Administrative
Report
N.1., File # 25-0045 Meeting Date: 2/11/2025
To: MAYOR AND CITY COUNCIL
From: ANDREW WINJE, PUBLIC WORKS DIRECTOR
TITLE
DISCUSSION AND POSSIBLE ACTION REGARDING THE CITY’S STORMWATER CAPTURE
POLICIES AND PROJECTS
EXECUTIVE SUMMARY
Stormwater capture is an important element of the City’s stormwater management plan, which seeks to address flood control, urban runoff water quality, and conservation of resources. These objectives are often met through programs and projects with overlapping benefits. The programs generally fall into two broad categories - those that address private property (usually at the development stage) and those implemented by the City through its Capital Improvement Program (CIP). As part of the City’s Strategic Plan, the City Council requested a report on the City’s stormwater capture policies and projects.
BACKGROUND
Stormwater capture is an important strategy for managing flood control, conserving resources, and improving the water quality of our receiving waters. As urban areas expand and climate change increases the frequency and intensity of storms, capturing stormwater where it falls helps reduce the likelihood that storm drains will become overwhelmed, which results in less flooding. Capturing stormwater close to the source reduces the concentration of water pollution in urban runoff, and the volume of runoff, reaching the ocean. Infiltration of stormwater also contributes to drought resilience by storing water in the soil, which can better sustain the native species and natural habitat in the area. Infiltration can also recharge groundwater aquifers used for rural and municipal wells, but this is not a significant factor in Redondo Beach.
Historically, like most jurisdictions, the City has been concerned with flood control and managed it by building infrastructure to remove as much water from streets as possible by routing it via underground pipes to the nearest receiving water. As local rainfall has become an increasingly important resource, and the harmful effects of urban runoff on receiving waters better understood, California developed a network of Regional Water Quality Control Boards that began to set goals and regulations for agencies that operate storm drain systems. In 2021, the Los Angeles Regional Water Quality Control Board adopted the 2021 R4-2021-0105 National Pollutant Discharge Elimination System (NPDES) Permit for discharges from the many municipal storm sewer systems in its jurisdiction, which includes the City of Redondo Beach.
The Permit includes numerous requirements that govern stormwater and urban runoff discharges from the storm drain system. It requires the implementation of Best Management Practices (BMPs) to
N.1., File # 25-0045 Meeting Date: 2/11/2025
from the storm drain system. It requires the implementation of Best Management Practices (BMPs) to reduce pollutants in stormwater and urban runoff that discharge into the ocean and other receiving waterbodies, focusing on preventing pollutants such as trash, nutrients, bacteria, oil, metals, and pesticides from entering waterways. These requirements apply to both public and private property.
While the City is responsible to see both parcel types comply with regulations, implementation of NPDES Permit requirements is handled in different ways.
Watershed Management Plan CIP Projects
The NPDES Permit requires the City to meet stormwater capture volumes for the public drainage system, as specified in the City’s updated Watershed Management Plan (WMP). The WMP outlines strategies, stormwater capture, and infiltration projects that are “reasonably assured” to address water quality concerns within the Permit limits. The Permit encourages a watershed-based approach to address region-specific water quality challenges collaboratively. The City of Redondo Beach, in collaboration with the cities of Hermosa Beach, Manhattan Beach, and Torrance, along with the Los Angeles County Flood Control District formed the Beach Cities Group to develop a WMP to comply with the NPDES Permit requirements. The City Council approved the first WMP on June 16, 2015 and approved the updated WMP on June 8, 2021.
The WMP includes regional projects that are centrally located near the downstream ends of a drainage area, where large volumes of runoff from the upstream tributary area can be addressed.
Due to its length, the 2021 Updated WMP is not attached but is available to download for review at the City’s Public Works Department Engineering Services Division Environmental Programs web page at Beach Cities Enhanced Watershed Management Plan.
The WMP stormwater capture projects located in Redondo Beach, with pending project compliance deadlines, are the Fulton Playfield Infiltration Regional Project, Beach Cities Joint Green Streets Project, Glen Anderson Park Regional Infiltration Project, and a number of distributed infiltration projects. The City is also participating in a regional project at Alondra Park, located in an unincorporated area of Los Angeles County, which is currently under construction. The Fulton Playfield project is undergoing final design. The Anderson Park Project is at the conceptual design stage. The Joint Green Streets Project is being headed up by the City of Torrance and will install local infiltration wells in 11 locations in Redondo Beach, with construction anticipated to begin in Summer/Fall 2025.
Distributed infiltration projects are more local in nature and target the diversion of runoff before it enters the storm drain system. Typical examples of this type of BMP include bioswales, rain gardens, and infiltration wells. Infiltration wells are typically 3 feet in diameter, are installed to approximately 50 feet deep, and rely on a dry well filled with gravel to sequester runoff prior to reaching a storm drain inlet to percolate that water into the ground over time, between storms. The City is fortunate to have sandy soils in many areas, making this an appropriate and promising technology. Staff have successfully installed 19 infiltration wells to date and has plans to install approximately 50 more dry wells through joint projects with other Beach Cities Group agencies and as additions to roadway rehabilitation projects. Infiltration wells process a high volume of water compared to other distributed BMPs, and have a small project footprint. While the technology is not old enough to fully understand lifecycle maintenance requirements, there is an advantage in not having to maintain or irrigate plant material as in other types of BMPs. Because the dry wells have lower cost points than regional projects, they are more likely to be added to street or parking lot projects, making them a relatively low-cost feature that can potentially be added, provided the funding source utilized allows for their
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inclusion.
Staff has been successful in obtaining Safe Clean Water Regional (Measure W) competitive grant project funding for its larger regional projects. However, some projects have a significant funding shortfall, and others are facing design challenges. Staff continues to work through these issues.
Aside from Measure W, there are very few outside funding programs to support the City’s goal to capture more stormwater. The availability of funds is critical for the successful implementation, and compliance, of the WMP. The total estimated capital cost for the Beach Cities Group WMP structural projects as shown in the four-year-old WMP shows a range of $64 - $73 million, with the projects physically located in and paid for by Redondo Beach is estimated from $18 - $21 million over the next 7 years. Unfortunately, significant cost increases on construction labor and materials have resulted in much higher project costs and staff believes Redondo’s future project cost funding deficit is better estimated at $26 million in 2025 dollars. Most of the City’s own funding (General Fund) committed to this infrastructure category goes to meet the immediate needs and deadlines associated with WMP projects. These projects target tributary areas of known impaired water bodies. Although BMPs in the tributary areas in the City where the Regional Board has not set pollution reduction deadlines can be considered, they are not likely to emerge as priority funding needs when compared to other General Fund demands. As such, it may be difficult to introduce expansive, City-funded, stormwater capture projects.
Private Property Stormwater Capture Requirements
One requirement of the NPDES Permit for private parcel property development is the installation of Low Impact Development (LID) construction strategies to manage stormwater at its source, that is, on the parcel being developed. LID strategies are enforced for new development and redevelopment projects on private property, in addition to City owned projects, through the City’s entitlement and permitting process. Stormwater capture and infiltration BMPs, along with the installation of permeable surfaces like pavers and porous concrete, and the use of bioswales, are all effective practices for managing and treating stormwater runoff. However, when it comes to achieving regulatory compliance, BMPs that maximize stormwater capture and infiltration offer the most significant benefits. These BMPs not only reduce runoff volume but also enhance water quality by allowing water to percolate through the soil, naturally filtering pollutants before they reach groundwater or downstream surface water bodies.
To implement the LID requirements, all planning priority projects (defined by the Regional Board and outlined below) are required to retain on-site the Stormwater Quality Design Volume defined as the runoff from the 0.75- inch 24-hour rain event or the 85th percentile 24-hour rain event, as determined from the Los Angeles County 85th percentile precipitation map, whichever is greater. A general rule of thumb is that the first 1 inch of rain must be captured and retained onsite. Staff estimates that the cost for a typical single family residential parcel to incorporate LID requirements is approximately $20,000 - $25,000. Priority Development Projects included in the City’s program are noted below:
· New Developments - Projects greater than 1 acre and adding more than 10,000 square feet of impervious surface. Additionally, industrial parks and commercial sites greater than 10,000 square feet of surface area.
· Redevelopments - Projects creating/replacing more than 5,000 square feet of impervious surface with greater than 10,000 square feet of impervious area and industrial parks or commercial sites greater than 10,000 square feet.
· Special Land Uses - Projects creating/replacing more than 5,000 square feet of impervious
N.1., File # 25-0045 Meeting Date: 2/11/2025
· Special Land Uses - Projects creating/replacing more than 5,000 square feet of impervious surface for restaurants, parking lots, automotive service facilities & gas stations. · Street and Road Construction - Projects greater than 10,000 square feet of impervious surface must follow U.S. EPA’s Green Streets guidance (2008).
· Projects located in the Coastal Zone and not exempt from the requirements to obtain a Coastal Development Permit.
The City of Redondo Beach added the final item on the above list of Priority Development Project types, beyond what the NPDES Permit requires. This addition helps to capture and infiltrate stormwater in the Coastal Zone, which is especially valuable due to its proximity to the ocean. This is not unusual for coastal communities. For instance, the cities of Hermosa Beach and Manhattan Beach have established stricter requirements citywide by lowering the threshold for requiring LID measures.
The Redondo beach Municipal Code also requires all projects requiring approval of a landscaping plan to follow the requirements of the State’s Model Water Efficient Landscaping Ordinance, which emphasizes implementation of stormwater management and rainwater retention regardless of the impairment status of the receiving water body to which the property is tributary.
Potential Expansion of Stormwater Capture
The City could consider expanding its list of Priority Development Project types. For instance, the City’s General Plan, 2024 DRAFT Update includes Policy OS-7.3 which states:
Groundwater Infiltration. Improve natural groundwater recharge by incorporating best management principles (BMPs), such as maximizing permeable surfaces, using native landscaping, and installing stormwater gardens, on new public and private projects and retrofits to incorporate BMPs. Consider expanding the application of the City’s “Low Impact Design” (LID) stormwater management program required in the Coastal Zone to the City’s Non-Coastal/Inland areas.
This would add to the cost of development throughout the City, but costs to the City are minimized as it only expands an existing program, and review costs incurred by the City are recovered through the existing fee structure.
To expand the City’s current stormwater capture projects and policies, the following are additional actions that could be considered:
· Direct more discretionary capital resources to the unfunded stormwater capture projects in the CIP and WMP
· Expand the Council’s 2006 Administrative Policy and Municipal Code to require stricter requirements by lowering the threshold of specific project types that require LID measures · Codify an in-lieu fee option to applicants for funding a larger, regional stormwater capture BMP vs smaller, localized BMPs
· Continue to pursue grant funds
· Direct staff to look into the potential of a Prop 218 type fee to fund future stormwater capture projects
COORDINATION
This report was coordinated by the Public Works and Community Development Departments.
N.1., File # 25-0045 Meeting Date: 2/11/2025
FISCAL IMPACT
There is no fiscal impact associated with this item.
APPROVED BY:
Mike Witzansky, City Manager
ATTACHEMENTS
· Link - Beach Cities Enhanced Watershed Management Plan