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flow. <br />. Vertical spacing determined by the above methods may be increased as much as 0.5 feet or <br />10 percent, whichever is greater, to provide better alignment or location, to avoid obstacles, to <br />adjust for equipment size, or to reach a satisfactory outlet. The drainage area above the ter- <br />race should not exceed the area that would be drained by a terrace with normal spacing. <br />. The terrace should have enough capacity to handle the peak runoff expected from a 2-year, <br />24-hour design storm without overtopping. <br />. The terrace cross-section should be proportioned to fit the land slope. <br />. The ridge height should include a reasonable settlement factor. <br />. The ridge should have a minimum top width of 3 feet at the design height. <br />. The minimum cross -sectional area of the terrace channel should be 8 square feet for land <br />slopes of 5 percent or less, 7 square feet for slopes from 5 to 8 percent, and 6 square feet for <br />slopes steeper than 8 percent. The terrace can be constructed wide enough to be maintained <br />using a small vehicle. <br />Maintenance Standards <br />Maintenance should be performed as needed. Terraces should be inspected regularly; at least once <br />per year, and after large storm events. <br />2019 Stormwater Management Manual for Western Washington <br />Volume 11 - Chapter 3 - Page 311 <br />