WSP01538

• File Number: 8210.470
• Description: Pacific Southwest Interagency Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1974
• Author: Unknown
• Title: Report of the Water Management Technical Subcommittee - Erosion and Sediment Yield Methods - April 1974
• Water Supply Pro - Doc Type: Report/Study

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EROSION AND SEDIMENT YIELD METHODS
REPORT OF THE WATER MANAGEMENT TECHNICAL SUBCOMMITTEE

Erosion and Sediment Yield Methodology Task Force, PSIAC

May 1974

INTRODUCTION

At the 71-3 meeting, the Pacific Southwest Interagency Committee
gave approval to the request of the Water Management Technical Sub-
committee to form a task force to work on erosion and sediment yield
methodology as .it applies to conditions in the Pacific Southwest.
Subsequently, an interagency task force was organized comprised of
the following members: Marvin C. Meier, Chairman, U.S. Forest Service;
Perry Y. Amimoto, California Division of Soil Conservation; Dale Burnett,
U.S. Army Corps of Engineers; Elliott M. Flaxman, Soil Conservation
Service; Richard F. Hadley, U.S. Geological Survey; Kenneth G. Renard,
Agricultural Research Service. Mr. Hadley became chairman in December 1972,
following the transfer of Mr. Meier out of the region.

The objectives of the task force are to review the literature and
evaluate and discuss methods of estimating on-site erosion and
downstream sediment yield as to the data requirements, applicability
to field project situations, reliability, and physical situations under
which they are valid.

The 1968 report of the Water Management Subcommittee entitled,
"Factors affecting sediment yield and measures for the reduction of
erosion and sediment yield, n outlined a procedure for estimating
sediment yield. That report was directed toward broad planning needs.
This report is directed toward detailed project planning and design
in the Pacific Southwest area.

Climatic and physiographic variability within the Pacific. Southwest
make problems of estimating sediment yield or on-site erosion difficult.
Although actual field measurements are most desirable, they are not
available in most areas, and time does not permit undertaking a detailed
data-collection program to obtain such information. Several prediction
methods have been developed from research generally with limited
climatic and physiographic variability. One of the objectives of this
report is to examine several of these methods and to provide guidelines
for their usefulness in the Pacific Southwest.

PROCESSES OF EROSION, TRANSPORT, AND DEPOSITION

The processes of erosion, transport, and deposition of particles,
either disintegrated rock or soil, represents sedimentation. These
processes are part of the normal cycle of geologic events that shape
the landforms of the Earth, and the rates at which the processes act
are dependent on such variables as rock or soil type, climate, relief,
plant cover, and land use. Interference by man in altering the land

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