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AW Chapter 4,: -,Best Man agement. Practices_for Erosion and Sediment. Control • 4.17 TEMPORARY RIGHT-OF-WAY DIVERSION • (ES BMP 1.17) Definition • A ridge of compacted soil or loose rock or gravel constructed across disturbed rights-of-way and similar sloping areas. Purpose �. To shorten the flow length within a long sloping right-of-way, thereby reducing the erosion potential by diverting storm runoff to a stabilized outlet or sediment trapping device. r Conditions Where Practice Apniles: . Generally, earthen diversions are- applicable where there will be little or no construction • traffic within the right-of-way. Gravel structures are. more ap"piicable to roads and other rights-of-way which accommodate vehicular traffic: • Planning Considerations Construction of utility lines and: roads often requires the clearing of long strips of .. right-of-way over sloping terrain. The volume.and velocity of stormwater runoff tend to increase in these. cleared strips and the potential for erosion is much greater since the vegetative cover is diminished or removed. To compensate forthe loss of vegetation, itis usually a good practice to break up the flow length within the cleared strip so that runoff does not have a chance to concentrate and cause erosion. At proper spacing intervals, Temporary Right -of -Way Diversions can significantly reduce the amount of erosion which ,. will occur until the area is permanently stabilized. Design Criteria • No formalAesign is required. The following criteria shall be met: ,. Drainage Area Less than 5 acres (2 he). For larger drainage areas use a DIVERSION. -Section 5.18 (ES • BMP 1.18). Dimensions The minimum allowable height measured from the upslope side of the diversion is 18 inches (45 cm). The minimum top width shall be 2 feet (60 cm) and the base width • minimum is 6 feet (1.8 m). (See Plate 4.17a) Side Slopes 3:1 or flatter to allow the passage of construction traffic.