Draining the Swamp: How Land Reclamation Hurts California’s Environment for People and Other Life Forms

One of the most famous, though possibly apocryphal, quotes to come out of the Vietnam War appeared in a Feb. 7, 1968, Associated Press report. It quoted an unnamed “United States Major” explaining why U.S. forces leveled the Vietnamese town of Ben Tre—in one succinct, memorable turn of phrase: “It became necessary to destroy the town to save it,” the major reportedly commented.

The quote lives on because, real or not, it seemed to perfectly encapsulate the absurdity of military logic.

Wetlands teem with life, home to 40 percent of the world’s species—thousands of plants and animals. As wetlands have disappeared, at least a quarter of those species face extinction. 

But the quote didn’t apply only to the military. In fact, it could easily be applied to the large-scale public improvement project that built much of what California is today—via a process known as “land reclamation.” The reclamation projects of the late 19th and early 20th century turned the so-called swamps of California’s Central Valley into some of the country’s most fertile agricultural land—but in the process, destroyed or damaged 90 percent of the wetlands that were the natural habitat for hundreds of species of birds, mammals, reptiles and many other kinds of life.

Reclamation isn’t only unhealthy for animals. Reclamation projects release greenhouse gases, contributing to global warming, while wetlands are natural carbon “sinks,” meaning they store carbon dioxide, preventing it from rising into the atmosphere. As wetlands disappear, CO2 has nowhere to go but up.

Did land reclamation save California by destroying it? What is the damage caused by turning wetlands into farmlands?

What Are Wetlands, Anyway?

Wetlands, according to the U.S. Environmental Protection Agency, are any areas where water sits on top of the soil for all or part of the year. Wetlands come in an assortment of types, but swamps, bogs and marshes are generally considered by scientists to be the most prevalent varieties. 

A swamp is a wetland where the water saturates the land permanently. Swamps are generally populated heavily by trees. Swamps are generally found in warmer climates, while bogs occur in colder regions.

Bogs form in a “kettle lake,” which is a depression in the ground caused by a glacier. As the pit fills with more and more growth, a sludgy substance known as peat forms along the bottom of the lake or pond. This stuff can be burned as fuel, but the substance may be best known for an incidental function that’s not necessarily essential to the ecosystem but may be its most fascinating feature of all—its ability to preserve dead bodies.

More than 1,000 bodies, ranging in age from about 2,000 to 4,000 years old (though a few are believed to be as old as 11,000 years), have been uncovered from nearly 300 bogs across Northern Europe, giving scientists extraordinary insight into what life—and death—was like for human beings alive in ancient times.

Not only do wetlands feed the human race, they also help to keep us safe. 

Finally, marshes are areas where, like swamps, water covers the ground for lengthy portions of the year. But unlike swamps, which are dominated by trees, marshes are characterized by thick growth of herbaceous plants—that is, plants with green stems, not woody roots. Another difference is that while trees can live for hundreds of years, herbaceous plants die and grow back on a yearly (or multi-year) cycle.

Each of those three categories has its own sub-categories—freshwater and saltwater for example. But generally speaking, most wetlands are swamps, bogs or marshes.

Why Do We Need Swamps, Bogs and Marshes?

Wetlands may, at first glance seem like a nuisance—just swathes of soggy, insect-ridden, useless land that may not even be all that pretty to look at. The California settlers of the Gold Rush era almost 175 years ago certainly thought so. Landowners and the early state government undertook a massive, multi-decade project of land reclamation, to replace the wetlands with dry land that could be farmed.

Farming and the food it produces is indeed a necessity. But so are wetlands. And that contradiction is the central problem with reclamation. Wetlands teem with life, home to 40 percent of the world’s species—thousands of plants and animals. As wetlands have disappeared, at least a quarter of those species face extinction.

When wetlands are destroyed through land reclamation or other types of “improvements,” they become major sources of greenhouse gas emissions.

Why should we, as human beings, care about a bunch of obscure plants and small animal types most of us have never heard of? Because, like plants and animals, we live in an ecosystem—a vast, interconnected community of living organisms and non-living entities (e.g. air, soil , sunlight) that makes up the fundamental unit of life on Earth. Our planet-wide ecosystem is made of millions of smaller ecosystems that must function properly, and in concert with each other, to maintain the overall health of the world and everyone in it.

Wetlands are some of the world’s most important and productive ecosystems, according to the EPA, ranking up there with coral reefs and rainforests. They generate vast volumes of food, allowing insects, vegetation, small fish and other organisms to thrive and become food for larger organisms—a cycle that runs up the food chain.

Wetlands provide direct benefits for humans as well as the overall benefit of letting the world continue to support life. Fish, shellfish, berries, rice and other human food sources all depend on healthy wetlands to exist. But not only do wetlands feed the human race, they also help to keep us safe.

Because, like giant natural sponges, they absorb and store large quantities of water, wetlands are essential for flood control, and in preventing agricultural crops from becoming waterlogged. A 2017 study at U.C. Santa Cruz, in collaboration with scientists from other institutions, found that wetlands in the northeast prevented $625 million in flood damage from 2012’s Hurricane Sandy, and that salt marshes reduce flood losses overall by 16 percent annually, on average.

Maintaining healthy wetlands also saves money by reducing the need for costly levee construction and dredging for the purposes of flood control.

Wetlands and Climate Change

Wetlands absorb more of the most prevalent greenhouse gas, carbon, than they release into the atmosphere, making them a crucial weapon in the battle against climate change. Worldwide, wetlands store about 700 billion tons of carbon, with another 96 million added every year. In California, all large facilities—such as power plants, oil refineries and so on—emitted about 94 million tons of carbon dioxide in the year 2021.

United States wetlands alone store 11.52 billion tons of carbon, and in the Western U.S., wetlands hold 200 million tons per hectare (about 10,000 square meters). According to the Global Center on Adaptation, wetlands store more carbon than any other type of ecosystem on Earth. Peatlands—that is, bogs as well as other types of wetlands known as fens and mires—hold twice as much carbon as all of the forests in the world combined.

Wetlands cover only 9 percent of the planet’s surface, but they hold 35 percent of the carbon. The darker side of this incredible benefit, however, is that when wetlands are destroyed through land reclamation or other types of “improvements,” they become major sources of greenhouse gas emissions. The amount of carbon dioxide from draining and burning peatlands is equal to about 10 percent of the world’s fossil fuel emissions on an annual basis.

How Land Reclamation Damages California

The Gold Rush era frenzy for “reclaiming” what were then simply characterized as “swamp” eventually eliminated approximately 90 percent of what was once 4 million acres of historical wetlands. In the Sacramento-San Joaquin Delta region, the reclamation of wetlands into farming islands led to the oxidation of once peat-filled soil.

Farming also caused the land to sink, resulting in many of those islands dropping to between 10 and 25 feet below sea level. As a result, flooding in the area has become more likely, and creates danger that levees can more easily break.

The loss of wetlands has also put dozens of species in danger of extinction. And while some species are disappearing, new species that don’t belong in the formerly swampy ecosystems invade the area. Non-native species cause food shortages by competing for limited resources, changing the character of the habitat and wiping out once thriving species of life.