THE NATIONAL ACADEMIES PRESS
500 Fifth Street, N.W. Washington, DC 20001
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this project was provided by the U.S. Environmental Protection Agency under Award No. X-82872401; U.S. Army Corps of Engineers Award No. DACW72-01-P-0076; U.S. Department of Agriculture, Cooperative State Research, Education, and Extension Service under Award No. 2001-38832-11510; U.S. Department of Agriculture-Research, Education, and Economics, Agricultural Research Service, Administrative and Financial Management, Extramural Agreements Division under Award No. 59-0790-1-136. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number 0-309-09318-X (Book)
International Standard Book Number 0-309-54586-2 (PDF)
Library of Congress Control Number 2005924663
Additional copies of this report are available from the
National Academies Press,
500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu.
Cover design by Van Nguyen, National Academies Press. Cover photograph by Lauren Alexander, Staff Officer with the Water Science and Technology Board, National Research Council. Copyright 2000 by Lauren Alexander Augustine.
Copyright 2005 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America.