Fundamentals of Engineering Design
The dominant sediment transport mechanism is primarily based on the soil and sediment
characteristics. Measurements of suspended load or bed load sample should be taken upstream of channel
and bank failure sites to estimate the sediment moving through a stable system. The accuracy of sediment
sampling techniques, however, are often limited. Julien (1995), Edwards and Glysson (1988) or Petersen
(1986) provide guides to field methods for measuring fluvial sediment. Alternatively, sediment transport
can be estimated using empirically based sediment transport capacity equations. Sediment transport can
be divided into three zones that describe the dominant mode of transport: bedload, mixed load, and
suspended load (Julien, 1995, p. 186).
The qualitative portion of a field investigation is an integral part of the overall assessment process.
Field observations should be recorded in an organized fashion on site assessment sheets which detail all
pertinent site characteristics. The sheets divide the description into channel, bed and bank investigations.
Thorne (1992) describes the use of evaluation sheets as an aid to field identification of the following channel
1. the state of vertical and lateral channel stability;
2. the relation of local bank retreat to channel instability;
3. the engineering and morphologic characteristics of the banks;
4. the dominant erosive forces and processes;
5. the state of bank stability and the major failure mechanisms; and
6. the input parameters necessary for modeling bank retreat.
The sheets are designed to provide a systematic and disciplined approach to the collection, recording, and
interpretation of both archive and field data.
Detailed cross sectional and planform sketches of the study reach should be made to supplement
the observations. The sketches should identify and locate the relative positions of:
1. the type of flow conditions;
2. bed and bank controls;
3. dominant bed materials and bed forms;