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Introduction
This website provides access to information on the
natural resources, economy, and human population of the
binational Salton Basin-Colorado River Delta region shown
above. It also aims to
facilitate information exchange and coordination among all
groups interested in the region. We hope it will prove
useful to students, researchers, decisionmakers and the
general public.
First developed in 1996, the website reflects the
experience and knowledge gained by SDSU scientists who have
for twenty years taught a course on the ecology of the
Colorado River delta region and for ten years been carrying
out research in the Salton Sea region.
A Unitary
Region
It may be helpful to point out the essential
physiographic and hydrologic unity of this region.
Structurally it occupies the Salton Trough, a small section
of the dynamic junction or 'crack' between the North
American and Pacific tectonic plates. The kilometer-deep
soils and sediments of the Coachella, Imperial and Mexicali
valleys and the lower delta region represent materials
ground out of the Rocky Mountains, the Grand Canyon, and
elsewhere by the Colorado River and its tributaries and
delivered into the tectonic crack. These are the delta
deposits of the Colorado River. Their areal extent is
roughly 8600 km2, not including the underwater
portion in the Sea of Cortez. The delta is not merely the
few hundred square kilometers of plains along the lower
river channel near the Sea of Cortez. A clear delineation of
the whole delta is seen in the endpiece
map in G. Sykes' classic monograph, The Colorado
Delta (1937).
Hydrologically the region consists of two principal
entities. One is the watershed of the Salton Sea, a terminal
saline lake that receives inflows from an area that extends
from Mt.San Gorgonio in the north to the Mexicali valley in
the south. The other is the watershed comprised of the
southern, exclusively Mexican part of the delta and adjacent
uplands and mountains. What little surface water flows there
are in this region travel mostly via old channels of the
Colorado to the Sea of Cortez. A third but much smaller
watershed is that containing the terminal saline lake Laguna
Macuata (Laguna Salada) and bounded by the Sierra de los
Cocopah and the Sierra de Juarez.
The distinctness of these three watersheds is partly
illusory, of course. At various times in the past, and
perhaps as recently as 500 years ago, the Colorado River
flowed into the Salton Sea basin creating a large, deep
freshwater lake there. This had an outflow to the Sea of
Cortez. But even now Colorado River water - in the form of
agricultural, municipal, and industrial wastewaters - is the
main water supply for the Salton Sea. Also, during years of
high flow in the Colorado it sometimes overflows into and
fills the below sea level Laguna Macuata basin creating a
lake 50-60 km long there.
Types of
Information
The website will present four general types of
information. First, it will serve as a network node that,
via directories and hyperlinks, lists and facilitates access
to websites of all institutions, agencies and organizations
that provide useful information of any sort on the region.
Second, it will present annotated bibliographies of
the scientific, technical, and general literature on the
region, including the extensive 'gray' literature of
government agencies, consulting firms, and other entitites.
Third, it will put on line the full text of certain
documents relevant to the region that are of special
interest and/or not easily accessed or available elsewhere.
These will include unpublished reports, legislation,
treaties, environmental impact reports (summaries only),
engineering analyses (summaries), organizational position
statements, political, legal, and editorial commentary, and
so on.
Fourth, it will present various sorts of original
information and databases developed by CIW scholars or
compiled by them from other sources.
We welcome suggestions regarding information,
documents or hyperlinks that you believe it would be useful
to incorporate into this site, as well as correction of any
errors present.
Joan S. Dainer, Webmaster
jdainer@sunstroke.sdsu.edu
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