Adapted from Sketches Magazine article “Update: ReWild Mission Bay,” by LaTresa Pearson
Mission Bay was once a thriving ecosystem filled with healthy salt marshes and a diverse range of flora and fauna. While development in recent decades has provided economic growth for the region, the natural ecosystems and the services they provide are under threat.
Key Takeaways: How Development in Rose Creek Threatens San Diego’s Natural Resources
- Development in Mission Bay has blocked the natural flow of Rose Creek to coastal wetlands, decreasing the ecosystem services these native habitats provide to us.
- As climate change causes sea levels to rise and flooding to threaten urban areas around San Diego, coastal wetlands are unable to provide support and mitigation due to development.
- ReWild is developing a plan to get San Diego’s wetlands back on track.
Development in Mission Bay
During the post-World War II years between 1945 and 1962, city leaders in San Diego decided tourism would be the best way to ensure the continued growth and prosperity of the region. As a result, they developed a plan to transform the coastal wetland area into the largest aquatic playground in the United States, thus creating Mission Bay Park. During development, crews dredged 25 million cubic yards of sand and silt to create the landforms of Mission Bay Park, which is now almost entirely human-constructed.
Campland, a popular campground of De Anza Point, sits on the water beside Rose Creek and overlooks Mission Bay. Rose Creek’s waters would naturally flow into the marsh, but instead, the creek is blocked by the campground, which sits on land that was artificially created during the Mission Bay development.
In an article published in The Journal of San Diego History in 2002, Ed Gabrielson, City Engineer during much of the creation of Mission Bay Park in the late 1950s and early 1960s, describes the process of creating De Anza Point and converting it into land suitable to build the now defunct De Anza Mobile Home Park:
“The original material that had been pumped onto De Anza Point was a mucky silt, which would not hold up equipment of any type,” he writes. “Although this material set for approximately three years, it never gave up its water content, and nothing could be built on it.” They ended up pumping a three-foot layer of “good sand” on top of the silt to make the ground suitable for building the mobile home park’s infrastructure.”
Impacts of Mission Bay Development on Natural Habitats
Unfortunately for the Kendall-Frost Marsh, the development that made San Diego a hub of tourism and economic growth is also what’s putting it at risk of environmental degradation. The “mucky silt” that was dredged and covered is exactly what makes coastal wetlands so good at storing carbon.
Vegetation communities have also been significantly impacted by development at Mission Bay. Although cordgrass and other tidal marsh plants live in saltwater, they need the nutrients and sediment that freshwater brings when it enters the marsh from rivers and creeks. “Kendall-Frost Marsh historically was the recipient of fresh water and sediment flow from Rose Creek, which in the 20th Century was channelized and caused to be shunted out to deeper water in Mission Bay,” explains Matthew T. Costa, a postdoctoral scholar in the Center for Climate Change and Adaptation at UCSD’s Scripps Institution of Oceanography. “That causes the fresh water and sediments in that water to immediately go into the bay rather than what would have naturally happened, which is that it would pass through the marsh.” The flow of fresh water and sediments from the watershed into the marsh is critical to the health and productivity of the entire coastal ecosystem, he explains.
These plants also build up sediment, which creates a buffer between rising waters and urban development, preventing flooding in coastal communities caused by storm surges and sea-level rise. Without a steady supply of fresh water from Rose Creek, the plant communities struggle to get the nutrients they need to sustain the ecosystem services provided by the wetlands, putting San Diego at increased risk of flooding and erosion as sea levels rise and coastal storms surge.
ReWild’s Vision for the Future
Fortunately, San Diego Audubon has been leading a collaborative effort to lay the foundation for coastal wetland restoration in the northeast corner of Mission Bay for more than a decade.
Adapting to Climate Change
“Probably the number one most important area that we can work on to help our wetlands sequester (store) carbon more effectively and be more resilient to sea level rise is to reconnect the wetlands to the watershed. In this case, rerouting Rose Creek in such a way that it spreads out across the marsh rather than going through a channel that’s been lined with riprap (loose stones) or other barriers,” says Costa, who has been researching and measuring carbon sequestration at the Kendall-Frost Marsh as part of Reconnecting to the Kendall-Frost Marsh, a collaborative project between San Diego Audubon, Scripps Institution of Oceanography, UC Natural Reserve System, Native Like Water, and Renascence, with funding from the Honda Marine Sciences Foundation.
Wild, Wilder, and Wildest
In addition to reconnecting Rose Creek, ReWild has developed comprehensive plans for restoring Mission Bay. Created through a multi-year, intensive, and science-based collaborative process, the ReWild Mission Bay Feasibility Study identifies three feasible wetland restoration alternatives for the northeast corner of Mission Bay, dubbed “Wild, Wilder, and Wildest”. Of the three plans from the study, the ReWild Mission Bay Coalition, led by San Diego Audubon and including more than 60 community organizations, advocates for the Wildest alternative because it optimizes water quality, sea level rise adaptation, and the ability for wetland habitats to persist over time.
The Wildest plan would provide 227 acres of new coastal wetland habitat, and the design would ensure that 75 acres of wetland would continue to exist by 2100, with a projected sea level rise of 5.5 feet. In addition, 4,800 feet of new interpretive trails would wind through the area, providing public access and educational opportunities. An estuarine science center and a visitor center would educate visitors about this coastal ecosystem, and there would be space for the Kumeyaay people to connect to lands in which they once lived and prospered before being forced inland to their current tribal lands.
Restoration planning is currently still underway. In January 2022, San Diego unveiled another wetland plan for the northeast corner of Mission Bay. Known as De Anza Natural, the plan hopes to strike a balance between land uses while still providing expanded wetland area and preparing for climate change resilience.
Read the whole article in our Sketches Summer 2022 issue.
Photos courtesy of Karen Straus and others.