Seawater intrusion

Sea level rise has already put coastal cities on notice thanks to increasing storm surges and even sunny day flooding at high tide. These challenges will continue to grow because global projections point to a mean sea level rise of at least one foot above year-2000 levels by the end of this century. However, many cities are facing another factor making them even more vulnerable to rising waters: land subsidence. The three of us – Pei-Chin Wu, Meng (Matt) Wei and Steven D'Hondt – are scientists at the University of Rhode Island Graduate School of Oceanography working with the U.S. Geological Survey to research challenges facing waterfront cities. Our findings indicate that land is sinking faster than sea levels are rising in many coastal cities throughout the world. By using radar images of the Earth’s surface collected from orbiting satellites, we measured subsidence rates in 99 coastal cities worldwide. These rates are highly variable within cities and from...

If you stand at practically any point on Earth, there is water moving through the ground beneath your feet. Groundwater provides about half of the world’s population with drinking water and nearly half of all water used to irrigate crops. It sustains rivers, lakes and wetlands during droughts. Groundwater is a renewable resource, but it can take decades or even centuries for some aquifers to recover after they are depleted. Current understanding of this challenge is based mainly on where and how frequently people record measurements of water levels in wells. In a newly published study, our team of data scientists, water specialists and policy experts compiled the first global-scale dataset of these levels. We analyzed millions of groundwater level measurements in 170,000 wells located in over 40 countries and mapped how groundwater levels have changed over time. Our study has two main findings. First, we show that rapid groundwater depletion is widespread around the worl...