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When developing a runoff and SESC strategy, remember that ______ and ______ ______ control is more effective and cost efficient than ______ control.
- soil erosion
Without proper planning, construction generally results in an ______ in runoff.
______ controls rarely reduce ______ or ______.
Fine sediment particles, such as ______ and ______, are difficult or impossible to capture with standard ______ control techniques. It is particularly important to emphasize ______ and ______ control on sites with fine textured soils.
- Silts, clays
List five construction practices that minimize runoff and control erosion:
- 1.) staging (phasing) - grading in a limited area is completed before proceeding with additional grading or earth change activities
- 2.) Vegetation - most effective
- 3.) Surface roughening (scarification)
- 4.) Diversions and channels - capture runoff and provide erosion control
- 5.) Grade stabilization structures - carry runoff from one level to another (ex: Pipe Downdrains / chute or flume - flat or round bottomed ditch usually lined with concrete or asphalt
List five sediment control practices:
- 1.) Dewatering - removal of groundwater, surface water, or storm water from a site to allow construction to be done "in the dry."
- 2.) Access and Exit roads
- 3.) Sedimentation Basins
- 4.) Catch Basins
- 5.) Storm drain inlet protection - (ex: silt sacks)
______, sometimes called ______ is part of scheduling. This is where grading and stabilization are finished in one area before proceeding to the next area.
The slope of a diversion channel must be adequate to provide good positive ______ but not so great as to create water velocities that will ______ the diversion channel.
Overland flow that is diverted must be disposed of without causing ______ or ______ ______ where it is undesirable.
- depositing sediment
Runoff may be disposed of onto ______ - ______ vegetation.
Well - established
______ ______ structures are used to carry runoff from one level to another.
______ occurs when water erodes small channels under or along the side of a water conveyance structure.
______ ______ are often used in roadside ditches to reduce
the velocity of water.
The center of the check dam should always be ______ ______ ______ than the outside edges to prevent scouring around the structure.
9 inches lower
The size of the stone used in check dams should be ______ as slope and/or velocity increases.
When anticipated channel velocities are too great to establish grass, the channel can be lined with erosion control ______ or ______ ______ mats.
- turf reinforcement
Sediment basins should be at least ______ times as long as wide. If this is not possible, ______ or ______ should be placed in the basin to increase the water's travel distance.
- baffles or convolutions
______ tends to settle rapidly in a sediment basin, but ______ and ______ sized particles may never settle out.
Some methods used to control wind erosion include:
a.) placing ______ ______ perpendicular to the prevailing wind direction
b.) keeping the soil ______
c.) spraying ______ binders on the soil surface
To be effective, all BMP's must be periodically ______, ______, and/or ______ when necessary.