CHAPTER 5
FUNDAMENTALS OF ENGINEERING DESIGN
The primary focus of Chapter 5 is the fundamentals of engineering design that were used in
developing the preliminary design of stabilization measures. Whenever appropriate, example computations
or methodologies will be presented. In particular, methods developed under the Demonstration Erosion
Control (DEC) Project will be used as an example. The DEC Project, administered by the U.S. Army
Corps of Engineers, provides for the development of a system for control of sediment, erosion, and flooding
in the hill areas of the Yazoo Basin in Northern Mississippi.
5.1
BACKGROUND INVESTIGATIONS
The background investigations section describes research that develops a characterization of the
basin parameters used to identify main river processes and controls that dominate flow conditions. The
background research examines the climate, geology, geography, and hydrology of the basin and determines
the relationships and effects of these parameters on the stream. In addition, these investigations should
identify any large-scale instability or disturbance that may be directly affecting the stream stability. An
integral part of the background investigations is the research on physical indicators and records of past
behaviors. The historical record should be examined, if available, and used to investigate past adjustments
as indicators of future adjustment. Local river surveys from area agencies, local archives, and county
government survey departments are excellent places to begin. Table 5.1 suggests some sources of historical
information.
The types of information that can be obtained from these sources are channel and reservoir surveys,
flood history, watershed workplans, bridge plans and surveys, watershed erosion information, geological
data, Drainage District records, land use records, existing erosion control features, land ownership
information, historical sediment yield data, and aerial photography. Past lateral and vertical migration
patterns and extreme flow events can be examined from historic maps, aerial photographs, historic photos
and descriptions, botanical records and paleostage indicators. Documentation of previous land use changes
can sometimes be correlated with and used to examine past stream response.
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