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Restoration Vital Signs
Two wetland re-habs got a follow-up check up this July. Both seem on the road to recovery according to scientists conducting preliminary tests of their vital signs, even though each got an entirely different treatment.
Restoration of Pond 2A -- a 550 acre former salt pond near the mouth of the Napa River -- was of the quick and cheap variety -- a few guys, a few well-placed sticks of dynamite and a resulting hole in the dike to let the tides in and prevent looming levee failure elsewhere. Restoration for Sonoma Baylands -- a 300 acre hayfield near the mouth of the Petaluma River -- was of the more high-design, big bucks and heavy equipment variety. Because the site had subsided about six feet, itwas reshaped and raised up -- with the help of two million cubic yards of mud imported from the Oakland harbor bottom and San Pablo Bay -- to create what designer Phil Williams thought a sound template for the natural evolution of wetlands. "These two sites show us the full spectrum of North Bay restoration possibilities and how critical a parameter ground elevation can be," says Williams. "Pond 2A wasn't very subsided so it was easy."
This July, Williams' field hands braved waste-deep muck to measure the depths of the channel serving Sonoma Baylands' 29-acre pilot unit. The levee preventing tides from entering the site was breached in January (a similar breach is planned for the 260-acre main unit this September). Measurements indicate that the channel has deepened and broadened over the past six months (see graph). Other signs of increasing tidal exchange -- which outside observers have been concerned was not occurring -include more blocks falling into the channel from the bank and spreading stands of pickleweed and cordgrass around the inside edge of the site, according to Williams. His research, carried out for the Coastal Conservancy, as well as bird, fish, water quality and elevation surveys overseen by the Army Corps, were released this August in the first annual monitoring report for Sonoma Baylands.
At Pond 2A, the most visible sign of marsh development is vegetation. Botanist Phyllis Faber found vegetative cover had increased from 10% in January 1995 when the levee was breached to 25-30% this July. "We've got a plant war going on over all this virgin territory," says Faber, who found a "striking diversity" of flora on site. Faber & Williams' field hands laid out transects to recheck vegetation later this year, put in "sediment plates" to measure deposits made on the original surface by tides -- these are no high-tech gizmos, just light switch covers nailed to the ground -- and set up markers and equipment for monitoring tidal exchange and slough channel development. Meanwhile, fish sampling shows that many less salt-tolerant species are beginning to use the former Cargill salt pond. According to fisheries consultant Bill Kier, these include striped bass, splittail minnows, inland silversides, anchovies and herring.
Trust monies from the 1988 Shell oil spill are paying to set up the Pond 2A monitoring program, which pond owner Cal Fish & Game will continue after the first year. Sonoma Baylands monitoring is coming out of several pockets -- Army Corps, Coastal Conservancy, and U.S. EPA. But funding for such monitoring is the exception, not the norm, for the dozens of restoration projects in the Estuary, according to Williams. With continuing calls for restoration standards from environmentalists and resource agencies concerned about the conversion of seasonal wetlands to create tidal wetlands, and with the use of dredged material to enhance wetland development, more and better post "restoration" monitoring seems here to stay.
What such monitoring should include, and how it can be set up so that the success of different restoration approaches on different types of sites can be compared, is now the subject of much discussion. Sonoma Baylands is serving as a kind of guinea pig.
The project's still not finalized monitoring plan sets out criteria for measuring the physical success of restoration elements such as the degree of erosion in the tidal channels serving the units, the concentrations of chemical constituents in the surface dredged material, and the tidal range achieved within five years.
"Monitoring should be oriented toward measuring the system's evolution," says Williams. "In a dynamic and evolving wetland, you've got to balance the need for milestones with letting nature do its work."
With so many restoration projects on line, however, U.S. Fish & Wildlife is now calling for site-specific performance criteria. In a July comment letter on the draft LTMS EIS/EIR (see centerfold), for example, the Service stated the need for quantitative success criteria for restoration of endangered species habitat, and for studying the fate of sediment-borne contaminants. "It's time we developed a way to look objectively at the scientific merit of all these restoration projects, " says the Service's Meri Moore. "As regulators, we need something to use as a yardstick."
The first few inches of this yardstick may be found in the ongoing evaluation of Sonoma Baylands and Pond 2A, and in the now evolving monitoring plan for a large Delta restoration using dredged material called Montezuma Wetlands, says Moore.
Contacts: Scott Miner (Sonoma Baylands monitoring report copies) (415)977-8537; Meri Moore (916)979-2116; Phil Williams (415)981-8363
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