Lusk_Hydraulic Capacity of Street Cross-sections.zip
2014-11-25: Minor update. I don't know why I was defining "Case" the hard way.
Streets with curbs and gutters are a key component in the overland conveyance of storm drainage. The purpose of the attached documents is to estimate the hydraulic capacity of one-half of a street cross-section for various conditions.
The attached .zip file contains five documents: two Mathcad Prime 3.0 worksheets, Adobe .pdf copies of the two worksheets for users of other versions of Mathcad, and an Excel spreadsheet that nearly duplicates one of the Mathcad worksheets. The genesis of these worksheets is a vintage 1989 SuperCalc 5 spreadsheet that I created for a storm drainage master plan. When I decided to create a Mathcad version of these calculations, I decided to also update and improve the spreadsheet in Excel. Although this added quite a bit of time to this process (creating nested IF statements in Excel to mimic the two programs I wrote in Mathcad was a major pain in caboose), I found that working on both simultaneously helped me to perfect the logic of the calculations. Each one helped me to correct errors in the other, so it wasn't time wasted even though I will probably not use the Excel version again. On the other hand, I have a friend who uses Excel but not Mathcad and he does have a use for it, so he will get a copy of the spreadsheet.
Here are descriptions of the documents included in the .zip file:
Lusk_Hydraulic Capacity of Street XSs_01_Rating Curves.mcdx — The purpose of this worksheet is to estimate the hydraulic capacity of one-half of a standard street cross-section for a range of gutter slopes and a range of flow depths. Using these results, this worksheet plots a family of rating curves for hydraulic capacity and other parameters. This worksheet uses five separate "hydraulic cases" to handle different street cross-section configurations, four that limit depth of flow to the top curb and one that limits depth of flow to the crown of the street. The primary application for this worksheet is preliminary design, although it can determine, for a single case, the depth of flow given a gutter slope and a peak flow rate. This is the worksheet to use for storm drainge master plans.
Lusk_Hydraulic Capacity of Street XSs_01_Rating Curves.pdf — Adobe Acrobat version of the preceding Mathcad worksheet.
Lusk_Hydraulic Capacity of Street XSs_02_Design.mcdx — The purpose of this worksheet is to estimate, for design purposes, the depths of flow and clear pavement widths in a standard half-street cross-section, given design gutter slopes and peak flow rates for various locations on a project. This is the worksheet to give the agency that reviews your street designs to prove that you have meet their street hydraulic conveyance requirements.
Lusk_Hydraulic Capacity of Street XSs_02_Design.pdf —Adobe Acrobat version of the preceding Mathcad worksheet.
Lusk_Hydraulic Capacity of Street XSs_Rating Curves.xlsx — This worksheet approximately duplicates Lusk_Hydraulic Capacity of Street XSs_01_Rating Curves.mcdx. The worksheet is protected, but without passwords. I do this to prevent accidental editing, which is something I have done more than once to my regret.