How the Dead Sea Became the Saltiest Lake on Earth

430 Meters Below Sea Level—Where Rivers Go to Die

The Jordan River flows 251 kilometers from the Sea of Galilee southward through one of the deepest continental rifts on Earth. It never reaches the ocean. Instead, it empties into a terminal lake so salty that virtually nothing lives in it, so dense that swimmers float without effort, and so low that its surface marks the lowest point of dry land on the planet: 430 meters below sea level. The Dead Sea earned its name. Water enters but never leaves—except by evaporation, which has been concentrating minerals here for hundreds of thousands of years.

How Tectonics Created a Salt Trap

The Dead Sea sits in the Jordan Rift Valley, part of the Dead Sea Transform fault system that separates the African Plate from the Arabian Plate. This rift has been pulling apart for roughly 15 million years, creating a deep graben—a block of crust that dropped between two parallel faults. The depression deepened over geological time, trapping water that had no outlet to the sea.

• The rift extends from the Red Sea north through the Arava Valley, Dead Sea, Jordan Valley, and into Lebanon
• The Dead Sea basin is over 300 meters deep at its maximum, with total depth from surface to bedrock exceeding 700 meters
• Salt deposits beneath the lake floor are over 2 kilometers thick, recording millions of years of evaporative cycles
• During the Pleistocene, a much larger predecessor—Lake Lisan—covered the entire Jordan Valley

Lake Lisan evaporated during warm dry periods and refilled during ice ages. Each evaporative cycle left salt behind. The Dead Sea inherited all of it.

Salinity That Defies Ordinary Chemistry

Ocean water averages 3.5% salinity. The Dead Sea reaches 34.2%—nearly ten times higher. But the salt composition differs dramatically from seawater.

The high magnesium and calcium content gives Dead Sea water its distinctive oily texture and extreme bitterness. Swallowing even a small amount causes nausea. Getting it in your eyes produces intense burning. The mineral composition also supports a multibillion-dollar cosmetics and therapeutic industry.

Shrinking at One Meter Per Year

The Dead Sea is disappearing. Since the 1960s, its surface has dropped more than 35 meters and its area has shrunk by roughly one-third. The southern basin dried out entirely and is now maintained as evaporation ponds by the Dead Sea Works (Israel) and Arab Potash Company (Jordan) for mineral extraction.

The cause is straightforward. The Jordan River, once the Dead Sea's primary freshwater source, has been diverted almost entirely for agriculture and drinking water by Israel, Jordan, and Syria. The river now delivers less than 10% of its historical flow.

• Historical Jordan River inflow: ~1.3 billion cubic meters per year
• Current inflow: ~100–200 million cubic meters per year
• Evaporation rate: ~1.4 billion cubic meters per year
• Net loss: approximately 700 million cubic meters annually
• Surface level drop: ~1 meter per year

The math is simple. More water leaves than enters. The deficit grows each year.

The Sinkhole Crisis

As the Dead Sea recedes, it leaves behind an underground layer of salt that was previously stable beneath the saturated lake. Fresh groundwater now reaches this salt layer and dissolves it rapidly, creating underground cavities that collapse without warning. These sinkholes have swallowed roads, buildings, date palm plantations, and tourist facilities along both the Israeli and Jordanian shorelines.

Over 6,000 sinkholes have appeared since the 1980s. New ones open at a rate of roughly 300–500 per year. Entire sections of highway have been rerouted. Ein Gedi, once a popular beach resort area, has been closed due to sinkhole danger. The geological instability is accelerating as the water level continues to drop.

The Red Sea–Dead Sea Canal Proposal

The most ambitious proposed solution is a canal or pipeline from the Red Sea to the Dead Sea, exploiting the 400-meter elevation difference to generate hydroelectric power while partially refilling the lake. The project has been studied since the 1960s and gained renewed momentum with a 2013 World Bank feasibility study.

Critics warn that mixing Red Sea water with Dead Sea chemistry could trigger gypsum crystallization, algal blooms, and fundamental changes to the Dead Sea's unique mineral balance. Environmental impact assessments remain contested. Political coordination between Israel, Jordan, and the Palestinian Authority adds another layer of complexity. The canal remains a proposal, not a project.

Therapeutic Traditions and Scientific Evidence

People have traveled to the Dead Sea for health benefits since Herod the Great built health resorts there in the first century BCE. Cleopatra reportedly secured exclusive rights to Dead Sea cosmetic ingredients. Modern clinical research has documented measurable benefits for specific conditions.

• Psoriasis patients show 75–90% improvement rates after 4-week Dead Sea climatotherapy programs
• The combination of mineral-rich mud, low-allergen atmosphere, filtered UV light (extra atmospheric thickness), and high bromine content creates conditions not replicated elsewhere
• Rheumatoid arthritis patients report reduced pain and improved joint mobility
• The barometric pressure at 430m below sea level increases oxygen partial pressure by roughly 5%

The Dead Sea is shrinking, cracking, and sinking. Its ancient chemistry, millions of years in the making, faces disruption within decades. Whether engineering or diplomacy can reverse the decline remains the defining question for the lowest place on Earth.