Groundwater levels across Nevada are dropping at alarming rates, threatening springs, wetlands and other habitats that sustain the state's unique plants and wildlife, according to a new study by researchers from The Nature Conservancy in Reno and the Desert Research Institute.
Researchers found that nearly 40% of thousands of wells analyzed statewide show significant declines in water levels from 1984-2021. The findings point to risks for groundwater-dependent ecosystems (GDEs) as drought conditions worsen and water demand rises.
"Our research shows that groundwater-dependent ecosystems in Nevada are already facing multiple, compounding stressors like excessive groundwater withdrawals and climate," said Laurel Saito, water strategy director for The Nature Conservancy and lead author of the study. "This highlights the urgency of advancing science-based solutions to protect these ecosystems."
Groundwater is the largest source of freshwater on Earth and a critical resource for people and nature, especially in arid regions like Nevada where surface water is scarce.
Researchers estimate about 20% of GDEs in Nevada were at moderate to high risk because more groundwater was being withdrawn than was estimated to be available. "In addition, at least 40% of all GDE types were in hydrographic areas that have more water rights committed than the estimated available groundwater, putting them at risk of overpumping if all committed water rights are fully used."
Dan McEvoy, co-author and researcher at the Desert Research Institute, said more frequent and intense droughts projected in coming years will likely worsen pressures on GDEs.
"We expect threats to groundwater-dependent ecosystems to intensify, putting even greater pressure on these vulnerable ecosystems," he said.
Different GDEs face varying degrees of risk from stressors. For example, groundwater withdrawals are the largest threat to wetlands, lakes and playas, and areas where cottonwoods and willows grow. Meanwhile, hooved animals like cattle, horses, elk and deer pose a greater risk to GDEs near springs and rivers -- areas where those animals seek drinking water, and in the process may alter plant life and flow paths of water.
Melissa Rohde, principal at Rohde Environmental Consulting and another co-author, said groundwater supports biodiversity, habitat and climate regulation, yet is rarely managed with environmental needs in mind. "Without stronger policies and collaborative management, natural areas that rely on groundwater risk drying and degrading," she said.
The paper outlines several strategies to help safeguard groundwater and restore ecosystems, including reducing excessive withdrawals, increasing monitoring and reporting, and incorporating environmental protections into land and water management policies. It also emphasizes collaboration among public and private partners and raising awareness about the value of groundwater-dependent ecosystems.
The authors said that while the study focuses on Nevada, its findings and recommendations apply to other arid regions worldwide facing similar challenges.
The published paper is available to read in the August issue of Hydrological Processes.