Thursday, March 12, 2009

Watersheds and a habitable planet

Dual LA and San Gabriel watershed basins - Due to pressures of urbanization both rivers have been highly modified with dams and concrete channeling resulting in a loss of habitat and human access to the rivers. Diversions of water for use in groundwater recharge, significant discharges of wastewaters including sewage treatment plant reclaimed waters, and non-point source contributions such as urban runoff have dramatically changed the natural hydrology of the rivers.

Watersheds sustain rivers and aquifers which sustain life, upon which human settlements rely. The issue is discussed at the International Rivers website, and centers on the impact of dams. The most recent resource information from them is as follows:

Track Major RIS Sites on Google Earth

Dams suspected of triggering earthquakes are strewn over all six continents. To learn about individual cases, see the website above and click on the individual pins for more info.

New Factsheet on Reservoir-Induced Seismicity

"A Faultline Runs Through It: Exposing the Hidden Dangers of Dam-Induced Earthquakes"

Besides posing a major risk to dams, scientists are increasingly certain that earthquakes can be triggered by the dams themselves. Globally, scientists believe that there are over 100 instances, strewn over six continents, of dam reservoirs inducing earthquakes. The most serious case could be the magnitude-7.9 Sichuan earthquake in China in May 2008, which some experts believe may have been induced by the Zipingpu Dam.