“The grass will be dead in a week,” my neighbor said when he offered to spray my lawn with herbicides. Alluring though his offer was to save me time and backache to peel back portions of grass and replace with a drought-tolerant landscape, I politely passed. The herbicide does more than kill unwanted plants; it kills the billions of beneficial microorganisms hidden in the soil, diminishing the soil’s natural capacity to keep water.
Soil alive with microorganisms, also referred to as soil with organic material, retains up to 10,000 times more water than soil without. When we treat our landscapes with chemicals to kill weeds, we’ve done little to discourage evaporation and runoff.
Nationwide, home gardeners apply 64 million pounds of pesticides on their yards, or 8 percent of all pesticides used annually. According to the U.S. Environmental Protection Agency, commercial and industry uses an additional 107 million pounds, or 12 percent. Agriculture uses the remaining 80 percent of pesticide, or 684 million pounds. And not represented in these statistics are chemical fertilizers, also found to diminish the water-holding capacity of the soil.
From California to Tennessee, electric road signs and billboards read, “Save Water, Severe Drought.” But this definition is narrow, focused on water reduction measures like low-flow showers and toilets, efficient appliances and turf removal. While these measures are important, speaking as someone who sold 80,000 shower timers, this limited definition fails to recognize the more pressing need to keep more water.
Let’s examine rainfall totals during California’s 10-day storm last December. Ten trillion gallons of water were dumped on the state, nearly the amount of water NASA scientists estimate California needs (11 trillion gallons) in reservoir storage to end the drought. The storm did little to replenish low water storage. Runoff and evaporation snatched two-thirds of the rainfall.
My neighbor’s yard is pavement, and he plans to swap out his front lawn with artificial turf. His concrete and soon to arrive plastic grass saves water as urged by water agencies, but these water saving strategies fail to keep water. These measures prevent rainfall from infiltrating through several layers of earth, thus impeding replenishment of groundwater supplies. A paper published in Enviro Health Perspectives Journal found that a 20-30 percent drop of infiltration impacts surface streams, rivers and lakes fed by groundwater supplies. A quarter of a million U.S. acres is paved or repaved every year, according to Bruce Ferguson, director of the University of Georgia School of Environmental Design and author of the book “Porous Pavements.”
The City of Chicago began repaving its 1,900 miles of alleys with pervious pavers, or permeable asphalt, under the Green Alleys program a decade ago. These green alleys absorb up to 80 percent of rainwater, decrease persistent flooding of alleyways, reduce storm water in sewers and recharge groundwater. The program now includes 3,775 miles of streets.
Capturing more rainfall will do more to buffer against future droughts than any urban initiatives focused on consumption. But few public roads, highways and parking lots around the nation are paved with permeable asphalts and concrete. Is it because kept water is not easily quantified?
Collectively, we have transformed our urban landscapes and farmland into quasi-pavement and paved over the rest. Until we “act differently,” as urged by California Gov. Jerry Brown when he announced the new water mandate, California along with many parts of the nation will continue to lose two-thirds of rainwater and moisture, when it has none to spare.
Florencia Ramirez is a graduate of the University of Chicago Harris School of Public Policy. Her forthcoming book, “Eat Less Water,” was awarded the Gift of Freedom, Creative Non-fiction Prize by A Room of Her Own Foundation. She wrote this for this newspaper.
