Keeping Our Feet Dry - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 202

but we have found that layers of different kinds of soil with a little bit of vegetation on
top makes a levee much stronger” than the Corps's rock armor.
Hart and Bea don't know each other, but they have arrived at the same conclusion:
the integration of traditional engineering—such as levees and floodwalls—and natural
defenses, such as reeds, will help restore the Delta and provide effective storm defenses.
Since 1977, Hart has been using plants such as tule—a tall marsh plant, with long,
grasslike leaves, pale brown flowers, and strong roots—to revive wetlands, reduce
erosion, and buffer embankments around Delta sloughs. Hart's primary “bioengineer-
ing” tool is the “brush box,” a series of fences made of vertical stakes filled in with hori-
zontal piles of brush that are planted along the sides of channels to break wave action.
Planting tule between the brush boxes and levee walls traps sediment, protects fish, and
further strengthens levees and embankments.
With government and private funding, Hart has established hundreds of yards of
brush boxes in the Delta, which he believes reduce wave energy by 60 to 80 percent;
when tule is added, the wave impact is reduced to nearly zero. The bioengineered ap-
proach, Hart said, is “far more effective and costs about one-hundredth the price in cer-
tain situations,” of the Corps's hard-engineered piles of stone.
The larger message of such initiatives is that it is not enough to simply reengineer our
water infrastructure; we must reengineer the way people think about water and our re-
lationship to it. As the Dutch have shown, the way man interacts with the environment
must change as conditions change. And in the twenty-first century the pace of change is
increasing.
In places such as the flooded Midwest or the suddenly dry Southeast, where people
have had a foretaste of our hydrological future, a vigorous dialogue about man and wa-
ter has sprung up, technical innovation is on the rise, and cooperation over shared re-
sources is being promoted. Yet more people are using more water than ever, in new
ways, and H 2 O is increasingly the focus of conflict. Tension is growing over privatiza-
tion, and among thirsty resources such as agriculture, power, fuel, and minerals. Frus-
trations over the growing demand for water and limited supply is boiling up across the
country, from hot, dense cities in Florida to chilly, remote villages in the Alaskan tun-
dra.