ASCE Los Angeles Section

Chino Corona Road, Chino, CA

Mill Creek Wetlands is a unique multi-jurisdictional project that creates, protects, and restores the region’s native ecosystems while enhancing recreational and educational uses as part of a regional watershed management plan. The project will function as a regional natural treatment facility to provide treatment of both wet weather and dry weather flows using natural wetland processes to address sediment, metals, bacteria, and nutrients.
During wet weather, the wetlands have a treatment capacity of 147 acre feet. They are estimated to treat an average of 2,050 acre-feet of wet weather runoff per year, equaling approximately 11% of average annual wet weather runoff in the Cucamonga Creek Channel. During dry weather, the wetlands divert 2.5 to 15 cubic feet per second of dry weather flow, resulting in the treatment of approximately 3,100 acre feet of dry weather flow per year. This figure corresponds to approximately 10% of total dry weather flow volume from Cucamonga Creek Channel. Excellent treatment capacity during wet and dry weather make the project an effective means of leveraging water quality benefits regionally year-round.

Mill Creek Wetlands is an innovative project enacting a regional approach to water quality enhancement by restoring 23 acres of native habitat to the Prado Basin while improving groundwater quality for downstream water users. Water flowing through Prado Basin is the principal source of recharge for the Orange County Groundwater Basin. In turn, groundwater pumped from the Orange County Groundwater Basin is the primary source of drinking water consumed and used in Orange County.
The project provides numerous community and environmental benefits. The project created 2.25 miles of recreational trails which provide future trail connections for the inter­ county trail system as well as the Coast to Crest Trail intended to connect the Santa Ana River Trail from its outfall in Orange County to the mountains i n San Bernardino. The new trail system also connects to the City of Chino Urban Buffer linear park/open space. 
Interpretive signage is located at trailheads and throughout the trail system to provide park users with a better understanding of the history of the area; local wildlife that might be viewed; information on native vegetation, including plant communities. Trails are ADA compliant and open from dawn to dusk at no cost to the public.
Construction materials were handpicked to enhance compatibility with the environment, balancing project goals and objectives with sustainability principles, environmental stewardship, and conservation of natural resources. Hiking trails and parking lots were built with permeable and semi-permeable surfaces.  Native, drought tolerant vegetation was planted to promote wildlife and endangered species habitats while minimizing the need for irrigation. Finally, a solar powered irrigation system was installed to conserve water.
Mill Creek Wetlands requires a minimal amount of human operation and maintenance, and the few human operation and maintenance activities required are carefully scheduled to avoid disrupting endangered species breeding and nesting habits.

The project was spearheaded by the City of Ontario and requiring the coordination and support from other agencies, including the City of Chino, the County of San Bernardino, the Inland Empire Utilities Agencies, the Orange County Water District, and the United States Army Corps of Engineers. The project’s unique regional approach was also supported by the State Water Resources Control Board, the Department of Water Resources, and the California Nat Ural Resources Agency through grant funding.  In addition, it is an integral part of the Santa Ana Watershed Project Authority’s Integrated Regional Water Management Plan. See letters of support in attached document.
The San Bernardino and Riverside Counties Branch awarded the Mill Creek Wetlands project as the Outstanding Public Sector Project of the Year.

See attached document.

Mill Creek Wetlands is a unique multi-jurisdictional project that creates, protects, and restores the region’s native ecosystems while enhancing recreational and educational uses as part of a regional watershed management plan.

Mill Creek Wetlands is a unique multi-jurisdictional project that creates, protects, and restores the region’s native ecosystems while enhancing recreational and educational uses as part of a regional watershed management plan. The project will function as a regional natural treatment facility to provide treatment of both wet weather and dry weather flows using natural wetland processes to address sediment, metals, bacteria, and nutrients. The innovative project enacts a regional approach to water quality enhancement by restoring 23 acres of native habitat to the Prado Basin while improving groundwater quality for downstream water users. The project also provides numerous community and environmental benefits, such as creating 2.25 miles of recreational trails and incorporating drought tolerant vegetation to promote wildlife and endangered species habitats.The project was spearheaded by the City of Ontario and requiring the coordination and support from other agencies, including the City of Chino, the County of San Bernardino, the Inland Empire Utilities Agencies, the Orange County Water District, and the United States Army Corps of Engineers. The project’s unique regional approach was also supported by the State Water Resources Control Board, the Department of Water Resources, and the California Nat Ural Resources Agency through grant funding.  In addition, it is an integral part of the Santa Ana Watershed Project Authority’s Integrated Regional Water Management Plan.