By John Rieping | All rights reserved | Previously published August 31, 2012, in The Madera Tribune
The San Joaquin Valley, the southern half of the large flat mountain-bound interior of California, has undergone many changes.
The Pacific Ocean birthed this valley we Maderans call home about 65 million years ago when it began to intermittently flood parts of the region. Eventually sediment from the sea and the rise of coastal mountain ranges choked off the valley from its mother 60 million years later.
Around 2 million years ago, glaciers started to transform the valley from a salty oceanic remnant into a freshwater lake. This was the Pleistocene Epoch, a time of ice ages, woolly mammoths, sabre-toothed cats, giant ground sloths, longhorned bison, birds with 25-foot wingspans, the first humans, and more.
For a glimpse of the former locals, visit the Fossil Discovery Center of Madera County at 19450 Ave. 21 1/2 in Chowchilla.
The last of San Joaquin Valley’s great lakes would be Lake Corcoran, which filled much of the valley about 700,000 years ago. The lake drained into the Monterey Bay via the Salinas River. Then shifts in the earth’s crust lifted the valley and lowered the San Francisco Bay area. This threw part of the lake against the coastal mountains, and the brute force of rushing water, boulders, and other sediment gouged paths to the bay. To this day, those channels remain the deepest parts of the bay.
San Francisco owes us one.
About 12,000 years ago, three major lakes persisted in the valley: Tulare Lake, Buena Vista Lake, and Kern Lake. The ancient trio would slowly starve to death after the Kern River became increasingly redirected for agricultural use from the late 19th century onward. Two small lakes, Lake Webb and Lake Evans, are the only survivors. Both rest on part of the former Buena Vista lakebed.
Before then the lakes supported much life in the valley, which consisted of grasslands and tule grass marshes. The artistic Chumash tribe depended mostly on ocean fishing to live, and yet their villages ranged from Southern California’s coast to the western edge of the San Joaquin Valley. The Miwok tribe, in contrast, dwelled in the nearby foothills of the Sierra Nevada mountains here. The Yowlumne Yokuts occupied the valley and the foothills. All three tribes relied at least partly on fishing.
Then came the Spanish, and local tribes were decimated by the European diseases carried by the newcomers.
The first to visit the San Joaquin Valley, then known as the Valle de los Tulares (Valley of the Tule Grass), would be Lt. Gabriel Moraga of the Spanish Army. In 1808, he left the Mission of San Jose (Saint Joseph) to scout for potential sites for new Christian missions from which to evangelize California natives. During his exploration, he named a small creek San Joaquin (Saint Joachim) after the grandfather of Jesus and father of Mary.
When it was later realized that the creek fed into a larger river, it too received the same name. As the river was the major ocean-going stream in the area, the valley too eventually adopted the name.
In time, the Spanish presence grew into dominion, which passed first to Mexico and then to the United States — and not peacefully.
The Spanish, Portuguese, Italians, and more would settle here and transform the valley into the “the food basket of the world” responsible for most of California’s agricultural exports. A variety of traditionally Mediterranean and Middle Eastern crops can be produced during its year-round growing season, and ranching and dairy are also strong.
Yet the ancient lakes are no more, and 95 percent of the valley’s wetlands perished for the sake of farm irrigation in the 19th and 20th centuries. In many places, the valley is now semi-arid desert.
Meanwhile farmland itself is being swallowed up by water-hungry urban sprawl — with 70,231 acres (28,092 hectares) lost from 1990 to 2004.
A two-year study in Madera County reported earlier this month found some land to be sinking about a foot per year due to overuse of groundwater. Overpumping water from an aquifer layer called Corcoran clay makes the clay unable to withstand the weight of the land above it. It’s compacted, incapable of holding water in the future.
The valley has a history of such subsidence, yet its cities and farms rely heavily on groundwater.
According to Judaism and Christianity, God delegated authority over the natural world to humanity (Bereishit/Genesis 1). We are caretakers of God’s property. Are we good stewards? Can we become better ones?