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runoff from the terrace or terrace system to a point where the outflow will not cause damage. Vegetative cover should be used in the outlet channel. . The design elevation of the water surface of the terrace should not be lower than the design elevation of the water surface in the outlet at their junction, when both are operating at design flow. . Vertical spacing determined by the above methods may be increased as much as 0.5 feet or 10 percent, whichever is greater, to provide better alignment or location, to avoid obstacles, to adjust for equipment size, or to reach a satisfactory outlet. The drainage area above the terrace should not exceed the area that would be drained by a terrace with normal spacing. . The terrace should have enough capacity to handle the peak runoff expected from a 2-year, 24-hour design storm without overtopping. . The terrace cross-section should be proportioned to fit the land slope. The ridge height should include a reasonable settlement factor. The ridge should have a min- imum top width of 3 feet at the design height. The minimum cross -sectional area of the terrace channel should be 8 square feet for land slopes of 5 percent or less, 7 square feet for slopes from 5 to 8 percent, and 6 square feet for slopes steeper than 8 percent. The terrace can be constructed wide enough to be maintained using a small vehicle. Maintenance Standards Maintenance should be performed as needed. Terraces should be inspected reg- ularly; at least once a year, and after large storm events. I 1 Cl 1 1 1 2014 Stormwater Management Manual for Westem Washington Volume 11 - Chapter 4 - Page 308