Biology Reference
In-Depth Information
INVASIVES MANAGEMENT
Wildlife managers used to tear out the eucalyptus tree windbreaks planted by
early ranchers in an effort to restore native species. These days the bay itself is
toppling them along the North Bay rim and tidal sloughs. The only thing hu-
mans have to do is allow the salt water to reach their root zones.
habitats, from mudflat and outboard marsh all the way up to seasonal
ponds and upland buffer zones.
“We're taking areas diked off by man and converted to agricultural use,
and then to military use, and restoring them back to what nature had here
originally,” explains Eric Polson, consulting civil engineer on the Hamilton
project. “It's going full circle, a 360-degree turnaround.”
Most sites in the midst of restoration look lunar, and Hamilton is no
exception. For a long time there were just miles of bare dirt, crisscrossed by
levees, and dotted with the bent elbows of backhoes. On a visit during the
construction period, the levees and ponds trembled with the passage of
yellow trucks with snouts, called “haulers,” as well as the rumblings of half
a dozen mudcats. These special bulldozers have a wider track than most,
enabling them to operate in mud and fluid environments without slipping.
Before the military could hand over its airfield for restoration, the
Army Corps had to do a fair amount of cleanup. Luckily, Hamilton served
as an operations center—rather than a weapons or aircraft or shipbuilding
factory—and there wasn't too much contamination.
The lowest hanging fruit for cleanup were the landfill and the shooting
range. Like many of the bay's landfills, Hamilton's mound of washing ma-
chines, car tires, tree trunks, and old fuel drums was capped, greened, and
plumbed with vents to off-gas methane. Just as in other hunting areas
around the bay, lead shot and bullets had to be scraped off the ground on
the shooting range. In the end, workers removed 5,000 cubic yards of soil
from the range, which was filled mostly with the spent firepower of the
Thompson or “Tommie” machine gun.
These were small cleanups compared to the work that had to be done
on the marsh plain outside the outboard levee, where the base's sewage
and storm-water outfalls once discharged to the bay, and where the mili-
tary also had a burn pit and debris pile. Here, the corps scraped down five
acres and moved 30,000 cubic yards of soil and sludge.
Army Corps environmental manager Ed Keller says the most serious
contamination at Hamilton came from leaking fuel tanks, both those used
for household heating oil and those employed for aviation gas and jet fuel.
In the airfield's heyday, jet fuel supply tankers hooked up to a pipeline that
