"In contrast to the dams of the bulldozer were the thousands of tiny inch-high dams that spontaneously formed during each storm. These dams, made of dead grass blades and other things that float, contoured the slopes perfectly and held back shallow pools of water. Line after line of these dams and ponds often terraced a slope, making it look like a series of miniature rice paddies." Photo of "Gaia dam" forming by a sprinkler on a lawn.

"If there was a low spot on the dam, the water overflowed there. The floating debris adhered there and built up that low section. The moment that low spot was raised level with the rest of the dam, no more water flowed that way so there was no more buildup. That is why these "accidental" dams were so remarkably level.

"If the water flowed around the end of the dam, the floating material drifted to that end, adhered there, and lengthened the dam along the contour of the slope. The dam rose and extended itself uniformly until the water oozed throughout the dam.

"These Gaia dams" (the name my wife gave them) transform a narrow rivulet into a spread-out ooze. A series break the momentum of the runoff. Water detained by the dams soaks into the ground rather than running off to converge in the main channels."

"After the storm the runoff subsides. The dams deflate and dry into easily overlooked strands of dried plant material contouring the slopes. These dams form everywhere--on grasslands, in forests, even in neighborhood street gutters (though the street sweepers keep swishing them away). They remind me that creating many small changes is more sustainable than trying to impose a few, large changes."

Back to Photographic Supplement