"Ground Water Depletion: A National Assessment and Global Perspective"
Leonard Konikow, Scientist, U.S. Geological Survey
Abstract: Development of ground-water resources for agricultural, industr...
"Ground Water Depletion: A National Assessment and Global Perspective" Leonard Konikow, Scientist, U.S. Geological Survey
Abstract: Development of ground-water resources for agricultural, industrial, and municipal purposes greatly expanded during the 20th century, and economic gains from ground-water use have been dramatic. In many places, however, ground-water reserves have been depleted to the extent that well yields have decreased, pumping costs have increased, water quality has deteriorated, aquatic ecosystems have been damaged by reduced ground-water discharge, and land has irreversibly subsided. Some causes and effects of groundwater depletion, however, are neither obvious nor easy to assess. A surprisingly large fraction of ground water pumped from confined aquifers derives from storage losses in adjacent confining layers, but depletion in low-permeability layers is difficult to estimate, rarely monitored, and too often overlooked. A new simplified method for estimating depletion from confining layers was developed, tested, and applied. Results indicate that depletion of storage in confining layers can greatly exceed the depletion from the confined aquifer itself. A nationwide assessment indicates that more than 700 km3 of water was depleted from ground-water systems in the U.S. in the past 100 years. Worldwide, the magnitude of ground-water depletion from storage may already be large enough to constitute a small but measurable contribution to sea-level rise during the 20th century.
Like to rate videos and let people know what you think?
Automatically share your ratings, favorites, and more on Facebook, Twitter, and Google Reader with YouTube Autoshare.
Autoshare makes certain YouTube activities public on the services you choose. Select only the services you are comfortable with - like Facebook, Twitter, or Google Reader - to let your friends know what you like on YouTube. You can turn Autoshare off at any time.
Like to share videos with friends?
Automatically share your ratings, favorites, and more on Facebook, Twitter, and Google Reader with YouTube Autoshare.
Autoshare makes certain YouTube activities public on the services you choose. Select only the services you are comfortable with - like Facebook, Twitter, or Google Reader - to let your friends know what you like on YouTube. You can turn Autoshare off at any time.
Autoshare makes certain YouTube activities public on the services you choose. Select only the services you are comfortable with - like Facebook, Twitter, or Google Reader - to let your friends know what you like on YouTube. You can turn Autoshare off at any time.