Manchester Pacific Gateway Project, San Diego California
The Manchester Pacific Gateway project comprises 15.89 acres of waterfront land owned by the Navy, which the Manchester Financial Group is redeveloping into multiple high-rise buildings, including a new Navy headquarters, office, hotel, and retail, as well as park uses as well as extensive subterranean parking/improvements. Manchester selected SCS Engineers to provide environmental consulting services to complete initial site assessments and investigations for construction.
Challenge
The project area covers a large portion of the San Diego Bay waterfront. Reclaimed circa 1914, several wharves transect the property, which was filled primarily with dredged sediments from the bay and other sources of terrestrial fill. Several historic uses of the land left environmental damage to the subsurface layer, such as elevated concentrations of lead and petroleum hydrocarbons. The entire 8-city block site needed to be excavated to 30 feet deep to accommodate subterranean parking and other uses. The excavation required exporting almost 800,000 cubic yards of soil.
Time and budget are always major concerns, but particularly on a property with a past, since there are more risks and more regulatory agencies involved before and during construction.
SCS used their extensive experience interacting with regulatory agencies to resolve issues quickly in the most practical, cost-effective manner to the satisfaction of all parties. In addition to our client, these parties include:
SCS completed extensive additional Phase II investigations and a Soil Management Plan, including the characterization of subsurface soils for export. The next step was to create a Community Health & Safety Plan demonstrating that the protection of public health and safeguarding environmental quality were well planned and fully compliant. The County of San Diego Department of Environmental Health approved both plans.
SCS next classified the soils into waste types for proper excavation and disposal. Soil types included inert or ‘clean’ soil, and several regulated and hazardous waste types. When SCS’s environmental engineers’ screen and certify Tier 1 inert fill soil, obtaining the values in conjunction with the San Diego Regional Water Quality Control Board (SDRWQCB) waste discharge requirements, the soil is perfectly safe to use. By doing so, the client was able to maintain all environmental quality and controls mandated by the SDRWQB and save significant costs and time.
SCS continues overseeing the segregation and the proper disposal of exported soils, some of which are hazardous wastes, which involve oversight from specialized disciplines to maintain complete compliance with health and safety as permitted. The site can have between 150 to 400 trucks entering and departing daily, so SCS increased on-site staff to minimize delays and to optimize safety.
The project is ongoing; a new Navy building is on schedule for completion in 2020, and the remaining areas redeveloped by 2022.
Outcomes and Benefits
To reduce costs for the disposal of approximately 7,000 cubic yards of export material originally classified as Federal Resource, Conservation, and Recovery Act (RCRA) hazardous waste, SCS treated the material onsite using a pugmill and mobile treatment unit to reclassify safely this material as a California hazardous waste. The treatment adds a proprietary admixture to reduce the metals leachability, which has resulted in an estimated disposal net cost savings of greater than $1.1 million.
SCS has conducted additional extensive soil characterization during grading activities to delineate further impacted soils minimizing soil disposal costs even more.
Work schedules are maintained without compromising the safety, work quality, or the environment. SCS’s size and depth of resources are deep.
Our extensive experience, reputation for ethical practices, and positive working relationships with the regulatory agencies that have jurisdiction over the project are valuable with Manchester. The SCS team provided a thorough understanding of, and compliance with, the numerous environmental issues associated with a redevelopment project of this nature and scale.
