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Background
Located in the City of Arcadia, within the Los Angeles County Fifth Supervisorial District, the Baldwin Lake and Tule Pond Restoration Project is a collaborative effort by the Los Angeles County Flood Control District, the Los Angeles County Department of Parks and Recreation, and the Arboretum Foundation to restore and enhance two prominent features at the Los Angeles County Arboretum and Botanical Gardens: Baldwin Lake (Lake) and Tule Pond (Pond). The project’s objectives are to invest in water quality, provide habitat rehabilitation, increased green space, and implement natural resources and processes.
History
Before the Arboretum was established, it was the site for a Native American settlement. After the arrival of the Spanish to California, Elias Baldwin purchased the land and established Baldwin Ranch in 1875. During the late 1880s, Mr. Baldwin dredged the Lake and deepened it to a depth of 12 to 15 feet. The site and its surrounding area became the Arboretum in 1947, when the State of California and the County of Los Angeles purchased the property. Over the years, the Lake has been featured in numerous movies and television shows. Additionally, the National Register of Historical Places listed the Lake as a support feature for the adjacent Queen Anne Cottage and Coach Barn.
Current Conditions
Today, the Lake is approximately 2.5 to 3 feet deep due to sediment and organic material accumulation. Since the original dredging of the Lake, urban and stormwater runoff draining into the man-made Pond upstream have contributed to soil contamination and deposition. Additionally, uncontrolled runoff during storm events and scouring from abrasive flows have led to erosion of the shore edge. These conditions have contributed to overall degradation, poor water quality, spikes in summer Lake water temperature, lack of water circulation, and overgrown vegetation. The Baldwin Lake and Tule Pond Restoration Project aims to address these issues by implementing flood control measures, restoration and enhancement elements, and water quality improvements.
Location
Los Angeles County Arboretum
301 N Baldwin Ave
Arcadia, CA 91007
For questions regarding the project, contact:
Travis Diaz tdiaz@dpw.lacounmty.gov
(626) 458-7327
Project Scope
In Baldwin Lake, the project proposes to remove sediment up to a depth of 14 feet to increase storage capacity, stabilize water temperatures, and sustain a healthy aquatic ecosystem. The project would also install a liner in the Lake to prevent water loss from seepage and an algae remediation system and aeration system to promote aquatic life and inhibit algae growth. Along the perimeter of the Lake, the project will install landscaping and irrigation system. A viewing deck with educational signage will also be constructed to increase the aesthetic of the Lake and provide educational opportunities.
To restore Tule Pond’s ability to act as an infiltration and pre-settling basin to Baldwin Lake and its capacity to capture and percolate stormwater, the project will re-grade and dredge the Pond up to 12 feet. Furthermore, to minimize pollutants from the watershed entering Tule Pond, the project will install four in-line treatment systems that will divert the 85th percentile storm to a hydrodynamic separator and media filtration system. The hydrodynamic separator will remove sediment, trash, and oils from the flow before entering a media filtration unit. The media filtration unit will then remove any additional sediment, debris, free-floating oil, heavy metals, and phosphorus not captured by the hydrodynamic separator. The project will also install landscaping and an irrigation system along the perimeter of the Pond to enhance its aesthetic.
Above all, the project will provide community benefits of enhanced, recreational green spaces and educational opportunities to visitors of the Arboretum. Each year, the Arboretum yields over 500,000 visitors, with the majority coming from the San Gabriel Valley, East Los Angeles, and the Inland Empire. In 2022, some 242 schools visited the Arboretum, with over 75% of the visiting schools being designated as Title 1 (more than 40% of the student body is classified as low income). The project is funded by the Los Angeles County Flood Control District, the Safe Clean Water Program and the Regional Park and Open Space District Prop A Excess funds allocated via Department of Parks and Recreation.
Environmental Documentation
The Los Angeles County Flood Control District is the Lead Agency and has prepared a Draft Mitigated Negative Declaration (MND) to evaluate any potential impacts to the environment pursuant to the California Environmental Quality Act. The 30-day public review period began on November 1, 2024 and concluded on December 2, 2024. More information about the draft public review period is available on the Notice of Intent linked below.
Click here to access the Draft MND.
Other Environmental Documents:
Timeline
Fall 2027: Construction Completion
Summer 2026: Construction Start
Spring 2025: Design Plan Completion
Winter 2021: Design Concept Completion
FAQs
What is the Safe Clean Water Program?
The Safe Clean Water Program provides local, dedicated funding to increase our local water supply, improve water quality, and protect public health. The Program aims to update LA County’s water system to prevent water loss, modernize the 100-year-old water system infrastructure, and help protect public health with safer, greener, healthier, and more livable spaces for all. Funding up to $285 million per year is generated for the Safe Clean Water Program by a special parcel tax of 2.5 cents of square foot of impermeable surface area on private properties in the LA County Flood Control District. The Program includes strict accountability, requiring all money stay local to protect our clean water and increase our local water supply with annual reports and independent audits required.
What are the benefits of this project?
The benefits of this project include investment in water quality, habitat rehabilitation, and community investment through increased green space and enhanced recreational spaces. Restoration of and enhancements to the Lake and Pond will improve water quality and flood control for the region by treating runoff and intercepting stormflows.
What is meant by the 85th percentile storm?
The 85th percentile storm describes a storm event in which the amount of rainfall it produces will be greater than 85% of other observed storms.
During the summer where will the water for the lake come from?
Deepening both the Lake and the Pond will increase the storage capacity of each. By being able to hold more water, they are less likely to dry out during the summer months. Typically, urban and stormwater runoff will drain into these bodies. If needed during the drier summer months, the Arboretum can purchase potable water from the City of Arcadia’s supply.
During the storms will the lake get too full?
During heavy storm events the lake will not get too full. Water in Baldwin Lake can be discharged into Arcadia Wash. Built by the United States Army Corps of Engineers, the Wash is now owned and maintained by the Los Angeles County Flood Control District.
How will we know if the project has improved the water quality after it is built?
Signs of improved water quality include low turbidity (the water looks clear), lack of odor, healthy aquatic life, and lack of visible algae. Additionally, a post construction monitoring program will be implemented to test the quality of the water.