1125 80TH ST SW 2016-01-01 MF Import

Table 3-3.2 Roof Downspout System Sizing Trench Dimensions Required Length of Trench per 100 square feet of Roof Surface" depth" width coarse sand 1 sand loamy sand sandy loam loam 1.5 ft. 1.0 ft. 1.12 2.17 4.77 7.71 10.86 1.5 ft. 0.85 1.64 3.46 5.57 7.91 2.0 ft. 0.68 1.31 2.71 4.35 6.25 2.5 ft. 0.57 1.08 2.23 3.57 5.18 3.0 ft. 0.48 0.93 1.89 3.03 4.43 3.5 ft. 0.42 0.81 1.65 2.63 3.87 4.0 ft. 0.38 0.71 1.46 2.33 3.44 2.0 ft. 1.0 ft. 0.93 1.79 3.90 6.26 8.69 1.5 ft. 0.71 1.37 2.86 4.56 6.44 2.0 ft. 0.57 1.10 2.25 3.58 5.13 2.5 ft. 0.48 0.92 1.86 2.95 4.29 3.0 ft. 0.41 0.78 1.59 2.53 3.68 3.5 ft. 0.36 0.68 1.38 2.22 3.22 4.0 ft. 0.32 0.60 1.23 1.97 2.86 2.5 ft. 1.0 ft. 0.79 1.53 3.32 5.29 7.29 1.5 ft. 0.61 1.18 2.46 3.88 5.44 2.0 ft. 0.50 0.96 1.95 3.07 4.38 2.5 ft. 0.42 0.80 1.61 2.54 3.67 3.0 ft. 0.36 0.68 1.38 2.19 3.16 3.5 ft. 0.32 0.59 1.21 1.93 2.76 4.0 ft. 0.28 0.53 1.07 1.72 2.47 3.0 ft. 1.0 ft. 0.68 1.33 2.89 4.58 6.28 1.5 ft. 0.54 1.04 2.16 3.38 4.71 2.0 ft. 0.44 0.84 1.72 2.68 3.82 2.5 ft. 0.37 0.71 1.43 2.25 3.21 3.0 ft. 0.32 0.61 1.23 1.94 2.76 3.5 ft. 0.28 0.53 1.08 1.71 2.43 4.0 ft. 0.25 0.47 0.96 1.52 2.17 'Lrpth refers to the depth of washed rock, not depth from surface ;'Soil textures to be determined using the results of soil gradation tests and the USDA Textural Triangle. Example: A trench 2 feet deep and 3.5 feet wide, dug in sandy loam soils, for runoff from a 1500 square foot roof, would need to be 33.3 feet long (chart value of 2.22 multiplied by 15).