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− | <font size=3>'''Typical diversion methods for working in the dry and their applicability'''.</font size><br> | + | <font size=3>'''Typical temporary stream crossing methods and their applicability'''.</font size><br> |
− | Link to this [[Typical diversion methods for working in the dry and their applicability|table]] | + | Link to this [[Typical temporary stream crossing methods and their applicability|table]] |
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Revision as of 16:19, 15 April 2019
Typical temporary stream crossing methods and their applicability.
Link to this table
Stream crossing type |
Applicability |
Limitations |
Temporary bridge |
- Results in least disturbance to stream bed and banks compared to other stream crossing methods
- Typically no time of year restrictions for use
- Generally most appropriate for streams with high flow velocities or steep gradients
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Use in large channels may require pier(s) or other supports, which increase disturbance to stream (see Construction recommendations and specifications). |
Temporary culvert (pipe) |
- Most common temporary stream crossing
- Most appropriate for short-term use
- Generally appropriate for perennial or intermittent streams
- Generally preferred over fords as disturbance to stream is limited to construction and removal
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- May not be appropriate for large streams or during high flow conditions
- Causes greatest obstruction to flow
- May damage channel cross-section; culvert crossings should be planned to limit the number of crossings needed
- Not appropriate for streams that are vertically degraded or incised
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Temporary ford (drive-through) |
- Most appropriate for short-term use.
- Generally appropriate for ephemeral or low flow perennial streams.
- Used when bridge or culvert crossings are not feasible; typically very shallow streams where stream banks are less than 4 feet above the stream invert.
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- Use should be limited to dry season.
- Use should be limited to streams whose beds are armored.
- May degrade water quality due to contact with construction vehicles and equipment
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