Mallard II

Mallard IInear theDumbarton Bridgein 2021
History
Name	Mallard II
Owner	Cargill Salt
In service	1936
Status	In service
Notes	Oldest operating dredge inCalifornia
General characteristics
Class and type	Dredger
Length	80 ft (24 m)
Beam	34 ft (10 m)
Draft	7 ft (2.1 m)

Mallard IImoving mud, with its bucket outstretched

Mallard IIis a wooden-hulledclamshell dredgerused to maintainleveeson theSan Francisco Bay Salt Ponds.Mallard IIwas constructed in 1936,and is "probably the oldest operating dredge in California";she is owned and operated byCargill Salt.

History

Mallard IIwas built in 1936, and has maintained the levees of the salt ponds ever since,except for a brief period duringWorld War IIduring which she was used to retrieveartillery shellsfrom the floor of the Bay nearMare Islandand thePort Chicago Naval Magazine.Over time, she received extensive upgrades (including a modern engine, steelA-frameand boom).The steel frame was installed byBethelehem Pacific's San Francisco shipyard in 1954, at which point she maintained levees on over 30,000 acres (12,000 ha) of ponds in theSouth Bayas well asNapa County.She has been described as a "floating wood-and-metal dinosaur", with a 2 cu yd (1.5 m³) bucket capable of moving as much as 2,000 cu yd (1,500 m³) of mud per day.While dredging, she is anchored by "spikes", and moves from place to place by "grabbing hold of the sea floor".Mallard IIwas used to construct such watercourses asNorth Creek;in 1972 she was briefly idled while the Leslie Salt Company sought dredging permits from theUnited States Army Corps of Engineers.Salt ponds on whichMallard IIis used must be kept at a higher water level than they otherwise would be, owing to herdraft.

In 2002, she was used for theEden Landingwetland restoration project, for which Cargill donated the use of the dredger and 400 man-hours of labor.

As of 2007, she was the only wooden-hulledclamshell dredgeroperating in San Francisco Bay, as well as "probably the oldest operating dredge in California", responsible for maintaining 200 miles (320 km) of levees betweenHayward,Redwood CityandSan Jose.She repairs and maintains approximately ten miles (16 km) of levee per year.Mallard IIcan operate for more than two months without being refueled.As of December 2020, she was still operational.

Levees

The levees surrounding theSan Francisco Bay Salt Pondsdate to the late 1800s, and were mostly constructed toreclaimland for agricultural purposes; the area enclosed by them was later used for salt production.In addition to their role in operating the salt ponds, the levees protectBay Areacities likeSan Josefrom being flooded by high tides.

Due to factors such aserosionandsubsidence,the levees require regular maintenance. Dredging material to increase the levees' height, the "least expensive technique available", consists of movingMallard IIinto a salt pond through a set oflocksand using herclamshell bucketto remove material from aborrow pit;this material is then deposited atop the levee.WhenMallard IIis present in a salt pond, waterfowl hunting is not permitted.

A December 2020 permit for a wetlands project issued by theCalifornia Department of Fish and Wildlifeprovided for maintenance of salt ponds to be carried out by the still-operationalMallard II,using the existing system of dredge locks, referred to as "the most technologically and economically feasible method for solar salt production in south San Francisco Bay".While it would be possible to reduce some of the adverse impacts of levee maintenance (mostly caused by the existence of the dredge lock system) by using a "transportable dredge", it was found that such a dredge would require more frequent refueling (every two weeks, as opposed to every two months withMallard II), as well as the use of large trucks and cranes to reposition it;Mallard II,therefore, was found to be the "most feasible alternative".A 2005 estimate of expenses for levee maintenance in the area put the cost of usingMallard IIat approximately $50,000 per month.