| 1. |
Which one of the conditions below should be noted when rating ditches? |
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Road appearance: Potholes, degradation, cracking, rutting, road edge erosion/“breaking off”, and suspicious wear and tear may indicate a ditch in need of maintenance. Roads also deteriorate because of undersized or clogged culverts or when the subgrade becomes saturated.3 |
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Ditch erosion or soil instability: Look for un-vegetated banks, sediment deposits in the ditch, unstable or eroding slopes, incision (channel deepening) and headcuts. Is the riprap in place or has it been undercut or washed away? Check culvert ends for signs of scour. |
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Water flow: How frequently does the ditch vegetation need to be mowed or otherwise reduced to provide adequate flow rates? Pools of standing water in a ditch or water ponding between culverts over long periods indicate either a drainage problem or that the ditch may be a wetland or stream. Are blockages or flood problems diverting the flow? Are the culverts adequately sized to carry the flow? Inspect culverts for signs of corrosion, separated joints, sagging bottoms, blockage, piping, fill settling, and sediment buildup.4 |
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All of the above |
| 2. |
Over time as a result of this movement, roadside ditches and culverts fill in with gravel and sediment. e periodic removal of this material is required to maintain the hydraulic capacity of the ditches and protect the roadway and travelling public. |
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Hydraulic capacity |
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Natural beauty |
| 3. |
In Routine Maintenance, work can generally be completed by maintenance staff in the field without major analysis or engineering. It includes work such as removing sediment that has filled in the ditch, replacing a damaged or corroded culvert of the same size and type under driveways or small roads, seeding a side slope, clearing brush, removing invasive species or noxious weeds, and mowing. Basic field measurements often precede routine maintenance. |
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True |
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False |
| 4. |
Non-routine Maintenance, ______________________________________. Non-routine maintenance often involves fixing headcuts, altering channel water carrying capacity, replacing culverts with different sizes or types, working in ditches that double as a stream or wetland, and combating major erosion. |
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work requires professional analysis or engineering and possibly one or more permits. |
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Does not need any permit |
| 5. |
If the ditch was not designed properly or is not adequately carrying the stormwater runoff it receives, a redesign may be needed to reduce repeated maintenance issues. Redesign needs to take place within the framework of regulations that apply to the particular ditch. |
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True |
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False |
| 6. |
In Fig 4. The debris that blocks the culvert should be removed to allow flow through freely. If the soils are disturbed during this process, the time should be taken to stabilize them using the erosion controls discussed in this course. |
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True |
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False |
| 7. |
A headcut in a ditch is an abrupt drop in the ditch bottom caused by erosion as the ditch adjusts to a natural or human-induced disturbance (Fig. 30). Most waterfalls (i.e. Niagara Falls) are large-scale examples of a headcut. |
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True |
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False |
| 8. |
Legal questions _________ when considering ditch maintenance and/or repair. Be proactive and request assistance from your local Soil and Water Conservation District (SWCD) or the appropriate authority before beginning. If you are not sure if your project is considered routine maintenance, check with your county SWCD staff. Tey can help you determine what permits may be required. |
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Can arise |
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Will not arise |
| 9. |
Figure (36 )is an example that you do not want to dig a U-shaped ditch with vertical side. Ditches with this profile are not stable, and will show significant erosion and sloughing. |
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True |
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False |
| 10. |
Here is an example to help if a permit is required or not:
Answer the following questions to help you determine if a permit(s) is required.
1. Is this a roadside upland ditch?
A. The ditch dries out between rainstorms and does not have running water much or all of the time; AND
B. The ditch does not look like a wetland or run through a wetland (Note: wetlands are not always obvious, see “wetland” in the Definitions section).
If either is false, it is NOT an upland road ditch and permits are likely to be required.
If BOTH A and B are true, it is likely an upland ditch, (but even then, depending on State you may require some kind of permit!) |
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True |
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False |
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