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BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

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Advantages• Reduces the erosion potential of runoff originating on the slope.• Improves the condition of the slope for plant establishment.• Reduces runoff velocities and increases infiltration.• Can be aesthetically pleasing when combined with successful vegetationestablishment.Disadvantages• Increased cost relative to alternative slope stabilization techniques.• Can be complicated to design and install, and may fail if not properlydesigned and installed.DESIGN CONSIDERATIONSFor complicated applications, consult with a licensed professional civil engineerwhen designing any retaining wall for a steep slope. For simple applicationswith terraces less than 3 feet in height, the following design considerations maybe applicable:• Various retaining walls can be selected to build terrace walls. Refer toSection 4.2.2.3, Retaining Wall for more details regarding designconsiderations.• Design the terrace wall heights and spacing of terraces to allow for levelgrading of soil behind the terraces (target a maximum 2 percent slope foreach terrace).INSTALLATION CONSIDERATIONS• Starting at the bottom of the slope, prepare a level surface for installation ofthe first retaining wall, which may include cutting into the slope.• Refer to Section 4.2.2.3, Retaining Wall for more details regardinginstallation considerations.• When installing retaining walls for terracing, consider leaving space betweenthe retaining wall and the uphill slope. When leveling the terrace above theretaining wall, fill the void space with soil taken from the cut on the uphillslope.• Flatten the slope behind the retaining wall and compact the soil firmlyagainst the downhill retaining wall. Over-excavate the uphill slope toprovide space to construct the next retaining wall for uphill terraces. Repeatthis process up the slope for each terrace.• Loosen the top 6 inches of compacted soil on the terraces to encouragevegetation establishment. Where necessary, add soil amendments such asmulch and compost.• If desired, plant native vegetation on the terraces. Irrigate the terraces asnecessary to improve plant establishment.Chapter 4: <strong>BMP</strong> ToolkitTRPA <strong>BMP</strong> Handbook4.2.2.2-Terracing 2012Page 2

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