251203_42 ERW_Stormwater Report

Project No: Calculated By: Checked By: Conduit Outlet Protection Calculations Scour Hole # S2 Design Parameters: Design Storm Flow for 25 Year, Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vertical Dimension of Outlet Pipe, D o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Horizontal Dimension of Outlet Pipe, W o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tailwater Depth, TW 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scour Hole Depth, y (1/2 D o or D o ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Apron Dimension Calculations: Minimum Bottom Width, W 1 = 2W o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Bottom Length, L 1 = 3D o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum Top Width (max side slope of 3:1) , W 2 . . . . . . . . . . . . . . . . . . . . . . . . Minimum Top Length (max side slope of 3:1) , L 2 . . . . . . . . . . . . . . . . . . . . . . . . Rip Rap Stone Size Calculations: Unit Dicharge, q = Q/D o = · 3.51 cfs per foot Case I: y = 1/2 D o 0.0125 q 1.33 = 1.45 in Therefore, use TW Apron Thickness, TH = 2×d 50 with filter fabric . . . . . . . . . . . . . . . . . . . . . Median Stone, d 50 = · W1 = L1 = W2 = L2 = Case II: y = D o 0.0082 q 1.33 = TW Apron Thickness, TH = 2×d 50 with filter fabric . . . . . . . . . . . . . . . . . . . . . . . Median Stone, d 50 = Notes: This document was created by an application that isn’t licensed to use novaPDF. Purchase a license to generate PDF files without this notice. d50 = TH =