"Ground Water Depletion: A National Assessment and Global Perspective"

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.

California Colloquium on Water

Water is the lifeblood of California. Without it, the landscape we know today would not exist. Throughout California’s history, water has been a source of food, commerce, energy, and recreation. It makes possible the bountiful Central Valley farms and the vibrant coastal cities. It has inspired countless poets and painters. Californians have simultaneously fought over water, marveled at its beauty, and - through impressive feats of engineering - moved it hundreds of miles.

The popular lecture series, the California Colloquium on Water, continues. Scholars of distinction in the fields of natural sciences, engineering, social sciences, humanities, law and environmental design will offer monthly lectures. These lectures are designed to increase the understanding and appreciation among students, faculty and the general public of water resources and to contribute to informed decisions about water in California.

The Colloquium is also offered as a 1 unit seminar, LA258. The instructor for Spring 2009 is Tim Ramirez. For further information, visit the webpage.

Presented below is the current semester's schedule, as well as a complete list of previous lectures. Many announcements and flyers are available in PDF format. When possible, WRCA videotapes the lectures; these VHS cassettes and DVDs are available for circulation on a case by case basis. Streaming video of the lectures, as well as PowerPoint and other electronic visual aids, when applicable, are also available from this page. <img src="http://www.lib.berkeley.edu/WRCA/images/icon_vidstream.gif" border="0" alt="streaming video" />Streaming video is presented via YouTube and in RealMedia (.rm) format.

SUMMER 2007: The Metropolitan Water District of Southern California (MWD) graciously funded the digitization of the California Colloquium lectures 2001-2004. All taped lectures are available online, chiefly in both YouTube (or Google Video) and RealMedia, as of July 6, 2007.

Lecture reminders and announcements of streaming video availability will be posted to WRCA's blog, On Water. Subscribe to the blog's RSS feed to receive these, and other, announcements electronically, or sign up to receive lecture reminders and new schedules via listserv email.

Directions and parking information is available from Visitor Services.

SPRING 2009 SCHEDULE

5:00-5:30pm - Reception and meet the speaker, outside of Room 250, Goldman School of Public Policy (2607 Hearst Ave at LeRoy).
5:30-7pm - Lecture, including a post-lecture question and answer session with the speaker. This semester the lectures will be held in Room 250, Goldman School of Public Policy (2607 Hearst Ave at LeRoy).