Save the cows!  Bring back the beavers! Dung beetles, all hail! These animals are major agents in preserving Earth’s precious water supply. In her heartening new book, Water in Plain Sight: Hope for a Thirsty World, Judith Schwartz brings us the stories of ecologists all over the world who are employing simple, old-fashioned, low-tech methods to solve the critical problem of keeping our warming planet hydrated.

Schwartz reminds us that offering water to another is “the universal gesture of peace and hospitality.”  Our vital need for it connects us all. But we humans have had the primary impact on the water cycle, an actuality that has led to climate change—which may be, as Senator Bernie Sanders and others have asserted, the single greatest threat facing our planet.

We must preserve water. Happily, we don’t need to produce water magically from nowhere: Earth has roughly the same amount it has always had.  Reclaiming it in water-deprived areas, including places like California as well as more obvious desert regions, is crucial.

Here are a few of the stories Schwartz offers about the wise change-agents who are conducting ingeniously simple and practical water-restoration projects around the world.

When Animals Cooperate, Grasslands Thrive

Down a dirt road in rural Zimbabwe, Schwartz finds Allan Savory, founder of the Africa Centre for Holistic Management. Savory points out that what matters about rain (Zimbabwe has periodic flooding) is not how much, but how effective it is.

Desertification is the loss of the land’s ability to sustain life, plant and animal.  On degraded land (25 percent of all world land) water washes away or evaporates unused.  On the other hand, grasslands (some 40 percent of the world’s landmass) thrive when animal behavior promotes soil fertility.

Random grazing overwhelms the grasses, while planned grazing—moving animals around—promotes mulch and plant residue, providing the right carpet for retention of water and more plant growth.  Bare ground can’t retain water. A previous book by Schwartz, Cows Save the Planet, explored this concept. Watch Allan Savory’s TED Talk.

The Beaver: Keystone Ecosystem Engineer

Beavers work ferociously hard at reconstructing their environment in wondrous formations.  Brock Dolman at the WATER Institute in Sonoma County, California, leads the Bring Back the Beaver Campaign, whose projects are aimed at creating ideal beaver environments.  Dolman says beavers are “keystone ecosystem engineers”; they do much to support water infrastructure—better than technological solutions like pipelines.  They build peaty, productive soil. When the Europeans arrived in this country, there were some 200 million beavers, but they’re down to around 10 million today.  The wetlands they created are mostly gone.  No more beaver coats!

Restoring the Water System . . . with Biology

If you have a thriving garden and grab a handful of the soil, it will fall into small clumps, or “aggregates.” The darker color represents all the carbon present (carbon is the main ingredient of soil organic matter). Ecologist Peter Donovan travels the continent in an old yellow school bus, measuring carbon in the soil.  When the land can’t hold the carbon, it releases carbon dioxide into the atmosphere. This is not earth-friendly.  Holistic, planned growing is just one way to return carbon to the soil.

On the other hand, if you have a nice green lawn, know that lawns are compacted due to the soil beneath and its thwarted root system. 49,000 square miles of U.S. land are in lawns; that’s almost the size of Arkansas.

Clearly, concrete is much worse at retention than lawns are. In New York City, about 80 percent of the land is impenetrable surface.  Water that runs off is a source of pollution. Many cities offer projects to make surfaces more permeable.  In Seattle, we have lots of rain gardens; my neighborhood library won awards for its green roof.  It’s a meadow up there!  All this amounts to restoring the water cycle . . .  with biology.

The mayor of Los Angeles and various agencies plan to transform a concrete water highway, which rushes the water beneath to the sea,  into a linear park . . . a “greenway” with trails and restored habitats.  Andy Lipkis, president of TreePeople in Los Angeles, promotes urban forest. Lipkis declares that we throw away 3.8 billions of gallons of water for every inch of rain that falls.  Some of these statistics are hard to believe, but the author has documented all in extensive notes.