“We forget that the water cycle and the life cycle are one.” — Jacques Cousteau
The natural cycles of our planet have enabled — and orchestrated — all life on Earth since time immemorial.
Each year, the Earth makes a complete orbit around the sun. With this planetary cycle comes the seasons. With the seasons come migrations, flowers, regeneration.
Of all the great cycles, none is more important to life than the water cycle. Fresh water is lifted from the oceans and the land by solar power, carried to new places by the winds. Falling on the land, that water moistens soils, nourishes trees and gathers into rivulets, streams, rivers and freshens estuaries before returning to the sea.
It is stunning to think that, by the middle of the 20th century, we gained the god-like power to fundamentally alter the abundance of water and the pace and direction of its flow. Industrial-strength pumps tap deep aquifers and concrete canals redirect water flows to cities and farms. Huge dams impound once-mighty rivers, turning water flow into water supply.
It is also stunning that it took so many years of manipulating the water cycle before we began to realize that, when we tamper too much with water’s rhythms, we can also seriously disrupt the choreography of nature.
Water’s natural rhythm is set by the seasons, but it is also tuned by the slope of the land and by the soils and the vegetation that cover the land. The seasons dictate how much water falls on the land, and how much will evaporate back into the sky. The amount and chemical quality of the water that eventually finds its way into streams and rivers depends greatly on how much is taken up by plants and crops along the way, and how fast the water moves across or through soils.
Every watershed on our planet is a truly unique expression of topography, vegetation and soil. As a result, the rhythm of water flowing through a watershed is distinctive — each watershed writes its own song in water notes.
And life dances to these water songs. Water rhythms choreograph the wildebeest migrations to the Mara River of Kenya, the return of salmon to the rivers of the Pacific Rim, the timing of the sandhill crane gathering on the Platte River of Nebraska, and the reproduction of plants big and small in wetlands and floodplains around the world.
Water rhythms run deep through human culture as well. High water brings fish and fisherpeople to the Tonle Sap of Cambodia. Receding floods moisten and fertilize the floodplain crops planted by Omo River tribes in Ethiopia. The livelihoods and cultures of at least 2 billion people continue to follow river rhythms closely, but nowhere can any of us escape the dictates of the water cycle on our lives.
My fascination with the rich ecological dramas of rivers drew me into science and graduate school. My deep concern over the severe disruption of river cycles and rhythms — and the life they sustain — brought me to The Nature Conservancy two decades ago.
There is nothing more threatening to our prosperity and happiness than tampering too much with the water cycle. Yes, we all need water, and the scope and scale of human needs is such that we need to manage water with hardware made of concrete and steel in many places. But our water experts in The Nature Conservancy are proving time and again that we can deliver the water and energy that people need while sustaining the diversity of life on our planet. In other words, sustainable development really does work.
The Conservancy is working tirelessly and urgently to both protect and restore the rhythms of water around the world because we know that our economies and the quality and diversity of life on Earth fundamentally depend on sustaining those rhythms. We’re working with farmers, cities, corporations, local communities and governments to help everyone use less water, pollute less and build and operate dams in ways that respect natural water rhythms.
I recently wrote a journal paper proposing that all water ecosystems — rivers, lakes, aquifers — be managed in such a way that their naturally-varying water rhythms and quality are maintained within “sustainability boundaries.” The basic idea is rather simple — we store and divert water to meet human needs, but we do so while preserving the essential natural rhythms of the water cycle. Our analysis suggests that water flows can likely be modified by up to 20% without seriously damaging natural ecosystems, but greater alterations will imperil ecological health. We’re showing water managers and dam operators how to operate within these sustainability boundaries and still deliver needed water and energy supplies.
We can find ways to meet our water needs, now and in the future. But we must do so with respect for nature’s powerful, life-giving cycles.
“What I came to say was/teach the children about the cycles/The life cycles. All other cycles./That’s what it’s all about, and it’s all forgot.” (From Gary Snyder’s poem “For/From Lew.”)
(Image: Wildbeest migration crossing the Mara River, Kenya. Image credit: BrianScott/Flickr through a Creative Commons license.)