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The California Delta: Vital, Enigmatic and Ever-Changing

The Sacramento-San Joaquin Delta is a vital water source and difficult to understand. It helps to try out new perspectives.

Written by Isabelle Groc Published on Read time Approx. 3 minutes
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Each year my family takes a week’s vacation in the Sacramento-San Joaquin Delta on our old sailboat. We often follow some Delta veterans who show us new places.

As an engineering professor working on California’s water problems, I research the Delta mainly as a water supply hub and a flood-prone landscape. Sailing the Delta affords me some wonderfully different perspectives. Here are some of them:

The Delta is a big place. Leisurely sailboat cruises from the western to the southern and northern ends of the Delta usually take a few days, with many miles of winding channels. Traversing the Delta flat out is a full day’s sail.

The Delta is a wet place in a dry region. Summer boating in the Delta is a study in contrasts. You’re in a watery place — surrounded by levees, sloughs, marsh, marinas, irrigated farms — and yet the backdrop is vividly waterless, with parched brown hills on the horizon. It’s a reminder that the Delta is an oasis in a mostly arid state.

The Delta is many different places. One of the Delta’s best recreational (and, potentially, ecological) assets is its variety. For example:

  • The north Delta features clearer water and larger wetlands, secluded anchorages (I’m not saying where) and colorful river towns (such as Rio Vista, Walnut Grove and Isleton).
  • Waters on the west are windier, saltier and muddier. (Marinas there struggle more with mud because of mixing sea salt.)
  • The flooded islands of the central and north Delta are very different from one another, from the deep anchorage of Mildred Island (now an atoll), to the fishing grounds of Franks Tract, the many small tracts (such as Rhode Island, Big Break and Little Mandeville Island), and the more native-fish friendly Sherman Lake and Liberty Island.
  • The south Delta has slower-moving waters, with more water hyacinth clogging channels, huge agricultural tracts and destinations near Stockton.

The Delta has great recreation for everyone. Recreationally and socially, the Delta is one of California’s most diverse playgrounds. It’s rich in fishing, boating, summer camping, history and scenic tourism. Given the prevailing summer winds, it is pleasant to sail east into the Delta, but hard to sail west out of the region.

The Delta has a wonderful history of change. Every year the Delta is a little different. In just a generation, the Delta has gained two new “lakes” as a result of levee failures and subsequent land abandonment on Mildred and Liberty islands. River channels are always changing, but many features endure. It is astonishing to see the remnants of deep river channels cut off decades ago.

Delta waterways are littered with failed solutions. A common example is the thousands of dead sticks installed along channels to combat erosion. Intuitively attractive and well-intended solutions sometimes don’t work – but someone did pay for them.

Invasive plants are taking over many places. Floating mats of water hyacinth are widespread in the south Delta and encroach some channels in the central Delta. Boaters can usually steer around the hyacinth. However, Brazilian waterweed, a home aquarium escapee, lurks below the surface in shallower water and can clog engine intakes.

The Delta ecosystem is now dominated by non-native species, but the natives are still there. The spread of invasive plants parallels the spread and dominance of non-native fishes. In most of the Delta more than 90 percent of the fish are non-native — but the fishing is good.

Move a few feet, and you often see a different Delta. From the water, the Delta is a lush recreational paradise. From the top of many levees, the Delta appears dangerously below sea level, thinly protected by narrow earthen levees. From land, much of the Delta looks economically vibrant with rows of crops and fruit trees.

All these viewpoints are so close together, yet so far apart.

Jay Lund, a lifelong sailor, is a professor of civil and environment engineering and director of the Center for Watershed Sciences at U.C. Davis. This article originally appeared on the center’s California WaterBlog.

Top image: An aerial photograph of the Sacramento-San Joaquin Delta, with Franks Tract in the foreground. (Delta Stewardship Council)

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