Affiliation:
1. Colorado State University
Abstract
Abstract
Groundwater in unconfined aquifers is essential for agricultural irrigation, drinking water, streamflow replenishment, and ecosystem viability. Here we use datasets of groundwater level measurements and aquifer thickness to quantify temporal trends of groundwater head, water table depth, and saturated thickness within unconfined aquifers for the conterminous United States during the 1920-2020 period. We then use these temporal trends to estimate fraction changes in saturated thickness, as a surrogate for groundwater storage, and time to depletion (years) for locations with declining groundwater levels. Approximately half (52%) of locations have a measured historical decline. Less than 1% of monitored locations exhibit a fraction change in saturated thickness of more than 75% over measurement history. Approximately 3% and 8% of locations with declining levels have estimated depletion times of less than 20 years and 50 years, respectively, principally in the western United States. However, many locations have abundant groundwater for centuries of use.
Publisher
Research Square Platform LLC
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