1. Area Measurements from Site Plans and Introduction to WinSLAMM Analyses Robert Pitt Dept. of Civil and Environmental Engineering University of Alabama Tuscaloosa, AL 35487

3. Little Shades Creek Subwatersheds Area (acres)1234All others Total Single family 33944867640117473611 Town homes 0208094122 Multi-family0471302787 School/ church 00381358109 Commercial881774282 All other701531991646211207 Total41767695158525895218

10. Characteristics of Land Development in Rocky Ridge Low density Medium density pre 1960 High density Strip commercial Office parks Directly connected imperviousness 6.118.981590.660.19 Impervious areas draining to pervious areas 4.76.2901.14 Pervious Areas89.1984.82769.438.67 Total100

32. Summary of Measured Areas Totally connected impervious areas: 25.9 acres – parking 15.3 acres – roofs (flat) 8.2 acres – streets (1.2 curb-miles and 33 ft wide) 2.4 acres Landscaped/open space 15.4 acres Total Area 41.3 acres

33. Stormwater Controls Biofiltration areas –52 units of 40 ft by 8 ft –Surface area: 320 ft 2 –Bottom area: 300 ft 2 –Depth: 1 ft –Vertical stand pipe: 0.5 ft. dia. 0.75 ft high –Broad-crested weir overflow: 8 ft long, 0.25 ft wide and 0.9 ft high –Amended soil: sandy loam

34. Stormwater Controls (cont.) Wet detention pond –Surface area at pond surface: 3% of 25.9 paved acres = 0.78 acres 0.5% of 15.4 unpaved acres = 0.077 acres Total area: 0.95 acres –Pond areas different depth: 0 ft 0 acres4 ft 0.95 acres 1 ft 0.1 acres5 ft 1.15 acres 2 ft 0.3 acres6 ft 1.25 acres 3 ft 0.5 acres7 ft 1.31 acres

49. Runoff Volume Changes Base conditions With biofiltration With pondWith biofilt. and pond Runoff volume (10 6 ft 3 /yr) 2.851.672.851.67 Average Rv0.590.350.590.35 Average CN98969896 % reduction in volume n/a41%0%41%

50. Particulate Solids Changes Base conditions With biofiltration With pondWith biofilt. and pond Particulate solids (lbs/yr) 30,25027,6503,6603,320 Part. size controlled (flw-wgt  meters) n/a 3.23.7 % reduc. in discharges n/a9%88%89%

51. Residential Area Source Areas Area (acres)Large lots Small lots Total area Roofs0.390.520.91 Driveways0.150.120.27 Sidewalks0.060.040.10 Landscaped areas 1.611.072.68 Subtotals2.211.753.96 Streets0.57 Undeveloped area 1.07 Total area: 5.60 acres

53. Example Area Calculations for Workshop Problem RoofsConcrete around buildings Street areas (widths) SidewalksParking islands Large landscaped areas Parking 0.49 (35) 0.3 (20) 0.29 (40) 3.57 acres 2.88 acres 1.08 acres 0.07 acres1.03 acres 3.98 acres8.07 acres 17.3%13.9%5.2%0.3%5.0%19.3%39.0%