Picture of Zoe Siegel

Zoe Siegel

Sprawl Development on Jersey Island Moves Forward In Contra Costa

Updated on January 15, 2023. Originally published on August 29, 2023.

In December 2023, the Ironhouse Sanitary District voted to extend company Montezuma Water’s Memorandum of Understanding (MOU) Agreement deadline by one year, allowing them to proceed with their plans to develop Jersey Island, a small, largely undeveloped island in the Delta in Contra Costa County, outside of the urban limit line.

Greenbelt Alliance is disappointed by this decision, which puts more valuable open spaces in the Bay Area at risk for unnecessary development at a location that is prone to climate hazards. “It’s important that we move beyond this to seek feasible alternatives. Not only because this is outside of the voter approved urban limit line but because this project does not align with the Delta Plan. The Delta Plan has two goals: to provide a more reliable water supply for California and protect, restore, and enhance the Delta ecosystem,” said resilience manager, Victor Flores, in his public comments at the meeting.

Between October and December 2023, dozens of supporters took action to request the Sanitary District to reconsider their intention of allowing Montezuma Water to proceed with sprawl development on the Island. Public agencies like the Delta Stewardship Council, Delta Protection Commission, and Contra Costa Supervisor Burgis wrote Ironhouse Sanitary District to inform them the project would not be approved under their policies and plans.


In 2021, the Ironhouse Sanitary District Board of Directors passed a resolution approving a development including 450 new single-family shoreline homes along with a hotel, a sports and recreation center, and a wild animal park. As a result, Montezuma Water, the developer, is pursuing the inclusion of Jersey Island into the City of Oakley’s Sphere of Influence (SOI) over the next year.

This proposed development includes 450 new single-family homes along the waterfront of Jersey Island. Placing homes on an island with minimal access to jobs and no transit connectivity will increase vehicle miles traveled (VMT) and associated greenhouse gas emissions (GHGs). Locating homes here will set the County back on both climate mitigation goals and sea level rise adaptation. Simultaneously, without adequate protection from flooding and sea level rise, the long-term safety of residents will be threatened and will likely require costly protection measures from climate hazards in the near future.

The interior and northeast portion of the proposal shows roughly 800 acres of “wildlife and habitat refuge” including “significant visitor opportunities, including Safari tours of the rehabilitation and re-wilding centers and overnight stays with the animals.”

This is just the first step towards annexation of Jersey Island into the City of Oakley—a multi-year process—which would be necessary for the existing proposal to move forward. Ultimately, Oakley residents will have to vote to extend the city’s Urban Limit Line—a boundary that marks the outer limit beyond which urban development will not be allowed—to allow for annexation.

Greenbelt Alliance knows the value of habitat and restoration to restore natural systems and rebuild the Bay Area’s vital coastal ecosystems—but the existing development proposal does not reflect these values. Instead, it would introduce exotic non-native species to the island and further disrupt the essential habitat of existing species through development, increased traffic, and ecosystem disruption from new invasive species.

This is not the climate-smart development that Contra Costa County needs. Proceeding with this development will increase climate-related risks at the detriment of existing natural assets the area’s habitat, carbon sequestration, and associated ecosystem services provider.

Share this post


Related Posts

Scroll to Top