Water is the foundation of life, and rivers are the arteries of our landscapes. But across the United States, these vital waterways face unprecedented threats from climate change, over-extraction, pollution, and habitat destruction. Once-mighty rivers that sustained ecosystems, communities, and economies for centuries are now shrinking, drying up, or becoming intermittent in flow. This environmental crisis unfolds gradually, making it easy to overlook until these precious resources are critically endangered. The following 13 American rivers represent some of the most alarming cases of waterways that are literally disappearing before our eyes, transforming the natural and human landscapes they once nurtured.
The Colorado River America’s Most Endangered River
The Colorado River, which carves the Grand Canyon and supplies water to 40 million people across seven states, is facing a catastrophic decline. After more than two decades of megadrought conditions, its major reservoirs—Lakes Mead and Powell—have dropped to historic lows, hovering around 30% of capacity. The river no longer reaches its natural outlet at the Gulf of California, drying up miles before the sea. Scientists estimate the Colorado River’s flow has diminished by approximately 20% over the past century, with projections suggesting an additional 9-31% reduction by 2050 due to climate change. The combination of reduced snowpack in the Rocky Mountains, increased evaporation due to higher temperatures, and ongoing overallocation of water rights has created what water managers describe as a “structural deficit,” where more water is promised to users than exists in the system.
The Rio Grande Running Dry in the Southwest
The Rio Grande, known as Río Bravo in Mexico, serves as both a natural border and a lifeline for communities in New Mexico, Texas, and Mexico. However, in recent years, lengthy stretches of this historic river have completely dried up during summer months. In 2022, the river dried nearly 50 miles north of Albuquerque—earlier and further north than ever recorded. Agricultural demands, urban development, and declining snowpack have all contributed to the river’s decline. Climate models suggest the Rio Grande basin could lose up to 50% of its current flow by the end of this century if current warming trends continue. The river’s disappearance isn’t just a water supply issue—it represents the collapse of riparian ecosystems that support hundreds of species, including the endangered southwestern willow flycatcher and Rio Grande silvery minnow, which now survives in less than 10% of its historical range.
The Sacramento-San Joaquin River System California’s Water Crisis
California’s Sacramento-San Joaquin river system and its delta form the hub of the state’s water infrastructure, supplying irrigation for the agricultural powerhouse of the Central Valley and drinking water for 25 million Californians. However, this vital waterway system is under severe stress. Excessive water diversions have reduced flows significantly, with some tributaries losing more than 70% of their historical discharge. During recent drought years, emergency water releases from reservoirs were required just to prevent complete ecosystem collapse in parts of the system. The reduced flows have contributed to saltwater intrusion into the Sacramento-San Joaquin Delta, threatening both freshwater habitats and drinking water quality. The California Department of Water Resources estimates that climate change will further reduce Sierra Nevada snowpack—the source of much of the rivers’ water—by 48-65% by the end of the century, potentially transforming these once-reliable rivers into seasonal waterways that run dry during summer months.
The Gila River A Southwestern Lifeline Disappearing
The Gila River, the last major free-flowing river in New Mexico, faces an uncertain future. This 649-mile-long waterway historically flowed year-round through New Mexico and Arizona before joining the Colorado River. Today, however, large sections run dry for months at a time due to diversions, groundwater pumping, and extended drought. Since 2000, the upper Gila’s average flow has decreased by approximately 15%, while some measurements suggest as much as a 30% reduction in overall volume since the mid-20th century. The river supports one of the highest concentrations of breeding birds in North America and provides critical habitat for endangered species like the southwestern willow flycatcher and the Gila trout. Development pressures continue to mount, with proposed dams and diversion projects that could further fragment and diminish this already threatened river. Climate projections predict the Gila basin could warm by 5-7°F by 2100, potentially reducing streamflow by an additional 35%.
The San Pedro River An Endangered Desert Oasis
The San Pedro River in southeastern Arizona represents one of the last undammed rivers in the Southwest and forms a crucial migratory corridor for millions of birds. This riparian oasis supports over 400 bird species and has been designated as a Globally Important Bird Area. However, groundwater pumping to support growing communities and agriculture has caused the water table to drop dramatically, turning what was once a perennial river into a mostly intermittent stream. According to U.S. Geological Survey monitoring, the number of days with zero flow at key measuring stations has increased by over 300% in the past two decades. A 2019 study found that nearly 50 miles of the river that historically flowed year-round now run dry during parts of the year. Climate change projections suggest that by 2100, the San Pedro could lose up to 77% of its remaining flow if current warming trends continue, effectively eliminating one of North America’s most important desert river ecosystems.
The Klamath River Declining Flows and Endangered Salmon
The Klamath River, flowing from southern Oregon into northern California, has been the center of one of the nation’s most contentious water conflicts. Once home to the third-largest salmon runs on the West Coast, the river has seen its flows reduced by up to 50% in some years due to agricultural diversions, hydroelectric dams, and drought. This reduction has devastated native fish populations, including Chinook salmon, coho salmon, and steelhead trout. In 2002, low water levels and warm temperatures contributed to a fish kill that left over 33,000 adult salmon dead, one of the largest salmon die-offs in U.S. history. Recent monitoring shows water temperatures in summer now routinely exceed lethal thresholds for salmon in many river sections. While dam removal projects currently underway offer some hope, climate change threatens to undermine restoration efforts. The U.S. Fish and Wildlife Service projects that by 2050, suitable salmon habitat in the Klamath basin could shrink by 30-70%, potentially leading to the local extinction of several salmon runs that have cultural and spiritual significance to local Native American tribes who have depended on these fish for thousands of years.
The Santa Cruz River Arizona’s Vanishing Heritage
The Santa Cruz River, which once flowed year-round through southern Arizona and northern Mexico, now exists primarily as a dry riverbed that flows only after significant rainfall events. Groundwater pumping beginning in the early 20th century gradually lowered the water table by more than 200 feet in some areas, causing the once-perennial stream to disappear. Historical accounts describe the Santa Cruz Valley as a lush riparian area with cottonwood-willow forests stretching for miles—a stark contrast to today’s dry channel. Some sections of the river now flow only thanks to treated wastewater releases, creating what ecologists call “effluent-dependent” streams. The disappearance of natural flow has eliminated 95% of the river’s original riparian habitat, threatening species like the endangered Gila topminnow and southwestern willow flycatcher. Restoration efforts have reestablished small sections of flow in Tucson, but these fragile gains face threats from ongoing development and climate change, which is expected to reduce regional precipitation by 15-25% by mid-century.
The Missouri River The Mighty River’s Declining Flow
The Missouri River, the longest river in North America, has seen dramatic alterations that have fundamentally changed its character and flow patterns. Six major dams built between 1940 and 1964 have transformed nearly a third of the river into a series of reservoirs, while channelization has shortened the river by approximately 200 miles. These human modifications, combined with climate change impacts on Rocky Mountain snowpack, have significantly reduced the river’s natural flow. Recent drought years have seen reservoir levels drop to historic lows, exposing archaeological sites and ghost towns normally hidden underwater. The U.S. Army Corps of Engineers reports that average flows in the Missouri River basin have declined approximately 7% since the 1960s, with models predicting an additional 10-20% reduction by 2060. These changes threaten not only water supplies for communities and agriculture but also endangered species like the pallid sturgeon, which has declined by 95% due to habitat loss and altered river dynamics.
The Verde River Arizona’s Last Perennial River Under Threat
The Verde River in central Arizona represents one of the state’s last continuously flowing rivers and provides critical habitat for over 90% of the wildlife species in the area. However, groundwater pumping in the upper watershed has already caused segments of the river to dry up seasonally. According to the U.S. Geological Survey, base flows in the Verde have declined by approximately 10 cubic feet per second per decade since the 1990s. Population growth in communities like Prescott, Cottonwood, and Camp Verde threatens to accelerate this trend through increased groundwater extraction. Studies by The Nature Conservancy indicate that without intervention, up to 30 miles of the Verde could cease flowing year-round by 2050. The river’s disappearance would devastate one of the Southwest’s most important riparian corridors, which supports endangered species like the southwestern willow flycatcher, yellow-billed cuckoo, and razorback sucker. Flow reductions also threaten the river-based recreation economy, which contributes approximately $54 million annually to local communities.
The Apalachicola River Victim of the Tri-State Water Wars
The Apalachicola River in Florida represents the downstream casualty of the decades-long “tri-state water war” between Georgia, Alabama, and Florida. Fed by the Chattahoochee and Flint rivers, which flow through Georgia, the Apalachicola has seen its discharge reduced by approximately 20% since the 1970s due to upstream water withdrawals, primarily to support metropolitan Atlanta’s growing water demands and Georgia’s agricultural irrigation. This reduction has devastated Apalachicola Bay’s once-thriving oyster industry, which collapsed in 2012 after years of insufficient freshwater flows. The bay, which once produced 90% of Florida’s oysters and 10% of the nation’s supply, is now closed to harvesting until at least 2025 in hopes of population recovery. The reduced river flow has also impacted endangered species like the Gulf sturgeon and fat threeridge mussel. Despite a Supreme Court ruling in Georgia’s favor in 2021, the fundamental ecological crisis continues, with climate change expected to further reduce flows by an additional 15-30% by 2060, according to the U.S. Army Corps of Engineers’ modeling.
The Virgin River Desert Lifeline Running Dry
The Virgin River, which flows through Utah, Arizona, and Nevada before joining the Colorado River at Lake Mead, has experienced dramatic declines in recent decades. This desert river system, which carved the iconic landscapes of Zion National Park, now sees approximately 30% less flow than it did in the mid-20th century. Population growth in communities like St. George, Utah—one of America’s fastest-growing metropolitan areas—has increased water demand, while climate change has reduced mountain snowpack that feeds the river. During recent drought years, sections of the Virgin that historically flowed year-round have run completely dry for months at a time. The river’s diminishment threatens the endangered southwestern willow flycatcher and Virgin River chub, which exist nowhere else on Earth. U.S. Geological Survey data indicates that natural springs feeding the Virgin River have declined in output by 30-50% since the 1950s due to groundwater depletion, suggesting the river’s troubles stem from both surface and subsurface water loss. Climate projections indicate the Virgin River basin could see an additional 20-35% flow reduction by 2070.
The Dolores River A “Wild and Scenic” River No More
The Dolores River in southwestern Colorado, once considered for “Wild and Scenic River” protection, now frequently runs dry below McPhee Dam, which was completed in 1984. Historical records indicate the river flowed at an average of 800 cubic feet per second during spring runoff prior to the dam’s construction; today, in approximately 8 out of 10 years, the lower river receives no managed releases at all, remaining completely dry except during occasional flash floods. This transformation has eliminated critical habitat for native fish species like the Colorado pikeminnow and razorback sucker. When releases do occur, they’re typically brief and insufficient to support river ecology. A 2021 study by Colorado State University found that 90% of the riparian cottonwood forests along the lower Dolores have disappeared or are in severe decline due to altered flow regimes. Climate change has exacerbated the situation, with the Dolores basin experiencing approximately 2°F of warming since the 1980s, leading to reduced snowpack and earlier spring runoff that the reservoir cannot always capture effectively.
The Salt River Phoenix’s Vanished Waterway
The Salt River once flowed year-round through what is now metropolitan Phoenix, supporting lush riparian forests and the indigenous Hohokam civilization’s extensive canal system. Today, the river exists primarily as a dry riverbed except after heavy rainfall, with its water completely diverted into canals or stored behind dams. Historical photographs from the early 1900s show a flowing river cutting through the desert landscape—a stark contrast to the dry channel that modern Phoenix residents know. Occasional monsoon floods still temporarily revive the river, but these brief pulses cannot sustain riparian ecosystems. The absence of regular flow has eliminated more than 95% of the cottonwood-willow forests that once lined the river’s banks. While small sections have been restored through the Rio Salado Project, which uses reclaimed water to create artificial wetlands, the natural river system has essentially disappeared. The loss of the Salt River as a functional ecosystem represents one of the most complete river disappearances in America, transforming what was once the lifeblood of the Sonoran Desert into little more than a flood control channel and occasional recreation area.
The Urgent Need for River Conservation and Restoration
The disappearance of these 13 rivers represents more than just a loss of water resources—it signals fundamental ecological and cultural damage across the American landscape. As climate change accelerates and population growth increases demands on water supplies, we face critical decisions about how to manage and protect our remaining river systems. Without comprehensive action addressing both climate change and water management reform, many more rivers may join this list in coming decades. Conservation approaches like water rights leasing for environmental flows, groundwater regulation, urban water efficiency programs, and dam removal, where appropriate, represent promising solutions. Indigenous water rights and traditional knowledge must also play a central role in river restoration. The fate of these disappearing rivers ultimately reflects our values as a society and our willingness to balance immediate human needs with the long-term health of the natural systems that sustain us. By recognizing these rivers’ plight now, we still have opportunities to reverse some of the damage before these vital waterways vanish completely from America’s landscape.
As a little kid, I fell in love with nature, wildlife, and animals. Living in the USA, South Africa, Italy, China and Germany gave me the opportunity to discover the world's Wildlife. My favorite animals are Mountain Gorillas, Siberian Tigers, and Great White Sharks.
I'm a certified PADI Open Water Diver, went to Everest Base Camp and Trekked Gorillas in Uganda. I hold a Master of Science in Economics and Finance.
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