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. Slopes with a stable rock face do not require roughening. <br />. Slopes where mowing is planned should not be excessively roughened. <br />Design and Installation Specifications <br />There are different methods for achieving a roughened soil surface on a slope, and the selection of <br />an appropriate method depends upon the type of slope. Roughening methods include stair -step <br />grading, grooving, contour furrows, and tracking. See Figure 11-3.5: Surface Roughening by Track- <br />ing and Contour Furrows. Factors to be considered in choosing a roughening method are slope <br />steepness, mowing requirements, and whether the slope is formed by cutting or filling. <br />. Disturbed areas that will not require mowing maybe stair -step graded, grooved, or left rough <br />after filling. <br />. Stair -step grading is particularly appropriate in soils containing large amounts of soft rock. <br />Each "step" catches material that sloughs from above, and provides a level site where veget- <br />ation can become established. Stairs should be wide enough to work with standard earth mov- <br />ing equipment. Stair steps must be on contour or gullies will form on the slope. <br />. Areas that will be mowed (these areas should have slopes less steep than 3H:1 V) may have <br />small furrows left by disking, harrowing, raking, or seed -planting machinery operated on the <br />contour. <br />• Graded areas with slopes steeper than 3H:1 V but less than 2H:1 V should be roughened <br />before seeding. This can be accomplished in a variety of ways, including "track walking," or <br />driving a crawler tractor up and down the slope, leaving a pattern of cleat imprints parallel to <br />slope contours. <br />. Tracking is done by operating equipment up and down the slope to leave horizontal depres- <br />sions in the soil. <br />Maintenance Standards <br />. Areas that are surface roughened should be seeded as quickly as possible. <br />. Regular inspections should be made of the area. If rills appear, they should be re -roughened <br />and re -seeded immediately. <br />2019 Stormwater Management Manual for Western Washington <br />Volume 11 - Chapter 3 - Page 308 <br />