Despite the destruction elsewhere of miles and miles of California coastal wetlands that are critical nurseries for many bird, fish and sea mammal species, the Ventura County Naval Base remains a stunning center of regional biodiversity: The Ventura County Naval Base at Point Mugu includes over 2,100 acres of healthy coastal wetlands. (That makes this functioning estuary 50-100 times the size of most lagoons and estuaries elsewhere on the Southern California coast.)
Immediately on entering Laguna Road are acres of open coastal marshlands, a jigsaw puzzle of water and land filled with birds like snowy white egrets and endangered light-footed clapper rails. Parallel to the road is a channel where the water comes in from the sea, providing twice-daily tidal revitalization to the upland marshes. The estuary is formed where the outflow of Calleguas Creek rushes out into the sea. Despite water quality concerns, this freshwater input allows the estuary to thrive, housing wild birds and about 200 resident harbor seals. This habitat feels pristine because the base is only used for certain kinds of tactical training, naval air and radar rather than for ships or ground-troop work, so the channel is closed to boats, even kayaks.
Along Beach Road, the endangered coastal dunes are filled with native plants like saltbush, sand verbena, spiny rush and beach evening primrose. The Navy removed a building and a former dump site where tons of dirt were removed, digging new channels and bringing in marshland plants to create restored wetlands in these areas.
This surprisingly effective balancing job between the military and the environment faces enormous major pressure from increasing climate change.
Beach Road was partly destroyed by storms last winter, and a small adjacent building was partially inundated and is now surrounded by flood walls. Tracking anticipated sea-level rise via the Coastal Resilience tool created by The Nature Conservancy and partners is helping to develop a planned retreat.
Beneath the shoreline is a submarine canyon extending 400 feet down. Divers describe the walls of this canyon as disconcertingly soft; maintaining the flow of incoming sand can protect from storm erosion. Thanks to funding from the Navy and regional partners, the USACE (U. S. Army Corp of Engineers) is dredging the channels at Ventura Harbor and Channel Islands Harbor to maintain their functionality and is committed to sending the sediment down coast to replicate natural sediment migration before there were harbors. Though the sediment load sent each year has been reduced, there is an effort to keep those yields at the natural sediment transport to maintain broad beaches and protect the coastline. The idea of potential dam removal at Rindge Dam and Matilija Dam have the interest of Natural Resources Manager at the Ventura County Naval Base Valerie Vartanian: their entrapped sediment is potential new sand, of benefit to the Navy and coastline communities.
Looking at the waves, big questions arise: what if the narrow road and beach are overtopped or undercut by a storm? What if that submarine canyon collapses? What about the lagoon? What about the Navy site?
“Then we would be a bay,” Vartanian said simply. The lack of worry, the assessment of the worst-case scenario was comforting: The Navy had thought that through and it would be different, but from the point of view of protecting critical military assets, we would be fine. And the habitat?
Vartanian has a plan to slow the impacts of sea-level rise on the base and the associated coastal wetlands. Assessing the complex array of natural and constructed channels that interlace the entire site, she said that, in all cases, as the tide rises, these channels’ water volume rises. As the tide sinks, the channel water volume sinks. In storms, this process radically accelerates and, with increased sea level rise, will be exacerbated. Maintaining the balance of habitat types at VCNB Point Mugu — flat beach, shoreline dunes, low land marsh, high marsh and upland habitat — is her goal. So before the shoreline moves inward, the plan is to dig each of the channels deeper and further inland. She calls it “pre-storation”; the Navy will prepare a space for new lowland and upland marsh and move plants to match the new terrain, providing a relatively seamless transition for the species on site today and preserving infrastructure. The Navy is working closely with adjacent landowners on climate change issues.
Maintaining the balance is a new series that will appear periodically focusing on the “pre-restoration” work of the wetlands and natural habitat at and near Ventura County Naval Base, Point Mugu.