complete drainage report rev 9

Scour Hole Design Project: Job #: Location: Design Storm: Computed By: Checked By: Date: WEH West Orange, NJ 25-YR ASM PWA 10/25/2024 Discharge not in Basin, Therefore Tailwater is less than 0.5 x Do Discharge Point Q (25-yr storm cfs) Inside Height of Outlet Culvert, Do (in) Inside Height of Outlet Culvert, Do (ft) Tailwater (ft), Tw Length of Apron, L (ft) Width of Culvert, Wo(in) Width of Culvert, Wo(ft) Width of Apron, W(ft) Where Y = 1/2 Do, Y(ft) Median Stone Diameter, D50 (ft) Where Y = Do, Y(ft) Median Stone Diameter, D50 (ft) PP-9 0.61 12 1.0 0.20 3.00 12 1.0 2.00 0.500 0.03 1.000 0.02 Note: Use D50 of 6 inches minimum Equations used: L=3*Do W=2*Wo Tw=0.2*Do (If Tw cannot be computed) Where Y=1/2 Do D50=(0.0125/Tw)*(q^1.33) Where Y=Do D50=(0.0082/Tw)*(q^1.33) Notes: 1. The use of scour holes shall comply with county or local ordinances which would restrict the use of such devices due to the possible problems with mosquito breeding. 2. No bends or curves at the intersection of the conduit and apron or scour hole will be permitted. 3. There shall be no over fall from the end of the apron to the receiving material. 4. The thickness of the riprap lining, filter, and quality shall meet the requirements in the Riprap Standard Section of the Standards for Soil Erosion Control in New Jersey.