the SWQDv onsite in order to maximize onsite compliance. For the remaining runoff that cannot feasibly be managed onsite, the project shall implement offsite mitigation on public and/or private land within the same sub-watershed as defined by the MS4 Permit. This shall include construction and perpetual maintenance of projects that will achieve at least the same level of runoff retention, infiltration and/or use, and water quality. All City Departments will assist the developer, when and where feasible, in the design, permitting and implementation of LID BMP projects within the public right-of-way, with a preference for utilizing the public right-of-way immediately adjacent to the subject development.
9. A Multi-Phased Project may comply with the standards and requirements of this section for all of its phases by: (a) designing a system acceptable to the Bureau of Sanitation to satisfy these standards and requirements for the entire Site during the first phase; and (b) implementing these standards and requirements for each phase of Development or Redevelopment of the Site during the first phase or prior to commencement of construction of a later phase, to the extent necessary to treat the stormwater from such later phase. For purposes of this section, "Multi-Phased Project" shall mean any Development or Redevelopment implemented over more than one phase, and the Site of a Multi-Phased Project shall include any land and water area designed and used to store, treat or manage stormwater runoff in connection with the Development or Redevelopment, including any tracts, lots or parcels of real property, whether Developed or not, associated with, functionally connected to, or under common ownership or control with such Development or Redevelopment.
10. The Director shall prepare, maintain and update, as deemed necessary and appropriate, the Development Best Management Practices Handbook to set LID standards and practices and standards for stormwater pollution mitigation, including urban and stormwater runoff quantity and quality control development principles and technologies for achieving the LID standards. The Development Best Management Practices Handbook shall also include technical feasibility and implementation parameters, alternative compliance for technical infeasibility, as well as other rules, requirements and procedures as the Director deems necessary for implementing the provisions of this section of the Los Angeles Municipal Code. The Board of Public Works shall adopt the Development Best Management Practices Handbook no later than 90 days after the adoption of this ordinance by the City Council and the Mayor.
11. The Director of the Bureau of Sanitation shall develop as deemed necessary and appropriate, in cooperation with other City departments and stakeholders, informational bulletins, training manuals and educational materials to assist in the implementation of the LID requirements.
12. The applicant can appeal the Director's determination of compliance with the provisions of this article to the Board of Public Works within 30 days of the date of the determination.
13. Any Development or Redevelopment that is exempted from LID requirements under Section D has the option to voluntarily opt in and incorporate into the project the LID requirements set forth herein. In such case, the Best Management Practices plan check fee associated with the project shall be waived and all LID related plan check processes shall be expedited.
(D) Exceptions to LID Requirements. The provisions of this Section do not apply to any of the following:
1. A Development or Redevelopment that only creates, adds or replaces less than 500 square feet of impervious area;
2. A Development or Redevelopment involving only emergency construction activity required to immediately protect public health and safety;
3. Infrastructure projects within the public right-of-way;
4. A Development or Redevelopment involving only activity related to gas, water, cable, or electricity services on private property;
5. A Development or Redevelopment involving only re-striping of permitted parking lots;
6. A project involving only exterior movie or television production sets, or facades on an existing developed site.
(E) Other Agencies of the City of Los Angeles. All City of Los Angeles departments, offices, entities and agencies, shall establish administrative procedures necessary to implement the provisions of this Article on their Development and Redevelopment projects and report their activities annually to the Board of Public Works.