Earthwork

The scars left by excessive cut and fill activities during construction in our western landscapes often leave long-lasting negative visual impacts. This is especially true of activities that disturb the highly mineralized soils of the arid west. Once the dark surface soil layer is disturbed, exposing the much lighter color of the subsurface soil, a strong contrast is created that may take many years to recover.

There are a number of ways to reduce the contrasts created by earthwork construction. Proper location and alignment are probably the most important factors. Fitting the proposed development to the existing landforms in a manner that minimizes the size of cuts and fills will greatly reduce visual impacts from earthwork. Other earthwork design techniques, such as balancing cut and fill or constructing with all fill or all cut should be considered, where appropriate, as methods to reduce strong visual impacts.

Other strategies may include:

• Hauling in or hauling out excessive earth cut or fill in sensitive viewing areas.
• Rounding and/or warping slopes (shaping cuts and fills to appear as natural forms).
• Bending slopes to match existing landforms.
• Retaining existing rock formations, vegetation, drainage, etc., whenever possible.
• Split-face rock blasting (cutting rock areas so that the resulting rock forms are irregular in shape, as opposed to making uniform “highway” rock cuts).
• Toning down freshly broken rock faces through the use of asphalt emulsions, rock stains, etc..
• Using retaining walls to reduce the amount and extent of earthwork.
• Retaining existing vegetation by using retaining walls, reducing surface disturbance, and protecting roots from damage during excavations.
• Avoiding soil types that will generate strong contrasts with the surrounding landscape when they are disturbed.
• Prohibiting dumping of excess earth/rock on downhill slopes.

Following are some examples of proper and improper earthwork construction:

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A varied side slope treatment creates a more natural-looking landscape.	Rounding the top and bottom of the slope and also undulating the face of the slope create a more natural-looking landscape.	The split-face rock blasting technique used on this project creates a more natural-looking rock face.

Incorporating features of the landscape into the design normally will yield a more natural-looking landscape.	This typical highway construction side slope treatment creates an unnatural form in the landscape. .

The rock gabion treatment of this hillside creates strong contrasts in line and color.	This recontoured slope blends well by repeating the existing forms and lines found in this landscape.

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